[dev.typeparams] all: merge dev.regabi (07569da) into dev.typeparams

Conflicts: - test/fixedbugs/issue27595.go - test/fixedbugs/issue30087.go - test/used.go Merge List: + 2020-12-28 07569dac4e [dev.regabi] all: merge master (1d78139) into dev.regabi + 2020-12-28 76136be027 [dev.regabi] cmd/compile: check for recursive import in ImportBody + 2020-12-28 fda7ec3a3f [dev.regabi] cmd/compile: remove Name.IsDDD, etc + 2020-12-28 098a6490b9 [dev.regabi] cmd/compile: remove Declare in makepartialcall + 2020-12-28 137f0d2e06 [dev.regabi] cmd/compile: remove unnecessary Name.Sym call + 2020-12-28 3383b5c74a [dev.regabi] cmd/compile: flatten dependency graph [generated] + 2020-12-28 f8afb8216a [dev.regabi] cmd/compile: rename CommStmt and CaseStmt [generated] + 2020-12-28 5f3bd59a0d [dev.regabi] cmd/compile: remove some unneeded code in package ir + 2020-12-28 3bdafb0d82 [dev.regabi] cmd/compile: remove CommStmt.List + 2020-12-28 2ecf52b841 [dev.regabi] cmd/compile: separate CommStmt from CaseStmt + 2020-12-28 ed9772e130 [dev.regabi] cmd/compile: add explicit file name in types generation + 2020-12-28 a59d26603f [dev.regabi] cmd/compile: use []*CaseStmt in {Select,Switch}Stmt + 2020-12-28 fbc4458c06 [dev.regabi] cmd/compile: simplify some tree traversal code + 2020-12-28 6c67677541 [dev.regabi] cmd/compile: simplify FuncName and PkgFuncName + 2020-12-28 676d794b81 [dev.regabi] cmd/compile: remove refersToCommonName + 2020-12-28 c98548e110 [dev.regabi] cmd/compile: merge ascompatee, ascompatee1, and reorder3 + 2020-12-28 4c215c4fa9 [dev.regabi] cmd/compile: simplify and optimize reorder3 + 2020-12-28 e6c973198d [dev.regabi] cmd/compile: stop mangling SelectorExpr.Sel for ODOTMETH + 2020-12-28 135ce1c485 [dev.regabi] cmd/compile: desugar OMETHEXPR into ONAME during walk + 2020-12-28 0f732f8c91 [dev.regabi] cmd/compile: minor walkExpr cleanups + 2020-12-28 0de8eafd98 [dev.regabi] cmd/compile: remove SelectorExpr.Offset field + 2020-12-28 a4f335f420 [dev.regabi] cmd/compile: always use a Field for ODOTPTR expressions + 2020-12-26 1d78139128 runtime/cgo: fix Android build with NDK 22 + 2020-12-25 2018b68a65 net/mail: don't use MDT in test + 2020-12-25 e4f293d853 [dev.regabi] cmd/compile: fix OCALLMETH desugaring + 2020-12-25 1d9a1f67d5 [dev.regabi] cmd/compile: don't emit reflect data for method types + 2020-12-25 396b6c2e7c [dev.regabi] cmd/compile: cleanup assignment typechecking + 2020-12-25 e24d2f3d05 [dev.regabi] cmd/compile: remove typ from RangeStmt + 2020-12-25 2785c691c2 [dev.regabi] cmd/compile: cleanup devirtualization docs + 2020-12-25 4b1d0fe66f [dev.regabi] cmd/compile: new devirtualization pkg [generated] + 2020-12-24 082cc8b7d9 [dev.regabi] cmd/compile: change ir.IsAssignable -> ir.IsAddressable + 2020-12-24 27b248b307 [dev.regabi] cmd/compile: separate range stmt Vars to Key, Value nodes + 2020-12-23 40818038bf [dev.regabi] cmd/compile: change CaseStmt.Vars to Var + 2020-12-23 b116404444 runtime: shift timeHistogram buckets and allow negative durations + 2020-12-23 8db7e2fecd runtime: fix allocs-by-size and frees-by-size buckets + 2020-12-23 fb96f07e1a runtime: fix nStackRoots comment about stack roots + 2020-12-23 d1502b3c72 lib/time, time/tzdata: update tzdata to 2020e + 2020-12-23 30c99cbb7a cmd/go: add the Retract field to 'go help mod edit' definition of the GoMod struct + 2020-12-23 49d0b239cb doc: fix a typo in contribute.html + 2020-12-23 9eeed291bc [dev.regabi] cmd/compile: eliminate usage of ir.Node in liveness + 2020-12-23 d1d64e4cea [dev.regabi] cmd/compile: split SliceExpr.List into separate fields + 2020-12-23 98a73030b0 cmd/go: in 'go get', promote named implicit dependencies to explicit + 2020-12-23 d19018e8f1 [dev.regabi] cmd/compile: split SliceHeaderExpr.LenCap into separate fields + 2020-12-23 53f082b0ee [dev.regabi] cmd/compile: cleanup export code further + 2020-12-23 31267f82e1 [dev.regabi] cmd/compile: simplify function/interface/struct typechecking + 2020-12-23 addade2cce [dev.regabi] cmd/compile: prefer types constructors over typecheck + 2020-12-23 18ebfb49e9 [dev.regabi] cmd/compile: cleanup noder + 2020-12-23 87a592b356 [dev.regabi] cmd/compile: cleanup import/export code + 2020-12-23 5898025026 [dev.regabi] cmd/compile: update mkbuiltin.go to use new type constructors + 2020-12-23 63c96c2ee7 [dev.regabi] cmd/compile: update mkbuiltin.go and re-enable TestBuiltin + 2020-12-23 fd6ba1c8a2 os/signal: fix a deadlock with syscall.AllThreadsSyscall() use + 2020-12-23 b0b0d98283 runtime: linux iscgo support for not blocking nptl signals + 2020-12-22 223331fc0c cmd/go/internal/modload: add hint for missing implicit dependency Change-Id: Iecb8a7dfb401b6ab383e97101cd81bfc201683f6
2025-05-05 15:43:04 +00:00 · 2020-12-28 00:39:13 -08:00 · 2020-12-28 00:39:13 -08:00 · a800acaae1
commit a800acaae1
parent dd40bbc57b 07569dac4e
90 changed files with 8552 additions and 8722 deletions
--- a/doc/contribute.html
+++ b/doc/contribute.html
@ -1129,7 +1129,7 @@ sometimes required because the standard library code you're modifying
 might require a newer version than the stable one you have installed).

 <pre>
-$ cd $GODIR/src/hash/sha1
+$ cd $GODIR/src/crypto/sha1
 $ [make changes...]
 $ $GODIR/bin/go test .
 </pre>
--- a/lib/time/update.bash
+++ b/lib/time/update.bash
@ -8,8 +8,8 @@
 # Consult https://www.iana.org/time-zones for the latest versions.

 # Versions to use.
-CODE=2020d
-DATA=2020d
+CODE=2020e
+DATA=2020e

 set -e
 rm -rf work
--- a/lib/time/zoneinfo.zip
+++ b/lib/time/zoneinfo.zip
--- a/src/cmd/compile/internal/devirtualize/devirtualize.go
+++ b/src/cmd/compile/internal/devirtualize/devirtualize.go
@ -0,0 +1,85 @@
+// Copyright 2020 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package devirtualize implements a simple "devirtualization"
+// optimization pass, which replaces interface method calls with
+// direct concrete-type method calls where possible.
+package devirtualize
+
+import (
+	"cmd/compile/internal/base"
+	"cmd/compile/internal/ir"
+	"cmd/compile/internal/typecheck"
+	"cmd/compile/internal/types"
+)
+
+// Func devirtualizes calls within fn where possible.
+func Func(fn *ir.Func) {
+	ir.CurFunc = fn
+	ir.VisitList(fn.Body, func(n ir.Node) {
+		if call, ok := n.(*ir.CallExpr); ok {
+			Call(call)
+		}
+	})
+}
+
+// Call devirtualizes the given call if possible.
+func Call(call *ir.CallExpr) {
+	if call.Op() != ir.OCALLINTER {
+		return
+	}
+	sel := call.X.(*ir.SelectorExpr)
+	r := ir.StaticValue(sel.X)
+	if r.Op() != ir.OCONVIFACE {
+		return
+	}
+	recv := r.(*ir.ConvExpr)
+
+	typ := recv.X.Type()
+	if typ.IsInterface() {
+		return
+	}
+
+	dt := ir.NewTypeAssertExpr(sel.Pos(), sel.X, nil)
+	dt.SetType(typ)
+	x := typecheck.Callee(ir.NewSelectorExpr(sel.Pos(), ir.OXDOT, dt, sel.Sel))
+	switch x.Op() {
+	case ir.ODOTMETH:
+		x := x.(*ir.SelectorExpr)
+		if base.Flag.LowerM != 0 {
+			base.WarnfAt(call.Pos(), "devirtualizing %v to %v", sel, typ)
+		}
+		call.SetOp(ir.OCALLMETH)
+		call.X = x
+	case ir.ODOTINTER:
+		// Promoted method from embedded interface-typed field (#42279).
+		x := x.(*ir.SelectorExpr)
+		if base.Flag.LowerM != 0 {
+			base.WarnfAt(call.Pos(), "partially devirtualizing %v to %v", sel, typ)
+		}
+		call.SetOp(ir.OCALLINTER)
+		call.X = x
+	default:
+		// TODO(mdempsky): Turn back into Fatalf after more testing.
+		if base.Flag.LowerM != 0 {
+			base.WarnfAt(call.Pos(), "failed to devirtualize %v (%v)", x, x.Op())
+		}
+		return
+	}
+
+	// Duplicated logic from typecheck for function call return
+	// value types.
+	//
+	// Receiver parameter size may have changed; need to update
+	// call.Type to get correct stack offsets for result
+	// parameters.
+	types.CheckSize(x.Type())
+	switch ft := x.Type(); ft.NumResults() {
+	case 0:
+	case 1:
+		call.SetType(ft.Results().Field(0).Type)
+	default:
+		call.SetType(ft.Results())
+	}
+}
--- a/src/cmd/compile/internal/escape/escape.go
+++ b/src/cmd/compile/internal/escape/escape.go
@ -347,21 +347,19 @@ func (e *escape) stmt(n ir.Node) {
 		e.loopDepth--

 	case ir.ORANGE:
-		// for List = range Right { Nbody }
+		// for Key, Value = range X { Body }
 		n := n.(*ir.RangeStmt)
 		e.loopDepth++
-		ks := e.addrs(n.Vars)
+		e.addr(n.Key)
+		k := e.addr(n.Value)
 		e.block(n.Body)
 		e.loopDepth--

-		// Right is evaluated outside the loop.
-		k := e.discardHole()
-		if len(ks) >= 2 {
+		// X is evaluated outside the loop.
 		if n.X.Type().IsArray() {
-				k = ks[1].note(n, "range")
+			k = k.note(n, "range")
 		} else {
-				k = ks[1].deref(n, "range-deref")
-			}
+			k = k.deref(n, "range-deref")
 		}
 		e.expr(e.later(k), n.X)

@ -371,9 +369,8 @@ func (e *escape) stmt(n ir.Node) {

 		var ks []hole
 		for _, cas := range n.Cases { // cases
-			cas := cas.(*ir.CaseStmt)
 			if typesw && n.Tag.(*ir.TypeSwitchGuard).Tag != nil {
-				cv := cas.Vars[0]
+				cv := cas.Var
 				k := e.dcl(cv) // type switch variables have no ODCL.
 				if cv.Type().HasPointers() {
 					ks = append(ks, k.dotType(cv.Type(), cas, "switch case"))
@ -393,7 +390,6 @@ func (e *escape) stmt(n ir.Node) {
 	case ir.OSELECT:
 		n := n.(*ir.SelectStmt)
 		for _, cas := range n.Cases {
-			cas := cas.(*ir.CaseStmt)
 			e.stmt(cas.Comm)
 			e.block(cas.Body)
 		}
@ -559,10 +555,9 @@ func (e *escape) exprSkipInit(k hole, n ir.Node) {
 	case ir.OSLICE, ir.OSLICEARR, ir.OSLICE3, ir.OSLICE3ARR, ir.OSLICESTR:
 		n := n.(*ir.SliceExpr)
 		e.expr(k.note(n, "slice"), n.X)
-		low, high, max := n.SliceBounds()
-		e.discard(low)
-		e.discard(high)
-		e.discard(max)
+		e.discard(n.Low)
+		e.discard(n.High)
+		e.discard(n.Max)

 	case ir.OCONV, ir.OCONVNOP:
 		n := n.(*ir.ConvExpr)
--- a/src/cmd/compile/internal/gc/main.go
+++ b/src/cmd/compile/internal/gc/main.go
@ -10,6 +10,7 @@ import (
 	"bufio"
 	"bytes"
 	"cmd/compile/internal/base"
+	"cmd/compile/internal/devirtualize"
 	"cmd/compile/internal/dwarfgen"
 	"cmd/compile/internal/escape"
 	"cmd/compile/internal/inline"
@ -243,7 +244,7 @@ func Main(archInit func(*ssagen.ArchInfo)) {
 	// Devirtualize.
 	for _, n := range typecheck.Target.Decls {
 		if n.Op() == ir.ODCLFUNC {
-			inline.Devirtualize(n.(*ir.Func))
+			devirtualize.Func(n.(*ir.Func))
 		}
 	}
 	ir.CurFunc = nil
--- a/src/cmd/compile/internal/inline/inl.go
+++ b/src/cmd/compile/internal/inline/inl.go
@ -324,9 +324,8 @@ func (v *hairyVisitor) doNode(n ir.Node) error {
 		if t == nil {
 			base.Fatalf("no function type for [%p] %+v\n", n.X, n.X)
 		}
-		if types.IsRuntimePkg(n.X.Sym().Pkg) {
-			fn := n.X.Sym().Name
-			if fn == "heapBits.nextArena" {
+		fn := ir.MethodExprName(n.X).Func
+		if types.IsRuntimePkg(fn.Sym().Pkg) && fn.Sym().Name == "heapBits.nextArena" {
 			// Special case: explicitly allow
 			// mid-stack inlining of
 			// runtime.heapBits.next even though
@ -334,9 +333,8 @@ func (v *hairyVisitor) doNode(n ir.Node) error {
 			// runtime.heapBits.nextArena.
 			break
 		}
-		}
-		if inlfn := ir.MethodExprName(n.X).Func; inlfn.Inl != nil {
-			v.budget -= inlfn.Inl.Cost
+		if fn.Inl != nil {
+			v.budget -= fn.Inl.Cost
 			break
 		}
 		// Call cost for non-leaf inlining.
@ -531,7 +529,7 @@ func inlnode(n ir.Node, maxCost int32, inlMap map[*ir.Func]bool, edit func(ir.No
 		// Prevent inlining some reflect.Value methods when using checkptr,
 		// even when package reflect was compiled without it (#35073).
 		n := n.(*ir.CallExpr)
-		if s := n.X.Sym(); base.Debug.Checkptr != 0 && types.IsReflectPkg(s.Pkg) && (s.Name == "Value.UnsafeAddr" || s.Name == "Value.Pointer") {
+		if s := ir.MethodExprName(n.X).Sym(); base.Debug.Checkptr != 0 && types.IsReflectPkg(s.Pkg) && (s.Name == "Value.UnsafeAddr" || s.Name == "Value.Pointer") {
 			return n
 		}
 	}
@ -1203,73 +1201,6 @@ func pruneUnusedAutos(ll []*ir.Name, vis *hairyVisitor) []*ir.Name {
 	return s
 }

-// Devirtualize replaces interface method calls within fn with direct
-// concrete-type method calls where applicable.
-func Devirtualize(fn *ir.Func) {
-	ir.CurFunc = fn
-	ir.VisitList(fn.Body, func(n ir.Node) {
-		if n.Op() == ir.OCALLINTER {
-			devirtualizeCall(n.(*ir.CallExpr))
-		}
-	})
-}
-
-func devirtualizeCall(call *ir.CallExpr) {
-	sel := call.X.(*ir.SelectorExpr)
-	r := ir.StaticValue(sel.X)
-	if r.Op() != ir.OCONVIFACE {
-		return
-	}
-	recv := r.(*ir.ConvExpr)
-
-	typ := recv.X.Type()
-	if typ.IsInterface() {
-		return
-	}
-
-	dt := ir.NewTypeAssertExpr(sel.Pos(), sel.X, nil)
-	dt.SetType(typ)
-	x := typecheck.Callee(ir.NewSelectorExpr(sel.Pos(), ir.OXDOT, dt, sel.Sel))
-	switch x.Op() {
-	case ir.ODOTMETH:
-		x := x.(*ir.SelectorExpr)
-		if base.Flag.LowerM != 0 {
-			base.WarnfAt(call.Pos(), "devirtualizing %v to %v", sel, typ)
-		}
-		call.SetOp(ir.OCALLMETH)
-		call.X = x
-	case ir.ODOTINTER:
-		// Promoted method from embedded interface-typed field (#42279).
-		x := x.(*ir.SelectorExpr)
-		if base.Flag.LowerM != 0 {
-			base.WarnfAt(call.Pos(), "partially devirtualizing %v to %v", sel, typ)
-		}
-		call.SetOp(ir.OCALLINTER)
-		call.X = x
-	default:
-		// TODO(mdempsky): Turn back into Fatalf after more testing.
-		if base.Flag.LowerM != 0 {
-			base.WarnfAt(call.Pos(), "failed to devirtualize %v (%v)", x, x.Op())
-		}
-		return
-	}
-
-	// Duplicated logic from typecheck for function call return
-	// value types.
-	//
-	// Receiver parameter size may have changed; need to update
-	// call.Type to get correct stack offsets for result
-	// parameters.
-	types.CheckSize(x.Type())
-	switch ft := x.Type(); ft.NumResults() {
-	case 0:
-	case 1:
-		call.SetType(ft.Results().Field(0).Type)
-	default:
-		call.SetType(ft.Results())
-	}
-}
-
 // numNonClosures returns the number of functions in list which are not closures.
 func numNonClosures(list []*ir.Func) int {
 	count := 0
--- a/src/cmd/compile/internal/ir/expr.go
+++ b/src/cmd/compile/internal/ir/expr.go
@ -572,14 +572,12 @@ type SelectorExpr struct {
 	miniExpr
 	X         Node
 	Sel       *types.Sym
-	Offset    int64
 	Selection *types.Field
 }

 func NewSelectorExpr(pos src.XPos, op Op, x Node, sel *types.Sym) *SelectorExpr {
 	n := &SelectorExpr{X: x, Sel: sel}
 	n.pos = pos
-	n.Offset = types.BADWIDTH
 	n.SetOp(op)
 	return n
 }
@ -596,6 +594,7 @@ func (n *SelectorExpr) SetOp(op Op) {
 func (n *SelectorExpr) Sym() *types.Sym    { return n.Sel }
 func (n *SelectorExpr) Implicit() bool     { return n.flags&miniExprImplicit != 0 }
 func (n *SelectorExpr) SetImplicit(b bool) { n.flags.set(miniExprImplicit, b) }
+func (n *SelectorExpr) Offset() int64      { return n.Selection.Offset }

 // Before type-checking, bytes.Buffer is a SelectorExpr.
 // After type-checking it becomes a Name.
@ -605,11 +604,13 @@ func (*SelectorExpr) CanBeNtype() {}
 type SliceExpr struct {
 	miniExpr
 	X    Node
-	List Nodes // TODO(rsc): Use separate Nodes
+	Low  Node
+	High Node
+	Max  Node
 }

-func NewSliceExpr(pos src.XPos, op Op, x Node) *SliceExpr {
-	n := &SliceExpr{X: x}
+func NewSliceExpr(pos src.XPos, op Op, x, low, high, max Node) *SliceExpr {
+	n := &SliceExpr{X: x, Low: low, High: high, Max: max}
 	n.pos = pos
 	n.op = op
 	return n
@ -624,61 +625,6 @@ func (n *SliceExpr) SetOp(op Op) {
 	}
 }

-// SliceBounds returns n's slice bounds: low, high, and max in expr[low:high:max].
-// n must be a slice expression. max is nil if n is a simple slice expression.
-func (n *SliceExpr) SliceBounds() (low, high, max Node) {
-	if len(n.List) == 0 {
-		return nil, nil, nil
-	}
-
-	switch n.Op() {
-	case OSLICE, OSLICEARR, OSLICESTR:
-		s := n.List
-		return s[0], s[1], nil
-	case OSLICE3, OSLICE3ARR:
-		s := n.List
-		return s[0], s[1], s[2]
-	}
-	base.Fatalf("SliceBounds op %v: %v", n.Op(), n)
-	return nil, nil, nil
-}
-
-// SetSliceBounds sets n's slice bounds, where n is a slice expression.
-// n must be a slice expression. If max is non-nil, n must be a full slice expression.
-func (n *SliceExpr) SetSliceBounds(low, high, max Node) {
-	switch n.Op() {
-	case OSLICE, OSLICEARR, OSLICESTR:
-		if max != nil {
-			base.Fatalf("SetSliceBounds %v given three bounds", n.Op())
-		}
-		s := n.List
-		if s == nil {
-			if low == nil && high == nil {
-				return
-			}
-			n.List = []Node{low, high}
-			return
-		}
-		s[0] = low
-		s[1] = high
-		return
-	case OSLICE3, OSLICE3ARR:
-		s := n.List
-		if s == nil {
-			if low == nil && high == nil && max == nil {
-				return
-			}
-			n.List = []Node{low, high, max}
-			return
-		}
-		s[0] = low
-		s[1] = high
-		s[2] = max
-		return
-	}
-	base.Fatalf("SetSliceBounds op %v: %v", n.Op(), n)
-}
-
 // IsSlice3 reports whether o is a slice3 op (OSLICE3, OSLICE3ARR).
 // o must be a slicing op.
 func (o Op) IsSlice3() bool {
@ -696,15 +642,15 @@ func (o Op) IsSlice3() bool {
 type SliceHeaderExpr struct {
 	miniExpr
 	Ptr Node
-	LenCap Nodes // TODO(rsc): Split into two Node fields
+	Len Node
+	Cap Node
 }

 func NewSliceHeaderExpr(pos src.XPos, typ *types.Type, ptr, len, cap Node) *SliceHeaderExpr {
-	n := &SliceHeaderExpr{Ptr: ptr}
+	n := &SliceHeaderExpr{Ptr: ptr, Len: len, Cap: cap}
 	n.pos = pos
 	n.op = OSLICEHEADER
 	n.typ = typ
-	n.LenCap = []Node{len, cap}
 	return n
 }

@ -829,12 +775,12 @@ func IsZero(n Node) bool {
 }

 // lvalue etc
-func IsAssignable(n Node) bool {
+func IsAddressable(n Node) bool {
 	switch n.Op() {
 	case OINDEX:
 		n := n.(*IndexExpr)
 		if n.X.Type() != nil && n.X.Type().IsArray() {
-			return IsAssignable(n.X)
+			return IsAddressable(n.X)
 		}
 		if n.X.Type() != nil && n.X.Type().IsString() {
 			return false
@ -845,7 +791,7 @@ func IsAssignable(n Node) bool {

 	case ODOT:
 		n := n.(*SelectorExpr)
-		return IsAssignable(n.X)
+		return IsAddressable(n.X)

 	case ONAME:
 		n := n.(*Name)
--- a/src/cmd/compile/internal/ir/fmt.go
+++ b/src/cmd/compile/internal/ir/fmt.go
@ -444,12 +444,15 @@ func stmtFmt(n Node, s fmt.State) {
 			break
 		}

-		if len(n.Vars) == 0 {
-			fmt.Fprintf(s, "for range %v { %v }", n.X, n.Body)
-			break
+		fmt.Fprint(s, "for")
+		if n.Key != nil {
+			fmt.Fprintf(s, " %v", n.Key)
+			if n.Value != nil {
+				fmt.Fprintf(s, ", %v", n.Value)
 			}
-
-		fmt.Fprintf(s, "for %.v = range %v { %v }", n.Vars, n.X, n.Body)
+			fmt.Fprint(s, " =")
+		}
+		fmt.Fprintf(s, " range %v { %v }", n.X, n.Body)

 	case OSELECT:
 		n := n.(*SelectStmt)
@ -475,7 +478,7 @@ func stmtFmt(n Node, s fmt.State) {
 		fmt.Fprintf(s, " { %v }", n.Cases)

 	case OCASE:
-		n := n.(*CaseStmt)
+		n := n.(*CaseClause)
 		if len(n.List) != 0 {
 			fmt.Fprintf(s, "case %.v", n.List)
 		} else {
@ -753,7 +756,7 @@ func exprFmt(n Node, s fmt.State, prec int) {
 			fmt.Fprint(s, ".<nil>")
 			return
 		}
-		fmt.Fprintf(s, ".%s", types.SymMethodName(n.Method.Sym))
+		fmt.Fprintf(s, ".%s", n.Method.Sym.Name)

 	case OXDOT, ODOT, ODOTPTR, ODOTINTER, ODOTMETH:
 		n := n.(*SelectorExpr)
@ -762,7 +765,7 @@ func exprFmt(n Node, s fmt.State, prec int) {
 			fmt.Fprint(s, ".<nil>")
 			return
 		}
-		fmt.Fprintf(s, ".%s", types.SymMethodName(n.Sel))
+		fmt.Fprintf(s, ".%s", n.Sel.Name)

 	case ODOTTYPE, ODOTTYPE2:
 		n := n.(*TypeAssertExpr)
@ -782,28 +785,24 @@ func exprFmt(n Node, s fmt.State, prec int) {
 		n := n.(*SliceExpr)
 		exprFmt(n.X, s, nprec)
 		fmt.Fprint(s, "[")
-		low, high, max := n.SliceBounds()
-		if low != nil {
-			fmt.Fprint(s, low)
+		if n.Low != nil {
+			fmt.Fprint(s, n.Low)
 		}
 		fmt.Fprint(s, ":")
-		if high != nil {
-			fmt.Fprint(s, high)
+		if n.High != nil {
+			fmt.Fprint(s, n.High)
 		}
 		if n.Op().IsSlice3() {
 			fmt.Fprint(s, ":")
-			if max != nil {
-				fmt.Fprint(s, max)
+			if n.Max != nil {
+				fmt.Fprint(s, n.Max)
 			}
 		}
 		fmt.Fprint(s, "]")

 	case OSLICEHEADER:
 		n := n.(*SliceHeaderExpr)
-		if len(n.LenCap) != 2 {
-			base.Fatalf("bad OSLICEHEADER list length %d", len(n.LenCap))
-		}
-		fmt.Fprintf(s, "sliceheader{%v,%v,%v}", n.Ptr, n.LenCap[0], n.LenCap[1])
+		fmt.Fprintf(s, "sliceheader{%v,%v,%v}", n.Ptr, n.Len, n.Cap)

 	case OCOMPLEX, OCOPY:
 		n := n.(*BinaryExpr)
--- a/src/cmd/compile/internal/ir/func.go
+++ b/src/cmd/compile/internal/ir/func.go
@ -206,50 +206,22 @@ func (f *Func) SetWBPos(pos src.XPos) {
 }

 // funcname returns the name (without the package) of the function n.
-func FuncName(n Node) string {
-	var f *Func
-	switch n := n.(type) {
-	case *Func:
-		f = n
-	case *Name:
-		f = n.Func
-	case *CallPartExpr:
-		f = n.Func
-	case *ClosureExpr:
-		f = n.Func
-	}
+func FuncName(f *Func) string {
 	if f == nil || f.Nname == nil {
 		return "<nil>"
 	}
-	return f.Nname.Sym().Name
+	return f.Sym().Name
 }

 // pkgFuncName returns the name of the function referenced by n, with package prepended.
 // This differs from the compiler's internal convention where local functions lack a package
 // because the ultimate consumer of this is a human looking at an IDE; package is only empty
 // if the compilation package is actually the empty string.
-func PkgFuncName(n Node) string {
-	var s *types.Sym
-	if n == nil {
-		return "<nil>"
-	}
-	if n.Op() == ONAME {
-		s = n.Sym()
-	} else {
-		var f *Func
-		switch n := n.(type) {
-		case *CallPartExpr:
-			f = n.Func
-		case *ClosureExpr:
-			f = n.Func
-		case *Func:
-			f = n
-		}
+func PkgFuncName(f *Func) string {
 	if f == nil || f.Nname == nil {
 		return "<nil>"
 	}
-		s = f.Nname.Sym()
-	}
+	s := f.Sym()
 	pkg := s.Pkg

 	p := base.Ctxt.Pkgpath
--- a/src/cmd/compile/internal/ir/mknode.go
+++ b/src/cmd/compile/internal/ir/mknode.go
@ -37,6 +37,8 @@ func main() {
 	nodeType := lookup("Node")
 	ntypeType := lookup("Ntype")
 	nodesType := lookup("Nodes")
+	slicePtrCaseClauseType := types.NewSlice(types.NewPointer(lookup("CaseClause")))
+	slicePtrCommClauseType := types.NewSlice(types.NewPointer(lookup("CommClause")))
 	ptrFieldType := types.NewPointer(lookup("Field"))
 	slicePtrFieldType := types.NewSlice(ptrFieldType)
 	ptrIdentType := types.NewPointer(lookup("Ident"))
@ -76,6 +78,10 @@ func main() {
 				switch {
 				case is(nodesType):
 					fmt.Fprintf(&buf, "c.%s = c.%s.Copy()\n", name, name)
+				case is(slicePtrCaseClauseType):
+					fmt.Fprintf(&buf, "c.%s = copyCases(c.%s)\n", name, name)
+				case is(slicePtrCommClauseType):
+					fmt.Fprintf(&buf, "c.%s = copyComms(c.%s)\n", name, name)
 				case is(ptrFieldType):
 					fmt.Fprintf(&buf, "if c.%s != nil { c.%s = c.%s.copy() }\n", name, name, name)
 				case is(slicePtrFieldType):
@ -94,6 +100,10 @@ func main() {
 				fmt.Fprintf(&buf, "err = maybeDo(n.%s, err, do)\n", name)
 			case is(nodesType):
 				fmt.Fprintf(&buf, "err = maybeDoList(n.%s, err, do)\n", name)
+			case is(slicePtrCaseClauseType):
+				fmt.Fprintf(&buf, "err = maybeDoCases(n.%s, err, do)\n", name)
+			case is(slicePtrCommClauseType):
+				fmt.Fprintf(&buf, "err = maybeDoComms(n.%s, err, do)\n", name)
 			case is(ptrFieldType):
 				fmt.Fprintf(&buf, "err = maybeDoField(n.%s, err, do)\n", name)
 			case is(slicePtrFieldType):
@ -113,6 +123,10 @@ func main() {
 				fmt.Fprintf(&buf, "n.%s = toNtype(maybeEdit(n.%s, edit))\n", name, name)
 			case is(nodesType):
 				fmt.Fprintf(&buf, "editList(n.%s, edit)\n", name)
+			case is(slicePtrCaseClauseType):
+				fmt.Fprintf(&buf, "editCases(n.%s, edit)\n", name)
+			case is(slicePtrCommClauseType):
+				fmt.Fprintf(&buf, "editComms(n.%s, edit)\n", name)
 			case is(ptrFieldType):
 				fmt.Fprintf(&buf, "editField(n.%s, edit)\n", name)
 			case is(slicePtrFieldType):
@ -155,10 +169,6 @@ func forNodeFields(typName string, typ *types.Struct, f func(name string, is fun
 		case "orig":
 			continue
 		}
-		switch typName + "." + v.Name() {
-		case "AddStringExpr.Alloc":
-			continue
-		}
 		f(v.Name(), func(t types.Type) bool { return types.Identical(t, v.Type()) })
 	}
 }
--- a/src/cmd/compile/internal/ir/name.go
+++ b/src/cmd/compile/internal/ir/name.go
@ -268,7 +268,6 @@ const (
 	nameInlLocal              // PAUTO created by inliner, derived from callee local
 	nameOpenDeferSlot         // if temporary var storing info for open-coded defers
 	nameLibfuzzerExtraCounter // if PEXTERN should be assigned to __libfuzzer_extra_counters section
-	nameIsDDD                 // is function argument a ...
 	nameAlias                 // is type name an alias
 )

@ -286,7 +285,6 @@ func (n *Name) InlFormal() bool             { return n.flags&nameInlFormal != 0
 func (n *Name) InlLocal() bool              { return n.flags&nameInlLocal != 0 }
 func (n *Name) OpenDeferSlot() bool         { return n.flags&nameOpenDeferSlot != 0 }
 func (n *Name) LibfuzzerExtraCounter() bool { return n.flags&nameLibfuzzerExtraCounter != 0 }
-func (n *Name) IsDDD() bool                 { return n.flags&nameIsDDD != 0 }

 func (n *Name) SetCaptured(b bool)              { n.flags.set(nameCaptured, b) }
 func (n *Name) setReadonly(b bool)              { n.flags.set(nameReadonly, b) }
@ -302,7 +300,6 @@ func (n *Name) SetInlFormal(b bool)             { n.flags.set(nameInlFormal, b)
 func (n *Name) SetInlLocal(b bool)              { n.flags.set(nameInlLocal, b) }
 func (n *Name) SetOpenDeferSlot(b bool)         { n.flags.set(nameOpenDeferSlot, b) }
 func (n *Name) SetLibfuzzerExtraCounter(b bool) { n.flags.set(nameLibfuzzerExtraCounter, b) }
-func (n *Name) SetIsDDD(b bool)                 { n.flags.set(nameIsDDD, b) }

 // MarkReadonly indicates that n is an ONAME with readonly contents.
 func (n *Name) MarkReadonly() {
--- a/src/cmd/compile/internal/ir/node_gen.go
+++ b/src/cmd/compile/internal/ir/node_gen.go
@ -226,29 +226,26 @@ func (n *CallPartExpr) editChildren(edit func(Node) Node) {
 	n.X = maybeEdit(n.X, edit)
 }

-func (n *CaseStmt) Format(s fmt.State, verb rune) { FmtNode(n, s, verb) }
-func (n *CaseStmt) copy() Node {
+func (n *CaseClause) Format(s fmt.State, verb rune) { FmtNode(n, s, verb) }
+func (n *CaseClause) copy() Node {
 	c := *n
 	c.init = c.init.Copy()
-	c.Vars = c.Vars.Copy()
 	c.List = c.List.Copy()
 	c.Body = c.Body.Copy()
 	return &c
 }
-func (n *CaseStmt) doChildren(do func(Node) error) error {
+func (n *CaseClause) doChildren(do func(Node) error) error {
 	var err error
 	err = maybeDoList(n.init, err, do)
-	err = maybeDoList(n.Vars, err, do)
+	err = maybeDo(n.Var, err, do)
 	err = maybeDoList(n.List, err, do)
-	err = maybeDo(n.Comm, err, do)
 	err = maybeDoList(n.Body, err, do)
 	return err
 }
-func (n *CaseStmt) editChildren(edit func(Node) Node) {
+func (n *CaseClause) editChildren(edit func(Node) Node) {
 	editList(n.init, edit)
-	editList(n.Vars, edit)
+	n.Var = maybeEdit(n.Var, edit)
 	editList(n.List, edit)
-	n.Comm = maybeEdit(n.Comm, edit)
 	editList(n.Body, edit)
 }

@ -296,6 +293,26 @@ func (n *ClosureReadExpr) editChildren(edit func(Node) Node) {
 	editList(n.init, edit)
 }

