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cmd/compile: use dictionary to convert type to shaped interface type

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When we convert a type to a shaped interface type, we are not able
to recognize the itab. So passing the itab by dictionary as the
workaround.

Fixes #52026.

Change-Id: I75c23c7dd215daf9761dc24116a8af2c28c6d948
Reviewed-on: https://go-review.googlesource.com/c/go/+/401034
Run-TryBot: Wayne Zuo <wdvxdr@golangcn.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Auto-Submit: Keith Randall <khr@golang.org>
Reviewed-by: Keith Randall <khr@google.com>
Reviewed-by: David Chase <drchase@google.com>
Reviewed-by: Keith Randall <khr@golang.org>
This commit is contained in:
Wayne Zuo 2022-04-19 21:24:33 +08:00 committed by Gopher Robot
parent 23f13255f0
commit 64b6e44ad7
2 changed files with 55 additions and 4 deletions
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9
src/cmd/compile/internal/noder/stencil.go
View File

@ -1325,8 +1