+func (n *CommClause) Format(s fmt.State, verb rune) { FmtNode(n, s, verb) }
+func (n *CommClause) copy() Node {
+	c := *n
+	c.init = c.init.Copy()
+	c.Body = c.Body.Copy()
+	return &c
+}
+func (n *CommClause) doChildren(do func(Node) error) error {
+	var err error
+	err = maybeDoList(n.init, err, do)
+	err = maybeDo(n.Comm, err, do)
+	err = maybeDoList(n.Body, err, do)
+	return err
+}
+func (n *CommClause) editChildren(edit func(Node) Node) {
+	editList(n.init, edit)
+	n.Comm = maybeEdit(n.Comm, edit)
+	editList(n.Body, edit)
+}
+
 func (n *CompLitExpr) Format(s fmt.State, verb rune) { FmtNode(n, s, verb) }
 func (n *CompLitExpr) copy() Node {
 	c := *n
@ -725,22 +742,23 @@ func (n *RangeStmt) Format(s fmt.State, verb rune) { FmtNode(n, s, verb) }
 func (n *RangeStmt) copy() Node {
 	c := *n
 	c.init = c.init.Copy()
-	c.Vars = c.Vars.Copy()
 	c.Body = c.Body.Copy()
 	return &c
 }
 func (n *RangeStmt) doChildren(do func(Node) error) error {
 	var err error
 	err = maybeDoList(n.init, err, do)
-	err = maybeDoList(n.Vars, err, do)
 	err = maybeDo(n.X, err, do)
+	err = maybeDo(n.Key, err, do)
+	err = maybeDo(n.Value, err, do)
 	err = maybeDoList(n.Body, err, do)
 	return err
 }
 func (n *RangeStmt) editChildren(edit func(Node) Node) {
 	editList(n.init, edit)
-	editList(n.Vars, edit)
 	n.X = maybeEdit(n.X, edit)
+	n.Key = maybeEdit(n.Key, edit)
+	n.Value = maybeEdit(n.Value, edit)
 	editList(n.Body, edit)
 }

@ -781,20 +799,20 @@ func (n *SelectStmt) Format(s fmt.State, verb rune) { FmtNode(n, s, verb) }
 func (n *SelectStmt) copy() Node {
 	c := *n
 	c.init = c.init.Copy()
-	c.Cases = c.Cases.Copy()
+	c.Cases = copyComms(c.Cases)
 	c.Compiled = c.Compiled.Copy()
 	return &c
 }
 func (n *SelectStmt) doChildren(do func(Node) error) error {
 	var err error
 	err = maybeDoList(n.init, err, do)
-	err = maybeDoList(n.Cases, err, do)
+	err = maybeDoComms(n.Cases, err, do)
 	err = maybeDoList(n.Compiled, err, do)
 	return err
 }
 func (n *SelectStmt) editChildren(edit func(Node) Node) {
 	editList(n.init, edit)
-	editList(n.Cases, edit)
+	editComms(n.Cases, edit)
 	editList(n.Compiled, edit)
 }

@ -838,40 +856,44 @@ func (n *SliceExpr) Format(s fmt.State, verb rune) { FmtNode(n, s, verb) }
 func (n *SliceExpr) copy() Node {
 	c := *n
 	c.init = c.init.Copy()
-	c.List = c.List.Copy()
 	return &c
 }
 func (n *SliceExpr) doChildren(do func(Node) error) error {
 	var err error
 	err = maybeDoList(n.init, err, do)
 	err = maybeDo(n.X, err, do)
-	err = maybeDoList(n.List, err, do)
+	err = maybeDo(n.Low, err, do)
+	err = maybeDo(n.High, err, do)
+	err = maybeDo(n.Max, err, do)
 	return err
 }
 func (n *SliceExpr) editChildren(edit func(Node) Node) {
 	editList(n.init, edit)
 	n.X = maybeEdit(n.X, edit)
-	editList(n.List, edit)
+	n.Low = maybeEdit(n.Low, edit)
+	n.High = maybeEdit(n.High, edit)
+	n.Max = maybeEdit(n.Max, edit)
 }

 func (n *SliceHeaderExpr) Format(s fmt.State, verb rune) { FmtNode(n, s, verb) }
 func (n *SliceHeaderExpr) copy() Node {
 	c := *n
 	c.init = c.init.Copy()
-	c.LenCap = c.LenCap.Copy()
 	return &c
 }
 func (n *SliceHeaderExpr) doChildren(do func(Node) error) error {
 	var err error
 	err = maybeDoList(n.init, err, do)
 	err = maybeDo(n.Ptr, err, do)
-	err = maybeDoList(n.LenCap, err, do)
+	err = maybeDo(n.Len, err, do)
+	err = maybeDo(n.Cap, err, do)
 	return err
 }
 func (n *SliceHeaderExpr) editChildren(edit func(Node) Node) {
 	editList(n.init, edit)
 	n.Ptr = maybeEdit(n.Ptr, edit)
-	editList(n.LenCap, edit)
+	n.Len = maybeEdit(n.Len, edit)
+	n.Cap = maybeEdit(n.Cap, edit)
 }

 func (n *SliceType) Format(s fmt.State, verb rune) { FmtNode(n, s, verb) }
@ -941,7 +963,7 @@ func (n *SwitchStmt) Format(s fmt.State, verb rune) { FmtNode(n, s, verb) }
 func (n *SwitchStmt) copy() Node {
 	c := *n
 	c.init = c.init.Copy()
-	c.Cases = c.Cases.Copy()
+	c.Cases = copyCases(c.Cases)
 	c.Compiled = c.Compiled.Copy()
 	return &c
 }
@ -949,14 +971,14 @@ func (n *SwitchStmt) doChildren(do func(Node) error) error {
 	var err error
 	err = maybeDoList(n.init, err, do)
 	err = maybeDo(n.Tag, err, do)
-	err = maybeDoList(n.Cases, err, do)
+	err = maybeDoCases(n.Cases, err, do)
 	err = maybeDoList(n.Compiled, err, do)
 	return err
 }
 func (n *SwitchStmt) editChildren(edit func(Node) Node) {
 	editList(n.init, edit)
 	n.Tag = maybeEdit(n.Tag, edit)
-	editList(n.Cases, edit)
+	editCases(n.Cases, edit)
 	editList(n.Compiled, edit)
 }

--- a/src/cmd/compile/internal/ir/scc.go
+++ b/src/cmd/compile/internal/ir/scc.go
@ -76,48 +76,27 @@ func (v *bottomUpVisitor) visit(n *Func) uint32 {
 	min := v.visitgen
 	v.stack = append(v.stack, n)

+	do := func(defn Node) {
+		if defn != nil {
+			if m := v.visit(defn.(*Func)); m < min {
+				min = m
+			}
+		}
+	}
+
 	Visit(n, func(n Node) {
 		switch n.Op() {
 		case ONAME:
-			n := n.(*Name)
-			if n.Class_ == PFUNC {
-				if n != nil && n.Name().Defn != nil {
-					if m := v.visit(n.Name().Defn.(*Func)); m < min {
-						min = m
-					}
-				}
-			}
-		case OMETHEXPR:
-			n := n.(*MethodExpr)
-			fn := MethodExprName(n)
-			if fn != nil && fn.Defn != nil {
-				if m := v.visit(fn.Defn.(*Func)); m < min {
-					min = m
-				}
-			}
-		case ODOTMETH:
-			n := n.(*SelectorExpr)
-			fn := MethodExprName(n)
-			if fn != nil && fn.Op() == ONAME && fn.Class_ == PFUNC && fn.Defn != nil {
-				if m := v.visit(fn.Defn.(*Func)); m < min {
-					min = m
-				}
-			}
-		case OCALLPART:
-			n := n.(*CallPartExpr)
-			fn := AsNode(n.Method.Nname)
-			if fn != nil && fn.Op() == ONAME {
-				if fn := fn.(*Name); fn.Class_ == PFUNC && fn.Name().Defn != nil {
-					if m := v.visit(fn.Name().Defn.(*Func)); m < min {
-						min = m
-					}
+			if n := n.(*Name); n.Class_ == PFUNC {
+				do(n.Defn)
 			}
+		case ODOTMETH, OCALLPART, OMETHEXPR:
+			if fn := MethodExprName(n); fn != nil {
+				do(fn.Defn)
 			}
 		case OCLOSURE:
 			n := n.(*ClosureExpr)
-			if m := v.visit(n.Func); m < min {
-				min = m
-			}
+			do(n.Func)
 		}
 	})

--- a/src/cmd/compile/internal/ir/stmt.go
+++ b/src/cmd/compile/internal/ir/stmt.go
@ -173,24 +173,94 @@ func NewBranchStmt(pos src.XPos, op Op, label *types.Sym) *BranchStmt {

 func (n *BranchStmt) Sym() *types.Sym { return n.Label }

-// A CaseStmt is a case statement in a switch or select: case List: Body.
-type CaseStmt struct {
+// A CaseClause is a case statement in a switch or select: case List: Body.
+type CaseClause struct {
 	miniStmt
-	Vars Nodes // declared variable for this case in type switch
+	Var  Node  // declared variable for this case in type switch
 	List Nodes // list of expressions for switch, early select
-	Comm Node  // communication case (Exprs[0]) after select is type-checked
 	Body Nodes
 }

-func NewCaseStmt(pos src.XPos, list, body []Node) *CaseStmt {
-	n := &CaseStmt{}
+func NewCaseStmt(pos src.XPos, list, body []Node) *CaseClause {
+	n := &CaseClause{List: list, Body: body}
 	n.pos = pos
 	n.op = OCASE
-	n.List.Set(list)
-	n.Body.Set(body)
 	return n
 }

+// TODO(mdempsky): Generate these with mknode.go.
+func copyCases(list []*CaseClause) []*CaseClause {
+	if list == nil {
+		return nil
+	}
+	c := make([]*CaseClause, len(list))
+	copy(c, list)
+	return c
+}
+func maybeDoCases(list []*CaseClause, err error, do func(Node) error) error {
+	if err != nil {
+		return err
+	}
+	for _, x := range list {
+		if x != nil {
+			if err := do(x); err != nil {
+				return err
+			}
+		}
+	}
+	return nil
+}
+func editCases(list []*CaseClause, edit func(Node) Node) {
+	for i, x := range list {
+		if x != nil {
+			list[i] = edit(x).(*CaseClause)
+		}
+	}
+}
+
+type CommClause struct {
+	miniStmt
+	Comm Node // communication case
+	Body Nodes
+}
+
+func NewCommStmt(pos src.XPos, comm Node, body []Node) *CommClause {
+	n := &CommClause{Comm: comm, Body: body}
+	n.pos = pos
+	n.op = OCASE
+	return n
+}
+
+// TODO(mdempsky): Generate these with mknode.go.
+func copyComms(list []*CommClause) []*CommClause {
+	if list == nil {
+		return nil
+	}
+	c := make([]*CommClause, len(list))
+	copy(c, list)
+	return c
+}
+func maybeDoComms(list []*CommClause, err error, do func(Node) error) error {
+	if err != nil {
+		return err
+	}
+	for _, x := range list {
+		if x != nil {
+			if err := do(x); err != nil {
+				return err
+			}
+		}
+	}
+	return nil
+}
+func editComms(list []*CommClause, edit func(Node) Node) {
+	for i, x := range list {
+		if x != nil {
+			list[i] = edit(x).(*CommClause)
+		}
+	}
+}
+
 // A ForStmt is a non-range for loop: for Init; Cond; Post { Body }
 // Op can be OFOR or OFORUNTIL (!Cond).
 type ForStmt struct {
@ -203,11 +273,13 @@ type ForStmt struct {
 	HasBreak bool
 }

-func NewForStmt(pos src.XPos, init []Node, cond, post Node, body []Node) *ForStmt {
+func NewForStmt(pos src.XPos, init Node, cond, post Node, body []Node) *ForStmt {
 	n := &ForStmt{Cond: cond, Post: post}
 	n.pos = pos
 	n.op = OFOR
-	n.init.Set(init)
+	if init != nil {
+		n.init = []Node{init}
+	}
 	n.Body.Set(body)
 	return n
 }
@ -290,32 +362,27 @@ func NewLabelStmt(pos src.XPos, label *types.Sym) *LabelStmt {

 func (n *LabelStmt) Sym() *types.Sym { return n.Label }

-// A RangeStmt is a range loop: for Vars = range X { Stmts }
-// Op can be OFOR or OFORUNTIL (!Cond).
+// A RangeStmt is a range loop: for Key, Value = range X { Body }
 type RangeStmt struct {
 	miniStmt
 	Label    *types.Sym
-	Vars     Nodes // TODO(rsc): Replace with Key, Value Node
 	Def      bool
 	X        Node
+	Key      Node
+	Value    Node
 	Body     Nodes
 	HasBreak bool
-	typ      *types.Type // TODO(rsc): Remove - use X.Type() instead
 	Prealloc *Name
 }

-func NewRangeStmt(pos src.XPos, vars []Node, x Node, body []Node) *RangeStmt {
-	n := &RangeStmt{X: x}
+func NewRangeStmt(pos src.XPos, key, value, x Node, body []Node) *RangeStmt {
+	n := &RangeStmt{X: x, Key: key, Value: value}
 	n.pos = pos
 	n.op = ORANGE
-	n.Vars.Set(vars)
 	n.Body.Set(body)
 	return n
 }

-func (n *RangeStmt) Type() *types.Type     { return n.typ }
-func (n *RangeStmt) SetType(x *types.Type) { n.typ = x }
-
 // A ReturnStmt is a return statement.
 type ReturnStmt struct {
 	miniStmt
@ -339,18 +406,17 @@ func (n *ReturnStmt) SetOrig(x Node) { n.orig = x }
 type SelectStmt struct {
 	miniStmt
 	Label    *types.Sym
-	Cases    Nodes
+	Cases    []*CommClause
 	HasBreak bool

 	// TODO(rsc): Instead of recording here, replace with a block?
 	Compiled Nodes // compiled form, after walkswitch
 }

-func NewSelectStmt(pos src.XPos, cases []Node) *SelectStmt {
-	n := &SelectStmt{}
+func NewSelectStmt(pos src.XPos, cases []*CommClause) *SelectStmt {
+	n := &SelectStmt{Cases: cases}
 	n.pos = pos
 	n.op = OSELECT
-	n.Cases.Set(cases)
 	return n
 }

@ -372,7 +438,7 @@ func NewSendStmt(pos src.XPos, ch, value Node) *SendStmt {
 type SwitchStmt struct {
 	miniStmt
 	Tag      Node
-	Cases    Nodes // list of *CaseStmt
+	Cases    []*CaseClause
 	Label    *types.Sym
 	HasBreak bool

@ -380,11 +446,10 @@ type SwitchStmt struct {
 	Compiled Nodes // compiled form, after walkswitch
 }

-func NewSwitchStmt(pos src.XPos, tag Node, cases []Node) *SwitchStmt {
-	n := &SwitchStmt{Tag: tag}
+func NewSwitchStmt(pos src.XPos, tag Node, cases []*CaseClause) *SwitchStmt {
+	n := &SwitchStmt{Tag: tag, Cases: cases}
 	n.pos = pos
 	n.op = OSWITCH
-	n.Cases.Set(cases)
 	return n
 }

--- a/src/cmd/compile/internal/ir/type.go
+++ b/src/cmd/compile/internal/ir/type.go
@ -115,14 +115,6 @@ func (n *StructType) SetOTYPE(t *types.Type) {
 	n.Fields = nil
 }

-func deepCopyFields(pos src.XPos, fields []*Field) []*Field {
-	var out []*Field
-	for _, f := range fields {
-		out = append(out, f.deepCopy(pos))
-	}
-	return out
-}
-
 // An InterfaceType represents a struct { ... } type syntax.
 type InterfaceType struct {
 	miniType
@ -250,26 +242,6 @@ func editFields(list []*Field, edit func(Node) Node) {
 	}
 }

-func (f *Field) deepCopy(pos src.XPos) *Field {
-	if f == nil {
-		return nil
-	}
-	fpos := pos
-	if !pos.IsKnown() {
-		fpos = f.Pos
-	}
-	decl := f.Decl
-	if decl != nil {
-		decl = DeepCopy(pos, decl).(*Name)
-	}
-	ntype := f.Ntype
-	if ntype != nil {
-		ntype = DeepCopy(pos, ntype).(Ntype)
-	}
-	// No keyed literal here: if a new struct field is added, we want this to stop compiling.
-	return &Field{fpos, f.Sym, ntype, f.Type, f.Embedded, f.IsDDD, f.Note, decl}
-}
-
 // A SliceType represents a []Elem type syntax.
 // If DDD is true, it's the ...Elem at the end of a function list.
 type SliceType struct {
--- a/src/cmd/compile/internal/ir/visit.go
+++ b/src/cmd/compile/internal/ir/visit.go
@ -217,10 +217,9 @@ func EditChildren(n Node, edit func(Node) Node) {
 // Note that editList only calls edit on the nodes in the list, not their children.
 // If x's children should be processed, edit(x) must call EditChildren(x, edit) itself.
 func editList(list Nodes, edit func(Node) Node) {
-	s := list
 	for i, x := range list {
 		if x != nil {
-			s[i] = edit(x)
+			list[i] = edit(x)
 		}
 	}
 }
--- a/src/cmd/compile/internal/liveness/plive.go
+++ b/src/cmd/compile/internal/liveness/plive.go
@ -24,6 +24,7 @@ import (
 	"cmd/compile/internal/ir"
 	"cmd/compile/internal/objw"
 	"cmd/compile/internal/ssa"
+	"cmd/compile/internal/typebits"
 	"cmd/compile/internal/types"
 	"cmd/internal/obj"
 	"cmd/internal/objabi"
@ -179,11 +180,7 @@ type progeffectscache struct {
 // nor do we care about non-local variables,
 // nor do we care about empty structs (handled by the pointer check),
 // nor do we care about the fake PAUTOHEAP variables.
-func ShouldTrack(nn ir.Node) bool {
-	if nn.Op() != ir.ONAME {
-		return false
-	}
-	n := nn.(*ir.Name)
+func ShouldTrack(n *ir.Name) bool {
 	return (n.Class_ == ir.PAUTO || n.Class_ == ir.PPARAM || n.Class_ == ir.PPARAMOUT) && n.Type().HasPointers()
 }

@ -248,19 +245,17 @@ const (
 // liveness effects v has on that variable.
 // If v does not affect any tracked variables, it returns -1, 0.
 func (lv *liveness) valueEffects(v *ssa.Value) (int32, liveEffect) {
-	n, e := affectedNode(v)
-	if e == 0 || n == nil || n.Op() != ir.ONAME { // cheapest checks first
+	n, e := affectedVar(v)
+	if e == 0 || n == nil { // cheapest checks first
 		return -1, 0
 	}
-
-	nn := n.(*ir.Name)
 	// AllocFrame has dropped unused variables from
 	// lv.fn.Func.Dcl, but they might still be referenced by
 	// OpVarFoo pseudo-ops. Ignore them to prevent "lost track of
 	// variable" ICEs (issue 19632).
 	switch v.Op {
 	case ssa.OpVarDef, ssa.OpVarKill, ssa.OpVarLive, ssa.OpKeepAlive:
-		if !nn.Name().Used() {
+		if !n.Name().Used() {
 			return -1, 0
 		}
 	}
@ -283,14 +278,14 @@ func (lv *liveness) valueEffects(v *ssa.Value) (int32, liveEffect) {
 		return -1, 0
 	}

-	if pos, ok := lv.idx[nn]; ok {
+	if pos, ok := lv.idx[n]; ok {
 		return pos, effect
 	}
 	return -1, 0
 }

-// affectedNode returns the *Node affected by v
-func affectedNode(v *ssa.Value) (ir.Node, ssa.SymEffect) {
+// affectedVar returns the *ir.Name node affected by v
+func affectedVar(v *ssa.Value) (*ir.Name, ssa.SymEffect) {
 	// Special cases.
 	switch v.Op {
 	case ssa.OpLoadReg:
@ -381,82 +376,6 @@ func (lv *liveness) blockEffects(b *ssa.Block) *blockEffects {
 	return &lv.be[b.ID]
 }

-// NOTE: The bitmap for a specific type t could be cached in t after
-// the first run and then simply copied into bv at the correct offset
-// on future calls with the same type t.
-func SetTypeBits(t *types.Type, off int64, bv bitvec.BitVec) {
-	if t.Align > 0 && off&int64(t.Align-1) != 0 {
-		base.Fatalf("onebitwalktype1: invalid initial alignment: type %v has alignment %d, but offset is %v", t, t.Align, off)
-	}
-	if !t.HasPointers() {
-		// Note: this case ensures that pointers to go:notinheap types
-		// are not considered pointers by garbage collection and stack copying.
-		return
-	}
-
-	switch t.Kind() {
-	case types.TPTR, types.TUNSAFEPTR, types.TFUNC, types.TCHAN, types.TMAP:
-		if off&int64(types.PtrSize-1) != 0 {
-			base.Fatalf("onebitwalktype1: invalid alignment, %v", t)
-		}
-		bv.Set(int32(off / int64(types.PtrSize))) // pointer
-
-	case types.TSTRING:
-		// struct { byte *str; intgo len; }
-		if off&int64(types.PtrSize-1) != 0 {
-			base.Fatalf("onebitwalktype1: invalid alignment, %v", t)
-		}
-		bv.Set(int32(off / int64(types.PtrSize))) //pointer in first slot
-
-	case types.TINTER:
-		// struct { Itab *tab;	void *data; }
-		// or, when isnilinter(t)==true:
-		// struct { Type *type; void *data; }
-		if off&int64(types.PtrSize-1) != 0 {
-			base.Fatalf("onebitwalktype1: invalid alignment, %v", t)
-		}
-		// The first word of an interface is a pointer, but we don't
-		// treat it as such.
-		// 1. If it is a non-empty interface, the pointer points to an itab
-		//    which is always in persistentalloc space.
-		// 2. If it is an empty interface, the pointer points to a _type.
-		//   a. If it is a compile-time-allocated type, it points into
-		//      the read-only data section.
-		//   b. If it is a reflect-allocated type, it points into the Go heap.
-		//      Reflect is responsible for keeping a reference to
-		//      the underlying type so it won't be GCd.
-		// If we ever have a moving GC, we need to change this for 2b (as
-		// well as scan itabs to update their itab._type fields).
-		bv.Set(int32(off/int64(types.PtrSize) + 1)) // pointer in second slot
-
-	case types.TSLICE:
-		// struct { byte *array; uintgo len; uintgo cap; }
-		if off&int64(types.PtrSize-1) != 0 {
-			base.Fatalf("onebitwalktype1: invalid TARRAY alignment, %v", t)
-		}
-		bv.Set(int32(off / int64(types.PtrSize))) // pointer in first slot (BitsPointer)
-
-	case types.TARRAY:
-		elt := t.Elem()
-		if elt.Width == 0 {
-			// Short-circuit for #20739.
-			break
-		}
-		for i := int64(0); i < t.NumElem(); i++ {
-			SetTypeBits(elt, off, bv)
-			off += elt.Width
-		}
-
-	case types.TSTRUCT:
-		for _, f := range t.Fields().Slice() {
-			SetTypeBits(f.Type, off+f.Offset, bv)
-		}
-
-	default:
-		base.Fatalf("onebitwalktype1: unexpected type, %v", t)
-	}
-}
-
 // Generates live pointer value maps for arguments and local variables. The
 // this argument and the in arguments are always assumed live. The vars
 // argument is a slice of *Nodes.
@ -469,10 +388,10 @@ func (lv *liveness) pointerMap(liveout bitvec.BitVec, vars []*ir.Name, args, loc
 		node := vars[i]
 		switch node.Class_ {
 		case ir.PAUTO:
-			SetTypeBits(node.Type(), node.FrameOffset()+lv.stkptrsize, locals)
+			typebits.Set(node.Type(), node.FrameOffset()+lv.stkptrsize, locals)

 		case ir.PPARAM, ir.PPARAMOUT:
-			SetTypeBits(node.Type(), node.FrameOffset(), args)
+			typebits.Set(node.Type(), node.FrameOffset(), args)
 		}
 	}
 }
@ -1315,15 +1234,15 @@ func WriteFuncMap(fn *ir.Func) {
 	off = objw.Uint32(lsym, off, uint32(bv.N))

 	if ir.IsMethod(fn) {
-		SetTypeBits(fn.Type().Recvs(), 0, bv)
+		typebits.Set(fn.Type().Recvs(), 0, bv)
 	}
 	if fn.Type().NumParams() > 0 {
-		SetTypeBits(fn.Type().Params(), 0, bv)
+		typebits.Set(fn.Type().Params(), 0, bv)
 	}
 	off = objw.BitVec(lsym, off, bv)

 	if fn.Type().NumResults() > 0 {
-		SetTypeBits(fn.Type().Results(), 0, bv)
+		typebits.Set(fn.Type().Results(), 0, bv)
 		off = objw.BitVec(lsym, off, bv)
 	}

--- a/src/cmd/compile/internal/noder/noder.go
+++ b/src/cmd/compile/internal/noder/noder.go
@ -510,11 +510,7 @@ func (p *noder) importDecl(imp *syntax.ImportDecl) {
 func (p *noder) varDecl(decl *syntax.VarDecl) []ir.Node {
 	names := p.declNames(ir.ONAME, decl.NameList)
 	typ := p.typeExprOrNil(decl.Type)
-
-	var exprs []ir.Node
-	if decl.Values != nil {
-		exprs = p.exprList(decl.Values)
-	}
+	exprs := p.exprList(decl.Values)

 	if pragma, ok := decl.Pragma.(*pragmas); ok {
 		if len(pragma.Embeds) > 0 {
@ -753,10 +749,14 @@ func (p *noder) param(param *syntax.Field, dddOk, final bool) *ir.Field {
 }

 func (p *noder) exprList(expr syntax.Expr) []ir.Node {
-	if list, ok := expr.(*syntax.ListExpr); ok {
-		return p.exprs(list.ElemList)
-	}
+	switch expr := expr.(type) {
+	case nil:
+		return nil
+	case *syntax.ListExpr:
+		return p.exprs(expr.ElemList)
+	default:
 		return []ir.Node{p.expr(expr)}
+	}
 }

 func (p *noder) exprs(exprs []syntax.Expr) []ir.Node {
@ -775,17 +775,14 @@ func (p *noder) expr(expr syntax.Expr) ir.Node {
 	case *syntax.Name:
 		return p.mkname(expr)
 	case *syntax.BasicLit:
-		n := ir.NewLiteral(p.basicLit(expr))
+		n := ir.NewBasicLit(p.pos(expr), p.basicLit(expr))
 		if expr.Kind == syntax.RuneLit {
 			n.SetType(types.UntypedRune)
 		}
 		n.SetDiag(expr.Bad) // avoid follow-on errors if there was a syntax error
 		return n
 	case *syntax.CompositeLit:
-		n := ir.NewCompLitExpr(p.pos(expr), ir.OCOMPLIT, nil, nil)
-		if expr.Type != nil {
-			n.Ntype = ir.Node(p.expr(expr.Type)).(ir.Ntype)
-		}
+		n := ir.NewCompLitExpr(p.pos(expr), ir.OCOMPLIT, p.typeExpr(expr.Type), nil)
 		l := p.exprs(expr.ElemList)
 		for i, e := range l {
 			l[i] = p.wrapname(expr.ElemList[i], e)
@ -818,17 +815,16 @@ func (p *noder) expr(expr syntax.Expr) ir.Node {
 		if expr.Full {
 			op = ir.OSLICE3
 		}
-		n := ir.NewSliceExpr(p.pos(expr), op, p.expr(expr.X))
+		x := p.expr(expr.X)
 		var index [3]ir.Node
-		for i, x := range &expr.Index {
-			if x != nil {
-				index[i] = p.expr(x)
+		for i, n := range &expr.Index {
+			if n != nil {
+				index[i] = p.expr(n)
 			}
 		}
-		n.SetSliceBounds(index[0], index[1], index[2])
-		return n
+		return ir.NewSliceExpr(p.pos(expr), op, x, index[0], index[1], index[2])
 	case *syntax.AssertExpr:
-		return ir.NewTypeAssertExpr(p.pos(expr), p.expr(expr.X), p.typeExpr(expr.Type).(ir.Ntype))
+		return ir.NewTypeAssertExpr(p.pos(expr), p.expr(expr.X), p.typeExpr(expr.Type))
 	case *syntax.Operation:
 		if expr.Op == syntax.Add && expr.Y != nil {
 			return p.sum(expr)
@ -852,8 +848,7 @@ func (p *noder) expr(expr syntax.Expr) ir.Node {
 		}
 		return ir.NewBinaryExpr(pos, op, x, y)
 	case *syntax.CallExpr:
-		n := ir.NewCallExpr(p.pos(expr), ir.OCALL, p.expr(expr.Fun), nil)
-		n.Args.Set(p.exprs(expr.ArgList))
+		n := ir.NewCallExpr(p.pos(expr), ir.OCALL, p.expr(expr.Fun), p.exprs(expr.ArgList))
 		n.IsDDD = expr.HasDots
 		return n

@ -1120,7 +1115,7 @@ func (p *noder) stmt(stmt syntax.Stmt) ir.Node {
 func (p *noder) stmtFall(stmt syntax.Stmt, fallOK bool) ir.Node {
 	p.setlineno(stmt)
 	switch stmt := stmt.(type) {
-	case *syntax.EmptyStmt:
+	case nil, *syntax.EmptyStmt:
 		return nil
 	case *syntax.LabeledStmt:
 		return p.labeledStmt(stmt, fallOK)
@ -1193,12 +1188,7 @@ func (p *noder) stmtFall(stmt syntax.Stmt, fallOK bool) ir.Node {
 		}
 		return ir.NewGoDeferStmt(p.pos(stmt), op, p.expr(stmt.Call))
 	case *syntax.ReturnStmt:
-		var results []ir.Node
-		if stmt.Results != nil {
-			results = p.exprList(stmt.Results)
-		}
-		n := ir.NewReturnStmt(p.pos(stmt), nil)
-		n.Results.Set(results)
+		n := ir.NewReturnStmt(p.pos(stmt), p.exprList(stmt.Results))
 		if len(n.Results) == 0 && ir.CurFunc != nil {
 			for _, ln := range ir.CurFunc.Dcl {
 				if ln.Class_ == ir.PPARAM {
@ -1292,14 +1282,11 @@ func (p *noder) blockStmt(stmt *syntax.BlockStmt) []ir.Node {

 func (p *noder) ifStmt(stmt *syntax.IfStmt) ir.Node {
 	p.openScope(stmt.Pos())
-	n := ir.NewIfStmt(p.pos(stmt), nil, nil, nil)
-	if stmt.Init != nil {
-		*n.PtrInit() = []ir.Node{p.stmt(stmt.Init)}
+	init := p.stmt(stmt.Init)
+	n := ir.NewIfStmt(p.pos(stmt), p.expr(stmt.Cond), p.blockStmt(stmt.Then), nil)
+	if init != nil {
+		*n.PtrInit() = []ir.Node{init}
 	}
-	if stmt.Cond != nil {
-		n.Cond = p.expr(stmt.Cond)
-	}
-	n.Body.Set(p.blockStmt(stmt.Then))
 	if stmt.Else != nil {
 		e := p.stmt(stmt.Else)
 		if e.Op() == ir.OBLOCK {
@ -1320,53 +1307,46 @@ func (p *noder) forStmt(stmt *syntax.ForStmt) ir.Node {
 			panic("unexpected RangeClause")
 		}

-		n := ir.NewRangeStmt(p.pos(r), nil, p.expr(r.X), nil)
+		n := ir.NewRangeStmt(p.pos(r), nil, nil, p.expr(r.X), nil)
 		if r.Lhs != nil {
 			n.Def = r.Def
-			n.Vars.Set(p.assignList(r.Lhs, n, n.Def))
+			lhs := p.assignList(r.Lhs, n, n.Def)
+			n.Key = lhs[0]
+			if len(lhs) > 1 {
+				n.Value = lhs[1]
+			}
 		}
 		n.Body.Set(p.blockStmt(stmt.Body))
 		p.closeAnotherScope()
 		return n
 	}

-	n := ir.NewForStmt(p.pos(stmt), nil, nil, nil, nil)
-	if stmt.Init != nil {
-		*n.PtrInit() = []ir.Node{p.stmt(stmt.Init)}
-	}
-	if stmt.Cond != nil {
-		n.Cond = p.expr(stmt.Cond)
-	}
-	if stmt.Post != nil {
-		n.Post = p.stmt(stmt.Post)
-	}
-	n.Body.Set(p.blockStmt(stmt.Body))
+	n := ir.NewForStmt(p.pos(stmt), p.stmt(stmt.Init), p.expr(stmt.Cond), p.stmt(stmt.Post), p.blockStmt(stmt.Body))
 	p.closeAnotherScope()
 	return n
 }

 func (p *noder) switchStmt(stmt *syntax.SwitchStmt) ir.Node {
 	p.openScope(stmt.Pos())
-	n := ir.NewSwitchStmt(p.pos(stmt), nil, nil)
-	if stmt.Init != nil {
-		*n.PtrInit() = []ir.Node{p.stmt(stmt.Init)}
-	}
-	if stmt.Tag != nil {
-		n.Tag = p.expr(stmt.Tag)
+
+	init := p.stmt(stmt.Init)
+	n := ir.NewSwitchStmt(p.pos(stmt), p.expr(stmt.Tag), nil)
+	if init != nil {
+		*n.PtrInit() = []ir.Node{init}
 	}

 	var tswitch *ir.TypeSwitchGuard
 	if l := n.Tag; l != nil && l.Op() == ir.OTYPESW {
 		tswitch = l.(*ir.TypeSwitchGuard)
 	}
-	n.Cases.Set(p.caseClauses(stmt.Body, tswitch, stmt.Rbrace))
+	n.Cases = p.caseClauses(stmt.Body, tswitch, stmt.Rbrace)

 	p.closeScope(stmt.Rbrace)
 	return n
 }

-func (p *noder) caseClauses(clauses []*syntax.CaseClause, tswitch *ir.TypeSwitchGuard, rbrace syntax.Pos) []ir.Node {
-	nodes := make([]ir.Node, 0, len(clauses))
+func (p *noder) caseClauses(clauses []*syntax.CaseClause, tswitch *ir.TypeSwitchGuard, rbrace syntax.Pos) []*ir.CaseClause {
+	nodes := make([]*ir.CaseClause, 0, len(clauses))
 	for i, clause := range clauses {
 		p.setlineno(clause)
 		if i > 0 {
@ -1374,14 +1354,11 @@ func (p *noder) caseClauses(clauses []*syntax.CaseClause, tswitch *ir.TypeSwitch
 		}
 		p.openScope(clause.Pos())

-		n := ir.NewCaseStmt(p.pos(clause), nil, nil)
-		if clause.Cases != nil {
-			n.List.Set(p.exprList(clause.Cases))
-		}
+		n := ir.NewCaseStmt(p.pos(clause), p.exprList(clause.Cases), nil)
 		if tswitch != nil && tswitch.Tag != nil {
 			nn := typecheck.NewName(tswitch.Tag.Sym())
 			typecheck.Declare(nn, typecheck.DeclContext)
-			n.Vars = []ir.Node{nn}
+			n.Var = nn
 			// keep track of the instances for reporting unused
 			nn.Defn = tswitch
 		}
@ -1416,13 +1393,11 @@ func (p *noder) caseClauses(clauses []*syntax.CaseClause, tswitch *ir.TypeSwitch
 }

 func (p *noder) selectStmt(stmt *syntax.SelectStmt) ir.Node {
-	n := ir.NewSelectStmt(p.pos(stmt), nil)
-	n.Cases.Set(p.commClauses(stmt.Body, stmt.Rbrace))
-	return n
+	return ir.NewSelectStmt(p.pos(stmt), p.commClauses(stmt.Body, stmt.Rbrace))
 }

-func (p *noder) commClauses(clauses []*syntax.CommClause, rbrace syntax.Pos) []ir.Node {
-	nodes := make([]ir.Node, 0, len(clauses))
+func (p *noder) commClauses(clauses []*syntax.CommClause, rbrace syntax.Pos) []*ir.CommClause {
+	nodes := make([]*ir.CommClause, len(clauses))
 	for i, clause := range clauses {
 		p.setlineno(clause)
 		if i > 0 {
@ -1430,12 +1405,7 @@ func (p *noder) commClauses(clauses []*syntax.CommClause, rbrace syntax.Pos) []i
 		}
 		p.openScope(clause.Pos())

-		n := ir.NewCaseStmt(p.pos(clause), nil, nil)
-		if clause.Comm != nil {
-			n.List = []ir.Node{p.stmt(clause.Comm)}
-		}
-		n.Body.Set(p.stmts(clause.Body))
-		nodes = append(nodes, n)
+		nodes[i] = ir.NewCommStmt(p.pos(clause), p.stmt(clause.Comm), p.stmts(clause.Body))
 	}
 	if len(clauses) > 0 {
 		p.closeScope(rbrace)
@ -2001,7 +1971,6 @@ func oldname(s *types.Sym) ir.Node {
 			c = typecheck.NewName(s)
 			c.Class_ = ir.PAUTOHEAP
 			c.SetIsClosureVar(true)
-			c.SetIsDDD(n.IsDDD())
 			c.Defn = n

 			// Link into list of active closure variables.
--- a/src/cmd/compile/internal/objw/prog.go
+++ b/src/cmd/compile/internal/objw/prog.go
@ -33,7 +33,6 @@ package objw
 import (
 	"cmd/compile/internal/base"
 	"cmd/compile/internal/ir"
-	"cmd/compile/internal/ssa"
 	"cmd/internal/obj"
 	"cmd/internal/objabi"
 	"cmd/internal/src"
@ -173,7 +172,7 @@ func (pp *Progs) Prog(as obj.As) *obj.Prog {
 	p.Pos = pp.Pos
 	if pp.Pos.IsStmt() == src.PosIsStmt {
 		// Clear IsStmt for later Progs at this pos provided that as can be marked as a stmt
-		if ssa.LosesStmtMark(as) {
+		if LosesStmtMark(as) {
 			return p
 		}
 		pp.Pos = pp.Pos.WithNotStmt()
@ -216,3 +215,12 @@ func (pp *Progs) SetText(fn *ir.Func) {
 	ptxt.From.Name = obj.NAME_EXTERN
 	ptxt.From.Sym = fn.LSym
 }
+
+// LosesStmtMark reports whether a prog with op as loses its statement mark on the way to DWARF.
+// The attributes from some opcodes are lost in translation.
+// TODO: this is an artifact of how funcpctab combines information for instructions at a single PC.
+// Should try to fix it there.
+func LosesStmtMark(as obj.As) bool {
+	// is_stmt does not work for these; it DOES for ANOP even though that generates no code.
+	return as == obj.APCDATA || as == obj.AFUNCDATA
+}
--- a/src/cmd/compile/internal/pkginit/initorder.go
+++ b/src/cmd/compile/internal/pkginit/initorder.go
@ -289,10 +289,6 @@ func (d *initDeps) inspectList(l ir.Nodes) { ir.VisitList(l, d.cachedVisit()) }
 // referenced by n, if any.
 func (d *initDeps) visit(n ir.Node) {
 	switch n.Op() {
-	case ir.OMETHEXPR:
-		n := n.(*ir.MethodExpr)
-		d.foundDep(ir.MethodExprName(n))
-
 	case ir.ONAME:
 		n := n.(*ir.Name)
 		switch n.Class_ {
@ -304,7 +300,7 @@ func (d *initDeps) visit(n ir.Node) {
 		n := n.(*ir.ClosureExpr)
 		d.inspectList(n.Func.Body)

-	case ir.ODOTMETH, ir.OCALLPART:
+	case ir.ODOTMETH, ir.OCALLPART, ir.OMETHEXPR:
 		d.foundDep(ir.MethodExprName(n))
 	}
 }
--- a/src/cmd/compile/internal/reflectdata/alg.go
+++ b/src/cmd/compile/internal/reflectdata/alg.go
@ -289,11 +289,11 @@ func hashfor(t *types.Type) ir.Node {

 	n := typecheck.NewName(sym)
 	ir.MarkFunc(n)
-	n.SetType(typecheck.NewFuncType(nil, []*ir.Field{
-		ir.NewField(base.Pos, nil, nil, types.NewPtr(t)),
-		ir.NewField(base.Pos, nil, nil, types.Types[types.TUINTPTR]),
-	}, []*ir.Field{
-		ir.NewField(base.Pos, nil, nil, types.Types[types.TUINTPTR]),
+	n.SetType(types.NewSignature(types.NoPkg, nil, []*types.Field{
+		types.NewField(base.Pos, nil, types.NewPtr(t)),
+		types.NewField(base.Pos, nil, types.Types[types.TUINTPTR]),
+	}, []*types.Field{
+		types.NewField(base.Pos, nil, types.Types[types.TUINTPTR]),
 	}))
 	return n
 }
@ -777,12 +777,12 @@ func hashmem(t *types.Type) ir.Node {

 	n := typecheck.NewName(sym)
 	ir.MarkFunc(n)
-	n.SetType(typecheck.NewFuncType(nil, []*ir.Field{
-		ir.NewField(base.Pos, nil, nil, types.NewPtr(t)),
-		ir.NewField(base.Pos, nil, nil, types.Types[types.TUINTPTR]),
-		ir.NewField(base.Pos, nil, nil, types.Types[types.TUINTPTR]),
-	}, []*ir.Field{
-		ir.NewField(base.Pos, nil, nil, types.Types[types.TUINTPTR]),
+	n.SetType(types.NewSignature(types.NoPkg, nil, []*types.Field{
+		types.NewField(base.Pos, nil, types.NewPtr(t)),
+		types.NewField(base.Pos, nil, types.Types[types.TUINTPTR]),
+		types.NewField(base.Pos, nil, types.Types[types.TUINTPTR]),
+	}, []*types.Field{
+		types.NewField(base.Pos, nil, types.Types[types.TUINTPTR]),
 	}))
 	return n
 }
--- a/src/cmd/compile/internal/reflectdata/reflect.go
+++ b/src/cmd/compile/internal/reflectdata/reflect.go
@ -16,8 +16,8 @@ import (
 	"cmd/compile/internal/escape"
 	"cmd/compile/internal/inline"
 	"cmd/compile/internal/ir"
-	"cmd/compile/internal/liveness"
 	"cmd/compile/internal/objw"
+	"cmd/compile/internal/typebits"
 	"cmd/compile/internal/typecheck"
 	"cmd/compile/internal/types"
 	"cmd/internal/gcprog"
@ -835,6 +835,9 @@ func TypeSym(t *types.Type) *types.Sym {
 	if t == nil || (t.IsPtr() && t.Elem() == nil) || t.IsUntyped() {
 		base.Fatalf("typenamesym %v", t)
 	}
+	if t.Kind() == types.TFUNC && t.Recv() != nil {
+		base.Fatalf("misuse of method type: %v", t)
+	}
 	s := types.TypeSym(t)
 	signatmu.Lock()
 	NeedRuntimeType(t)
@ -1419,7 +1422,11 @@ func WriteBasicTypes() {
 		// The latter is the type of an auto-generated wrapper.
 		WriteType(types.NewPtr(types.ErrorType))

-		WriteType(typecheck.NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, types.ErrorType)}, []*ir.Field{ir.NewField(base.Pos, nil, nil, types.Types[types.TSTRING])}))
+		WriteType(types.NewSignature(types.NoPkg, nil, []*types.Field{
+			types.NewField(base.Pos, nil, types.ErrorType),
+		}, []*types.Field{
+			types.NewField(base.Pos, nil, types.Types[types.TSTRING]),
+		}))

 		// add paths for runtime and main, which 6l imports implicitly.
 		dimportpath(ir.Pkgs.Runtime)
@ -1545,7 +1552,7 @@ func fillptrmask(t *types.Type, ptrmask []byte) {
 	}

 	vec := bitvec.New(8 * int32(len(ptrmask)))
-	liveness.SetTypeBits(t, 0, vec)
+	typebits.Set(t, 0, vec)

 	nptr := types.PtrDataSize(t) / int64(types.PtrSize)
 	for i := int64(0); i < nptr; i++ {
@ -1856,7 +1863,7 @@ func MarkUsedIfaceMethod(n *ir.CallExpr) {
 	r.Sym = tsym
 	// dot.Xoffset is the method index * Widthptr (the offset of code pointer
 	// in itab).
-	midx := dot.Offset / int64(types.PtrSize)
+	midx := dot.Offset() / int64(types.PtrSize)
 	r.Add = InterfaceMethodOffset(ityp, midx)
 	r.Type = objabi.R_USEIFACEMETHOD
 }
--- a/src/cmd/compile/internal/ssa/numberlines.go
+++ b/src/cmd/compile/internal/ssa/numberlines.go
@ -5,7 +5,6 @@
 package ssa

 import (
-	"cmd/internal/obj"
 	"cmd/internal/src"
 	"fmt"
 	"sort"
@ -23,15 +22,6 @@ func isPoorStatementOp(op Op) bool {
 	return false
 }

-// LosesStmtMark reports whether a prog with op as loses its statement mark on the way to DWARF.
-// The attributes from some opcodes are lost in translation.
-// TODO: this is an artifact of how funcpctab combines information for instructions at a single PC.
-// Should try to fix it there.
-func LosesStmtMark(as obj.As) bool {
-	// is_stmt does not work for these; it DOES for ANOP even though that generates no code.
-	return as == obj.APCDATA || as == obj.AFUNCDATA
-}
-
 // nextGoodStatementIndex returns an index at i or later that is believed
 // to be a good place to start the statement for b.  This decision is
 // based on v's Op, the possibility of a better later operation, and
--- a/src/cmd/compile/internal/ssagen/ssa.go
+++ b/src/cmd/compile/internal/ssagen/ssa.go
@ -214,10 +214,7 @@ func InitConfig() {
 func getParam(n *ir.CallExpr, i int) *types.Field {
 	t := n.X.Type()
 	if n.Op() == ir.OCALLMETH {
-		if i == 0 {
-			return t.Recv()
-		}
-		return t.Params().Field(i - 1)
+		base.Fatalf("OCALLMETH missed by walkCall")
 	}
 	return t.Params().Field(i)
 }
@ -1166,7 +1163,7 @@ func (s *state) stmt(n ir.Node) {
 		}
 		fallthrough

-	case ir.OCALLMETH, ir.OCALLINTER:
+	case ir.OCALLINTER:
 		n := n.(*ir.CallExpr)
 		s.callResult(n, callNormal)
 		if n.Op() == ir.OCALLFUNC && n.X.Op() == ir.ONAME && n.X.(*ir.Name).Class_ == ir.PFUNC {
@ -1367,7 +1364,7 @@ func (s *state) stmt(n ir.Node) {
 			// We're assigning a slicing operation back to its source.
 			// Don't write back fields we aren't changing. See issue #14855.
 			rhs := rhs.(*ir.SliceExpr)
-			i, j, k := rhs.SliceBounds()
+			i, j, k := rhs.Low, rhs.High, rhs.Max
 			if i != nil && (i.Op() == ir.OLITERAL && i.Val().Kind() == constant.Int && ir.Int64Val(i) == 0) {
 				// [0:...] is the same as [:...]
 				i = nil
@ -2111,10 +2108,6 @@ func (s *state) expr(n ir.Node) *ssa.Value {
 		n := n.(*ir.UnaryExpr)
 		aux := n.X.Sym().Linksym()
 		return s.entryNewValue1A(ssa.OpAddr, n.Type(), aux, s.sb)
-	case ir.OMETHEXPR:
-		n := n.(*ir.MethodExpr)
-		sym := staticdata.FuncSym(n.FuncName().Sym()).Linksym()
-		return s.entryNewValue1A(ssa.OpAddr, types.NewPtr(n.Type()), sym, s.sb)
 	case ir.ONAME:
 		n := n.(*ir.Name)
 		if n.Class_ == ir.PFUNC {
@ -2736,7 +2729,7 @@ func (s *state) expr(n ir.Node) *ssa.Value {
 		// SSA, then load just the selected field. This
 		// prevents false memory dependencies in race/msan
 		// instrumentation.
-		if ir.IsAssignable(n) && !s.canSSA(n) {
+		if ir.IsAddressable(n) && !s.canSSA(n) {
 			p := s.addr(n)
 			return s.load(n.Type(), p)
 		}
@ -2746,7 +2739,7 @@ func (s *state) expr(n ir.Node) *ssa.Value {
 	case ir.ODOTPTR:
 		n := n.(*ir.SelectorExpr)
 		p := s.exprPtr(n.X, n.Bounded(), n.Pos())
-		p = s.newValue1I(ssa.OpOffPtr, types.NewPtr(n.Type()), n.Offset, p)
+		p = s.newValue1I(ssa.OpOffPtr, types.NewPtr(n.Type()), n.Offset(), p)
 		return s.load(n.Type(), p)

 	case ir.OINDEX:
@ -2844,23 +2837,22 @@ func (s *state) expr(n ir.Node) *ssa.Value {
 	case ir.OSLICEHEADER:
 		n := n.(*ir.SliceHeaderExpr)
 		p := s.expr(n.Ptr)
-		l := s.expr(n.LenCap[0])
-		c := s.expr(n.LenCap[1])
+		l := s.expr(n.Len)
+		c := s.expr(n.Cap)
 		return s.newValue3(ssa.OpSliceMake, n.Type(), p, l, c)

 	case ir.OSLICE, ir.OSLICEARR, ir.OSLICE3, ir.OSLICE3ARR:
 		n := n.(*ir.SliceExpr)
 		v := s.expr(n.X)
 		var i, j, k *ssa.Value
-		low, high, max := n.SliceBounds()
-		if low != nil {
-			i = s.expr(low)
+		if n.Low != nil {
+			i = s.expr(n.Low)
 		}
-		if high != nil {
-			j = s.expr(high)
+		if n.High != nil {
+			j = s.expr(n.High)
 		}
-		if max != nil {
-			k = s.expr(max)
+		if n.Max != nil {
+			k = s.expr(n.Max)
 		}
 		p, l, c := s.slice(v, i, j, k, n.Bounded())
 		return s.newValue3(ssa.OpSliceMake, n.Type(), p, l, c)
@ -2869,12 +2861,11 @@ func (s *state) expr(n ir.Node) *ssa.Value {
 		n := n.(*ir.SliceExpr)
 		v := s.expr(n.X)
 		var i, j *ssa.Value
-		low, high, _ := n.SliceBounds()
-		if low != nil {
-			i = s.expr(low)
+		if n.Low != nil {
+			i = s.expr(n.Low)
 		}
-		if high != nil {
-			j = s.expr(high)
+		if n.High != nil {
+			j = s.expr(n.High)
 		}
 		p, l, _ := s.slice(v, i, j, nil, n.Bounded())
 		return s.newValue2(ssa.OpStringMake, n.Type(), p, l)
@ -4398,16 +4389,7 @@ func (s *state) openDeferRecord(n *ir.CallExpr) {
 			opendefer.closure = closure
 		}
 	} else if n.Op() == ir.OCALLMETH {
-		if fn.Op() != ir.ODOTMETH {
-			base.Fatalf("OCALLMETH: n.Left not an ODOTMETH: %v", fn)
-		}
-		fn := fn.(*ir.SelectorExpr)
-		closureVal := s.getMethodClosure(fn)
-		// We must always store the function value in a stack slot for the
-		// runtime panic code to use. But in the defer exit code, we will
-		// call the method directly.
-		closure := s.openDeferSave(nil, fn.Type(), closureVal)
-		opendefer.closureNode = closure.Aux.(*ir.Name)
+		base.Fatalf("OCALLMETH missed by walkCall")
 	} else {
 		if fn.Op() != ir.ODOTINTER {
 			base.Fatalf("OCALLINTER: n.Left not an ODOTINTER: %v", fn.Op())
@ -4681,18 +4663,7 @@ func (s *state) call(n *ir.CallExpr, k callKind, returnResultAddr bool) *ssa.Val
 			s.maybeNilCheckClosure(closure, k)
 		}
 	case ir.OCALLMETH:
-		if fn.Op() != ir.ODOTMETH {
-			s.Fatalf("OCALLMETH: n.Left not an ODOTMETH: %v", fn)
-		}
-		fn := fn.(*ir.SelectorExpr)
-		testLateExpansion = k != callDeferStack && ssa.LateCallExpansionEnabledWithin(s.f)
-		if k == callNormal {
-			sym = fn.Sel
-			break
-		}
-		closure = s.getMethodClosure(fn)
-		// Note: receiver is already present in n.Rlist, so we don't
-		// want to set it here.
+		base.Fatalf("OCALLMETH missed by walkCall")
 	case ir.OCALLINTER:
 		if fn.Op() != ir.ODOTINTER {
 			s.Fatalf("OCALLINTER: n.Left not an ODOTINTER: %v", fn.Op())
@ -4757,9 +4728,7 @@ func (s *state) call(n *ir.CallExpr, k callKind, returnResultAddr bool) *ssa.Val
 		}
 		// Set receiver (for method calls).
 		if n.Op() == ir.OCALLMETH {
-			f := ft.Recv()
-			s.storeArgWithBase(args[0], f.Type, addr, off+f.Offset)
-			args = args[1:]
+			base.Fatalf("OCALLMETH missed by walkCall")
 		}
 		// Set other args.
 		for _, f := range ft.Params().Fields().Slice() {
@ -4827,11 +4796,7 @@ func (s *state) call(n *ir.CallExpr, k callKind, returnResultAddr bool) *ssa.Val
 		t := n.X.Type()
 		args := n.Rargs
 		if n.Op() == ir.OCALLMETH {
-			f := t.Recv()
-			ACArg, arg := s.putArg(args[0], f.Type, argStart+f.Offset, testLateExpansion)
-			ACArgs = append(ACArgs, ACArg)
-			callArgs = append(callArgs, arg)
-			args = args[1:]
+			base.Fatalf("OCALLMETH missed by walkCall")
 		}
 		for i, n := range args {
 			f := t.Params().Field(i)
@ -4949,29 +4914,13 @@ func (s *state) maybeNilCheckClosure(closure *ssa.Value, k callKind) {
 	}
 }

-// getMethodClosure returns a value representing the closure for a method call
-func (s *state) getMethodClosure(fn *ir.SelectorExpr) *ssa.Value {
-	// Make a name n2 for the function.
-	// fn.Sym might be sync.(*Mutex).Unlock.
-	// Make a PFUNC node out of that, then evaluate it.
-	// We get back an SSA value representing &sync.(*Mutex).Unlock·f.
-	// We can then pass that to defer or go.
-	n2 := ir.NewNameAt(fn.Pos(), fn.Sel)
-	n2.Curfn = s.curfn
-	n2.Class_ = ir.PFUNC
-	// n2.Sym already existed, so it's already marked as a function.
-	n2.SetPos(fn.Pos())
-	n2.SetType(types.Types[types.TUINT8]) // fake type for a static closure. Could use runtime.funcval if we had it.
-	return s.expr(n2)
-}
-
 // getClosureAndRcvr returns values for the appropriate closure and receiver of an
 // interface call
 func (s *state) getClosureAndRcvr(fn *ir.SelectorExpr) (*ssa.Value, *ssa.Value) {
 	i := s.expr(fn.X)
 	itab := s.newValue1(ssa.OpITab, types.Types[types.TUINTPTR], i)
 	s.nilCheck(itab)
-	itabidx := fn.Offset + 2*int64(types.PtrSize) + 8 // offset of fun field in runtime.itab
+	itabidx := fn.Offset() + 2*int64(types.PtrSize) + 8 // offset of fun field in runtime.itab
 	closure := s.newValue1I(ssa.OpOffPtr, s.f.Config.Types.UintptrPtr, itabidx, itab)
 	rcvr := s.newValue1(ssa.OpIData, s.f.Config.Types.BytePtr, i)
 	return closure, rcvr
@ -5075,11 +5024,11 @@ func (s *state) addr(n ir.Node) *ssa.Value {
 	case ir.ODOT:
 		n := n.(*ir.SelectorExpr)
 		p := s.addr(n.X)
-		return s.newValue1I(ssa.OpOffPtr, t, n.Offset, p)
+		return s.newValue1I(ssa.OpOffPtr, t, n.Offset(), p)
 	case ir.ODOTPTR:
 		n := n.(*ir.SelectorExpr)
 		p := s.exprPtr(n.X, n.Bounded(), n.Pos())
-		return s.newValue1I(ssa.OpOffPtr, t, n.Offset, p)
+		return s.newValue1I(ssa.OpOffPtr, t, n.Offset(), p)
 	case ir.OCLOSUREREAD:
 		n := n.(*ir.ClosureReadExpr)
 		return s.newValue1I(ssa.OpOffPtr, t, n.Offset,
@ -5091,7 +5040,7 @@ func (s *state) addr(n ir.Node) *ssa.Value {
 		}
 		addr := s.addr(n.X)
 		return s.newValue1(ssa.OpCopy, t, addr) // ensure that addr has the right type
-	case ir.OCALLFUNC, ir.OCALLINTER, ir.OCALLMETH:
+	case ir.OCALLFUNC, ir.OCALLINTER:
 		n := n.(*ir.CallExpr)
 		return s.callAddr(n, callNormal)
 	case ir.ODOTTYPE:
@ -6328,7 +6277,7 @@ type State struct {
 // Prog appends a new Prog.
 func (s *State) Prog(as obj.As) *obj.Prog {
 	p := s.pp.Prog(as)
-	if ssa.LosesStmtMark(as) {
+	if objw.LosesStmtMark(as) {
 		return p
 	}
 	// Float a statement start to the beginning of any same-line run.
@ -7116,22 +7065,18 @@ func (s *State) UseArgs(n int64) {
 // fieldIdx finds the index of the field referred to by the ODOT node n.
 func fieldIdx(n *ir.SelectorExpr) int {
 	t := n.X.Type()
-	f := n.Sel
 	if !t.IsStruct() {
 		panic("ODOT's LHS is not a struct")
 	}

-	var i int
-	for _, t1 := range t.Fields().Slice() {
-		if t1.Sym != f {
-			i++
-			continue
-		}
-		if t1.Offset != n.Offset {
+	for i, f := range t.Fields().Slice() {
+		if f.Sym == n.Sel {
+			if f.Offset != n.Offset() {
 				panic("field offset doesn't match")
 			}
 			return i
 		}
+	}
 	panic(fmt.Sprintf("can't find field in expr %v\n", n))

 	// TODO: keep the result of this function somewhere in the ODOT Node
--- a/src/cmd/compile/internal/staticinit/sched.go
+++ b/src/cmd/compile/internal/staticinit/sched.go
@ -469,7 +469,7 @@ func StaticLoc(n ir.Node) (name *ir.Name, offset int64, ok bool) {
 		if name, offset, ok = StaticLoc(n.X); !ok {
 			break
 		}
-		offset += n.Offset
+		offset += n.Offset()
 		return name, offset, true

 	case ir.OINDEX:
--- a/src/cmd/compile/internal/typebits/typebits.go
+++ b/src/cmd/compile/internal/typebits/typebits.go
@ -0,0 +1,87 @@
+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package typebits
+
+import (
+	"cmd/compile/internal/base"
+	"cmd/compile/internal/bitvec"
+	"cmd/compile/internal/types"
+)
+
+// NOTE: The bitmap for a specific type t could be cached in t after
+// the first run and then simply copied into bv at the correct offset
+// on future calls with the same type t.
+func Set(t *types.Type, off int64, bv bitvec.BitVec) {
+	if t.Align > 0 && off&int64(t.Align-1) != 0 {
+		base.Fatalf("onebitwalktype1: invalid initial alignment: type %v has alignment %d, but offset is %v", t, t.Align, off)
+	}
+	if !t.HasPointers() {
+		// Note: this case ensures that pointers to go:notinheap types
+		// are not considered pointers by garbage collection and stack copying.
+		return
+	}
+
+	switch t.Kind() {
+	case types.TPTR, types.TUNSAFEPTR, types.TFUNC, types.TCHAN, types.TMAP:
+		if off&int64(types.PtrSize-1) != 0 {
+			base.Fatalf("onebitwalktype1: invalid alignment, %v", t)
+		}
+		bv.Set(int32(off / int64(types.PtrSize))) // pointer
+
+	case types.TSTRING:
+		// struct { byte *str; intgo len; }
+		if off&int64(types.PtrSize-1) != 0 {
+			base.Fatalf("onebitwalktype1: invalid alignment, %v", t)
+		}
+		bv.Set(int32(off / int64(types.PtrSize))) //pointer in first slot
+
+	case types.TINTER:
+		// struct { Itab *tab;	void *data; }
+		// or, when isnilinter(t)==true:
+		// struct { Type *type; void *data; }
+		if off&int64(types.PtrSize-1) != 0 {
+			base.Fatalf("onebitwalktype1: invalid alignment, %v", t)
+		}
+		// The first word of an interface is a pointer, but we don't
+		// treat it as such.
+		// 1. If it is a non-empty interface, the pointer points to an itab
+		//    which is always in persistentalloc space.
+		// 2. If it is an empty interface, the pointer points to a _type.
+		//   a. If it is a compile-time-allocated type, it points into
+		//      the read-only data section.
+		//   b. If it is a reflect-allocated type, it points into the Go heap.
+		//      Reflect is responsible for keeping a reference to
+		//      the underlying type so it won't be GCd.
+		// If we ever have a moving GC, we need to change this for 2b (as
+		// well as scan itabs to update their itab._type fields).
+		bv.Set(int32(off/int64(types.PtrSize) + 1)) // pointer in second slot
+
+	case types.TSLICE:
+		// struct { byte *array; uintgo len; uintgo cap; }
+		if off&int64(types.PtrSize-1) != 0 {
+			base.Fatalf("onebitwalktype1: invalid TARRAY alignment, %v", t)
+		}
+		bv.Set(int32(off / int64(types.PtrSize))) // pointer in first slot (BitsPointer)
+
+	case types.TARRAY:
+		elt := t.Elem()
+		if elt.Width == 0 {
+			// Short-circuit for #20739.
+			break
+		}
+		for i := int64(0); i < t.NumElem(); i++ {
+			Set(elt, off, bv)
+			off += elt.Width
+		}
+
+	case types.TSTRUCT:
+		for _, f := range t.Fields().Slice() {
+			Set(f.Type, off+f.Offset, bv)
+		}
+
+	default:
+		base.Fatalf("onebitwalktype1: unexpected type, %v", t)
+	}
+}
--- a/src/cmd/compile/internal/typecheck/builtin.go
+++ b/src/cmd/compile/internal/typecheck/builtin.go
@ -3,9 +3,8 @@
 package typecheck

 import (
-	"cmd/compile/internal/base"
-	"cmd/compile/internal/ir"
 	"cmd/compile/internal/types"
+	"cmd/internal/src"
 )

 var runtimeDecls = [...]struct {
@ -212,133 +211,133 @@ func runtimeTypes() []*types.Type {
 	typs[1] = types.NewPtr(typs[0])
 	typs[2] = types.Types[types.TANY]
 	typs[3] = types.NewPtr(typs[2])
-	typs[4] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[3])})
+	typs[4] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[1])}, []*types.Field{types.NewField(src.NoXPos, nil, typs[3])})
 	typs[5] = types.Types[types.TUINTPTR]
 	typs[6] = types.Types[types.TBOOL]
 	typs[7] = types.Types[types.TUNSAFEPTR]
-	typs[8] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[5]), ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[6])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[7])})
-	typs[9] = NewFuncType(nil, nil, nil)
+	typs[8] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[5]), types.NewField(src.NoXPos, nil, typs[1]), types.NewField(src.NoXPos, nil, typs[6])}, []*types.Field{types.NewField(src.NoXPos, nil, typs[7])})
+	typs[9] = types.NewSignature(types.NoPkg, nil, nil, nil)
 	typs[10] = types.Types[types.TINTER]
-	typs[11] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[10])}, nil)
+	typs[11] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[10])}, nil)
 	typs[12] = types.Types[types.TINT32]
 	typs[13] = types.NewPtr(typs[12])
-	typs[14] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[13])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[10])})
+	typs[14] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[13])}, []*types.Field{types.NewField(src.NoXPos, nil, typs[10])})
 	typs[15] = types.Types[types.TINT]
-	typs[16] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[15]), ir.NewField(base.Pos, nil, nil, typs[15])}, nil)
+	typs[16] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[15]), types.NewField(src.NoXPos, nil, typs[15])}, nil)
 	typs[17] = types.Types[types.TUINT]
-	typs[18] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[17]), ir.NewField(base.Pos, nil, nil, typs[15])}, nil)
-	typs[19] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[6])}, nil)
+	typs[18] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[17]), types.NewField(src.NoXPos, nil, typs[15])}, nil)
+	typs[19] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[6])}, nil)
 	typs[20] = types.Types[types.TFLOAT64]
-	typs[21] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[20])}, nil)
+	typs[21] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[20])}, nil)
 	typs[22] = types.Types[types.TINT64]
-	typs[23] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[22])}, nil)
+	typs[23] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[22])}, nil)
 	typs[24] = types.Types[types.TUINT64]
-	typs[25] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[24])}, nil)
+	typs[25] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[24])}, nil)
 	typs[26] = types.Types[types.TCOMPLEX128]
-	typs[27] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[26])}, nil)
+	typs[27] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[26])}, nil)
 	typs[28] = types.Types[types.TSTRING]
-	typs[29] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[28])}, nil)
-	typs[30] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[2])}, nil)
-	typs[31] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[5])}, nil)
+	typs[29] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[28])}, nil)
+	typs[30] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[2])}, nil)
+	typs[31] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[5])}, nil)
 	typs[32] = types.NewArray(typs[0], 32)
 	typs[33] = types.NewPtr(typs[32])
-	typs[34] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[33]), ir.NewField(base.Pos, nil, nil, typs[28]), ir.NewField(base.Pos, nil, nil, typs[28])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[28])})
-	typs[35] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[33]), ir.NewField(base.Pos, nil, nil, typs[28]), ir.NewField(base.Pos, nil, nil, typs[28]), ir.NewField(base.Pos, nil, nil, typs[28])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[28])})
-	typs[36] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[33]), ir.NewField(base.Pos, nil, nil, typs[28]), ir.NewField(base.Pos, nil, nil, typs[28]), ir.NewField(base.Pos, nil, nil, typs[28]), ir.NewField(base.Pos, nil, nil, typs[28])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[28])})
-	typs[37] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[33]), ir.NewField(base.Pos, nil, nil, typs[28]), ir.NewField(base.Pos, nil, nil, typs[28]), ir.NewField(base.Pos, nil, nil, typs[28]), ir.NewField(base.Pos, nil, nil, typs[28]), ir.NewField(base.Pos, nil, nil, typs[28])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[28])})
+	typs[34] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[33]), types.NewField(src.NoXPos, nil, typs[28]), types.NewField(src.NoXPos, nil, typs[28])}, []*types.Field{types.NewField(src.NoXPos, nil, typs[28])})
+	typs[35] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[33]), types.NewField(src.NoXPos, nil, typs[28]), types.NewField(src.NoXPos, nil, typs[28]), types.NewField(src.NoXPos, nil, typs[28])}, []*types.Field{types.NewField(src.NoXPos, nil, typs[28])})
+	typs[36] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[33]), types.NewField(src.NoXPos, nil, typs[28]), types.NewField(src.NoXPos, nil, typs[28]), types.NewField(src.NoXPos, nil, typs[28]), types.NewField(src.NoXPos, nil, typs[28])}, []*types.Field{types.NewField(src.NoXPos, nil, typs[28])})
+	typs[37] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[33]), types.NewField(src.NoXPos, nil, typs[28]), types.NewField(src.NoXPos, nil, typs[28]), types.NewField(src.NoXPos, nil, typs[28]), types.NewField(src.NoXPos, nil, typs[28]), types.NewField(src.NoXPos, nil, typs[28])}, []*types.Field{types.NewField(src.NoXPos, nil, typs[28])})
 	typs[38] = types.NewSlice(typs[28])
-	typs[39] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[33]), ir.NewField(base.Pos, nil, nil, typs[38])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[28])})
-	typs[40] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[28]), ir.NewField(base.Pos, nil, nil, typs[28])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[15])})
+	typs[39] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[33]), types.NewField(src.NoXPos, nil, typs[38])}, []*types.Field{types.NewField(src.NoXPos, nil, typs[28])})
+	typs[40] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[28]), types.NewField(src.NoXPos, nil, typs[28])}, []*types.Field{types.NewField(src.NoXPos, nil, typs[15])})
 	typs[41] = types.NewArray(typs[0], 4)
 	typs[42] = types.NewPtr(typs[41])
-	typs[43] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[42]), ir.NewField(base.Pos, nil, nil, typs[22])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[28])})
-	typs[44] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[33]), ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[15])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[28])})
-	typs[45] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[15])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[28])})
+	typs[43] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[42]), types.NewField(src.NoXPos, nil, typs[22])}, []*types.Field{types.NewField(src.NoXPos, nil, typs[28])})
+	typs[44] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[33]), types.NewField(src.NoXPos, nil, typs[1]), types.NewField(src.NoXPos, nil, typs[15])}, []*types.Field{types.NewField(src.NoXPos, nil, typs[28])})
+	typs[45] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[1]), types.NewField(src.NoXPos, nil, typs[15])}, []*types.Field{types.NewField(src.NoXPos, nil, typs[28])})
 	typs[46] = types.RuneType
 	typs[47] = types.NewSlice(typs[46])
-	typs[48] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[33]), ir.NewField(base.Pos, nil, nil, typs[47])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[28])})
+	typs[48] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[33]), types.NewField(src.NoXPos, nil, typs[47])}, []*types.Field{types.NewField(src.NoXPos, nil, typs[28])})
 	typs[49] = types.NewSlice(typs[0])
-	typs[50] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[33]), ir.NewField(base.Pos, nil, nil, typs[28])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[49])})
+	typs[50] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[33]), types.NewField(src.NoXPos, nil, typs[28])}, []*types.Field{types.NewField(src.NoXPos, nil, typs[49])})
 	typs[51] = types.NewArray(typs[46], 32)
 	typs[52] = types.NewPtr(typs[51])
-	typs[53] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[52]), ir.NewField(base.Pos, nil, nil, typs[28])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[47])})
-	typs[54] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[3]), ir.NewField(base.Pos, nil, nil, typs[15]), ir.NewField(base.Pos, nil, nil, typs[3]), ir.NewField(base.Pos, nil, nil, typs[15]), ir.NewField(base.Pos, nil, nil, typs[5])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[15])})
-	typs[55] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[28]), ir.NewField(base.Pos, nil, nil, typs[15])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[46]), ir.NewField(base.Pos, nil, nil, typs[15])})
-	typs[56] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[28])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[15])})
-	typs[57] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[2])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[2])})
-	typs[58] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[2])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[7])})
-	typs[59] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[3])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[2])})
-	typs[60] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[2])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[2]), ir.NewField(base.Pos, nil, nil, typs[6])})
-	typs[61] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[1])}, nil)
-	typs[62] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1])}, nil)
+	typs[53] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[52]), types.NewField(src.NoXPos, nil, typs[28])}, []*types.Field{types.NewField(src.NoXPos, nil, typs[47])})
+	typs[54] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[3]), types.NewField(src.NoXPos, nil, typs[15]), types.NewField(src.NoXPos, nil, typs[3]), types.NewField(src.NoXPos, nil, typs[15]), types.NewField(src.NoXPos, nil, typs[5])}, []*types.Field{types.NewField(src.NoXPos, nil, typs[15])})
+	typs[55] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[28]), types.NewField(src.NoXPos, nil, typs[15])}, []*types.Field{types.NewField(src.NoXPos, nil, typs[46]), types.NewField(src.NoXPos, nil, typs[15])})
+	typs[56] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[28])}, []*types.Field{types.NewField(src.NoXPos, nil, typs[15])})
+	typs[57] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[1]), types.NewField(src.NoXPos, nil, typs[2])}, []*types.Field{types.NewField(src.NoXPos, nil, typs[2])})
+	typs[58] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[2])}, []*types.Field{types.NewField(src.NoXPos, nil, typs[7])})
+	typs[59] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[1]), types.NewField(src.NoXPos, nil, typs[3])}, []*types.Field{types.NewField(src.NoXPos, nil, typs[2])})
+	typs[60] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[1]), types.NewField(src.NoXPos, nil, typs[2])}, []*types.Field{types.NewField(src.NoXPos, nil, typs[2]), types.NewField(src.NoXPos, nil, typs[6])})
+	typs[61] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[1]), types.NewField(src.NoXPos, nil, typs[1]), types.NewField(src.NoXPos, nil, typs[1])}, nil)
+	typs[62] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[1])}, nil)
 	typs[63] = types.NewPtr(typs[5])
-	typs[64] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[63]), ir.NewField(base.Pos, nil, nil, typs[7]), ir.NewField(base.Pos, nil, nil, typs[7])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[6])})
+	typs[64] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[63]), types.NewField(src.NoXPos, nil, typs[7]), types.NewField(src.NoXPos, nil, typs[7])}, []*types.Field{types.NewField(src.NoXPos, nil, typs[6])})
 	typs[65] = types.Types[types.TUINT32]
-	typs[66] = NewFuncType(nil, nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[65])})
+	typs[66] = types.NewSignature(types.NoPkg, nil, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[65])})
 	typs[67] = types.NewMap(typs[2], typs[2])
-	typs[68] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[22]), ir.NewField(base.Pos, nil, nil, typs[3])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[67])})
-	typs[69] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[15]), ir.NewField(base.Pos, nil, nil, typs[3])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[67])})
-	typs[70] = NewFuncType(nil, nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[67])})
-	typs[71] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[67]), ir.NewField(base.Pos, nil, nil, typs[3])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[3])})
-	typs[72] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[67]), ir.NewField(base.Pos, nil, nil, typs[2])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[3])})
-	typs[73] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[67]), ir.NewField(base.Pos, nil, nil, typs[3]), ir.NewField(base.Pos, nil, nil, typs[1])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[3])})
-	typs[74] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[67]), ir.NewField(base.Pos, nil, nil, typs[3])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[3]), ir.NewField(base.Pos, nil, nil, typs[6])})
-	typs[75] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[67]), ir.NewField(base.Pos, nil, nil, typs[2])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[3]), ir.NewField(base.Pos, nil, nil, typs[6])})
-	typs[76] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[67]), ir.NewField(base.Pos, nil, nil, typs[3]), ir.NewField(base.Pos, nil, nil, typs[1])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[3]), ir.NewField(base.Pos, nil, nil, typs[6])})
-	typs[77] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[67]), ir.NewField(base.Pos, nil, nil, typs[3])}, nil)
-	typs[78] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[67]), ir.NewField(base.Pos, nil, nil, typs[2])}, nil)
-	typs[79] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[3])}, nil)
-	typs[80] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[67])}, nil)
+	typs[68] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[1]), types.NewField(src.NoXPos, nil, typs[22]), types.NewField(src.NoXPos, nil, typs[3])}, []*types.Field{types.NewField(src.NoXPos, nil, typs[67])})
+	typs[69] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[1]), types.NewField(src.NoXPos, nil, typs[15]), types.NewField(src.NoXPos, nil, typs[3])}, []*types.Field{types.NewField(src.NoXPos, nil, typs[67])})
+	typs[70] = types.NewSignature(types.NoPkg, nil, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[67])})
+	typs[71] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[1]), types.NewField(src.NoXPos, nil, typs[67]), types.NewField(src.NoXPos, nil, typs[3])}, []*types.Field{types.NewField(src.NoXPos, nil, typs[3])})
+	typs[72] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[1]), types.NewField(src.NoXPos, nil, typs[67]), types.NewField(src.NoXPos, nil, typs[2])}, []*types.Field{types.NewField(src.NoXPos, nil, typs[3])})
+	typs[73] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[1]), types.NewField(src.NoXPos, nil, typs[67]), types.NewField(src.NoXPos, nil, typs[3]), types.NewField(src.NoXPos, nil, typs[1])}, []*types.Field{types.NewField(src.NoXPos, nil, typs[3])})
+	typs[74] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[1]), types.NewField(src.NoXPos, nil, typs[67]), types.NewField(src.NoXPos, nil, typs[3])}, []*types.Field{types.NewField(src.NoXPos, nil, typs[3]), types.NewField(src.NoXPos, nil, typs[6])})
+	typs[75] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[1]), types.NewField(src.NoXPos, nil, typs[67]), types.NewField(src.NoXPos, nil, typs[2])}, []*types.Field{types.NewField(src.NoXPos, nil, typs[3]), types.NewField(src.NoXPos, nil, typs[6])})
+	typs[76] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[1]), types.NewField(src.NoXPos, nil, typs[67]), types.NewField(src.NoXPos, nil, typs[3]), types.NewField(src.NoXPos, nil, typs[1])}, []*types.Field{types.NewField(src.NoXPos, nil, typs[3]), types.NewField(src.NoXPos, nil, typs[6])})
+	typs[77] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[1]), types.NewField(src.NoXPos, nil, typs[67]), types.NewField(src.NoXPos, nil, typs[3])}, nil)
+	typs[78] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[1]), types.NewField(src.NoXPos, nil, typs[67]), types.NewField(src.NoXPos, nil, typs[2])}, nil)
+	typs[79] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[3])}, nil)
+	typs[80] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[1]), types.NewField(src.NoXPos, nil, typs[67])}, nil)
 	typs[81] = types.NewChan(typs[2], types.Cboth)
-	typs[82] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[22])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[81])})
-	typs[83] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[15])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[81])})
+	typs[82] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[1]), types.NewField(src.NoXPos, nil, typs[22])}, []*types.Field{types.NewField(src.NoXPos, nil, typs[81])})
+	typs[83] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[1]), types.NewField(src.NoXPos, nil, typs[15])}, []*types.Field{types.NewField(src.NoXPos, nil, typs[81])})
 	typs[84] = types.NewChan(typs[2], types.Crecv)
-	typs[85] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[84]), ir.NewField(base.Pos, nil, nil, typs[3])}, nil)
-	typs[86] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[84]), ir.NewField(base.Pos, nil, nil, typs[3])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[6])})
+	typs[85] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[84]), types.NewField(src.NoXPos, nil, typs[3])}, nil)
+	typs[86] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[84]), types.NewField(src.NoXPos, nil, typs[3])}, []*types.Field{types.NewField(src.NoXPos, nil, typs[6])})
 	typs[87] = types.NewChan(typs[2], types.Csend)
-	typs[88] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[87]), ir.NewField(base.Pos, nil, nil, typs[3])}, nil)
+	typs[88] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[87]), types.NewField(src.NoXPos, nil, typs[3])}, nil)
 	typs[89] = types.NewArray(typs[0], 3)
-	typs[90] = NewStructType([]*ir.Field{ir.NewField(base.Pos, Lookup("enabled"), nil, typs[6]), ir.NewField(base.Pos, Lookup("pad"), nil, typs[89]), ir.NewField(base.Pos, Lookup("needed"), nil, typs[6]), ir.NewField(base.Pos, Lookup("cgo"), nil, typs[6]), ir.NewField(base.Pos, Lookup("alignme"), nil, typs[24])})
-	typs[91] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[3]), ir.NewField(base.Pos, nil, nil, typs[3])}, nil)
-	typs[92] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[3])}, nil)
-	typs[93] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[3]), ir.NewField(base.Pos, nil, nil, typs[15]), ir.NewField(base.Pos, nil, nil, typs[3]), ir.NewField(base.Pos, nil, nil, typs[15])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[15])})
-	typs[94] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[87]), ir.NewField(base.Pos, nil, nil, typs[3])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[6])})
-	typs[95] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[3]), ir.NewField(base.Pos, nil, nil, typs[84])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[6])})
+	typs[90] = types.NewStruct(types.NoPkg, []*types.Field{types.NewField(src.NoXPos, Lookup("enabled"), typs[6]), types.NewField(src.NoXPos, Lookup("pad"), typs[89]), types.NewField(src.NoXPos, Lookup("needed"), typs[6]), types.NewField(src.NoXPos, Lookup("cgo"), typs[6]), types.NewField(src.NoXPos, Lookup("alignme"), typs[24])})
+	typs[91] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[1]), types.NewField(src.NoXPos, nil, typs[3]), types.NewField(src.NoXPos, nil, typs[3])}, nil)
+	typs[92] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[1]), types.NewField(src.NoXPos, nil, typs[3])}, nil)
+	typs[93] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[1]), types.NewField(src.NoXPos, nil, typs[3]), types.NewField(src.NoXPos, nil, typs[15]), types.NewField(src.NoXPos, nil, typs[3]), types.NewField(src.NoXPos, nil, typs[15])}, []*types.Field{types.NewField(src.NoXPos, nil, typs[15])})
+	typs[94] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[87]), types.NewField(src.NoXPos, nil, typs[3])}, []*types.Field{types.NewField(src.NoXPos, nil, typs[6])})
+	typs[95] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[3]), types.NewField(src.NoXPos, nil, typs[84])}, []*types.Field{types.NewField(src.NoXPos, nil, typs[6])})
 	typs[96] = types.NewPtr(typs[6])
-	typs[97] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[3]), ir.NewField(base.Pos, nil, nil, typs[96]), ir.NewField(base.Pos, nil, nil, typs[84])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[6])})
-	typs[98] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[63])}, nil)
-	typs[99] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[63]), ir.NewField(base.Pos, nil, nil, typs[15]), ir.NewField(base.Pos, nil, nil, typs[15]), ir.NewField(base.Pos, nil, nil, typs[6])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[15]), ir.NewField(base.Pos, nil, nil, typs[6])})
-	typs[100] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[15]), ir.NewField(base.Pos, nil, nil, typs[15])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[7])})
-	typs[101] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[22]), ir.NewField(base.Pos, nil, nil, typs[22])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[7])})
-	typs[102] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[15]), ir.NewField(base.Pos, nil, nil, typs[15]), ir.NewField(base.Pos, nil, nil, typs[7])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[7])})
+	typs[97] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[3]), types.NewField(src.NoXPos, nil, typs[96]), types.NewField(src.NoXPos, nil, typs[84])}, []*types.Field{types.NewField(src.NoXPos, nil, typs[6])})
+	typs[98] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[63])}, nil)
+	typs[99] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[1]), types.NewField(src.NoXPos, nil, typs[1]), types.NewField(src.NoXPos, nil, typs[63]), types.NewField(src.NoXPos, nil, typs[15]), types.NewField(src.NoXPos, nil, typs[15]), types.NewField(src.NoXPos, nil, typs[6])}, []*types.Field{types.NewField(src.NoXPos, nil, typs[15]), types.NewField(src.NoXPos, nil, typs[6])})
+	typs[100] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[1]), types.NewField(src.NoXPos, nil, typs[15]), types.NewField(src.NoXPos, nil, typs[15])}, []*types.Field{types.NewField(src.NoXPos, nil, typs[7])})
+	typs[101] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[1]), types.NewField(src.NoXPos, nil, typs[22]), types.NewField(src.NoXPos, nil, typs[22])}, []*types.Field{types.NewField(src.NoXPos, nil, typs[7])})
+	typs[102] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[1]), types.NewField(src.NoXPos, nil, typs[15]), types.NewField(src.NoXPos, nil, typs[15]), types.NewField(src.NoXPos, nil, typs[7])}, []*types.Field{types.NewField(src.NoXPos, nil, typs[7])})
 	typs[103] = types.NewSlice(typs[2])
-	typs[104] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[103]), ir.NewField(base.Pos, nil, nil, typs[15])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[103])})
-	typs[105] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[3]), ir.NewField(base.Pos, nil, nil, typs[3]), ir.NewField(base.Pos, nil, nil, typs[5])}, nil)
-	typs[106] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[7]), ir.NewField(base.Pos, nil, nil, typs[5])}, nil)
-	typs[107] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[3]), ir.NewField(base.Pos, nil, nil, typs[3]), ir.NewField(base.Pos, nil, nil, typs[5])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[6])})
-	typs[108] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[3]), ir.NewField(base.Pos, nil, nil, typs[3])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[6])})
-	typs[109] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[7]), ir.NewField(base.Pos, nil, nil, typs[7])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[6])})
-	typs[110] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[7]), ir.NewField(base.Pos, nil, nil, typs[5]), ir.NewField(base.Pos, nil, nil, typs[5])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[5])})
-	typs[111] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[7]), ir.NewField(base.Pos, nil, nil, typs[5])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[5])})
-	typs[112] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[22]), ir.NewField(base.Pos, nil, nil, typs[22])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[22])})
-	typs[113] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[24]), ir.NewField(base.Pos, nil, nil, typs[24])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[24])})
-	typs[114] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[20])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[22])})
-	typs[115] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[20])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[24])})
-	typs[116] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[20])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[65])})
-	typs[117] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[22])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[20])})
-	typs[118] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[24])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[20])})
-	typs[119] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[65])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[20])})
-	typs[120] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[26]), ir.NewField(base.Pos, nil, nil, typs[26])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[26])})
-	typs[121] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[5]), ir.NewField(base.Pos, nil, nil, typs[5])}, nil)
-	typs[122] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[5]), ir.NewField(base.Pos, nil, nil, typs[5]), ir.NewField(base.Pos, nil, nil, typs[5])}, nil)
-	typs[123] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[7]), ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[5])}, nil)
+	typs[104] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[1]), types.NewField(src.NoXPos, nil, typs[103]), types.NewField(src.NoXPos, nil, typs[15])}, []*types.Field{types.NewField(src.NoXPos, nil, typs[103])})
+	typs[105] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[3]), types.NewField(src.NoXPos, nil, typs[3]), types.NewField(src.NoXPos, nil, typs[5])}, nil)
+	typs[106] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[7]), types.NewField(src.NoXPos, nil, typs[5])}, nil)
+	typs[107] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[3]), types.NewField(src.NoXPos, nil, typs[3]), types.NewField(src.NoXPos, nil, typs[5])}, []*types.Field{types.NewField(src.NoXPos, nil, typs[6])})
+	typs[108] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[3]), types.NewField(src.NoXPos, nil, typs[3])}, []*types.Field{types.NewField(src.NoXPos, nil, typs[6])})
+	typs[109] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[7]), types.NewField(src.NoXPos, nil, typs[7])}, []*types.Field{types.NewField(src.NoXPos, nil, typs[6])})
+	typs[110] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[7]), types.NewField(src.NoXPos, nil, typs[5]), types.NewField(src.NoXPos, nil, typs[5])}, []*types.Field{types.NewField(src.NoXPos, nil, typs[5])})
+	typs[111] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[7]), types.NewField(src.NoXPos, nil, typs[5])}, []*types.Field{types.NewField(src.NoXPos, nil, typs[5])})
+	typs[112] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[22]), types.NewField(src.NoXPos, nil, typs[22])}, []*types.Field{types.NewField(src.NoXPos, nil, typs[22])})
+	typs[113] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[24]), types.NewField(src.NoXPos, nil, typs[24])}, []*types.Field{types.NewField(src.NoXPos, nil, typs[24])})
+	typs[114] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[20])}, []*types.Field{types.NewField(src.NoXPos, nil, typs[22])})
+	typs[115] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[20])}, []*types.Field{types.NewField(src.NoXPos, nil, typs[24])})
+	typs[116] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[20])}, []*types.Field{types.NewField(src.NoXPos, nil, typs[65])})
+	typs[117] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[22])}, []*types.Field{types.NewField(src.NoXPos, nil, typs[20])})
+	typs[118] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[24])}, []*types.Field{types.NewField(src.NoXPos, nil, typs[20])})
+	typs[119] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[65])}, []*types.Field{types.NewField(src.NoXPos, nil, typs[20])})
+	typs[120] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[26]), types.NewField(src.NoXPos, nil, typs[26])}, []*types.Field{types.NewField(src.NoXPos, nil, typs[26])})
+	typs[121] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[5]), types.NewField(src.NoXPos, nil, typs[5])}, nil)
+	typs[122] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[5]), types.NewField(src.NoXPos, nil, typs[5]), types.NewField(src.NoXPos, nil, typs[5])}, nil)
+	typs[123] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[7]), types.NewField(src.NoXPos, nil, typs[1]), types.NewField(src.NoXPos, nil, typs[5])}, nil)
 	typs[124] = types.NewSlice(typs[7])
-	typs[125] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[7]), ir.NewField(base.Pos, nil, nil, typs[124])}, nil)
+	typs[125] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[7]), types.NewField(src.NoXPos, nil, typs[124])}, nil)
 	typs[126] = types.Types[types.TUINT8]
-	typs[127] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[126]), ir.NewField(base.Pos, nil, nil, typs[126])}, nil)
+	typs[127] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[126]), types.NewField(src.NoXPos, nil, typs[126])}, nil)
 	typs[128] = types.Types[types.TUINT16]
-	typs[129] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[128]), ir.NewField(base.Pos, nil, nil, typs[128])}, nil)
-	typs[130] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[65]), ir.NewField(base.Pos, nil, nil, typs[65])}, nil)
-	typs[131] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[24]), ir.NewField(base.Pos, nil, nil, typs[24])}, nil)
+	typs[129] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[128]), types.NewField(src.NoXPos, nil, typs[128])}, nil)
+	typs[130] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[65]), types.NewField(src.NoXPos, nil, typs[65])}, nil)
+	typs[131] = types.NewSignature(types.NoPkg, nil, []*types.Field{types.NewField(src.NoXPos, nil, typs[24]), types.NewField(src.NoXPos, nil, typs[24])}, nil)
 	return typs[:]
 }
--- a/src/cmd/compile/internal/typecheck/builtin_test.go
+++ b/src/cmd/compile/internal/typecheck/builtin_test.go
@ -13,7 +13,6 @@ import (
 )

 func TestBuiltin(t *testing.T) {
-	t.Skip("mkbuiltin needs fixing")
 	testenv.MustHaveGoRun(t)
 	t.Parallel()

--- a/src/cmd/compile/internal/typecheck/const.go
+++ b/src/cmd/compile/internal/typecheck/const.go
@ -929,7 +929,7 @@ func evalunsafe(n ir.Node) int64 {
 				fallthrough
 			case ir.ODOT:
 				r := r.(*ir.SelectorExpr)
-				v += r.Offset
+				v += r.Offset()
 				next = r.X
 			default:
 				ir.Dump("unsafenmagic", tsel)
--- a/src/cmd/compile/internal/typecheck/dcl.go
+++ b/src/cmd/compile/internal/typecheck/dcl.go
@ -281,72 +281,6 @@ func CheckFuncStack() {
 	}
 }

-// turn a parsed function declaration into a type
-func NewFuncType(nrecv *ir.Field, nparams, nresults []*ir.Field) *types.Type {
-	funarg := func(n *ir.Field) *types.Field {
-		lno := base.Pos
-		base.Pos = n.Pos
-
-		if n.Ntype != nil {
-			n.Type = typecheckNtype(n.Ntype).Type()
-			n.Ntype = nil
-		}
-
-		f := types.NewField(n.Pos, n.Sym, n.Type)
-		f.SetIsDDD(n.IsDDD)
-		if n.Decl != nil {
-			n.Decl.SetType(f.Type)
-			f.Nname = n.Decl
-		}
-
-		base.Pos = lno
-		return f
-	}
-	funargs := func(nn []*ir.Field) []*types.Field {
-		res := make([]*types.Field, len(nn))
-		for i, n := range nn {
-			res[i] = funarg(n)
-		}
-		return res
-	}
-
-	var recv *types.Field
-	if nrecv != nil {
-		recv = funarg(nrecv)
-	}
-
-	t := types.NewSignature(types.LocalPkg, recv, funargs(nparams), funargs(nresults))
-	checkdupfields("argument", t.Recvs().FieldSlice(), t.Params().FieldSlice(), t.Results().FieldSlice())
-	return t
-}
-
-// convert a parsed id/type list into
-// a type for struct/interface/arglist
-func NewStructType(l []*ir.Field) *types.Type {
-	lno := base.Pos
-
-	fields := make([]*types.Field, len(l))
-	for i, n := range l {
-		base.Pos = n.Pos
-
-		if n.Ntype != nil {
-			n.Type = typecheckNtype(n.Ntype).Type()
-			n.Ntype = nil
-		}
-		f := types.NewField(n.Pos, n.Sym, n.Type)
-		if n.Embedded {
-			checkembeddedtype(n.Type)
-			f.Embedded = 1
-		}
-		f.Note = n.Note
-		fields[i] = f
-	}
-	checkdupfields("field", fields)
-
-	base.Pos = lno
-	return types.NewStruct(types.LocalPkg, fields)
-}
-
 // Add a method, declared as a function.
 // - msym is the method symbol
 // - t is function type (with receiver)
@ -513,7 +447,6 @@ func funcarg(n *ir.Field, ctxt ir.Class) {
 	name := ir.NewNameAt(n.Pos, n.Sym)
 	n.Decl = name
 	name.Ntype = n.Ntype
-	name.SetIsDDD(n.IsDDD)
 	Declare(name, ctxt)

 	vargen++
@ -527,7 +460,6 @@ func funcarg2(f *types.Field, ctxt ir.Class) {
 	n := ir.NewNameAt(f.Pos, f.Sym)
 	f.Nname = n
 	n.SetType(f.Type)
-	n.SetIsDDD(f.IsDDD())
 	Declare(n, ctxt)
 }

@ -604,27 +536,6 @@ func initname(s string) bool {
 	return s == "init"
 }

-func tointerface(nmethods []*ir.Field) *types.Type {
-	if len(nmethods) == 0 {
-		return types.Types[types.TINTER]
-	}
-
-	lno := base.Pos
-
-	methods := make([]*types.Field, len(nmethods))
-	for i, n := range nmethods {
-		base.Pos = n.Pos
-		if n.Ntype != nil {
-			n.Type = typecheckNtype(n.Ntype).Type()
-			n.Ntype = nil
-		}
-		methods[i] = types.NewField(n.Pos, n.Sym, n.Type)
-	}
-
-	base.Pos = lno
-	return types.NewInterface(types.LocalPkg, methods)
-}
-
 var vargen int

 func Temp(t *types.Type) *ir.Name {
@ -643,6 +554,9 @@ func TempAt(pos src.XPos, curfn *ir.Func, t *types.Type) *ir.Name {
 	if t == nil {
 		base.Fatalf("tempAt called with nil type")
 	}
+	if t.Kind() == types.TFUNC && t.Recv() != nil {
+		base.Fatalf("misuse of method type: %v", t)
+	}

 	s := &types.Sym{
 		Name: autotmpname(len(curfn.Dcl)),
@ -676,30 +590,26 @@ func autotmpname(n int) string {

 // f is method type, with receiver.
 // return function type, receiver as first argument (or not).
-func NewMethodType(f *types.Type, receiver *types.Type) *types.Type {
-	inLen := f.Params().Fields().Len()
-	if receiver != nil {
-		inLen++
-	}
-	in := make([]*ir.Field, 0, inLen)
-
-	if receiver != nil {
-		d := ir.NewField(base.Pos, nil, nil, receiver)
-		in = append(in, d)
+func NewMethodType(sig *types.Type, recv *types.Type) *types.Type {
+	nrecvs := 0
+	if recv != nil {
+		nrecvs++
 	}

-	for _, t := range f.Params().Fields().Slice() {
-		d := ir.NewField(base.Pos, nil, nil, t.Type)
-		d.IsDDD = t.IsDDD()
-		in = append(in, d)
+	params := make([]*types.Field, nrecvs+sig.Params().Fields().Len())
+	if recv != nil {
+		params[0] = types.NewField(base.Pos, nil, recv)
+	}
+	for i, param := range sig.Params().Fields().Slice() {
+		d := types.NewField(base.Pos, nil, param.Type)
+		d.SetIsDDD(param.IsDDD())
+		params[nrecvs+i] = d
 	}

-	outLen := f.Results().Fields().Len()
-	out := make([]*ir.Field, 0, outLen)
-	for _, t := range f.Results().Fields().Slice() {
-		d := ir.NewField(base.Pos, nil, nil, t.Type)
-		out = append(out, d)
+	results := make([]*types.Field, sig.Results().Fields().Len())
+	for i, t := range sig.Results().Fields().Slice() {
+		results[i] = types.NewField(base.Pos, nil, t.Type)
 	}

-	return NewFuncType(nil, in, out)
+	return types.NewSignature(types.LocalPkg, nil, params, results)
 }
--- a/src/cmd/compile/internal/typecheck/expr.go
+++ b/src/cmd/compile/internal/typecheck/expr.go
@ -571,7 +571,6 @@ func tcDot(n *ir.SelectorExpr, top int) ir.Node {
 	}

 	n.X = typecheck(n.X, ctxExpr|ctxType)
-
 	n.X = DefaultLit(n.X, nil)

 	t := n.X.Type()
@ -581,8 +580,6 @@ func tcDot(n *ir.SelectorExpr, top int) ir.Node {
 		return n
 	}

-	s := n.Sel
-
 	if n.X.Op() == ir.OTYPE {
 		return typecheckMethodExpr(n)
 	}
@ -629,7 +626,10 @@ func tcDot(n *ir.SelectorExpr, top int) ir.Node {
 	}

 	if (n.Op() == ir.ODOTINTER || n.Op() == ir.ODOTMETH) && top&ctxCallee == 0 {
-		return tcCallPart(n, s)
+		// Create top-level function.
+		fn := makepartialcall(n)
+
+		return ir.NewCallPartExpr(n.Pos(), n.X, n.Selection, fn)
 	}
 	return n
 }
@ -831,24 +831,18 @@ func tcSPtr(n *ir.UnaryExpr) ir.Node {

 // tcSlice typechecks an OSLICE or OSLICE3 node.
 func tcSlice(n *ir.SliceExpr) ir.Node {
-	n.X = Expr(n.X)
-	low, high, max := n.SliceBounds()
+	n.X = DefaultLit(Expr(n.X), nil)
+	n.Low = indexlit(Expr(n.Low))
+	n.High = indexlit(Expr(n.High))
+	n.Max = indexlit(Expr(n.Max))
 	hasmax := n.Op().IsSlice3()
-	low = Expr(low)
-	high = Expr(high)
-	max = Expr(max)
-	n.X = DefaultLit(n.X, nil)
-	low = indexlit(low)
-	high = indexlit(high)
-	max = indexlit(max)
-	n.SetSliceBounds(low, high, max)
 	l := n.X
 	if l.Type() == nil {
 		n.SetType(nil)
 		return n
 	}
 	if l.Type().IsArray() {
-		if !ir.IsAssignable(n.X) {
+		if !ir.IsAddressable(n.X) {
 			base.Errorf("invalid operation %v (slice of unaddressable value)", n)
 			n.SetType(nil)
 			return n
@ -886,19 +880,19 @@ func tcSlice(n *ir.SliceExpr) ir.Node {
 		return n
 	}

-	if low != nil && !checksliceindex(l, low, tp) {
+	if n.Low != nil && !checksliceindex(l, n.Low, tp) {
 		n.SetType(nil)
 		return n
 	}
-	if high != nil && !checksliceindex(l, high, tp) {
+	if n.High != nil && !checksliceindex(l, n.High, tp) {
 		n.SetType(nil)
 		return n
 	}
-	if max != nil && !checksliceindex(l, max, tp) {
+	if n.Max != nil && !checksliceindex(l, n.Max, tp) {
 		n.SetType(nil)
 		return n
 	}
-	if !checksliceconst(low, high) || !checksliceconst(low, max) || !checksliceconst(high, max) {
+	if !checksliceconst(n.Low, n.High) || !checksliceconst(n.Low, n.Max) || !checksliceconst(n.High, n.Max) {
 		n.SetType(nil)
 		return n
 	}
@ -924,30 +918,22 @@ func tcSliceHeader(n *ir.SliceHeaderExpr) ir.Node {
 		base.Fatalf("need unsafe.Pointer for OSLICEHEADER")
 	}

-	if x := len(n.LenCap); x != 2 {
-		base.Fatalf("expected 2 params (len, cap) for OSLICEHEADER, got %d", x)
-	}
-
 	n.Ptr = Expr(n.Ptr)
-	l := Expr(n.LenCap[0])
-	c := Expr(n.LenCap[1])
-	l = DefaultLit(l, types.Types[types.TINT])
-	c = DefaultLit(c, types.Types[types.TINT])
+	n.Len = DefaultLit(Expr(n.Len), types.Types[types.TINT])
+	n.Cap = DefaultLit(Expr(n.Cap), types.Types[types.TINT])

-	if ir.IsConst(l, constant.Int) && ir.Int64Val(l) < 0 {
+	if ir.IsConst(n.Len, constant.Int) && ir.Int64Val(n.Len) < 0 {
 		base.Fatalf("len for OSLICEHEADER must be non-negative")
 	}

-	if ir.IsConst(c, constant.Int) && ir.Int64Val(c) < 0 {
+	if ir.IsConst(n.Cap, constant.Int) && ir.Int64Val(n.Cap) < 0 {
 		base.Fatalf("cap for OSLICEHEADER must be non-negative")
 	}

-	if ir.IsConst(l, constant.Int) && ir.IsConst(c, constant.Int) && constant.Compare(l.Val(), token.GTR, c.Val()) {
+	if ir.IsConst(n.Len, constant.Int) && ir.IsConst(n.Cap, constant.Int) && constant.Compare(n.Len.Val(), token.GTR, n.Cap.Val()) {
 		base.Fatalf("len larger than cap for OSLICEHEADER")
 	}

-	n.LenCap[0] = l
-	n.LenCap[1] = c
 	return n
 }

--- a/src/cmd/compile/internal/typecheck/func.go
+++ b/src/cmd/compile/internal/typecheck/func.go
@ -73,17 +73,17 @@ func ClosureType(clo *ir.ClosureExpr) *types.Type {
 	// The information appears in the binary in the form of type descriptors;
 	// the struct is unnamed so that closures in multiple packages with the
 	// same struct type can share the descriptor.
-	fields := []*ir.Field{
-		ir.NewField(base.Pos, Lookup(".F"), nil, types.Types[types.TUINTPTR]),
+	fields := []*types.Field{
+		types.NewField(base.Pos, Lookup(".F"), types.Types[types.TUINTPTR]),
 	}
 	for _, v := range clo.Func.ClosureVars {
 		typ := v.Type()
 		if !v.Byval() {
 			typ = types.NewPtr(typ)
 		}
-		fields = append(fields, ir.NewField(base.Pos, v.Sym(), nil, typ))
+		fields = append(fields, types.NewField(base.Pos, v.Sym(), typ))
 	}
-	typ := NewStructType(fields)
+	typ := types.NewStruct(types.NoPkg, fields)
 	typ.SetNoalg(true)
 	return typ
 }
@ -92,9 +92,9 @@ func ClosureType(clo *ir.ClosureExpr) *types.Type {
 // needed in the closure for n (n must be a OCALLPART node).
 // The address of a variable of the returned type can be cast to a func.
 func PartialCallType(n *ir.CallPartExpr) *types.Type {
-	t := NewStructType([]*ir.Field{
-		ir.NewField(base.Pos, Lookup("F"), nil, types.Types[types.TUINTPTR]),
-		ir.NewField(base.Pos, Lookup("R"), nil, n.X.Type()),
+	t := types.NewStruct(types.NoPkg, []*types.Field{
+		types.NewField(base.Pos, Lookup("F"), types.Types[types.TUINTPTR]),
+		types.NewField(base.Pos, Lookup("R"), n.X.Type()),
 	})
 	t.SetNoalg(true)
 	return t
@ -249,7 +249,9 @@ var globClosgen int32

 // makepartialcall returns a DCLFUNC node representing the wrapper function (*-fm) needed
 // for partial calls.
-func makepartialcall(dot *ir.SelectorExpr, t0 *types.Type, meth *types.Sym) *ir.Func {
+func makepartialcall(dot *ir.SelectorExpr) *ir.Func {
+	t0 := dot.Type()
+	meth := dot.Sel
 	rcvrtype := dot.X.Type()
 	sym := ir.MethodSymSuffix(rcvrtype, meth, "-fm")

@ -263,11 +265,10 @@ func makepartialcall(dot *ir.SelectorExpr, t0 *types.Type, meth *types.Sym) *ir.
 	ir.CurFunc = nil

 	// Set line number equal to the line number where the method is declared.
-	var m *types.Field
-	if lookdot0(meth, rcvrtype, &m, false) == 1 && m.Pos.IsKnown() {
-		base.Pos = m.Pos
+	if pos := dot.Selection.Pos; pos.IsKnown() {
+		base.Pos = pos
 	}
-	// Note: !m.Pos.IsKnown() happens for method expressions where
+	// Note: !dot.Selection.Pos.IsKnown() happens for method expressions where
 	// the method is implicitly declared. The Error method of the
 	// built-in error type is one such method.  We leave the line
 	// number at the use of the method expression in this
@ -280,18 +281,17 @@ func makepartialcall(dot *ir.SelectorExpr, t0 *types.Type, meth *types.Sym) *ir.
 	fn := DeclFunc(sym, tfn)
 	fn.SetDupok(true)
 	fn.SetNeedctxt(true)
+	fn.SetWrapper(true)

 	// Declare and initialize variable holding receiver.
 	cr := ir.NewClosureRead(rcvrtype, types.Rnd(int64(types.PtrSize), int64(rcvrtype.Align)))
-	ptr := NewName(Lookup(".this"))
-	Declare(ptr, ir.PAUTO)
-	ptr.SetUsed(true)
+	var ptr *ir.Name
 	var body []ir.Node
 	if rcvrtype.IsPtr() || rcvrtype.IsInterface() {
-		ptr.SetType(rcvrtype)
+		ptr = Temp(rcvrtype)
 		body = append(body, ir.NewAssignStmt(base.Pos, ptr, cr))
 	} else {
-		ptr.SetType(types.NewPtr(rcvrtype))
+		ptr = Temp(types.NewPtr(rcvrtype))
 		body = append(body, ir.NewAssignStmt(base.Pos, ptr, NodAddr(cr)))
 	}

@ -382,23 +382,6 @@ func tcClosure(clo *ir.ClosureExpr, top int) {
 	Target.Decls = append(Target.Decls, fn)
 }

-func tcCallPart(n ir.Node, sym *types.Sym) *ir.CallPartExpr {
-	switch n.Op() {
-	case ir.ODOTINTER, ir.ODOTMETH:
-		break
-
-	default:
-		base.Fatalf("invalid typecheckpartialcall")
-	}
-	dot := n.(*ir.SelectorExpr)
-
-	// Create top-level function.
-	fn := makepartialcall(dot, dot.Type(), sym)
-	fn.SetWrapper(true)
-
-	return ir.NewCallPartExpr(dot.Pos(), dot.X, dot.Selection, fn)
-}
-
 // type check function definition
 // To be called by typecheck, not directly.
 // (Call typecheckFunc instead.)
@ -542,9 +525,7 @@ func tcCall(n *ir.CallExpr, top int) ir.Node {
 	default:
 		n.SetOp(ir.OCALLFUNC)
 		if t.Kind() != types.TFUNC {
-			// TODO(mdempsky): Remove "o.Sym() != nil" once we stop
-			// using ir.Name for numeric literals.
-			if o := ir.Orig(l); o.Name() != nil && o.Sym() != nil && types.BuiltinPkg.Lookup(o.Sym().Name).Def != nil {
+			if o := ir.Orig(l); o.Name() != nil && types.BuiltinPkg.Lookup(o.Sym().Name).Def != nil {
 				// be more specific when the non-function
 				// name matches a predeclared function
 				base.Errorf("cannot call non-function %L, declared at %s",
--- a/src/cmd/compile/internal/typecheck/iexport.go
+++ b/src/cmd/compile/internal/typecheck/iexport.go
@ -594,23 +594,15 @@ func (w *exportWriter) selector(s *types.Sym) {
 		base.Fatalf("missing currPkg")
 	}

-	// Method selectors are rewritten into method symbols (of the
-	// form T.M) during typechecking, but we want to write out
-	// just the bare method name.
-	name := s.Name
-	if i := strings.LastIndex(name, "."); i >= 0 {
-		name = name[i+1:]
-	} else {
 	pkg := w.currPkg
-		if types.IsExported(name) {
+	if types.IsExported(s.Name) {
 		pkg = types.LocalPkg
 	}
 	if s.Pkg != pkg {
 		base.Fatalf("package mismatch in selector: %v in package %q, but want %q", s, s.Pkg.Path, pkg.Path)
 	}
-	}

-	w.string(name)
+	w.string(s.Name)
 }

 func (w *exportWriter) typ(t *types.Type) {
@ -858,8 +850,6 @@ func intSize(typ *types.Type) (signed bool, maxBytes uint) {
 // according to the maximum number of bytes needed to encode a value
 // of type typ. As a special case, 8-bit types are always encoded as a
 // single byte.
-//
-// TODO(mdempsky): Is this level of complexity really worthwhile?
 func (w *exportWriter) mpint(x constant.Value, typ *types.Type) {
 	signed, maxBytes := intSize(typ)

@ -1145,7 +1135,7 @@ func (w *exportWriter) stmt(n ir.Node) {
 		n := n.(*ir.RangeStmt)
 		w.op(ir.ORANGE)
 		w.pos(n.Pos())
-		w.stmtList(n.Vars)
+		w.exprsOrNil(n.Key, n.Value)
 		w.expr(n.X)
 		w.stmtList(n.Body)

@ -1154,8 +1144,7 @@ func (w *exportWriter) stmt(n ir.Node) {
 		w.op(n.Op())
 		w.pos(n.Pos())
 		w.stmtList(n.Init())
-		w.exprsOrNil(nil, nil) // TODO(rsc): Delete (and fix importer).
-		w.caseList(n)
+		w.commList(n.Cases)

 	case ir.OSWITCH:
 		n := n.(*ir.SwitchStmt)
@ -1163,7 +1152,7 @@ func (w *exportWriter) stmt(n ir.Node) {
 		w.pos(n.Pos())
 		w.stmtList(n.Init())
 		w.exprsOrNil(n.Tag, nil)
-		w.caseList(n)
+		w.caseList(n.Cases, isNamedTypeSwitch(n.Tag))

 	// case OCASE:
 	//	handled by caseList
@ -1187,39 +1176,32 @@ func (w *exportWriter) stmt(n ir.Node) {
 	}
 }

-func isNamedTypeSwitch(n ir.Node) bool {
-	if n.Op() != ir.OSWITCH {
-		return false
-	}
-	sw := n.(*ir.SwitchStmt)
-	if sw.Tag == nil || sw.Tag.Op() != ir.OTYPESW {
-		return false
-	}
-	guard := sw.Tag.(*ir.TypeSwitchGuard)
-	return guard.Tag != nil
+func isNamedTypeSwitch(x ir.Node) bool {
+	guard, ok := x.(*ir.TypeSwitchGuard)
+	return ok && guard.Tag != nil
 }

-func (w *exportWriter) caseList(sw ir.Node) {
-	namedTypeSwitch := isNamedTypeSwitch(sw)
-
-	var cases []ir.Node
-	if sw.Op() == ir.OSWITCH {
-		cases = sw.(*ir.SwitchStmt).Cases
-	} else {
-		cases = sw.(*ir.SelectStmt).Cases
-	}
+func (w *exportWriter) caseList(cases []*ir.CaseClause, namedTypeSwitch bool) {
 	w.uint64(uint64(len(cases)))
 	for _, cas := range cases {
-		cas := cas.(*ir.CaseStmt)
 		w.pos(cas.Pos())
 		w.stmtList(cas.List)
 		if namedTypeSwitch {
-			w.localName(cas.Vars[0].(*ir.Name))
+			w.localName(cas.Var.(*ir.Name))
 		}
 		w.stmtList(cas.Body)
 	}
 }

+func (w *exportWriter) commList(cases []*ir.CommClause) {
+	w.uint64(uint64(len(cases)))
+	for _, cas := range cases {
+		w.pos(cas.Pos())
+		w.node(cas.Comm)
+		w.stmtList(cas.Body)
+	}
+}
+
 func (w *exportWriter) exprList(list ir.Nodes) {
 	for _, n := range list {
 		w.expr(n)
@ -1313,7 +1295,7 @@ func (w *exportWriter) expr(n ir.Node) {
 			s = n.Tag.Sym()
 		}
 		w.localIdent(s, 0) // declared pseudo-variable, if any
-		w.exprsOrNil(n.X, nil)
+		w.expr(n.X)

 	// case OTARRAY, OTMAP, OTCHAN, OTSTRUCT, OTINTER, OTFUNC:
 	// 	should have been resolved by typechecking - handled by default case
@ -1348,7 +1330,8 @@ func (w *exportWriter) expr(n ir.Node) {
 		n := n.(*ir.KeyExpr)
 		w.op(ir.OKEY)
 		w.pos(n.Pos())
-		w.exprsOrNil(n.Key, n.Value)
+		w.expr(n.Key)
+		w.expr(n.Value)

 	// case OSTRUCTKEY:
 	//	unreachable - handled in case OSTRUCTLIT by elemList
@ -1387,17 +1370,15 @@ func (w *exportWriter) expr(n ir.Node) {
 		w.op(ir.OSLICE)
 		w.pos(n.Pos())
 		w.expr(n.X)
-		low, high, _ := n.SliceBounds()
-		w.exprsOrNil(low, high)
+		w.exprsOrNil(n.Low, n.High)

 	case ir.OSLICE3, ir.OSLICE3ARR:
 		n := n.(*ir.SliceExpr)
 		w.op(ir.OSLICE3)
 		w.pos(n.Pos())
 		w.expr(n.X)
-		low, high, max := n.SliceBounds()
-		w.exprsOrNil(low, high)
-		w.expr(max)
+		w.exprsOrNil(n.Low, n.High)
+		w.expr(n.Max)

 	case ir.OCOPY, ir.OCOMPLEX:
 		// treated like other builtin calls (see e.g., OREAL)
@ -1412,8 +1393,8 @@ func (w *exportWriter) expr(n ir.Node) {
 		n := n.(*ir.ConvExpr)
 		w.op(ir.OCONV)
 		w.pos(n.Pos())
-		w.expr(n.X)
 		w.typ(n.Type())
+		w.expr(n.X)

 	case ir.OREAL, ir.OIMAG, ir.OCAP, ir.OCLOSE, ir.OLEN, ir.ONEW, ir.OPANIC:
 		n := n.(*ir.UnaryExpr)
@ -1544,6 +1525,7 @@ func (w *exportWriter) fieldList(list ir.Nodes) {
 	w.uint64(uint64(len(list)))
 	for _, n := range list {
 		n := n.(*ir.StructKeyExpr)
+		w.pos(n.Pos())
 		w.selector(n.Field)
 		w.expr(n.Value)
 	}
--- a/src/cmd/compile/internal/typecheck/iimport.go
+++ b/src/cmd/compile/internal/typecheck/iimport.go
@ -71,7 +71,12 @@ func ImportBody(fn *ir.Func) {
 		base.Fatalf("missing import reader for %v", fn)
 	}

+	if inimport {
+		base.Fatalf("recursive inimport")
+	}
+	inimport = true
 	r.doInline(fn)
+	inimport = false
 }

 func importReaderFor(sym *types.Sym, importers map[*types.Sym]iimporterAndOffset) *importReader {
@ -767,10 +772,10 @@ func (r *importReader) stmtList() []ir.Node {
 	return list
 }

-func (r *importReader) caseList(sw ir.Node) []ir.Node {
-	namedTypeSwitch := isNamedTypeSwitch(sw)
+func (r *importReader) caseList(switchExpr ir.Node) []*ir.CaseClause {
+	namedTypeSwitch := isNamedTypeSwitch(switchExpr)

-	cases := make([]ir.Node, r.uint64())
+	cases := make([]*ir.CaseClause, r.uint64())
 	for i := range cases {
 		cas := ir.NewCaseStmt(r.pos(), nil, nil)
 		cas.List.Set(r.stmtList())
@ -780,8 +785,8 @@ func (r *importReader) caseList(sw ir.Node) []ir.Node {
 			// Sym for diagnostics anyway.
 			caseVar := ir.NewNameAt(cas.Pos(), r.ident())
 			Declare(caseVar, DeclContext)
-			cas.Vars = []ir.Node{caseVar}
-			caseVar.Defn = sw.(*ir.SwitchStmt).Tag
+			cas.Var = caseVar
+			caseVar.Defn = switchExpr
 		}
 		cas.Body.Set(r.stmtList())
 		cases[i] = cas
@ -789,6 +794,14 @@ func (r *importReader) caseList(sw ir.Node) []ir.Node {
 	return cases
 }

+func (r *importReader) commList() []*ir.CommClause {
+	cases := make([]*ir.CommClause, r.uint64())
+	for i := range cases {
+		cases[i] = ir.NewCommStmt(r.pos(), r.node(), r.stmtList())
+	}
+	return cases
+}
+
 func (r *importReader) exprList() []ir.Node {
 	var list []ir.Node
 	for {
@ -821,7 +834,7 @@ func (r *importReader) node() ir.Node {
 		pos := r.pos()
 		typ := r.typ()

-		n := npos(pos, NodNil())
+		n := ir.NewNilExpr(pos)
 		n.SetType(typ)
 		return n

@ -829,7 +842,7 @@ func (r *importReader) node() ir.Node {
 		pos := r.pos()
 		typ := r.typ()

-		n := npos(pos, ir.NewLiteral(r.value(typ)))
+		n := ir.NewBasicLit(pos, r.value(typ))
 		n.SetType(typ)
 		return n

@ -851,8 +864,7 @@ func (r *importReader) node() ir.Node {
 		if s := r.ident(); s != nil {
 			tag = ir.NewIdent(pos, s)
 		}
-		expr, _ := r.exprsOrNil()
-		return ir.NewTypeSwitchGuard(pos, tag, expr)
+		return ir.NewTypeSwitchGuard(pos, tag, r.expr())

 	// case OTARRAY, OTMAP, OTCHAN, OTSTRUCT, OTINTER, OTFUNC:
 	//      unreachable - should have been resolved by typechecking
@ -864,26 +876,16 @@ func (r *importReader) node() ir.Node {
 	//	unreachable - mapped to case OADDR below by exporter

 	case ir.OSTRUCTLIT:
-		// TODO(mdempsky): Export position information for OSTRUCTKEY nodes.
-		savedlineno := base.Pos
-		base.Pos = r.pos()
-		n := ir.NewCompLitExpr(base.Pos, ir.OCOMPLIT, ir.TypeNode(r.typ()).(ir.Ntype), nil)
-		n.List.Set(r.elemList()) // special handling of field names
-		base.Pos = savedlineno
-		return n
+		return ir.NewCompLitExpr(r.pos(), ir.OCOMPLIT, ir.TypeNode(r.typ()), r.fieldList())

 	// case OARRAYLIT, OSLICELIT, OMAPLIT:
 	// 	unreachable - mapped to case OCOMPLIT below by exporter

 	case ir.OCOMPLIT:
-		n := ir.NewCompLitExpr(r.pos(), ir.OCOMPLIT, ir.TypeNode(r.typ()).(ir.Ntype), nil)
-		n.List.Set(r.exprList())
-		return n
+		return ir.NewCompLitExpr(r.pos(), ir.OCOMPLIT, ir.TypeNode(r.typ()), r.exprList())

 	case ir.OKEY:
-		pos := r.pos()
-		left, right := r.exprsOrNil()
-		return ir.NewKeyExpr(pos, left, right)
+		return ir.NewKeyExpr(r.pos(), r.expr(), r.expr())

 	// case OSTRUCTKEY:
 	//	unreachable - handled in case OSTRUCTLIT by elemList
@ -913,22 +915,19 @@ func (r *importReader) node() ir.Node {
 		return ir.NewIndexExpr(r.pos(), r.expr(), r.expr())

 	case ir.OSLICE, ir.OSLICE3:
-		n := ir.NewSliceExpr(r.pos(), op, r.expr())
+		pos, x := r.pos(), r.expr()
 		low, high := r.exprsOrNil()
 		var max ir.Node
-		if n.Op().IsSlice3() {
+		if op.IsSlice3() {
 			max = r.expr()
 		}
-		n.SetSliceBounds(low, high, max)
-		return n
+		return ir.NewSliceExpr(pos, op, x, low, high, max)

 	// case OCONV, OCONVIFACE, OCONVNOP, OBYTES2STR, ORUNES2STR, OSTR2BYTES, OSTR2RUNES, ORUNESTR:
 	// 	unreachable - mapped to OCONV case below by exporter

 	case ir.OCONV:
-		n := ir.NewConvExpr(r.pos(), ir.OCONV, nil, r.expr())
-		n.SetType(r.typ())
-		return n
+		return ir.NewConvExpr(r.pos(), ir.OCONV, r.typ(), r.expr())

 	case ir.OCOPY, ir.OCOMPLEX, ir.OREAL, ir.OIMAG, ir.OAPPEND, ir.OCAP, ir.OCLOSE, ir.ODELETE, ir.OLEN, ir.OMAKE, ir.ONEW, ir.OPANIC, ir.ORECOVER, ir.OPRINT, ir.OPRINTN:
 		n := builtinCall(r.pos(), op)
@ -942,10 +941,10 @@ func (r *importReader) node() ir.Node {
 	// 	unreachable - mapped to OCALL case below by exporter

 	case ir.OCALL:
-		n := ir.NewCallExpr(r.pos(), ir.OCALL, nil, nil)
-		n.PtrInit().Set(r.stmtList())
-		n.X = r.expr()
-		n.Args.Set(r.exprList())
+		pos := r.pos()
+		init := r.stmtList()
+		n := ir.NewCallExpr(pos, ir.OCALL, r.expr(), r.exprList())
+		n.PtrInit().Set(init)
 		n.IsDDD = r.bool()
 		return n

@ -979,7 +978,7 @@ func (r *importReader) node() ir.Node {
 	case ir.OADDSTR:
 		pos := r.pos()
 		list := r.exprList()
-		x := npos(pos, list[0])
+		x := list[0]
 		for _, y := range list[1:] {
 			x = ir.NewBinaryExpr(pos, ir.OADD, x, y)
 		}
@ -1006,9 +1005,7 @@ func (r *importReader) node() ir.Node {
 		return ir.NewAssignStmt(r.pos(), r.expr(), r.expr())

 	case ir.OASOP:
-		n := ir.NewAssignOpStmt(r.pos(), ir.OXXX, nil, nil)
-		n.AsOp = r.op()
-		n.X = r.expr()
+		n := ir.NewAssignOpStmt(r.pos(), r.op(), r.expr(), nil)
 		if !r.bool() {
 			n.Y = ir.NewInt(1)
 			n.IncDec = true
@ -1021,15 +1018,10 @@ func (r *importReader) node() ir.Node {
 	// 	unreachable - mapped to OAS2 case below by exporter

 	case ir.OAS2:
-		n := ir.NewAssignListStmt(r.pos(), ir.OAS2, nil, nil)
-		n.Lhs.Set(r.exprList())
-		n.Rhs.Set(r.exprList())
-		return n
+		return ir.NewAssignListStmt(r.pos(), ir.OAS2, r.exprList(), r.exprList())

 	case ir.ORETURN:
-		n := ir.NewReturnStmt(r.pos(), nil)
-		n.Results.Set(r.exprList())
-		return n
+		return ir.NewReturnStmt(r.pos(), r.exprList())

 	// case ORETJMP:
 	// 	unreachable - generated by compiler for trampolin routines (not exported)
@ -1038,57 +1030,50 @@ func (r *importReader) node() ir.Node {
 		return ir.NewGoDeferStmt(r.pos(), op, r.expr())

 	case ir.OIF:
-		n := ir.NewIfStmt(r.pos(), nil, nil, nil)
-		n.PtrInit().Set(r.stmtList())
-		n.Cond = r.expr()
-		n.Body.Set(r.stmtList())
-		n.Else.Set(r.stmtList())
+		pos, init := r.pos(), r.stmtList()
+		n := ir.NewIfStmt(pos, r.expr(), r.stmtList(), r.stmtList())
+		n.PtrInit().Set(init)
 		return n

 	case ir.OFOR:
-		n := ir.NewForStmt(r.pos(), nil, nil, nil, nil)
-		n.PtrInit().Set(r.stmtList())
-		left, right := r.exprsOrNil()
-		n.Cond = left
-		n.Post = right
-		n.Body.Set(r.stmtList())
+		pos, init := r.pos(), r.stmtList()
+		cond, post := r.exprsOrNil()
+		n := ir.NewForStmt(pos, nil, cond, post, r.stmtList())
+		n.PtrInit().Set(init)
 		return n

 	case ir.ORANGE:
-		n := ir.NewRangeStmt(r.pos(), nil, nil, nil)
-		n.Vars.Set(r.stmtList())
-		n.X = r.expr()
-		n.Body.Set(r.stmtList())
-		return n
+		pos := r.pos()
+		k, v := r.exprsOrNil()
+		return ir.NewRangeStmt(pos, k, v, r.expr(), r.stmtList())

 	case ir.OSELECT:
-		n := ir.NewSelectStmt(r.pos(), nil)
-		n.PtrInit().Set(r.stmtList())
-		r.exprsOrNil() // TODO(rsc): Delete (and fix exporter). These are always nil.
-		n.Cases.Set(r.caseList(n))
+		pos := r.pos()
+		init := r.stmtList()
+		n := ir.NewSelectStmt(pos, r.commList())
+		n.PtrInit().Set(init)
 		return n

 	case ir.OSWITCH:
-		n := ir.NewSwitchStmt(r.pos(), nil, nil)
-		n.PtrInit().Set(r.stmtList())
-		left, _ := r.exprsOrNil()
-		n.Tag = left
-		n.Cases.Set(r.caseList(n))
+		pos := r.pos()
+		init := r.stmtList()
+		x, _ := r.exprsOrNil()
+		n := ir.NewSwitchStmt(pos, x, r.caseList(x))
+		n.PtrInit().Set(init)
 		return n

 	// case OCASE:
 	//	handled by caseList

 	case ir.OFALL:
-		n := ir.NewBranchStmt(r.pos(), ir.OFALL, nil)
-		return n
+		return ir.NewBranchStmt(r.pos(), ir.OFALL, nil)

 	// case OEMPTY:
 	// 	unreachable - not emitted by exporter

 	case ir.OBREAK, ir.OCONTINUE, ir.OGOTO:
-		var sym *types.Sym
 		pos := r.pos()
+		var sym *types.Sym
 		if label := r.string(); label != "" {
 			sym = Lookup(label)
 		}
@ -1111,12 +1096,10 @@ func (r *importReader) op() ir.Op {
 	return ir.Op(r.uint64())
 }

-func (r *importReader) elemList() []ir.Node {
-	c := r.uint64()
-	list := make([]ir.Node, c)
+func (r *importReader) fieldList() []ir.Node {
+	list := make([]ir.Node, r.uint64())
 	for i := range list {
-		s := r.ident()
-		list[i] = ir.NewStructKeyExpr(base.Pos, s, r.expr())
+		list[i] = ir.NewStructKeyExpr(r.pos(), r.ident(), r.expr())
 	}
 	return list
 }
@ -1135,8 +1118,3 @@ func (r *importReader) exprsOrNil() (a, b ir.Node) {
 func builtinCall(pos src.XPos, op ir.Op) *ir.CallExpr {
 	return ir.NewCallExpr(pos, ir.OCALL, ir.NewIdent(base.Pos, types.BuiltinPkg.Lookup(ir.OpNames[op])), nil)
 }
-
-func npos(pos src.XPos, n ir.Node) ir.Node {
-	n.SetPos(pos)
-	return n
-}
--- a/src/cmd/compile/internal/typecheck/mkbuiltin.go
+++ b/src/cmd/compile/internal/typecheck/mkbuiltin.go
@ -36,8 +36,8 @@ func main() {
 	fmt.Fprintln(&b, "package typecheck")
 	fmt.Fprintln(&b)
 	fmt.Fprintln(&b, `import (`)
-	fmt.Fprintln(&b, `      "cmd/compile/internal/ir"`)
 	fmt.Fprintln(&b, `      "cmd/compile/internal/types"`)
+	fmt.Fprintln(&b, `      "cmd/internal/src"`)
 	fmt.Fprintln(&b, `)`)

 	mkbuiltin(&b, "runtime")
@ -169,7 +169,7 @@ func (i *typeInterner) mktype(t ast.Expr) string {
 		}
 		return fmt.Sprintf("types.NewChan(%s, %s)", i.subtype(t.Value), dir)
 	case *ast.FuncType:
-		return fmt.Sprintf("functype(nil, %s, %s)", i.fields(t.Params, false), i.fields(t.Results, false))
+		return fmt.Sprintf("types.NewSignature(types.NoPkg, nil, %s, %s)", i.fields(t.Params, false), i.fields(t.Results, false))
 	case *ast.InterfaceType:
 		if len(t.Methods.List) != 0 {
 			log.Fatal("non-empty interfaces unsupported")
@ -180,7 +180,7 @@ func (i *typeInterner) mktype(t ast.Expr) string {
 	case *ast.StarExpr:
 		return fmt.Sprintf("types.NewPtr(%s)", i.subtype(t.X))
 	case *ast.StructType:
-		return fmt.Sprintf("tostruct(%s)", i.fields(t.Fields, true))
+		return fmt.Sprintf("types.NewStruct(types.NoPkg, %s)", i.fields(t.Fields, true))

 	default:
 		log.Fatalf("unhandled type: %#v", t)
@ -196,18 +196,18 @@ func (i *typeInterner) fields(fl *ast.FieldList, keepNames bool) string {
 	for _, f := range fl.List {
 		typ := i.subtype(f.Type)
 		if len(f.Names) == 0 {
-			res = append(res, fmt.Sprintf("anonfield(%s)", typ))
+			res = append(res, fmt.Sprintf("types.NewField(src.NoXPos, nil, %s)", typ))
 		} else {
 			for _, name := range f.Names {
 				if keepNames {
-					res = append(res, fmt.Sprintf("namedfield(%q, %s)", name.Name, typ))
+					res = append(res, fmt.Sprintf("types.NewField(src.NoXPos, Lookup(%q), %s)", name.Name, typ))
 				} else {
-					res = append(res, fmt.Sprintf("anonfield(%s)", typ))
+					res = append(res, fmt.Sprintf("types.NewField(src.NoXPos, nil, %s)", typ))
 				}
 			}
 		}
 	}
-	return fmt.Sprintf("[]*ir.Field{%s}", strings.Join(res, ", "))
+	return fmt.Sprintf("[]*types.Field{%s}", strings.Join(res, ", "))
 }

 func intconst(e ast.Expr) int64 {
--- a/src/cmd/compile/internal/typecheck/stmt.go
+++ b/src/cmd/compile/internal/typecheck/stmt.go
@ -11,27 +11,29 @@ import (
 	"cmd/internal/src"
 )

+func RangeExprType(t *types.Type) *types.Type {
+	if t.IsPtr() && t.Elem().IsArray() {
+		return t.Elem()
+	}
+	return t
+}
+
 func typecheckrangeExpr(n *ir.RangeStmt) {
 	n.X = Expr(n.X)
-
-	t := n.X.Type()
-	if t == nil {
+	if n.X.Type() == nil {
 		return
 	}
+
+	t := RangeExprType(n.X.Type())
 	// delicate little dance.  see typecheckas2
-	ls := n.Vars
-	for i1, n1 := range ls {
-		if !ir.DeclaredBy(n1, n) {
-			ls[i1] = AssignExpr(ls[i1])
+	if n.Key != nil && !ir.DeclaredBy(n.Key, n) {
+		n.Key = AssignExpr(n.Key)
 	}
+	if n.Value != nil && !ir.DeclaredBy(n.Value, n) {
+		n.Value = AssignExpr(n.Value)
 	}

-	if t.IsPtr() && t.Elem().IsArray() {
-		t = t.Elem()
-	}
-	n.SetType(t)
-
-	var t1, t2 *types.Type
+	var tk, tv *types.Type
 	toomany := false
 	switch t.Kind() {
 	default:
@ -39,12 +41,12 @@ func typecheckrangeExpr(n *ir.RangeStmt) {
 		return

 	case types.TARRAY, types.TSLICE:
-		t1 = types.Types[types.TINT]
-		t2 = t.Elem()
+		tk = types.Types[types.TINT]
+		tv = t.Elem()

 	case types.TMAP:
-		t1 = t.Key()
-		t2 = t.Elem()
+		tk = t.Key()
+		tv = t.Elem()

 	case types.TCHAN:
 		if !t.ChanDir().CanRecv() {
@ -52,61 +54,35 @@ func typecheckrangeExpr(n *ir.RangeStmt) {
 			return
 		}

-		t1 = t.Elem()
-		t2 = nil
-		if len(n.Vars) == 2 {
+		tk = t.Elem()
+		tv = nil
+		if n.Value != nil {
 			toomany = true
 		}

 	case types.TSTRING:
-		t1 = types.Types[types.TINT]
-		t2 = types.RuneType
+		tk = types.Types[types.TINT]
+		tv = types.RuneType
 	}

-	if len(n.Vars) > 2 || toomany {
+	if toomany {
 		base.ErrorfAt(n.Pos(), "too many variables in range")
 	}

-	var v1, v2 ir.Node
-	if len(n.Vars) != 0 {
-		v1 = n.Vars[0]
-	}
-	if len(n.Vars) > 1 {
-		v2 = n.Vars[1]
-	}
-
-	// this is not only an optimization but also a requirement in the spec.
-	// "if the second iteration variable is the blank identifier, the range
-	// clause is equivalent to the same clause with only the first variable
-	// present."
-	if ir.IsBlank(v2) {
-		if v1 != nil {
-			n.Vars = []ir.Node{v1}
-		}
-		v2 = nil
-	}
-
-	if v1 != nil {
-		if ir.DeclaredBy(v1, n) {
-			v1.SetType(t1)
-		} else if v1.Type() != nil {
-			if op, why := assignop(t1, v1.Type()); op == ir.OXXX {
-				base.ErrorfAt(n.Pos(), "cannot assign type %v to %L in range%s", t1, v1, why)
+	do := func(nn ir.Node, t *types.Type) {
+		if nn != nil {
+			if ir.DeclaredBy(nn, n) {
+				nn.SetType(t)
+			} else if nn.Type() != nil {
+				if op, why := assignop(t, nn.Type()); op == ir.OXXX {
+					base.ErrorfAt(n.Pos(), "cannot assign type %v to %L in range%s", t, nn, why)
 				}
 			}
-		checkassign(n, v1)
-	}
-
-	if v2 != nil {
-		if ir.DeclaredBy(v2, n) {
-			v2.SetType(t2)
-		} else if v2.Type() != nil {
-			if op, why := assignop(t2, v2.Type()); op == ir.OXXX {
-				base.ErrorfAt(n.Pos(), "cannot assign type %v to %L in range%s", t2, v2, why)
+			checkassign(n, nn)
 		}
 	}
-		checkassign(n, v2)
-	}
+	do(n.Key, tk)
+	do(n.Value, tv)
 }

 // type check assignment.
@ -117,47 +93,16 @@ func tcAssign(n *ir.AssignStmt) {
 		defer tracePrint("typecheckas", n)(nil)
 	}

-	// delicate little dance.
-	// the definition of n may refer to this assignment
-	// as its definition, in which case it will call typecheckas.
-	// in that case, do not call typecheck back, or it will cycle.
-	// if the variable has a type (ntype) then typechecking
-	// will not look at defn, so it is okay (and desirable,
-	// so that the conversion below happens).
-	n.X = Resolve(n.X)
-
-	if !ir.DeclaredBy(n.X, n) || n.X.Name().Ntype != nil {
+	if n.Y == nil {
 		n.X = AssignExpr(n.X)
+		return
 	}

-	// Use ctxMultiOK so we can emit an "N variables but M values" error
-	// to be consistent with typecheckas2 (#26616).
-	n.Y = typecheck(n.Y, ctxExpr|ctxMultiOK)
-	checkassign(n, n.X)
-	if n.Y != nil && n.Y.Type() != nil {
-		if n.Y.Type().IsFuncArgStruct() {
-			base.Errorf("assignment mismatch: 1 variable but %v returns %d values", n.Y.(*ir.CallExpr).X, n.Y.Type().NumFields())
-			// Multi-value RHS isn't actually valid for OAS; nil out
-			// to indicate failed typechecking.
-			n.Y.SetType(nil)
-		} else if n.X.Type() != nil {
-			n.Y = AssignConv(n.Y, n.X.Type(), "assignment")
-		}
-	}
+	lhs, rhs := []ir.Node{n.X}, []ir.Node{n.Y}
+	assign(n, lhs, rhs)
+	n.X, n.Y = lhs[0], rhs[0]

-	if ir.DeclaredBy(n.X, n) && n.X.Name().Ntype == nil {
-		n.Y = DefaultLit(n.Y, nil)
-		n.X.SetType(n.Y.Type())
-	}
-
-	// second half of dance.
-	// now that right is done, typecheck the left
-	// just to get it over with.  see dance above.
-	n.SetTypecheck(1)
-
-	if n.X.Typecheck() == 0 {
-		n.X = AssignExpr(n.X)
-	}
+	// TODO(mdempsky): This seems out of place.
 	if !ir.IsBlank(n.X) {
 		types.CheckSize(n.X.Type()) // ensure width is calculated for backend
 	}
@ -168,132 +113,118 @@ func tcAssignList(n *ir.AssignListStmt) {
 		defer tracePrint("typecheckas2", n)(nil)
 	}

-	ls := n.Lhs
-	for i1, n1 := range ls {
+	assign(n, n.Lhs, n.Rhs)
+}
+
+func assign(stmt ir.Node, lhs, rhs []ir.Node) {
 	// delicate little dance.
-		n1 = Resolve(n1)
-		ls[i1] = n1
+	// the definition of lhs may refer to this assignment
+	// as its definition, in which case it will call typecheckas.
+	// in that case, do not call typecheck back, or it will cycle.
+	// if the variable has a type (ntype) then typechecking
+	// will not look at defn, so it is okay (and desirable,
+	// so that the conversion below happens).

-		if !ir.DeclaredBy(n1, n) || n1.Name().Ntype != nil {
-			ls[i1] = AssignExpr(ls[i1])
-		}
-	}
-
-	cl := len(n.Lhs)
-	cr := len(n.Rhs)
-	if cl > 1 && cr == 1 {
-		n.Rhs[0] = typecheck(n.Rhs[0], ctxExpr|ctxMultiOK)
+	checkLHS := func(i int, typ *types.Type) {
+		lhs[i] = Resolve(lhs[i])
+		if n := lhs[i]; typ != nil && ir.DeclaredBy(n, stmt) && n.Name().Ntype == nil {
+			if typ.Kind() != types.TNIL {
+				n.SetType(defaultType(typ))
 			} else {
-		Exprs(n.Rhs)
+				base.Errorf("use of untyped nil")
+			}
+		}
+		if lhs[i].Typecheck() == 0 {
+			lhs[i] = AssignExpr(lhs[i])
+		}
+		checkassign(stmt, lhs[i])
 	}
-	checkassignlist(n, n.Lhs)

-	var l ir.Node
-	var r ir.Node
-	if cl == cr {
-		// easy
-		ls := n.Lhs
-		rs := n.Rhs
-		for il, nl := range ls {
-			nr := rs[il]
-			if nl.Type() != nil && nr.Type() != nil {
-				rs[il] = AssignConv(nr, nl.Type(), "assignment")
-			}
-			if ir.DeclaredBy(nl, n) && nl.Name().Ntype == nil {
-				rs[il] = DefaultLit(rs[il], nil)
-				nl.SetType(rs[il].Type())
+	assignType := func(i int, typ *types.Type) {
+		checkLHS(i, typ)
+		if typ != nil {
+			checkassignto(typ, lhs[i])
 		}
 	}

-		goto out
-	}
-
-	l = n.Lhs[0]
-	r = n.Rhs[0]
-
-	// x,y,z = f()
-	if cr == 1 {
-		if r.Type() == nil {
-			goto out
-		}
-		switch r.Op() {
-		case ir.OCALLMETH, ir.OCALLINTER, ir.OCALLFUNC:
-			if !r.Type().IsFuncArgStruct() {
-				break
-			}
-			cr = r.Type().NumFields()
-			if cr != cl {
-				goto mismatch
-			}
-			r.(*ir.CallExpr).Use = ir.CallUseList
-			n.SetOp(ir.OAS2FUNC)
-			for i, l := range n.Lhs {
-				f := r.Type().Field(i)
-				if f.Type != nil && l.Type() != nil {
-					checkassignto(f.Type, l)
-				}
-				if ir.DeclaredBy(l, n) && l.Name().Ntype == nil {
-					l.SetType(f.Type)
-				}
-			}
-			goto out
+	cr := len(rhs)
+	if len(rhs) == 1 {
+		rhs[0] = typecheck(rhs[0], ctxExpr|ctxMultiOK)
+		if rtyp := rhs[0].Type(); rtyp != nil && rtyp.IsFuncArgStruct() {
+			cr = rtyp.NumFields()
 		}
+	} else {
+		Exprs(rhs)
 	}

 	// x, ok = y
-	if cl == 2 && cr == 1 {
-		if r.Type() == nil {
-			goto out
-		}
-		switch r.Op() {
-		case ir.OINDEXMAP, ir.ORECV, ir.ODOTTYPE:
+assignOK:
+	for len(lhs) == 2 && cr == 1 {
+		stmt := stmt.(*ir.AssignListStmt)
+		r := rhs[0]
+
 		switch r.Op() {
 		case ir.OINDEXMAP:
-				n.SetOp(ir.OAS2MAPR)
+			stmt.SetOp(ir.OAS2MAPR)
 		case ir.ORECV:
-				n.SetOp(ir.OAS2RECV)
+			stmt.SetOp(ir.OAS2RECV)
 		case ir.ODOTTYPE:
 			r := r.(*ir.TypeAssertExpr)
-				n.SetOp(ir.OAS2DOTTYPE)
+			stmt.SetOp(ir.OAS2DOTTYPE)
 			r.SetOp(ir.ODOTTYPE2)
-			}
-			if l.Type() != nil {
-				checkassignto(r.Type(), l)
-			}
-			if ir.DeclaredBy(l, n) {
-				l.SetType(r.Type())
-			}
-			l := n.Lhs[1]
-			if l.Type() != nil && !l.Type().IsBoolean() {
-				checkassignto(types.Types[types.TBOOL], l)
-			}
-			if ir.DeclaredBy(l, n) && l.Name().Ntype == nil {
-				l.SetType(types.Types[types.TBOOL])
-			}
-			goto out
-		}
-	}
-
-mismatch:
-	switch r.Op() {
 		default:
-		base.Errorf("assignment mismatch: %d variables but %d values", cl, cr)
-	case ir.OCALLFUNC, ir.OCALLMETH, ir.OCALLINTER:
-		r := r.(*ir.CallExpr)
-		base.Errorf("assignment mismatch: %d variables but %v returns %d values", cl, r.X, cr)
+			break assignOK
 		}

-	// second half of dance
-out:
-	n.SetTypecheck(1)
-	ls = n.Lhs
-	for i1, n1 := range ls {
-		if n1.Typecheck() == 0 {
-			ls[i1] = AssignExpr(ls[i1])
+		assignType(0, r.Type())
+		assignType(1, types.UntypedBool)
+		return
+	}
+
+	if len(lhs) != cr {
+		if r, ok := rhs[0].(*ir.CallExpr); ok && len(rhs) == 1 {
+			if r.Type() != nil {
+				base.ErrorfAt(stmt.Pos(), "assignment mismatch: %d variable%s but %v returns %d value%s", len(lhs), plural(len(lhs)), r.X, cr, plural(cr))
+			}
+		} else {
+			base.ErrorfAt(stmt.Pos(), "assignment mismatch: %d variable%s but %v value%s", len(lhs), plural(len(lhs)), len(rhs), plural(len(rhs)))
+		}
+
+		for i := range lhs {
+			checkLHS(i, nil)
+		}
+		return
+	}
+
+	// x,y,z = f()
+	if cr > len(rhs) {
+		stmt := stmt.(*ir.AssignListStmt)
+		stmt.SetOp(ir.OAS2FUNC)
+		r := rhs[0].(*ir.CallExpr)
+		r.Use = ir.CallUseList
+		rtyp := r.Type()
+
+		for i := range lhs {
+			assignType(i, rtyp.Field(i).Type)
+		}
+		return
+	}
+
+	for i, r := range rhs {
+		checkLHS(i, r.Type())
+		if lhs[i].Type() != nil {
+			rhs[i] = AssignConv(r, lhs[i].Type(), "assignment")
 		}
 	}
 }

+func plural(n int) string {
+	if n == 1 {
+		return ""
+	}
+	return "s"
+}
+
 // tcFor typechecks an OFOR node.
 func tcFor(n *ir.ForStmt) ir.Node {
 	Stmts(n.Init())
@ -399,11 +330,11 @@ func tcRange(n *ir.RangeStmt) {

 	// second half of dance, the first half being typecheckrangeExpr
 	n.SetTypecheck(1)
-	ls := n.Vars
-	for i1, n1 := range ls {
-		if n1.Typecheck() == 0 {
-			ls[i1] = AssignExpr(ls[i1])
+	if n.Key != nil && n.Key.Typecheck() == 0 {
+		n.Key = AssignExpr(n.Key)
 	}
+	if n.Value != nil && n.Value.Typecheck() == 0 {
+		n.Value = AssignExpr(n.Value)
 	}

 	decldepth++
@ -429,31 +360,23 @@ func tcReturn(n *ir.ReturnStmt) ir.Node {

 // select
 func tcSelect(sel *ir.SelectStmt) {
-	var def ir.Node
+	var def *ir.CommClause
 	lno := ir.SetPos(sel)
 	Stmts(sel.Init())
 	for _, ncase := range sel.Cases {
-		ncase := ncase.(*ir.CaseStmt)
-
-		if len(ncase.List) == 0 {
+		if ncase.Comm == nil {
 			// default
 			if def != nil {
 				base.ErrorfAt(ncase.Pos(), "multiple defaults in select (first at %v)", ir.Line(def))
 			} else {
 				def = ncase
 			}
-		} else if len(ncase.List) > 1 {
-			base.ErrorfAt(ncase.Pos(), "select cases cannot be lists")
 		} else {
-			ncase.List[0] = Stmt(ncase.List[0])
-			n := ncase.List[0]
+			n := Stmt(ncase.Comm)
 			ncase.Comm = n
-			ncase.List.Set(nil)
-			oselrecv2 := func(dst, recv ir.Node, colas bool) {
-				n := ir.NewAssignListStmt(n.Pos(), ir.OSELRECV2, nil, nil)
-				n.Lhs = []ir.Node{dst, ir.BlankNode}
-				n.Rhs = []ir.Node{recv}
-				n.Def = colas
+			oselrecv2 := func(dst, recv ir.Node, def bool) {
+				n := ir.NewAssignListStmt(n.Pos(), ir.OSELRECV2, []ir.Node{dst, ir.BlankNode}, []ir.Node{recv})
+				n.Def = def
 				n.SetTypecheck(1)
 				ncase.Comm = n
 			}
@ -577,7 +500,6 @@ func tcSwitchExpr(n *ir.SwitchStmt) {
 	var defCase ir.Node
 	var cs constSet
 	for _, ncase := range n.Cases {
-		ncase := ncase.(*ir.CaseStmt)
 		ls := ncase.List
 		if len(ls) == 0 { // default:
 			if defCase != nil {
@ -646,7 +568,6 @@ func tcSwitchType(n *ir.SwitchStmt) {
 	var defCase, nilCase ir.Node
 	var ts typeSet
 	for _, ncase := range n.Cases {
-		ncase := ncase.(*ir.CaseStmt)
 		ls := ncase.List
 		if len(ls) == 0 { // default:
 			if defCase != nil {
@ -694,7 +615,7 @@ func tcSwitchType(n *ir.SwitchStmt) {
 			ts.add(ncase.Pos(), n1.Type())
 		}

-		if len(ncase.Vars) != 0 {
+		if ncase.Var != nil {
 			// Assign the clause variable's type.
 			vt := t
 			if len(ls) == 1 {
@ -707,7 +628,7 @@ func tcSwitchType(n *ir.SwitchStmt) {
 				}
 			}

-			nvar := ncase.Vars[0]
+			nvar := ncase.Var
 			nvar.SetType(vt)
 			if vt != nil {
 				nvar = AssignExpr(nvar)
@ -716,7 +637,7 @@ func tcSwitchType(n *ir.SwitchStmt) {
 				nvar.SetTypecheck(1)
 				nvar.SetWalkdef(1)
 			}
-			ncase.Vars[0] = nvar
+			ncase.Var = nvar
 		}

 		Stmts(ncase.Body)
--- a/src/cmd/compile/internal/typecheck/type.go
+++ b/src/cmd/compile/internal/typecheck/type.go
@ -73,13 +73,42 @@ func tcChanType(n *ir.ChanType) ir.Node {

 // tcFuncType typechecks an OTFUNC node.
 func tcFuncType(n *ir.FuncType) ir.Node {
-	n.SetOTYPE(NewFuncType(n.Recv, n.Params, n.Results))
+	misc := func(f *types.Field, nf *ir.Field) {
+		f.SetIsDDD(nf.IsDDD)
+		if nf.Decl != nil {
+			nf.Decl.SetType(f.Type)
+			f.Nname = nf.Decl
+		}
+	}
+
+	lno := base.Pos
+
+	var recv *types.Field
+	if n.Recv != nil {
+		recv = tcField(n.Recv, misc)
+	}
+
+	t := types.NewSignature(types.LocalPkg, recv, tcFields(n.Params, misc), tcFields(n.Results, misc))
+	checkdupfields("argument", t.Recvs().FieldSlice(), t.Params().FieldSlice(), t.Results().FieldSlice())
+
+	base.Pos = lno
+
+	n.SetOTYPE(t)
 	return n
 }

 // tcInterfaceType typechecks an OTINTER node.
 func tcInterfaceType(n *ir.InterfaceType) ir.Node {
-	n.SetOTYPE(tointerface(n.Methods))
+	if len(n.Methods) == 0 {
+		n.SetOTYPE(types.Types[types.TINTER])
+		return n
+	}
+	
+	lno := base.Pos
+	methods := tcFields(n.Methods, nil)
+	base.Pos = lno
+
+	n.SetOTYPE(types.NewInterface(types.LocalPkg, methods))
 	return n
 }

@ -117,6 +146,43 @@ func tcSliceType(n *ir.SliceType) ir.Node {

 // tcStructType typechecks an OTSTRUCT node.
 func tcStructType(n *ir.StructType) ir.Node {
-	n.SetOTYPE(NewStructType(n.Fields))
+	lno := base.Pos
+
+	fields := tcFields(n.Fields, func(f *types.Field, nf *ir.Field) {
+		if nf.Embedded {
+			checkembeddedtype(f.Type)
+			f.Embedded = 1
+		}
+		f.Note = nf.Note
+	})
+	checkdupfields("field", fields)
+
+	base.Pos = lno
+	n.SetOTYPE(types.NewStruct(types.LocalPkg, fields))
 	return n
 }
+
+// tcField typechecks a generic Field.
+// misc can be provided to handle specialized typechecking.
+func tcField(n *ir.Field, misc func(*types.Field, *ir.Field)) *types.Field {
+	base.Pos = n.Pos
+	if n.Ntype != nil {
+		n.Type = typecheckNtype(n.Ntype).Type()
+		n.Ntype = nil
+	}
+	f := types.NewField(n.Pos, n.Sym, n.Type)
+	if misc != nil {
+		misc(f, n)
+	}
+	return f
+}
+
+// tcFields typechecks a slice of generic Fields.
+// misc can be provided to handle specialized typechecking.
+func tcFields(l []*ir.Field, misc func(*types.Field, *ir.Field)) []*types.Field {
+	fields := make([]*types.Field, len(l))
+	for i, n := range l {
+		fields[i] = tcField(n, misc)
+	}
+	return fields
+}
--- a/src/cmd/compile/internal/typecheck/typecheck.go
+++ b/src/cmd/compile/internal/typecheck/typecheck.go
@ -251,13 +251,7 @@ func Resolve(n ir.Node) (res ir.Node) {
 			}
 		}

-		if inimport {
-			base.Fatalf("recursive inimport")
-		}
-		inimport = true
-		n = expandDecl(n)
-		inimport = false
-		return n
+		return expandDecl(n)
 	}

 	r := ir.AsNode(n.Sym().Def)
@ -1232,7 +1226,7 @@ func lookdot(n *ir.SelectorExpr, t *types.Type, dostrcmp int) *types.Field {
 		if f1.Offset == types.BADWIDTH {
 			base.Fatalf("lookdot badwidth %v %p", f1, f1)
 		}
-		n.Offset = f1.Offset
+		n.Selection = f1
 		n.SetType(f1.Type)
 		if t.IsInterface() {
 			if n.X.Type().IsPtr() {
@ -1243,7 +1237,6 @@ func lookdot(n *ir.SelectorExpr, t *types.Type, dostrcmp int) *types.Field {

 			n.SetOp(ir.ODOTINTER)
 		}
-		n.Selection = f1
 		return f1
 	}

@ -1298,11 +1291,9 @@ func lookdot(n *ir.SelectorExpr, t *types.Type, dostrcmp int) *types.Field {
 			return nil
 		}

-		n.Sel = ir.MethodSym(n.X.Type(), f2.Sym)
-		n.Offset = f2.Offset
+		n.Selection = f2
 		n.SetType(f2.Type)
 		n.SetOp(ir.ODOTMETH)
-		n.Selection = f2

 		return f2
 	}
@ -1638,7 +1629,7 @@ func nonexported(sym *types.Sym) bool {
 }

 func checklvalue(n ir.Node, verb string) {
-	if !ir.IsAssignable(n) {
+	if !ir.IsAddressable(n) {
 		base.Errorf("cannot %s %v", verb, n)
 	}
 }
@ -1656,7 +1647,7 @@ func checkassign(stmt ir.Node, n ir.Node) {
 		}
 	}

-	if ir.IsAssignable(n) {
+	if ir.IsAddressable(n) {
 		return
 	}
 	if n.Op() == ir.OINDEXMAP {
@ -1690,6 +1681,11 @@ func checkassignlist(stmt ir.Node, l ir.Nodes) {
 }

 func checkassignto(src *types.Type, dst ir.Node) {
+	// TODO(mdempsky): Handle all untyped types correctly.
+	if src == types.UntypedBool && dst.Type().IsBoolean() {
+		return
+	}
+
 	if op, why := assignop(src, dst.Type()); op == ir.OXXX {
 		base.Errorf("cannot assign %v to %L in multiple assignment%s", src, dst, why)
 		return
@ -2101,7 +2097,6 @@ func isTermNode(n ir.Node) bool {
 		}
 		def := false
 		for _, cas := range n.Cases {
-			cas := cas.(*ir.CaseStmt)
 			if !isTermNodes(cas.Body) {
 				return false
 			}
@ -2117,7 +2112,6 @@ func isTermNode(n ir.Node) bool {
 			return false
 		}
 		for _, cas := range n.Cases {
-			cas := cas.(*ir.CaseStmt)
 			if !isTermNodes(cas.Body) {
 				return false
 			}
@ -2216,9 +2210,6 @@ func deadcodeslice(nn *ir.Nodes) {
 		case ir.OBLOCK:
 			n := n.(*ir.BlockStmt)
 			deadcodeslice(&n.List)
-		case ir.OCASE:
-			n := n.(*ir.CaseStmt)
-			deadcodeslice(&n.Body)
 		case ir.OFOR:
 			n := n.(*ir.ForStmt)
 			deadcodeslice(&n.Body)
@ -2231,10 +2222,14 @@ func deadcodeslice(nn *ir.Nodes) {
 			deadcodeslice(&n.Body)
 		case ir.OSELECT:
 			n := n.(*ir.SelectStmt)
-			deadcodeslice(&n.Cases)
+			for _, cas := range n.Cases {
+				deadcodeslice(&cas.Body)
+			}
 		case ir.OSWITCH:
 			n := n.(*ir.SwitchStmt)
-			deadcodeslice(&n.Cases)
+			for _, cas := range n.Cases {
+				deadcodeslice(&cas.Body)
+			}
 		}

 		if cut {
--- a/src/cmd/compile/internal/types/alg.go
+++ b/src/cmd/compile/internal/types/alg.go
@ -10,7 +10,7 @@ import "cmd/compile/internal/base"
 // hashing a Type.
 type AlgKind int

-//go:generate stringer -type AlgKind -trimprefix A
+//go:generate stringer -type AlgKind -trimprefix A alg.go

 const (
 	// These values are known by runtime.
--- a/src/cmd/compile/internal/types/algkind_string.go
+++ b/src/cmd/compile/internal/types/algkind_string.go
@ -1,4 +1,4 @@
-// Code generated by "stringer -type AlgKind -trimprefix A"; DO NOT EDIT.
+// Code generated by "stringer -type AlgKind -trimprefix A alg.go"; DO NOT EDIT.

 package types

--- a/src/cmd/compile/internal/types/fmt.go
+++ b/src/cmd/compile/internal/types/fmt.go
@ -180,15 +180,6 @@ func symfmt(b *bytes.Buffer, s *Sym, verb rune, mode fmtMode) {
 	b.WriteString(s.Name)
 }

-func SymMethodName(s *Sym) string {
-	// Skip leading "type." in method name
-	name := s.Name
-	if i := strings.LastIndex(name, "."); i >= 0 {
-		name = name[i+1:]
-	}
-	return name
-}
-
 // Type

 var BasicTypeNames = []string{
@ -595,7 +586,10 @@ func fldconv(b *bytes.Buffer, f *Field, verb rune, mode fmtMode, visited map[*Ty
 			if funarg != FunargNone {
 				name = fmt.Sprint(f.Nname)
 			} else if verb == 'L' {
-				name = SymMethodName(s)
+				name = s.Name
+				if name == ".F" {
+					name = "F" // Hack for toolstash -cmp.
+				}
 				if !IsExported(name) && mode != fmtTypeIDName {
 					name = sconv(s, 0, mode) // qualify non-exported names (used on structs, not on funarg)
 				}
--- a/src/cmd/compile/internal/types/goversion.go
+++ b/src/cmd/compile/internal/types/goversion.go
@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.

-//go:generate go run mkbuiltin.go
-
 package types

 import (
--- a/src/cmd/compile/internal/types/etype_string.go
+++ b/src/cmd/compile/internal/types/etype_string.go
@ -1,4 +1,4 @@
-// Code generated by "stringer -type EType -trimprefix T"; DO NOT EDIT.
+// Code generated by "stringer -type Kind -trimprefix T type.go"; DO NOT EDIT.

 package types

@ -48,13 +48,13 @@ func _() {
 	_ = x[NTYPE-37]
 }

-const _EType_name = "xxxINT8UINT8INT16UINT16INT32UINT32INT64UINT64INTUINTUINTPTRCOMPLEX64COMPLEX128FLOAT32FLOAT64BOOLPTRFUNCSLICEARRAYSTRUCTCHANMAPINTERFORWANYSTRINGUNSAFEPTRIDEALNILBLANKFUNCARGSCHANARGSSSATUPLERESULTSNTYPE"
+const _Kind_name = "xxxINT8UINT8INT16UINT16INT32UINT32INT64UINT64INTUINTUINTPTRCOMPLEX64COMPLEX128FLOAT32FLOAT64BOOLPTRFUNCSLICEARRAYSTRUCTCHANMAPINTERFORWANYSTRINGUNSAFEPTRIDEALNILBLANKFUNCARGSCHANARGSSSATUPLERESULTSNTYPE"

-var _EType_index = [...]uint8{0, 3, 7, 12, 17, 23, 28, 34, 39, 45, 48, 52, 59, 68, 78, 85, 92, 96, 99, 103, 108, 113, 119, 123, 126, 131, 135, 138, 144, 153, 158, 161, 166, 174, 182, 185, 190, 197, 202}
+var _Kind_index = [...]uint8{0, 3, 7, 12, 17, 23, 28, 34, 39, 45, 48, 52, 59, 68, 78, 85, 92, 96, 99, 103, 108, 113, 119, 123, 126, 131, 135, 138, 144, 153, 158, 161, 166, 174, 182, 185, 190, 197, 202}

 func (i Kind) String() string {
-	if i >= Kind(len(_EType_index)-1) {
-		return "EType(" + strconv.FormatInt(int64(i), 10) + ")"
+	if i >= Kind(len(_Kind_index)-1) {
+		return "Kind(" + strconv.FormatInt(int64(i), 10) + ")"
 	}
-	return _EType_name[_EType_index[i]:_EType_index[i+1]]
+	return _Kind_name[_Kind_index[i]:_Kind_index[i+1]]
 }
--- a/src/cmd/compile/internal/types/type.go
+++ b/src/cmd/compile/internal/types/type.go
@ -33,9 +33,9 @@ type VarObject interface {
 	RecordFrameOffset(int64) // save frame offset
 }

-//go:generate stringer -type EType -trimprefix T
+//go:generate stringer -type Kind -trimprefix T type.go

-// EType describes a kind of type.
+// Kind describes a kind of type.
 type Kind uint8

 const (
--- a/src/cmd/compile/internal/walk/assign.go
+++ b/src/cmd/compile/internal/walk/assign.go
@ -297,54 +297,6 @@ func fncall(l ir.Node, rt *types.Type) bool {
 	return true
 }

-func ascompatee(op ir.Op, nl, nr []ir.Node, init *ir.Nodes) []ir.Node {
-	// check assign expression list to
-	// an expression list. called in
-	//	expr-list = expr-list
-
-	// ensure order of evaluation for function calls
-	for i := range nl {
-		nl[i] = safeExpr(nl[i], init)
-	}
-	for i1 := range nr {
-		nr[i1] = safeExpr(nr[i1], init)
-	}
-
-	var nn []*ir.AssignStmt
-	i := 0
-	for ; i < len(nl); i++ {
-		if i >= len(nr) {
-			break
-		}
-		// Do not generate 'x = x' during return. See issue 4014.
-		if op == ir.ORETURN && ir.SameSafeExpr(nl[i], nr[i]) {
-			continue
-		}
-		nn = append(nn, ascompatee1(nl[i], nr[i], init))
-	}
-
-	// cannot happen: caller checked that lists had same length
-	if i < len(nl) || i < len(nr) {
-		var nln, nrn ir.Nodes
-		nln.Set(nl)
-		nrn.Set(nr)
-		base.Fatalf("error in shape across %+v %v %+v / %d %d [%s]", nln, op, nrn, len(nl), len(nr), ir.FuncName(ir.CurFunc))
-	}
-	return reorder3(nn)
-}
-
-func ascompatee1(l ir.Node, r ir.Node, init *ir.Nodes) *ir.AssignStmt {
-	// convas will turn map assigns into function calls,
-	// making it impossible for reorder3 to work.
-	n := ir.NewAssignStmt(base.Pos, l, r)
-
-	if l.Op() == ir.OINDEXMAP {
-		return n
-	}
-
-	return convas(n, init)
-}
-
 // check assign type list to
 // an expression list. called in
 //	expr-list = func()
@ -387,39 +339,79 @@ func ascompatet(nl ir.Nodes, nr *types.Type) []ir.Node {
 	return append(nn, mm...)
 }

-// reorder3
-// from ascompatee
-//	a,b = c,d
-// simultaneous assignment. there cannot
-// be later use of an earlier lvalue.
-//
-// function calls have been removed.
-func reorder3(all []*ir.AssignStmt) []ir.Node {
+// check assign expression list to
+// an expression list. called in
+//	expr-list = expr-list
+func ascompatee(op ir.Op, nl, nr []ir.Node, init *ir.Nodes) []ir.Node {
+	// cannot happen: should have been rejected during type checking
+	if len(nl) != len(nr) {
+		base.Fatalf("assignment operands mismatch: %+v / %+v", ir.Nodes(nl), ir.Nodes(nr))
+	}
+
+	// ensure order of evaluation for function calls
+	for i := range nl {
+		nl[i] = safeExpr(nl[i], init)
+	}
+	for i := range nr {
+		nr[i] = safeExpr(nr[i], init)
+	}
+
+	var assigned ir.NameSet
+	var memWrite bool
+
+	// affected reports whether expression n could be affected by
+	// the assignments applied so far.
+	affected := func(n ir.Node) bool {
+		return ir.Any(n, func(n ir.Node) bool {
+			if n.Op() == ir.ONAME && assigned.Has(n.(*ir.Name)) {
+				return true
+			}
+			if memWrite && readsMemory(n) {
+				return true
+			}
+			return false
+		})
+	}
+
 	// If a needed expression may be affected by an
 	// earlier assignment, make an early copy of that
 	// expression and use the copy instead.
 	var early []ir.Node
+	save := func(np *ir.Node) {
+		if n := *np; affected(n) {
+			tmp := ir.Node(typecheck.Temp(n.Type()))
+			as := typecheck.Stmt(ir.NewAssignStmt(base.Pos, tmp, n))
+			early = append(early, as)
+			*np = tmp
+		}
+	}

-	var mapinit ir.Nodes
-	for i, n := range all {
-		l := n.X
+	var late []ir.Node
+	for i, l := range nl {
+		r := nr[i]
+
+		// Do not generate 'x = x' during return. See issue 4014.
+		if op == ir.ORETURN && ir.SameSafeExpr(l, r) {
+			continue
+		}
+
+		as := ir.NewAssignStmt(base.Pos, l, r)

 		// Save subexpressions needed on left side.
 		// Drill through non-dereferences.
 		for {
-			switch ll := l; ll.Op() {
-			case ir.ODOT:
-				ll := ll.(*ir.SelectorExpr)
-				l = ll.X
-				continue
-			case ir.OPAREN:
-				ll := ll.(*ir.ParenExpr)
-				l = ll.X
-				continue
-			case ir.OINDEX:
-				ll := ll.(*ir.IndexExpr)
+			switch ll := l.(type) {
+			case *ir.IndexExpr:
 				if ll.X.Type().IsArray() {
-					ll.Index = reorder3save(ll.Index, all, i, &early)
+					save(&ll.Index)
+					l = ll.X
+					continue
+				}
+			case *ir.ParenExpr:
+				l = ll.X
+				continue
+			case *ir.SelectorExpr:
+				if ll.Op() == ir.ODOT {
 					l = ll.X
 					continue
 				}
@ -427,143 +419,50 @@ func reorder3(all []*ir.AssignStmt) []ir.Node {
 			break
 		}

+		var name *ir.Name
 		switch l.Op() {
 		default:
-			base.Fatalf("reorder3 unexpected lvalue %v", l.Op())
-
+			base.Fatalf("unexpected lvalue %v", l.Op())
 		case ir.ONAME:
-			break
-
+			name = l.(*ir.Name)
 		case ir.OINDEX, ir.OINDEXMAP:
 			l := l.(*ir.IndexExpr)
-			l.X = reorder3save(l.X, all, i, &early)
-			l.Index = reorder3save(l.Index, all, i, &early)
-			if l.Op() == ir.OINDEXMAP {
-				all[i] = convas(all[i], &mapinit)
-			}
-
+			save(&l.X)
+			save(&l.Index)
 		case ir.ODEREF:
 			l := l.(*ir.StarExpr)
-			l.X = reorder3save(l.X, all, i, &early)
+			save(&l.X)
 		case ir.ODOTPTR:
 			l := l.(*ir.SelectorExpr)
-			l.X = reorder3save(l.X, all, i, &early)
+			save(&l.X)
 		}

 		// Save expression on right side.
-		all[i].Y = reorder3save(all[i].Y, all, i, &early)
+		save(&as.Y)
+
+		late = append(late, convas(as, init))
+
+		if name == nil || name.Addrtaken() || name.Class_ == ir.PEXTERN || name.Class_ == ir.PAUTOHEAP {
+			memWrite = true
+			continue
 		}
-
-	early = append(mapinit, early...)
-	for _, as := range all {
-		early = append(early, as)
-	}
-	return early
-}
-
-// if the evaluation of *np would be affected by the
-// assignments in all up to but not including the ith assignment,
-// copy into a temporary during *early and
-// replace *np with that temp.
-// The result of reorder3save MUST be assigned back to n, e.g.
-// 	n.Left = reorder3save(n.Left, all, i, early)
-func reorder3save(n ir.Node, all []*ir.AssignStmt, i int, early *[]ir.Node) ir.Node {
-	if !aliased(n, all[:i]) {
-		return n
-	}
-
-	q := ir.Node(typecheck.Temp(n.Type()))
-	as := typecheck.Stmt(ir.NewAssignStmt(base.Pos, q, n))
-	*early = append(*early, as)
-	return q
-}
-
-// Is it possible that the computation of r might be
-// affected by assignments in all?
-func aliased(r ir.Node, all []*ir.AssignStmt) bool {
-	if r == nil {
-		return false
-	}
-
-	// Treat all fields of a struct as referring to the whole struct.
-	// We could do better but we would have to keep track of the fields.
-	for r.Op() == ir.ODOT {
-		r = r.(*ir.SelectorExpr).X
-	}
-
-	// Look for obvious aliasing: a variable being assigned
-	// during the all list and appearing in n.
-	// Also record whether there are any writes to addressable
-	// memory (either main memory or variables whose addresses
-	// have been taken).
-	memwrite := false
-	for _, as := range all {
+		if ir.IsBlank(name) {
 			// We can ignore assignments to blank.
-		if ir.IsBlank(as.X) {
 			continue
 		}
-
-		lv := ir.OuterValue(as.X)
-		if lv.Op() != ir.ONAME {
-			memwrite = true
-			continue
-		}
-		l := lv.(*ir.Name)
-
-		switch l.Class_ {
-		default:
-			base.Fatalf("unexpected class: %v, %v", l, l.Class_)
-
-		case ir.PAUTOHEAP, ir.PEXTERN:
-			memwrite = true
-			continue
-
-		case ir.PAUTO, ir.PPARAM, ir.PPARAMOUT:
-			if l.Name().Addrtaken() {
-				memwrite = true
-				continue
+		assigned.Add(name)
 	}

-			if refersToName(l, r) {
-				// Direct hit: l appears in r.
-				return true
-			}
-		}
-	}
-
-	// The variables being written do not appear in r.
-	// However, r might refer to computed addresses
-	// that are being written.
-
-	// If no computed addresses are affected by the writes, no aliasing.
-	if !memwrite {
-		return false
-	}
-
-	// If r does not refer to any variables whose addresses have been taken,
-	// then the only possible writes to r would be directly to the variables,
-	// and we checked those above, so no aliasing problems.
-	if !anyAddrTaken(r) {
-		return false
-	}
-
-	// Otherwise, both the writes and r refer to computed memory addresses.
-	// Assume that they might conflict.
-	return true
+	return append(early, late...)
 }

-// anyAddrTaken reports whether the evaluation n,
-// which appears on the left side of an assignment,
-// may refer to variables whose addresses have been taken.
-func anyAddrTaken(n ir.Node) bool {
-	return ir.Any(n, func(n ir.Node) bool {
+// readsMemory reports whether the evaluation n directly reads from
+// memory that might be written to indirectly.
+func readsMemory(n ir.Node) bool {
 	switch n.Op() {
 	case ir.ONAME:
 		n := n.(*ir.Name)
-			return n.Class_ == ir.PEXTERN || n.Class_ == ir.PAUTOHEAP || n.Name().Addrtaken()
-
-		case ir.ODOT: // but not ODOTPTR - should have been handled in aliased.
-			base.Fatalf("anyAddrTaken unexpected ODOT")
+		return n.Class_ == ir.PEXTERN || n.Class_ == ir.PAUTOHEAP || n.Addrtaken()

 	case ir.OADD,
 		ir.OAND,
@ -574,6 +473,7 @@ func anyAddrTaken(n ir.Node) bool {
 		ir.OCONVIFACE,
 		ir.OCONVNOP,
 		ir.ODIV,
+		ir.ODOT,
 		ir.ODOTTYPE,
 		ir.OLITERAL,
 		ir.OLSH,
@ -590,65 +490,9 @@ func anyAddrTaken(n ir.Node) bool {
 		ir.OXOR:
 		return false
 	}
+
 	// Be conservative.
 	return true
-	})
-}
-
-// refersToName reports whether r refers to name.
-func refersToName(name *ir.Name, r ir.Node) bool {
-	return ir.Any(r, func(r ir.Node) bool {
-		return r.Op() == ir.ONAME && r == name
-	})
-}
-
-// refersToCommonName reports whether any name
-// appears in common between l and r.
-// This is called from sinit.go.
-func refersToCommonName(l ir.Node, r ir.Node) bool {
-	if l == nil || r == nil {
-		return false
-	}
-
-	// This could be written elegantly as a Find nested inside a Find:
-	//
-	//	found := ir.Find(l, func(l ir.Node) interface{} {
-	//		if l.Op() == ir.ONAME {
-	//			return ir.Find(r, func(r ir.Node) interface{} {
-	//				if r.Op() == ir.ONAME && l.Name() == r.Name() {
-	//					return r
-	//				}
-	//				return nil
-	//			})
-	//		}
-	//		return nil
-	//	})
-	//	return found != nil
-	//
-	// But that would allocate a new closure for the inner Find
-	// for each name found on the left side.
-	// It may not matter at all, but the below way of writing it
-	// only allocates two closures, not O(|L|) closures.
-
-	var doL, doR func(ir.Node) error
-	var targetL *ir.Name
-	doR = func(r ir.Node) error {
-		if r.Op() == ir.ONAME && r.Name() == targetL {
-			return stop
-		}
-		return ir.DoChildren(r, doR)
-	}
-	doL = func(l ir.Node) error {
-		if l.Op() == ir.ONAME {
-			l := l.(*ir.Name)
-			targetL = l.Name()
-			if doR(r) == stop {
-				return stop
-			}
-		}
-		return ir.DoChildren(l, doL)
-	}
-	return doL(l) == stop
 }

 // expand append(l1, l2...) to
@ -700,17 +544,15 @@ func appendSlice(n *ir.CallExpr, init *ir.Nodes) ir.Node {
 	nodes.Append(nif)

 	// s = s[:n]
-	nt := ir.NewSliceExpr(base.Pos, ir.OSLICE, s)
-	nt.SetSliceBounds(nil, nn, nil)
+	nt := ir.NewSliceExpr(base.Pos, ir.OSLICE, s, nil, nn, nil)
 	nt.SetBounded(true)
 	nodes.Append(ir.NewAssignStmt(base.Pos, s, nt))

 	var ncopy ir.Node
 	if elemtype.HasPointers() {
 		// copy(s[len(l1):], l2)
-		slice := ir.NewSliceExpr(base.Pos, ir.OSLICE, s)
+		slice := ir.NewSliceExpr(base.Pos, ir.OSLICE, s, ir.NewUnaryExpr(base.Pos, ir.OLEN, l1), nil, nil)
 		slice.SetType(s.Type())
-		slice.SetSliceBounds(ir.NewUnaryExpr(base.Pos, ir.OLEN, l1), nil, nil)

 		ir.CurFunc.SetWBPos(n.Pos())

@ -724,9 +566,8 @@ func appendSlice(n *ir.CallExpr, init *ir.Nodes) ir.Node {
 		// rely on runtime to instrument:
 		//  copy(s[len(l1):], l2)
 		// l2 can be a slice or string.
-		slice := ir.NewSliceExpr(base.Pos, ir.OSLICE, s)
+		slice := ir.NewSliceExpr(base.Pos, ir.OSLICE, s, ir.NewUnaryExpr(base.Pos, ir.OLEN, l1), nil, nil)
 		slice.SetType(s.Type())
-		slice.SetSliceBounds(ir.NewUnaryExpr(base.Pos, ir.OLEN, l1), nil, nil)

 		ptr1, len1 := backingArrayPtrLen(cheapExpr(slice, &nodes))
 		ptr2, len2 := backingArrayPtrLen(l2)
@ -870,8 +711,7 @@ func extendSlice(n *ir.CallExpr, init *ir.Nodes) ir.Node {
 	nodes = append(nodes, nif)

 	// s = s[:n]
-	nt := ir.NewSliceExpr(base.Pos, ir.OSLICE, s)
-	nt.SetSliceBounds(nil, nn, nil)
+	nt := ir.NewSliceExpr(base.Pos, ir.OSLICE, s, nil, nn, nil)
 	nt.SetBounded(true)
 	nodes = append(nodes, ir.NewAssignStmt(base.Pos, s, nt))

--- a/src/cmd/compile/internal/walk/builtin.go
+++ b/src/cmd/compile/internal/walk/builtin.go
@ -95,8 +95,7 @@ func walkAppend(n *ir.CallExpr, init *ir.Nodes, dst ir.Node) ir.Node {
 	nn := typecheck.Temp(types.Types[types.TINT])
 	l = append(l, ir.NewAssignStmt(base.Pos, nn, ir.NewUnaryExpr(base.Pos, ir.OLEN, ns))) // n = len(s)

-	slice := ir.NewSliceExpr(base.Pos, ir.OSLICE, ns) // ...s[:n+argc]
-	slice.SetSliceBounds(nil, ir.NewBinaryExpr(base.Pos, ir.OADD, nn, na), nil)
+	slice := ir.NewSliceExpr(base.Pos, ir.OSLICE, ns, nil, ir.NewBinaryExpr(base.Pos, ir.OADD, nn, na), nil) // ...s[:n+argc]
 	slice.SetBounded(true)
 	l = append(l, ir.NewAssignStmt(base.Pos, ns, slice)) // s = s[:n+argc]

@ -408,8 +407,7 @@ func walkMakeSlice(n *ir.MakeExpr, init *ir.Nodes) ir.Node {
 		t = types.NewArray(t.Elem(), i) // [r]T
 		var_ := typecheck.Temp(t)
 		appendWalkStmt(init, ir.NewAssignStmt(base.Pos, var_, nil))  // zero temp
-		r := ir.NewSliceExpr(base.Pos, ir.OSLICE, var_)             // arr[:l]
-		r.SetSliceBounds(nil, l, nil)
+		r := ir.NewSliceExpr(base.Pos, ir.OSLICE, var_, nil, l, nil) // arr[:l]
 		// The conv is necessary in case n.Type is named.
 		return walkExpr(typecheck.Expr(typecheck.Conv(r, n.Type())), init)
 	}
@ -438,7 +436,8 @@ func walkMakeSlice(n *ir.MakeExpr, init *ir.Nodes) ir.Node {
 	fn := typecheck.LookupRuntime(fnname)
 	m.Ptr = mkcall1(fn, types.Types[types.TUNSAFEPTR], init, reflectdata.TypePtr(t.Elem()), typecheck.Conv(len, argtype), typecheck.Conv(cap, argtype))
 	m.Ptr.MarkNonNil()
-	m.LenCap = []ir.Node{typecheck.Conv(len, types.Types[types.TINT]), typecheck.Conv(cap, types.Types[types.TINT])}
+	m.Len = typecheck.Conv(len, types.Types[types.TINT])
+	m.Cap = typecheck.Conv(cap, types.Types[types.TINT])
 	return walkExpr(typecheck.Expr(m), init)
 }

@ -471,7 +470,8 @@ func walkMakeSliceCopy(n *ir.MakeExpr, init *ir.Nodes) ir.Node {
 		sh := ir.NewSliceHeaderExpr(base.Pos, nil, nil, nil, nil)
 		sh.Ptr = mkcall1(fn, types.Types[types.TUNSAFEPTR], init, size, typecheck.NodNil(), ir.NewBool(false))
 		sh.Ptr.MarkNonNil()
-		sh.LenCap = []ir.Node{length, length}
+		sh.Len = length
+		sh.Cap = length
 		sh.SetType(t)

 		s := typecheck.Temp(t)
@ -493,7 +493,8 @@ func walkMakeSliceCopy(n *ir.MakeExpr, init *ir.Nodes) ir.Node {
 	s := ir.NewSliceHeaderExpr(base.Pos, nil, nil, nil, nil)
 	s.Ptr = mkcall1(fn, types.Types[types.TUNSAFEPTR], init, reflectdata.TypePtr(t.Elem()), length, copylen, typecheck.Conv(copyptr, types.Types[types.TUNSAFEPTR]))
 	s.Ptr.MarkNonNil()
-	s.LenCap = []ir.Node{length, length}
+	s.Len = length
+	s.Cap = length
 	s.SetType(t)
 	return walkExpr(typecheck.Expr(s), init)
 }
--- a/src/cmd/compile/internal/walk/compare.go
+++ b/src/cmd/compile/internal/walk/compare.go
@ -155,7 +155,7 @@ func walkCompare(n *ir.BinaryExpr, init *ir.Nodes) ir.Node {
 	// Chose not to inline. Call equality function directly.
 	if !inline {
 		// eq algs take pointers; cmpl and cmpr must be addressable
-		if !ir.IsAssignable(cmpl) || !ir.IsAssignable(cmpr) {
+		if !ir.IsAddressable(cmpl) || !ir.IsAddressable(cmpr) {
 			base.Fatalf("arguments of comparison must be lvalues - %v %v", cmpl, cmpr)
 		}

@ -428,11 +428,11 @@ func eqFor(t *types.Type) (n ir.Node, needsize bool) {
 		sym := reflectdata.TypeSymPrefix(".eq", t)
 		n := typecheck.NewName(sym)
 		ir.MarkFunc(n)
-		n.SetType(typecheck.NewFuncType(nil, []*ir.Field{
-			ir.NewField(base.Pos, nil, nil, types.NewPtr(t)),
-			ir.NewField(base.Pos, nil, nil, types.NewPtr(t)),
-		}, []*ir.Field{
-			ir.NewField(base.Pos, nil, nil, types.Types[types.TBOOL]),
+		n.SetType(types.NewSignature(types.NoPkg, nil, []*types.Field{
+			types.NewField(base.Pos, nil, types.NewPtr(t)),
+			types.NewField(base.Pos, nil, types.NewPtr(t)),
+		}, []*types.Field{
+			types.NewField(base.Pos, nil, types.Types[types.TBOOL]),
 		}))
 		return n, false
 	}
--- a/src/cmd/compile/internal/walk/complit.go
+++ b/src/cmd/compile/internal/walk/complit.go
@ -425,7 +425,7 @@ func slicelit(ctxt initContext, n *ir.CompLitExpr, var_ ir.Node, init *ir.Nodes)
 	}

 	// make slice out of heap (6)
-	a = ir.NewAssignStmt(base.Pos, var_, ir.NewSliceExpr(base.Pos, ir.OSLICE, vauto))
+	a = ir.NewAssignStmt(base.Pos, var_, ir.NewSliceExpr(base.Pos, ir.OSLICE, vauto, nil, nil, nil))

 	a = typecheck.Stmt(a)
 	a = orderStmtInPlace(a, map[string][]*ir.Name{})
@ -629,6 +629,7 @@ func oaslit(n *ir.AssignStmt, init *ir.Nodes) bool {
 		// not a special composite literal assignment
 		return false
 	}
+	x := n.X.(*ir.Name)
 	if !types.Identical(n.X.Type(), n.Y.Type()) {
 		// not a special composite literal assignment
 		return false
@ -640,7 +641,7 @@ func oaslit(n *ir.AssignStmt, init *ir.Nodes) bool {
 		return false

 	case ir.OSTRUCTLIT, ir.OARRAYLIT, ir.OSLICELIT, ir.OMAPLIT:
-		if refersToCommonName(n.X, n.Y) {
+		if ir.Any(n.Y, func(y ir.Node) bool { return ir.Uses(y, x) }) {
 			// not a special composite literal assignment
 			return false
 		}
--- a/src/cmd/compile/internal/walk/convert.go
+++ b/src/cmd/compile/internal/walk/convert.go
@ -178,7 +178,7 @@ func walkConvInterface(n *ir.ConvExpr, init *ir.Nodes) ir.Node {
 		// with a non-interface, especially in a switch on interface value
 		// with non-interface cases, is not visible to order.stmt, so we
 		// have to fall back on allocating a temp here.
-		if !ir.IsAssignable(v) {
+		if !ir.IsAddressable(v) {
 			v = copyExpr(v, v.Type(), init)
 		}
 		v = typecheck.NodAddr(v)
@ -260,7 +260,7 @@ func walkStringToBytes(n *ir.ConvExpr, init *ir.Nodes) ir.Node {
 		}

 		// Slice the [n]byte to a []byte.
-		slice := ir.NewSliceExpr(n.Pos(), ir.OSLICEARR, p)
+		slice := ir.NewSliceExpr(n.Pos(), ir.OSLICEARR, p, nil, nil, nil)
 		slice.SetType(n.Type())
 		slice.SetTypecheck(1)
 		return walkExpr(slice, init)
--- a/src/cmd/compile/internal/walk/expr.go
+++ b/src/cmd/compile/internal/walk/expr.go
@ -26,15 +26,6 @@ func walkExpr(n ir.Node, init *ir.Nodes) ir.Node {
 		return n
 	}

-	// Eagerly checkwidth all expressions for the back end.
-	if n.Type() != nil && !n.Type().WidthCalculated() {
-		switch n.Type().Kind() {
-		case types.TBLANK, types.TNIL, types.TIDEAL:
-		default:
-			types.CheckSize(n.Type())
-		}
-	}
-
 	if init == n.PtrInit() {
 		// not okay to use n->ninit when walking n,
 		// because we might replace n with some other node
@ -70,23 +61,14 @@ func walkExpr(n ir.Node, init *ir.Nodes) ir.Node {

 	n = walkExpr1(n, init)

-	// Expressions that are constant at run time but not
-	// considered const by the language spec are not turned into
-	// constants until walk. For example, if n is y%1 == 0, the
-	// walk of y%1 may have replaced it by 0.
-	// Check whether n with its updated args is itself now a constant.
-	t := n.Type()
-	n = typecheck.EvalConst(n)
-	if n.Type() != t {
-		base.Fatalf("evconst changed Type: %v had type %v, now %v", n, t, n.Type())
+	// Eagerly compute sizes of all expressions for the back end.
+	if typ := n.Type(); typ != nil && typ.Kind() != types.TBLANK && !typ.IsFuncArgStruct() {
+		types.CheckSize(typ)
 	}
-	if n.Op() == ir.OLITERAL {
-		n = typecheck.Expr(n)
+	if ir.IsConst(n, constant.String) {
 		// Emit string symbol now to avoid emitting
 		// any concurrently during the backend.
-		if v := n.Val(); v.Kind() == constant.String {
-			_ = staticdata.StringSym(n.Pos(), constant.StringVal(v))
-		}
+		_ = staticdata.StringSym(n.Pos(), constant.StringVal(n.Val()))
 	}

 	updateHasCall(n)
@ -106,7 +88,7 @@ func walkExpr1(n ir.Node, init *ir.Nodes) ir.Node {
 		base.Fatalf("walkexpr: switch 1 unknown op %+v", n.Op())
 		panic("unreachable")

-	case ir.ONONAME, ir.OGETG, ir.ONEWOBJ, ir.OMETHEXPR:
+	case ir.ONONAME, ir.OGETG, ir.ONEWOBJ:
 		return n

 	case ir.OTYPE, ir.ONAME, ir.OLITERAL, ir.ONIL, ir.ONAMEOFFSET:
@ -116,6 +98,11 @@ func walkExpr1(n ir.Node, init *ir.Nodes) ir.Node {
 		// stringsym for constant strings.
 		return n

+	case ir.OMETHEXPR:
+		// TODO(mdempsky): Do this right after type checking.
+		n := n.(*ir.MethodExpr)
+		return n.FuncName()
+
 	case ir.ONOT, ir.ONEG, ir.OPLUS, ir.OBITNOT, ir.OREAL, ir.OIMAG, ir.OSPTR, ir.OITAB, ir.OIDATA:
 		n := n.(*ir.UnaryExpr)
 		n.X = walkExpr(n.X, init)
@ -429,7 +416,7 @@ func safeExpr(n ir.Node, init *ir.Nodes) ir.Node {
 	}

 	// make a copy; must not be used as an lvalue
-	if ir.IsAssignable(n) {
+	if ir.IsAddressable(n) {
 		base.Fatalf("missing lvalue case in safeexpr: %v", n)
 	}
 	return cheapExpr(n, init)
@ -535,22 +522,28 @@ func walkCall1(n *ir.CallExpr, init *ir.Nodes) {
 		return // already walked
 	}

-	params := n.X.Type().Params()
+	// If this is a method call t.M(...),
+	// rewrite into a function call T.M(t, ...).
+	// TODO(mdempsky): Do this right after type checking.
+	if n.Op() == ir.OCALLMETH {
+		withRecv := make([]ir.Node, len(n.Args)+1)
+		dot := n.X.(*ir.SelectorExpr)
+		withRecv[0] = dot.X
+		copy(withRecv[1:], n.Args)
+		n.Args = withRecv
+
+		dot = ir.NewSelectorExpr(dot.Pos(), ir.OXDOT, ir.TypeNode(dot.X.Type()), dot.Selection.Sym)
+
+		n.SetOp(ir.OCALLFUNC)
+		n.X = typecheck.Expr(dot)
+	}
+
 	args := n.Args
+	params := n.X.Type().Params()

 	n.X = walkExpr(n.X, init)
 	walkExprList(args, init)

-	// If this is a method call, add the receiver at the beginning of the args.
-	if n.Op() == ir.OCALLMETH {
-		withRecv := make([]ir.Node, len(args)+1)
-		dot := n.X.(*ir.SelectorExpr)
-		withRecv[0] = dot.X
-		dot.X = nil
-		copy(withRecv[1:], args)
-		args = withRecv
-	}
-
 	// For any argument whose evaluation might require a function call,
 	// store that argument into a temporary variable,
 	// to prevent that calls from clobbering arguments already on the stack.
@ -559,16 +552,7 @@ func walkCall1(n *ir.CallExpr, init *ir.Nodes) {
 	for i, arg := range args {
 		updateHasCall(arg)
 		// Determine param type.
-		var t *types.Type
-		if n.Op() == ir.OCALLMETH {
-			if i == 0 {
-				t = n.X.Type().Recv().Type
-			} else {
-				t = params.Field(i - 1).Type
-			}
-		} else {
-			t = params.Field(i).Type
-		}
+		t := params.Field(i).Type
 		if base.Flag.Cfg.Instrumenting || fncall(arg, t) {
 			// make assignment of fncall to tempAt
 			tmp := typecheck.Temp(t)
@ -786,21 +770,19 @@ func walkSlice(n *ir.SliceExpr, init *ir.Nodes) ir.Node {
 		n.X = walkExpr(n.X, init)
 	}

-	low, high, max := n.SliceBounds()
-	low = walkExpr(low, init)
-	if low != nil && ir.IsZero(low) {
+	n.Low = walkExpr(n.Low, init)
+	if n.Low != nil && ir.IsZero(n.Low) {
 		// Reduce x[0:j] to x[:j] and x[0:j:k] to x[:j:k].
-		low = nil
+		n.Low = nil
 	}
-	high = walkExpr(high, init)
-	max = walkExpr(max, init)
-	n.SetSliceBounds(low, high, max)
+	n.High = walkExpr(n.High, init)
+	n.Max = walkExpr(n.Max, init)
 	if checkSlice {
-		n.X = walkCheckPtrAlignment(n.X.(*ir.ConvExpr), init, max)
+		n.X = walkCheckPtrAlignment(n.X.(*ir.ConvExpr), init, n.Max)
 	}

 	if n.Op().IsSlice3() {
-		if max != nil && max.Op() == ir.OCAP && ir.SameSafeExpr(n.X, max.(*ir.UnaryExpr).X) {
+		if n.Max != nil && n.Max.Op() == ir.OCAP && ir.SameSafeExpr(n.X, n.Max.(*ir.UnaryExpr).X) {
 			// Reduce x[i:j:cap(x)] to x[i:j].
 			if n.Op() == ir.OSLICE3 {
 				n.SetOp(ir.OSLICE)
@ -817,20 +799,18 @@ func walkSlice(n *ir.SliceExpr, init *ir.Nodes) ir.Node {
 // walkSliceHeader walks an OSLICEHEADER node.
 func walkSliceHeader(n *ir.SliceHeaderExpr, init *ir.Nodes) ir.Node {
 	n.Ptr = walkExpr(n.Ptr, init)
-	n.LenCap[0] = walkExpr(n.LenCap[0], init)
-	n.LenCap[1] = walkExpr(n.LenCap[1], init)
+	n.Len = walkExpr(n.Len, init)
+	n.Cap = walkExpr(n.Cap, init)
 	return n
 }

 // TODO(josharian): combine this with its caller and simplify
 func reduceSlice(n *ir.SliceExpr) ir.Node {
-	low, high, max := n.SliceBounds()
-	if high != nil && high.Op() == ir.OLEN && ir.SameSafeExpr(n.X, high.(*ir.UnaryExpr).X) {
+	if n.High != nil && n.High.Op() == ir.OLEN && ir.SameSafeExpr(n.X, n.High.(*ir.UnaryExpr).X) {
 		// Reduce x[i:len(x)] to x[i:].
-		high = nil
+		n.High = nil
 	}
-	n.SetSliceBounds(low, high, max)
-	if (n.Op() == ir.OSLICE || n.Op() == ir.OSLICESTR) && low == nil && high == nil {
+	if (n.Op() == ir.OSLICE || n.Op() == ir.OSLICESTR) && n.Low == nil && n.High == nil {
 		// Reduce x[:] to x.
 		if base.Debug.Slice > 0 {
 			base.Warn("slice: omit slice operation")
@ -969,22 +949,13 @@ func usefield(n *ir.SelectorExpr) {
 	case ir.ODOT, ir.ODOTPTR:
 		break
 	}
-	if n.Sel == nil {
-		// No field name.  This DOTPTR was built by the compiler for access
-		// to runtime data structures.  Ignore.
-		return
-	}

-	t := n.X.Type()
-	if t.IsPtr() {
-		t = t.Elem()
-	}
 	field := n.Selection
 	if field == nil {
 		base.Fatalf("usefield %v %v without paramfld", n.X.Type(), n.Sel)
 	}
-	if field.Sym != n.Sel || field.Offset != n.Offset {
-		base.Fatalf("field inconsistency: %v,%v != %v,%v", field.Sym, field.Offset, n.Sel, n.Offset)
+	if field.Sym != n.Sel {
+		base.Fatalf("field inconsistency: %v != %v", field.Sym, n.Sel)
 	}
 	if !strings.Contains(field.Note, "go:\"track\"") {
 		return
--- a/src/cmd/compile/internal/walk/order.go
+++ b/src/cmd/compile/internal/walk/order.go
@ -235,7 +235,7 @@ func (o *orderState) safeExpr(n ir.Node) ir.Node {
 // because we emit explicit VARKILL instructions marking the end of those
 // temporaries' lifetimes.
 func isaddrokay(n ir.Node) bool {
-	return ir.IsAssignable(n) && (n.Op() != ir.ONAME || n.(*ir.Name).Class_ == ir.PEXTERN || ir.IsAutoTmp(n))
+	return ir.IsAddressable(n) && (n.Op() != ir.ONAME || n.(*ir.Name).Class_ == ir.PEXTERN || ir.IsAutoTmp(n))
 }

 // addrTemp ensures that n is okay to pass by address to runtime routines.
@ -843,12 +843,13 @@ func (o *orderState) stmt(n ir.Node) {
 		n.X = o.expr(n.X, nil)

 		orderBody := true
-		switch n.Type().Kind() {
+		xt := typecheck.RangeExprType(n.X.Type())
+		switch xt.Kind() {
 		default:
 			base.Fatalf("order.stmt range %v", n.Type())

 		case types.TARRAY, types.TSLICE:
-			if len(n.Vars) < 2 || ir.IsBlank(n.Vars[1]) {
+			if n.Value == nil || ir.IsBlank(n.Value) {
 				// for i := range x will only use x once, to compute len(x).
 				// No need to copy it.
 				break
@ -885,9 +886,10 @@ func (o *orderState) stmt(n ir.Node) {

 			// n.Prealloc is the temp for the iterator.
 			// hiter contains pointers and needs to be zeroed.
-			n.Prealloc = o.newTemp(reflectdata.MapIterType(n.Type()), true)
+			n.Prealloc = o.newTemp(reflectdata.MapIterType(xt), true)
 		}
-		o.exprListInPlace(n.Vars)
+		n.Key = o.exprInPlace(n.Key)
+		n.Value = o.exprInPlace(n.Value)
 		if orderBody {
 			orderBlock(&n.Body, o.free)
 		}
@ -912,7 +914,6 @@ func (o *orderState) stmt(n ir.Node) {
 		n := n.(*ir.SelectStmt)
 		t := o.markTemp()
 		for _, ncas := range n.Cases {
-			ncas := ncas.(*ir.CaseStmt)
 			r := ncas.Comm
 			ir.SetPos(ncas)

@ -994,7 +995,6 @@ func (o *orderState) stmt(n ir.Node) {
 		// Also insert any ninit queued during the previous loop.
 		// (The temporary cleaning must follow that ninit work.)
 		for _, cas := range n.Cases {
-			cas := cas.(*ir.CaseStmt)
 			orderBlock(&cas.Body, o.free)
 			cas.Body.Prepend(o.cleanTempNoPop(t)...)

@ -1034,13 +1034,12 @@ func (o *orderState) stmt(n ir.Node) {
 		n := n.(*ir.SwitchStmt)
 		if base.Debug.Libfuzzer != 0 && !hasDefaultCase(n) {
 			// Add empty "default:" case for instrumentation.
-			n.Cases.Append(ir.NewCaseStmt(base.Pos, nil, nil))
+			n.Cases = append(n.Cases, ir.NewCaseStmt(base.Pos, nil, nil))
 		}

 		t := o.markTemp()
 		n.Tag = o.expr(n.Tag, nil)
 		for _, ncas := range n.Cases {
-			ncas := ncas.(*ir.CaseStmt)
 			o.exprListInPlace(ncas.List)
 			orderBlock(&ncas.Body, o.free)
 		}
@ -1054,7 +1053,6 @@ func (o *orderState) stmt(n ir.Node) {

 func hasDefaultCase(n *ir.SwitchStmt) bool {
 	for _, ncas := range n.Cases {
-		ncas := ncas.(*ir.CaseStmt)
 		if len(ncas.List) == 0 {
 			return true
 		}
@ -1296,14 +1294,9 @@ func (o *orderState) expr1(n, lhs ir.Node) ir.Node {
 	case ir.OSLICE, ir.OSLICEARR, ir.OSLICESTR, ir.OSLICE3, ir.OSLICE3ARR:
 		n := n.(*ir.SliceExpr)
 		n.X = o.expr(n.X, nil)
-		low, high, max := n.SliceBounds()
-		low = o.expr(low, nil)
-		low = o.cheapExpr(low)
-		high = o.expr(high, nil)
-		high = o.cheapExpr(high)
-		max = o.expr(max, nil)
-		max = o.cheapExpr(max)
-		n.SetSliceBounds(low, high, max)
+		n.Low = o.cheapExpr(o.expr(n.Low, nil))
+		n.High = o.cheapExpr(o.expr(n.High, nil))
+		n.Max = o.cheapExpr(o.expr(n.Max, nil))
 		if lhs == nil || lhs.Op() != ir.ONAME && !ir.SameSafeExpr(lhs, n.X) {
 			return o.copyExpr(n)
 		}
--- a/src/cmd/compile/internal/walk/range.go
+++ b/src/cmd/compile/internal/walk/range.go
@ -56,20 +56,11 @@ func walkRange(nrange *ir.RangeStmt) ir.Node {
 	//	hb: hidden bool
 	//	a, v1, v2: not hidden aggregate, val 1, 2

-	t := nrange.Type()
-
 	a := nrange.X
+	t := typecheck.RangeExprType(a.Type())
 	lno := ir.SetPos(a)

-	var v1, v2 ir.Node
-	l := len(nrange.Vars)
-	if l > 0 {
-		v1 = nrange.Vars[0]
-	}
-
-	if l > 1 {
-		v2 = nrange.Vars[1]
-	}
+	v1, v2 := nrange.Key, nrange.Value

 	if ir.IsBlank(v2) {
 		v2 = nil
@ -121,7 +112,7 @@ func walkRange(nrange *ir.RangeStmt) ir.Node {
 		}

 		// for v1, v2 := range ha { body }
-		if cheapComputableIndex(nrange.Type().Elem().Width) {
+		if cheapComputableIndex(t.Elem().Width) {
 			// v1, v2 = hv1, ha[hv1]
 			tmp := ir.NewIndexExpr(base.Pos, ha, hv1)
 			tmp.SetBounded(true)
@ -150,7 +141,7 @@ func walkRange(nrange *ir.RangeStmt) ir.Node {
 		ifGuard.Cond = ir.NewBinaryExpr(base.Pos, ir.OLT, hv1, hn)
 		nfor.SetOp(ir.OFORUNTIL)

-		hp := typecheck.Temp(types.NewPtr(nrange.Type().Elem()))
+		hp := typecheck.Temp(types.NewPtr(t.Elem()))
 		tmp := ir.NewIndexExpr(base.Pos, ha, ir.NewInt(0))
 		tmp.SetBounded(true)
 		init = append(init, ir.NewAssignStmt(base.Pos, hp, typecheck.NodAddr(tmp)))
@ -343,15 +334,12 @@ func isMapClear(n *ir.RangeStmt) bool {
 		return false
 	}

-	if n.Op() != ir.ORANGE || n.Type().Kind() != types.TMAP || len(n.Vars) != 1 {
-		return false
-	}
-
-	k := n.Vars[0]
-	if k == nil || ir.IsBlank(k) {
+	t := n.X.Type()
+	if n.Op() != ir.ORANGE || t.Kind() != types.TMAP || n.Key == nil || n.Value != nil {
 		return false
 	}

+	k := n.Key
 	// Require k to be a new variable name.
 	if !ir.DeclaredBy(k, n) {
 		return false
@ -372,7 +360,7 @@ func isMapClear(n *ir.RangeStmt) bool {
 	}

 	// Keys where equality is not reflexive can not be deleted from maps.
-	if !types.IsReflexive(m.Type().Key()) {
+	if !types.IsReflexive(t.Key()) {
 		return false
 	}

@ -428,7 +416,7 @@ func arrayClear(loop *ir.RangeStmt, v1, v2, a ir.Node) ir.Node {
 		return nil
 	}

-	elemsize := loop.Type().Elem().Width
+	elemsize := typecheck.RangeExprType(loop.X.Type()).Elem().Width
 	if elemsize <= 0 || !ir.IsZero(stmt.Y) {
 		return nil
 	}
--- a/src/cmd/compile/internal/walk/select.go
+++ b/src/cmd/compile/internal/walk/select.go
@ -21,7 +21,7 @@ func walkSelect(sel *ir.SelectStmt) {
 	sel.PtrInit().Set(nil)

 	init = append(init, walkSelectCases(sel.Cases)...)
-	sel.Cases = ir.Nodes{}
+	sel.Cases = nil

 	sel.Compiled.Set(init)
 	walkStmtList(sel.Compiled)
@ -29,7 +29,7 @@ func walkSelect(sel *ir.SelectStmt) {
 	base.Pos = lno
 }

-func walkSelectCases(cases ir.Nodes) []ir.Node {
+func walkSelectCases(cases []*ir.CommClause) []ir.Node {
 	ncas := len(cases)
 	sellineno := base.Pos

@ -40,7 +40,7 @@ func walkSelectCases(cases ir.Nodes) []ir.Node {

 	// optimization: one-case select: single op.
 	if ncas == 1 {
-		cas := cases[0].(*ir.CaseStmt)
+		cas := cases[0]
 		ir.SetPos(cas)
 		l := cas.Init()
 		if cas.Comm != nil { // not default:
@ -73,9 +73,8 @@ func walkSelectCases(cases ir.Nodes) []ir.Node {

 	// convert case value arguments to addresses.
 	// this rewrite is used by both the general code and the next optimization.
-	var dflt *ir.CaseStmt
+	var dflt *ir.CommClause
 	for _, cas := range cases {
-		cas := cas.(*ir.CaseStmt)
 		ir.SetPos(cas)
 		n := cas.Comm
 		if n == nil {
@ -99,9 +98,9 @@ func walkSelectCases(cases ir.Nodes) []ir.Node {

 	// optimization: two-case select but one is default: single non-blocking op.
 	if ncas == 2 && dflt != nil {
-		cas := cases[0].(*ir.CaseStmt)
+		cas := cases[0]
 		if cas == dflt {
-			cas = cases[1].(*ir.CaseStmt)
+			cas = cases[1]
 		}

 		n := cas.Comm
@ -147,7 +146,7 @@ func walkSelectCases(cases ir.Nodes) []ir.Node {
 	if dflt != nil {
 		ncas--
 	}
-	casorder := make([]*ir.CaseStmt, ncas)
+	casorder := make([]*ir.CommClause, ncas)
 	nsends, nrecvs := 0, 0

 	var init []ir.Node
@ -170,7 +169,6 @@ func walkSelectCases(cases ir.Nodes) []ir.Node {

 	// register cases
 	for _, cas := range cases {
-		cas := cas.(*ir.CaseStmt)
 		ir.SetPos(cas)

 		init = append(init, cas.Init()...)
@ -244,7 +242,7 @@ func walkSelectCases(cases ir.Nodes) []ir.Node {
 	}

 	// dispatch cases
-	dispatch := func(cond ir.Node, cas *ir.CaseStmt) {
+	dispatch := func(cond ir.Node, cas *ir.CommClause) {
 		cond = typecheck.Expr(cond)
 		cond = typecheck.DefaultLit(cond, nil)

@ -287,9 +285,9 @@ var scase *types.Type
 // Keep in sync with src/runtime/select.go.
 func scasetype() *types.Type {
 	if scase == nil {
-		scase = typecheck.NewStructType([]*ir.Field{
-			ir.NewField(base.Pos, typecheck.Lookup("c"), nil, types.Types[types.TUNSAFEPTR]),
-			ir.NewField(base.Pos, typecheck.Lookup("elem"), nil, types.Types[types.TUNSAFEPTR]),
+		scase = types.NewStruct(types.NoPkg, []*types.Field{
+			types.NewField(base.Pos, typecheck.Lookup("c"), types.Types[types.TUNSAFEPTR]),
+			types.NewField(base.Pos, typecheck.Lookup("elem"), types.Types[types.TUNSAFEPTR]),
 		})
 		scase.SetNoalg(true)
 	}
--- a/src/cmd/compile/internal/walk/switch.go
+++ b/src/cmd/compile/internal/walk/switch.go
@ -71,7 +71,6 @@ func walkSwitchExpr(sw *ir.SwitchStmt) {
 	var defaultGoto ir.Node
 	var body ir.Nodes
 	for _, ncase := range sw.Cases {
-		ncase := ncase.(*ir.CaseStmt)
 		label := typecheck.AutoLabel(".s")
 		jmp := ir.NewBranchStmt(ncase.Pos(), ir.OGOTO, label)

@ -96,7 +95,7 @@ func walkSwitchExpr(sw *ir.SwitchStmt) {
 			body.Append(br)
 		}
 	}
-	sw.Cases.Set(nil)
+	sw.Cases = nil

 	if defaultGoto == nil {
 		br := ir.NewBranchStmt(base.Pos, ir.OBREAK, nil)
@ -259,7 +258,6 @@ func allCaseExprsAreSideEffectFree(sw *ir.SwitchStmt) bool {
 	// enough.

 	for _, ncase := range sw.Cases {
-		ncase := ncase.(*ir.CaseStmt)
 		for _, v := range ncase.List {
 			if v.Op() != ir.OLITERAL {
 				return false
@ -318,26 +316,14 @@ func walkSwitchType(sw *ir.SwitchStmt) {
 	sw.Compiled.Append(ifNil)

 	// Load hash from type or itab.
-	dotHash := ir.NewSelectorExpr(base.Pos, ir.ODOTPTR, itab, nil)
-	dotHash.SetType(types.Types[types.TUINT32])
-	dotHash.SetTypecheck(1)
-	if s.facename.Type().IsEmptyInterface() {
-		dotHash.Offset = int64(2 * types.PtrSize) // offset of hash in runtime._type
-	} else {
-		dotHash.Offset = int64(2 * types.PtrSize) // offset of hash in runtime.itab
-	}
-	dotHash.SetBounded(true) // guaranteed not to fault
+	dotHash := typeHashFieldOf(base.Pos, itab)
 	s.hashname = copyExpr(dotHash, dotHash.Type(), &sw.Compiled)

 	br := ir.NewBranchStmt(base.Pos, ir.OBREAK, nil)
 	var defaultGoto, nilGoto ir.Node
 	var body ir.Nodes
 	for _, ncase := range sw.Cases {
-		ncase := ncase.(*ir.CaseStmt)
-		var caseVar ir.Node
-		if len(ncase.Vars) != 0 {
-			caseVar = ncase.Vars[0]
-		}
+		caseVar := ncase.Var

 		// For single-type cases with an interface type,
 		// we initialize the case variable as part of the type assertion.
@ -395,7 +381,7 @@ func walkSwitchType(sw *ir.SwitchStmt) {
 		body.Append(ncase.Body...)
 		body.Append(br)
 	}
-	sw.Cases.Set(nil)
+	sw.Cases = nil

 	if defaultGoto == nil {
 		defaultGoto = br
@ -412,6 +398,32 @@ func walkSwitchType(sw *ir.SwitchStmt) {
 	walkStmtList(sw.Compiled)
 }

+// typeHashFieldOf returns an expression to select the type hash field
+// from an interface's descriptor word (whether a *runtime._type or
+// *runtime.itab pointer).
+func typeHashFieldOf(pos src.XPos, itab *ir.UnaryExpr) *ir.SelectorExpr {
+	if itab.Op() != ir.OITAB {
+		base.Fatalf("expected OITAB, got %v", itab.Op())
+	}
+	var hashField *types.Field
+	if itab.X.Type().IsEmptyInterface() {
+		// runtime._type's hash field
+		if rtypeHashField == nil {
+			rtypeHashField = runtimeField("hash", int64(2*types.PtrSize), types.Types[types.TUINT32])
+		}
+		hashField = rtypeHashField
+	} else {
+		// runtime.itab's hash field
+		if itabHashField == nil {
+			itabHashField = runtimeField("hash", int64(2*types.PtrSize), types.Types[types.TUINT32])
+		}
+		hashField = itabHashField
+	}
+	return boundedDotPtr(pos, itab, hashField)
+}
+
+var rtypeHashField, itabHashField *types.Field
+
 // A typeSwitch walks a type switch.
 type typeSwitch struct {
 	// Temporary variables (i.e., ONAMEs) used by type switch dispatch logic:
--- a/src/cmd/compile/internal/walk/walk.go
+++ b/src/cmd/compile/internal/walk/walk.go
@ -539,12 +539,30 @@ func calcHasCall(n ir.Node) bool {

 // itabType loads the _type field from a runtime.itab struct.
 func itabType(itab ir.Node) ir.Node {
-	typ := ir.NewSelectorExpr(base.Pos, ir.ODOTPTR, itab, nil)
-	typ.SetType(types.NewPtr(types.Types[types.TUINT8]))
-	typ.SetTypecheck(1)
-	typ.Offset = int64(types.PtrSize) // offset of _type in runtime.itab
-	typ.SetBounded(true)              // guaranteed not to fault
-	return typ
+	if itabTypeField == nil {
+		// runtime.itab's _type field
+		itabTypeField = runtimeField("_type", int64(types.PtrSize), types.NewPtr(types.Types[types.TUINT8]))
+	}
+	return boundedDotPtr(base.Pos, itab, itabTypeField)
+}
+
+var itabTypeField *types.Field
+
+// boundedDotPtr returns a selector expression representing ptr.field
+// and omits nil-pointer checks for ptr.
+func boundedDotPtr(pos src.XPos, ptr ir.Node, field *types.Field) *ir.SelectorExpr {
+	sel := ir.NewSelectorExpr(pos, ir.ODOTPTR, ptr, field.Sym)
+	sel.Selection = field
+	sel.SetType(field.Type)
+	sel.SetTypecheck(1)
+	sel.SetBounded(true) // guaranteed not to fault
+	return sel
+}
+
+func runtimeField(name string, offset int64, typ *types.Type) *types.Field {
+	f := types.NewField(src.NoXPos, ir.Pkgs.Runtime.Lookup(name), typ)
+	f.Offset = offset
+	return f
 }

 // ifaceData loads the data field from an interface.
--- a/src/cmd/go/alldocs.go
+++ b/src/cmd/go/alldocs.go
@ -1192,6 +1192,7 @@
 // 		Require []Require
 // 		Exclude []Module
 // 		Replace []Replace
+// 		Retract []Retract
 // 	}
 //
 // 	type Require struct {
--- a/src/cmd/go/internal/modcmd/edit.go
+++ b/src/cmd/go/internal/modcmd/edit.go
@ -95,6 +95,7 @@ writing it back to go.mod. The JSON output corresponds to these Go types:
 		Require []Require
 		Exclude []Module
 		Replace []Replace
+		Retract []Retract
 	}

 	type Require struct {
--- a/src/cmd/go/internal/modload/buildlist.go
+++ b/src/cmd/go/internal/modload/buildlist.go
@ -28,6 +28,11 @@ import (
 //
 var buildList []module.Version

+// additionalExplicitRequirements is a list of modules paths for which
+// WriteGoMod should record explicit requirements, even if they would be
+// selected without those requirements. Each path must also appear in buildList.
+var additionalExplicitRequirements []string
+
 // capVersionSlice returns s with its cap reduced to its length.
 func capVersionSlice(s []module.Version) []module.Version {
 	return s[:len(s):len(s)]
@ -121,6 +126,12 @@ func EditBuildList(ctx context.Context, add, mustSelect []module.Version) error

 	if !inconsistent {
 		buildList = final
+		additionalExplicitRequirements = make([]string, 0, len(mustSelect))
+		for _, m := range mustSelect {
+			if m.Version != "none" {
+				additionalExplicitRequirements = append(additionalExplicitRequirements, m.Path)
+			}
+		}
 		return nil
 	}

--- a/src/cmd/go/internal/modload/init.go
+++ b/src/cmd/go/internal/modload/init.go
@ -15,6 +15,7 @@ import (
 	"os"
 	"path"
 	"path/filepath"
+	"sort"
 	"strconv"
 	"strings"
 	"sync"
@ -27,6 +28,7 @@ import (
 	"cmd/go/internal/modfetch"
 	"cmd/go/internal/mvs"
 	"cmd/go/internal/search"
+	"cmd/go/internal/str"

 	"golang.org/x/mod/modfile"
 	"golang.org/x/mod/module"
@ -845,13 +847,15 @@ func AllowWriteGoMod() {
 // MinReqs returns a Reqs with minimal additional dependencies of Target,
 // as will be written to go.mod.
 func MinReqs() mvs.Reqs {
-	var retain []string
+	retain := append([]string{}, additionalExplicitRequirements...)
 	for _, m := range buildList[1:] {
 		_, explicit := index.require[m]
 		if explicit || loaded.direct[m.Path] {
 			retain = append(retain, m.Path)
 		}
 	}
+	sort.Strings(retain)
+	str.Uniq(&retain)
 	min, err := mvs.Req(Target, retain, &mvsReqs{buildList: buildList})
 	if err != nil {
 		base.Fatalf("go: %v", err)
--- a/src/cmd/go/internal/modload/load.go
+++ b/src/cmd/go/internal/modload/load.go
@ -863,12 +863,21 @@ func loadFromRoots(params loaderParams) *loader {
 	for _, pkg := range ld.pkgs {
 		if pkg.mod == Target {
 			for _, dep := range pkg.imports {
-				if dep.mod.Path != "" {
+				if dep.mod.Path != "" && dep.mod.Path != Target.Path && index != nil {
+					_, explicit := index.require[dep.mod]
+					if allowWriteGoMod && cfg.BuildMod == "readonly" && !explicit {
+						// TODO(#40775): attach error to package instead of using
+						// base.Errorf. Ideally, 'go list' should not fail because of this,
+						// but today, LoadPackages calls WriteGoMod unconditionally, which
+						// would fail with a less clear message.
+						base.Errorf("go: %[1]s: package %[2]s imported from implicitly required module; try 'go get -d %[1]s' to add missing requirements", pkg.path, dep.path)
+					}
 					ld.direct[dep.mod.Path] = true
 				}
 			}
 		}
 	}
+	base.ExitIfErrors()

 	// If we didn't scan all of the imports from the main module, or didn't use
 	// imports.AnyTags, then we didn't necessarily load every package that
--- a/src/cmd/go/internal/modload/query.go
+++ b/src/cmd/go/internal/modload/query.go
@ -21,6 +21,7 @@ import (
 	"cmd/go/internal/imports"
 	"cmd/go/internal/modfetch"
 	"cmd/go/internal/search"
+	"cmd/go/internal/str"
 	"cmd/go/internal/trace"

 	"golang.org/x/mod/module"
@ -1005,13 +1006,8 @@ func (rr *replacementRepo) Versions(prefix string) ([]string, error) {
 	sort.Slice(versions, func(i, j int) bool {
 		return semver.Compare(versions[i], versions[j]) < 0
 	})
-	uniq := versions[:1]
-	for _, v := range versions {
-		if v != uniq[len(uniq)-1] {
-			uniq = append(uniq, v)
-		}
-	}
-	return uniq, nil
+	str.Uniq(&versions)
+	return versions, nil
 }

 func (rr *replacementRepo) Stat(rev string) (*modfetch.RevInfo, error) {
--- a/src/cmd/go/internal/str/str.go
+++ b/src/cmd/go/internal/str/str.go
@ -96,6 +96,20 @@ func Contains(x []string, s string) bool {
 	return false
 }

+// Uniq removes consecutive duplicate strings from ss.
+func Uniq(ss *[]string) {
+	if len(*ss) <= 1 {
+		return
+	}
+	uniq := (*ss)[:1]
+	for _, s := range *ss {
+		if s != uniq[len(uniq)-1] {
+			uniq = append(uniq, s)
+		}
+	}
+	*ss = uniq
+}
+
 func isSpaceByte(c byte) bool {
 	return c == ' ' || c == '\t' || c == '\n' || c == '\r'
 }
--- a/src/cmd/go/testdata/script/mod_get_promote_implicit.txt
+++ b/src/cmd/go/testdata/script/mod_get_promote_implicit.txt
@ -0,0 +1,88 @@
+cp go.mod.orig go.mod
+
+# If we list a package in an implicit dependency imported from the main module,
+# we should get an error because the dependency should have an explicit
+# requirement.
+go list -m indirect-with-pkg
+stdout '^indirect-with-pkg v1.0.0 => ./indirect-with-pkg$'
+! go list ./use-indirect
+stderr '^go: m/use-indirect: package indirect-with-pkg imported from implicitly required module; try ''go get -d m/use-indirect'' to add missing requirements$'
+
+# We can promote the implicit requirement by getting the importing package,
+# as hinted.
+go get -d m/use-indirect
+cmp go.mod go.mod.use
+cp go.mod.orig go.mod
+
+# We can also promote implicit requirements using 'go get' on them, or their
+# packages. This gives us "// indirect" requirements, since 'go get' doesn't
+# know they're needed by the main module. See #43131 for the rationale.
+go get -d indirect-with-pkg indirect-without-pkg
+cmp go.mod go.mod.indirect
+
+-- go.mod.orig --
+module m
+
+go 1.16
+
+require direct v1.0.0
+
+replace (
+	direct v1.0.0 => ./direct
+	indirect-with-pkg v1.0.0 => ./indirect-with-pkg
+	indirect-without-pkg v1.0.0 => ./indirect-without-pkg
+)
+-- go.mod.use --
+module m
+
+go 1.16
+
+require (
+	direct v1.0.0
+	indirect-with-pkg v1.0.0
+)
+
+replace (
+	direct v1.0.0 => ./direct
+	indirect-with-pkg v1.0.0 => ./indirect-with-pkg
+	indirect-without-pkg v1.0.0 => ./indirect-without-pkg
+)
+-- go.mod.indirect --
+module m
+
+go 1.16
+
+require (
+	direct v1.0.0
+	indirect-with-pkg v1.0.0 // indirect
+	indirect-without-pkg v1.0.0 // indirect
+)
+
+replace (
+	direct v1.0.0 => ./direct
+	indirect-with-pkg v1.0.0 => ./indirect-with-pkg
+	indirect-without-pkg v1.0.0 => ./indirect-without-pkg
+)
+-- use-indirect/use-indirect.go --
+package use
+
+import _ "indirect-with-pkg"
+-- direct/go.mod --
+module direct
+
+go 1.16
+
+require (
+	indirect-with-pkg v1.0.0
+	indirect-without-pkg v1.0.0
+)
+-- indirect-with-pkg/go.mod --
+module indirect-with-pkg
+
+go 1.16
+-- indirect-with-pkg/p.go --
+package p
+-- indirect-without-pkg/go.mod --
+module indirect-without-pkg
+
+go 1.16
--- a/src/net/mail/message_test.go
+++ b/src/net/mail/message_test.go
@ -107,8 +107,8 @@ func TestDateParsing(t *testing.T) {
 			time.Date(1997, 11, 20, 9, 55, 6, 0, time.FixedZone("", -6*60*60)),
 		},
 		{
-			"Thu, 20 Nov 1997 09:55:06 MDT (MDT)",
-			time.Date(1997, 11, 20, 9, 55, 6, 0, time.FixedZone("MDT", 0)),
+			"Thu, 20 Nov 1997 09:55:06 GMT (GMT)",
+			time.Date(1997, 11, 20, 9, 55, 6, 0, time.UTC),
 		},
 		{
 			"Fri, 21 Nov 1997 09:55:06 +1300 (TOT)",
@ -278,8 +278,8 @@ func TestDateParsingCFWS(t *testing.T) {
 			true,
 		},
 		{
-			"Fri, 21 Nov 1997 09:55:06 MDT (MDT)",
-			time.Date(1997, 11, 21, 9, 55, 6, 0, time.FixedZone("MDT", 0)),
+			"Fri, 21 Nov 1997 09:55:06 GMT (GMT)",
+			time.Date(1997, 11, 21, 9, 55, 6, 0, time.UTC),
 			true,
 		},
 	}
--- a/src/os/signal/signal_linux_test.go
+++ b/src/os/signal/signal_linux_test.go
@ -0,0 +1,42 @@
+// Copyright 2020 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build linux
+
+package signal
+
+import (
+	"os"
+	"syscall"
+	"testing"
+	"time"
+)
+
+const prSetKeepCaps = 8
+
+// This test validates that syscall.AllThreadsSyscall() can reliably
+// reach all 'm' (threads) of the nocgo runtime even when one thread
+// is blocked waiting to receive signals from the kernel. This monitors
+// for a regression vs. the fix for #43149.
+func TestAllThreadsSyscallSignals(t *testing.T) {
+	if _, _, err := syscall.AllThreadsSyscall(syscall.SYS_PRCTL, prSetKeepCaps, 0, 0); err == syscall.ENOTSUP {
+		t.Skip("AllThreadsSyscall disabled with cgo")
+	}
+
+	sig := make(chan os.Signal, 1)
+	Notify(sig, os.Interrupt)
+
+	for i := 0; i <= 100; i++ {
+		if _, _, errno := syscall.AllThreadsSyscall(syscall.SYS_PRCTL, prSetKeepCaps, uintptr(i&1), 0); errno != 0 {
+			t.Fatalf("[%d] failed to set KEEP_CAPS=%d: %v", i, i&1, errno)
+		}
+	}
+
+	select {
+	case <-time.After(10 * time.Millisecond):
+	case <-sig:
+		t.Fatal("unexpected signal")
+	}
+	Stop(sig)
+}
--- a/src/runtime/cgo/gcc_linux_386.c
+++ b/src/runtime/cgo/gcc_linux_386.c
@ -12,7 +12,7 @@ static void *threadentry(void*);
 static void (*setg_gcc)(void*);

 // This will be set in gcc_android.c for android-specific customization.
-void (*x_cgo_inittls)(void **tlsg, void **tlsbase);
+void (*x_cgo_inittls)(void **tlsg, void **tlsbase) __attribute__((common));

 void
 x_cgo_init(G *g, void (*setg)(void*), void **tlsg, void **tlsbase)
--- a/src/runtime/cgo/gcc_linux_amd64.c
+++ b/src/runtime/cgo/gcc_linux_amd64.c
@ -14,7 +14,7 @@ static void* threadentry(void*);
 static void (*setg_gcc)(void*);

 // This will be set in gcc_android.c for android-specific customization.
-void (*x_cgo_inittls)(void **tlsg, void **tlsbase);
+void (*x_cgo_inittls)(void **tlsg, void **tlsbase) __attribute__((common));

 void
 x_cgo_init(G *g, void (*setg)(void*), void **tlsg, void **tlsbase)
--- a/src/runtime/cgo/gcc_linux_arm.c
+++ b/src/runtime/cgo/gcc_linux_arm.c
@ -10,7 +10,7 @@

 static void *threadentry(void*);

-void (*x_cgo_inittls)(void **tlsg, void **tlsbase);
+void (*x_cgo_inittls)(void **tlsg, void **tlsbase) __attribute__((common));
 static void (*setg_gcc)(void*);

 void
--- a/src/runtime/cgo/gcc_linux_arm64.c
+++ b/src/runtime/cgo/gcc_linux_arm64.c
@ -12,7 +12,7 @@

 static void *threadentry(void*);

-void (*x_cgo_inittls)(void **tlsg, void **tlsbase);
+void (*x_cgo_inittls)(void **tlsg, void **tlsbase) __attribute__((common));
 static void (*setg_gcc)(void*);

 void
--- a/src/runtime/export_test.go
+++ b/src/runtime/export_test.go
@ -1201,12 +1201,12 @@ type TimeHistogram timeHistogram

 // Counts returns the counts for the given bucket, subBucket indices.
 // Returns true if the bucket was valid, otherwise returns the counts
-// for the overflow bucket and false.
+// for the underflow bucket and false.
 func (th *TimeHistogram) Count(bucket, subBucket uint) (uint64, bool) {
 	t := (*timeHistogram)(th)
 	i := bucket*TimeHistNumSubBuckets + subBucket
 	if i >= uint(len(t.counts)) {
-		return t.overflow, false
+		return t.underflow, false
 	}
 	return t.counts[i], true
 }
--- a/src/runtime/histogram.go
+++ b/src/runtime/histogram.go
@ -70,16 +70,14 @@ const (
 // atomically.
 type timeHistogram struct {
 	counts    [timeHistNumSuperBuckets * timeHistNumSubBuckets]uint64
-	overflow uint64
+	underflow uint64
 }

 // record adds the given duration to the distribution.
-//
-// Although the duration is an int64 to facilitate ease-of-use
-// with e.g. nanotime, the duration must be non-negative.
 func (h *timeHistogram) record(duration int64) {
 	if duration < 0 {
-		throw("timeHistogram encountered negative duration")
+		atomic.Xadd64(&h.underflow, 1)
+		return
 	}
 	// The index of the exponential bucket is just the index
 	// of the highest set bit adjusted for how many bits we
@ -92,15 +90,17 @@ func (h *timeHistogram) record(duration int64) {
 		superBucket = uint(sys.Len64(uint64(duration))) - timeHistSubBucketBits
 		if superBucket*timeHistNumSubBuckets >= uint(len(h.counts)) {
 			// The bucket index we got is larger than what we support, so
-			// add into the special overflow bucket.
-			atomic.Xadd64(&h.overflow, 1)
-			return
-		}
+			// include this count in the highest bucket, which extends to
+			// infinity.
+			superBucket = timeHistNumSuperBuckets - 1
+			subBucket = timeHistNumSubBuckets - 1
+		} else {
 			// The linear subbucket index is just the timeHistSubBucketsBits
 			// bits after the top bit. To extract that value, shift down
 			// the duration such that we leave the top bit and the next bits
 			// intact, then extract the index.
 			subBucket = uint((duration >> (superBucket - 1)) % timeHistNumSubBuckets)
+		}
 	} else {
 		subBucket = uint(duration)
 	}
@ -128,7 +128,7 @@ func timeHistogramMetricsBuckets() []float64 {
 		// index to combine it with the bucketMin.
 		subBucketShift := uint(0)
 		if i > 1 {
-			// The first two buckets are exact with respect to integers,
+			// The first two super buckets are exact with respect to integers,
 			// so we'll never have to shift the sub-bucket index. Thereafter,
 			// we shift up by 1 with each subsequent bucket.
 			subBucketShift = uint(i - 2)
--- a/src/runtime/histogram_test.go
+++ b/src/runtime/histogram_test.go
@ -5,6 +5,7 @@
 package runtime_test

 import (
+	"math"
 	. "runtime"
 	"testing"
 )
@ -32,8 +33,8 @@ func TestTimeHistogram(t *testing.T) {
 			h.Record(base + v)
 		}
 	}
-	// Hit the overflow bucket.
-	h.Record(int64(^uint64(0) >> 1))
+	// Hit the underflow bucket.
+	h.Record(int64(-1))

 	// Check to make sure there's exactly one count in each
 	// bucket.
@ -41,7 +42,7 @@ func TestTimeHistogram(t *testing.T) {
 		for j := uint(0); j < TimeHistNumSubBuckets; j++ {
 			c, ok := h.Count(i, j)
 			if !ok {
-				t.Errorf("hit overflow bucket unexpectedly: (%d, %d)", i, j)
+				t.Errorf("hit underflow bucket unexpectedly: (%d, %d)", i, j)
 			} else if c != 1 {
 				t.Errorf("bucket (%d, %d) has count that is not 1: %d", i, j, c)
 			}
@ -49,10 +50,21 @@ func TestTimeHistogram(t *testing.T) {
 	}
 	c, ok := h.Count(TimeHistNumSuperBuckets, 0)
 	if ok {
-		t.Errorf("expected to hit overflow bucket: (%d, %d)", TimeHistNumSuperBuckets, 0)
+		t.Errorf("expected to hit underflow bucket: (%d, %d)", TimeHistNumSuperBuckets, 0)
 	}
 	if c != 1 {
-		t.Errorf("overflow bucket has count that is not 1: %d", c)
+		t.Errorf("underflow bucket has count that is not 1: %d", c)
 	}
+
+	// Check overflow behavior.
+	// By hitting a high value, we should just be adding into the highest bucket.
+	h.Record(math.MaxInt64)
+	c, ok = h.Count(TimeHistNumSuperBuckets-1, TimeHistNumSubBuckets-1)
+	if !ok {
+		t.Error("hit underflow bucket in highest bucket unexpectedly")
+	} else if c != 2 {
+		t.Errorf("highest has count that is not 2: %d", c)
+	}
+
 	dummyTimeHistogram = TimeHistogram{}
 }
--- a/src/runtime/metrics.go
+++ b/src/runtime/metrics.go
@ -43,7 +43,18 @@ func initMetrics() {
 	}
 	sizeClassBuckets = make([]float64, _NumSizeClasses)
 	for i := range sizeClassBuckets {
-		sizeClassBuckets[i] = float64(class_to_size[i])
+		// Size classes have an inclusive upper-bound
+		// and exclusive lower bound (e.g. 48-byte size class is
+		// (32, 48]) whereas we want and inclusive lower-bound
+		// and exclusive upper-bound (e.g. 48-byte size class is
+		// [33, 49). We can achieve this by shifting all bucket
+		// boundaries up by 1.
+		//
+		// Also, a float64 can precisely represent integers with
+		// value up to 2^53 and size classes are relatively small
+		// (nowhere near 2^48 even) so this will give us exact
+		// boundaries.
+		sizeClassBuckets[i] = float64(class_to_size[i] + 1)
 	}
 	timeHistBuckets = timeHistogramMetricsBuckets()
 	metrics = map[string]metricData{
@ -105,9 +116,9 @@ func initMetrics() {
 		"/gc/pauses:seconds": {
 			compute: func(_ *statAggregate, out *metricValue) {
 				hist := out.float64HistOrInit(timeHistBuckets)
-				hist.counts[len(hist.counts)-1] = atomic.Load64(&memstats.gcPauseDist.overflow)
+				hist.counts[0] = atomic.Load64(&memstats.gcPauseDist.underflow)
 				for i := range hist.buckets {
-					hist.counts[i] = atomic.Load64(&memstats.gcPauseDist.counts[i])
+					hist.counts[i+1] = atomic.Load64(&memstats.gcPauseDist.counts[i])
 				}
 			},
 		},
--- a/src/runtime/metrics_test.go
+++ b/src/runtime/metrics_test.go
@ -154,6 +154,12 @@ func TestReadMetricsConsistency(t *testing.T) {
 	if totalVirtual.got != totalVirtual.want {
 		t.Errorf(`"/memory/classes/total:bytes" does not match sum of /memory/classes/**: got %d, want %d`, totalVirtual.got, totalVirtual.want)
 	}
+	if objects.alloc.Counts[0] > 0 {
+		t.Error("found counts for objects of non-positive size in allocs-by-size")
+	}
+	if objects.free.Counts[0] > 0 {
+		t.Error("found counts for objects of non-positive size in frees-by-size")
+	}
 	if len(objects.alloc.Buckets) != len(objects.free.Buckets) {
 		t.Error("allocs-by-size and frees-by-size buckets don't match in length")
 	} else if len(objects.alloc.Counts) != len(objects.free.Counts) {
--- a/src/runtime/mgcmark.go
+++ b/src/runtime/mgcmark.go
@ -101,8 +101,7 @@ func gcMarkRootPrepare() {
 	// Gs may be created after this point, but it's okay that we
 	// ignore them because they begin life without any roots, so
 	// there's nothing to scan, and any roots they create during
-	// the concurrent phase will be scanned during mark
-	// termination.
+	// the concurrent phase will be caught by the write barrier.
 	work.nStackRoots = int(atomic.Loaduintptr(&allglen))

 	work.markrootNext = 0
--- a/src/runtime/os_js.go
+++ b/src/runtime/os_js.go
@ -72,7 +72,7 @@ func clearSignalHandlers() {
 }

 //go:nosplit
-func sigblock() {
+func sigblock(exiting bool) {
 }

 // Called to initialize a new m (including the bootstrap m).
--- a/src/runtime/os_linux.go
+++ b/src/runtime/os_linux.go
@ -301,6 +301,24 @@ func getHugePageSize() uintptr {
 func osinit() {
 	ncpu = getproccount()
 	physHugePageSize = getHugePageSize()
+	if iscgo {
+		// #42494 glibc and musl reserve some signals for
+		// internal use and require they not be blocked by
+		// the rest of a normal C runtime. When the go runtime
+		// blocks...unblocks signals, temporarily, the blocked
+		// interval of time is generally very short. As such,
+		// these expectations of *libc code are mostly met by
+		// the combined go+cgo system of threads. However,
+		// when go causes a thread to exit, via a return from
+		// mstart(), the combined runtime can deadlock if
+		// these signals are blocked. Thus, don't block these
+		// signals when exiting threads.
+		// - glibc: SIGCANCEL (32), SIGSETXID (33)
+		// - musl: SIGTIMER (32), SIGCANCEL (33), SIGSYNCCALL (34)
+		sigdelset(&sigsetAllExiting, 32)
+		sigdelset(&sigsetAllExiting, 33)
+		sigdelset(&sigsetAllExiting, 34)
+	}
 	osArchInit()
 }

--- a/src/runtime/os_plan9.go
+++ b/src/runtime/os_plan9.go
@ -195,7 +195,7 @@ func msigrestore(sigmask sigset) {
 func clearSignalHandlers() {
 }

-func sigblock() {
+func sigblock(exiting bool) {
 }

 // Called to initialize a new m (including the bootstrap m).
--- a/src/runtime/os_windows.go
+++ b/src/runtime/os_windows.go
@ -886,7 +886,7 @@ func clearSignalHandlers() {
 }

 //go:nosplit
-func sigblock() {
+func sigblock(exiting bool) {
 }

 // Called to initialize a new m (including the bootstrap m).
--- a/src/runtime/proc.go
+++ b/src/runtime/proc.go
@ -1313,7 +1313,7 @@ func mexit(osStack bool) {
 		throw("locked m0 woke up")
 	}

-	sigblock()
+	sigblock(true)
 	unminit()

 	// Free the gsignal stack.
@ -1515,6 +1515,7 @@ func syscall_runtime_doAllThreadsSyscall(fn func(bool) bool) {
 	if netpollinited() {
 		netpollBreak()
 	}
+	sigRecvPrepareForFixup()
 	_g_ := getg()
 	if raceenabled {
 		// For m's running without racectx, we loan out the
@ -1754,7 +1755,7 @@ func needm() {
 	// starting a new m to run Go code via newosproc.
 	var sigmask sigset
 	sigsave(&sigmask)
-	sigblock()
+	sigblock(false)

 	// Lock extra list, take head, unlock popped list.
 	// nilokay=false is safe here because of the invariant above,
@ -1903,7 +1904,7 @@ func dropm() {
 	// Setg(nil) clears g, which is the signal handler's cue not to run Go handlers.
 	// It's important not to try to handle a signal between those two steps.
 	sigmask := mp.sigmask
-	sigblock()
+	sigblock(false)
 	unminit()

 	mnext := lockextra(true)
@ -3776,7 +3777,7 @@ func beforefork() {
 	// group. See issue #18600.
 	gp.m.locks++
 	sigsave(&gp.m.sigmask)
-	sigblock()
+	sigblock(false)

 	// This function is called before fork in syscall package.
 	// Code between fork and exec must not allocate memory nor even try to grow stack.
--- a/src/runtime/signal_unix.go
+++ b/src/runtime/signal_unix.go
@ -1042,15 +1042,26 @@ func msigrestore(sigmask sigset) {
 	sigprocmask(_SIG_SETMASK, &sigmask, nil)
 }

-// sigblock blocks all signals in the current thread's signal mask.
+// sigsetAllExiting is used by sigblock(true) when a thread is
+// exiting. sigset_all is defined in OS specific code, and per GOOS
+// behavior may override this default for sigsetAllExiting: see
+// osinit().
+var sigsetAllExiting = sigset_all
+
+// sigblock blocks signals in the current thread's signal mask.
 // This is used to block signals while setting up and tearing down g
-// when a non-Go thread calls a Go function.
-// The OS-specific code is expected to define sigset_all.
+// when a non-Go thread calls a Go function. When a thread is exiting
+// we use the sigsetAllExiting value, otherwise the OS specific
+// definition of sigset_all is used.
 // This is nosplit and nowritebarrierrec because it is called by needm
 // which may be called on a non-Go thread with no g available.
 //go:nosplit
 //go:nowritebarrierrec
-func sigblock() {
+func sigblock(exiting bool) {
+	if exiting {
+		sigprocmask(_SIG_SETMASK, &sigsetAllExiting, nil)
+		return
+	}
 	sigprocmask(_SIG_SETMASK, &sigset_all, nil)
 }

--- a/src/runtime/sigqueue.go
+++ b/src/runtime/sigqueue.go
@ -12,12 +12,16 @@
 // sigsend is called by the signal handler to queue a new signal.
 // signal_recv is called by the Go program to receive a newly queued signal.
 // Synchronization between sigsend and signal_recv is based on the sig.state
-// variable. It can be in 3 states: sigIdle, sigReceiving and sigSending.
+// variable. It can be in 4 states: sigIdle, sigReceiving, sigSending and sigFixup.
 // sigReceiving means that signal_recv is blocked on sig.Note and there are no
 // new pending signals.
 // sigSending means that sig.mask *may* contain new pending signals,
 // signal_recv can't be blocked in this state.
 // sigIdle means that there are no new pending signals and signal_recv is not blocked.
+// sigFixup is a transient state that can only exist as a short
+// transition from sigReceiving and then on to sigIdle: it is
+// used to ensure the AllThreadsSyscall()'s mDoFixup() operation
+// occurs on the sleeping m, waiting to receive a signal.
 // Transitions between states are done atomically with CAS.
 // When signal_recv is unblocked, it resets sig.Note and rechecks sig.mask.
 // If several sigsends and signal_recv execute concurrently, it can lead to
@ -59,6 +63,7 @@ const (
 	sigIdle = iota
 	sigReceiving
 	sigSending
+	sigFixup
 )

 // sigsend delivers a signal from sighandler to the internal signal delivery queue.
@ -112,6 +117,9 @@ Send:
 				notewakeup(&sig.note)
 				break Send
 			}
+		case sigFixup:
+			// nothing to do - we need to wait for sigIdle.
+			osyield()
 		}
 	}

@ -119,6 +127,19 @@ Send:
 	return true
 }

+// sigRecvPrepareForFixup is used to temporarily wake up the
+// signal_recv() running thread while it is blocked waiting for the
+// arrival of a signal. If it causes the thread to wake up, the
+// sig.state travels through this sequence: sigReceiving -> sigFixup
+// -> sigIdle -> sigReceiving and resumes. (This is only called while
+// GC is disabled.)
+//go:nosplit
+func sigRecvPrepareForFixup() {
+	if atomic.Cas(&sig.state, sigReceiving, sigFixup) {
+		notewakeup(&sig.note)
+	}
+}
+
 // Called to receive the next queued signal.
 // Must only be called from a single goroutine at a time.
 //go:linkname signal_recv os/signal.signal_recv
@ -146,8 +167,17 @@ func signal_recv() uint32 {
 					}
 					notetsleepg(&sig.note, -1)
 					noteclear(&sig.note)
+					if !atomic.Cas(&sig.state, sigFixup, sigIdle) {
 						break Receive
 					}
+					// Getting here, the code will
+					// loop around again to sleep
+					// in state sigReceiving. This
+					// path is taken when
+					// sigRecvPrepareForFixup()
+					// has been called by another
+					// thread.
+				}
 			case sigSending:
 				if atomic.Cas(&sig.state, sigSending, sigIdle) {
 					break Receive
--- a/src/runtime/sigqueue_plan9.go
+++ b/src/runtime/sigqueue_plan9.go
@ -92,6 +92,13 @@ func sendNote(s *byte) bool {
 	return true
 }

+// sigRecvPrepareForFixup is a no-op on plan9. (This would only be
+// called while GC is disabled.)
+//
+//go:nosplit
+func sigRecvPrepareForFixup() {
+}
+
 // Called to receive the next queued signal.
 // Must only be called from a single goroutine at a time.
 //go:linkname signal_recv os/signal.signal_recv
--- a/src/syscall/syscall_linux_test.go
+++ b/src/syscall/syscall_linux_test.go
@ -597,6 +597,14 @@ func compareStatus(filter, expect string) error {
 	return nil
 }

+// killAThread locks the goroutine to an OS thread and exits; this
+// causes an OS thread to terminate.
+func killAThread(c <-chan struct{}) {
+	runtime.LockOSThread()
+	<-c
+	return
+}
+
 // TestSetuidEtc performs tests on all of the wrapped system calls
 // that mirror to the 9 glibc syscalls with POSIX semantics. The test
 // here is considered authoritative and should compile and run
@ -647,6 +655,11 @@ func TestSetuidEtc(t *testing.T) {
 	}

 	for i, v := range vs {
+		// Generate some thread churn as we execute the tests.
+		c := make(chan struct{})
+		go killAThread(c)
+		close(c)
+
 		if err := v.fn(); err != nil {
 			t.Errorf("[%d] %q failed: %v", i, v.call, err)
 			continue
--- a/src/time/tzdata/zipdata.go
+++ b/src/time/tzdata/zipdata.go
--- a/test/fixedbugs/issue27595.go
+++ b/test/fixedbugs/issue27595.go
@ -8,7 +8,7 @@ package main

 var a = twoResults()       // ERROR "assignment mismatch: 1 variable but twoResults returns 2 values|2\-valued"
 var b, c, d = twoResults() // ERROR "assignment mismatch: 3 variables but twoResults returns 2 values|cannot initialize"
-var e, f = oneResult()     // ERROR "assignment mismatch: 2 variables but oneResult returns 1 values|cannot initialize"
+var e, f = oneResult()     // ERROR "assignment mismatch: 2 variables but oneResult returns 1 value|cannot initialize"

 func twoResults() (int, int) {
 	return 1, 2
--- a/test/fixedbugs/issue30087.go
+++ b/test/fixedbugs/issue30087.go
@ -7,9 +7,9 @@
 package main

 func main() {
-	var a, b = 1    // ERROR "assignment mismatch: 2 variables but 1 values|wrong number of initializations|cannot initialize"
-	_ = 1, 2        // ERROR "assignment mismatch: 1 variables but 2 values|number of variables does not match|cannot assign"
-	c, d := 1       // ERROR "assignment mismatch: 2 variables but 1 values|wrong number of initializations|cannot initialize"
+	var a, b = 1    // ERROR "assignment mismatch: 2 variables but 1 value|wrong number of initializations|cannot initialize"
+	_ = 1, 2        // ERROR "assignment mismatch: 1 variable but 2 values|number of variables does not match|cannot assign"
+	c, d := 1       // ERROR "assignment mismatch: 2 variables but 1 value|wrong number of initializations|cannot initialize"
 	e, f := 1, 2, 3 // ERROR "assignment mismatch: 2 variables but 3 values|wrong number of initializations|cannot initialize"
 	_, _, _, _ = c, d, e, f
 }
--- a/test/fixedbugs/issue31053.dir/main.go
+++ b/test/fixedbugs/issue31053.dir/main.go
@ -35,8 +35,8 @@ func main() {
 	_ = f.Exported
 	_ = f.exported    // ERROR "f.exported undefined .type f1.Foo has no field or method exported, but does have Exported."
 	_ = f.Unexported  // ERROR "f.Unexported undefined .type f1.Foo has no field or method Unexported."
-	_ = f.unexported  // ERROR "f.unexported undefined .cannot refer to unexported field or method f1..\*Foo..unexported."
-	f.unexported = 10 // ERROR "f.unexported undefined .cannot refer to unexported field or method f1..\*Foo..unexported."
-	f.unexported()    // ERROR "f.unexported undefined .cannot refer to unexported field or method f1..\*Foo..unexported."
+	_ = f.unexported  // ERROR "f.unexported undefined .cannot refer to unexported field or method unexported."
+	f.unexported = 10 // ERROR "f.unexported undefined .cannot refer to unexported field or method unexported."
+	f.unexported()    // ERROR "f.unexported undefined .cannot refer to unexported field or method unexported."
 	_ = f.hook        // ERROR "f.hook undefined .cannot refer to unexported field or method hook."
 }
--- a/test/used.go
+++ b/test/used.go
@ -63,6 +63,7 @@ func _() {
 	_ = f1()               // ok
 	_, _ = f2()            // ok
 	_ = f2()               // ERROR "assignment mismatch: 1 variable but f2 returns 2 values|cannot assign"
+	_ = f1(), 0            // ERROR "assignment mismatch: 1 variable but 2 values|cannot assign"
 	T.M0                   // ERROR "T.M0 .* not used"
 	t.M0                   // ERROR "t.M0 .* not used"
 	cap                    // ERROR "use of builtin cap not in function call|must be called"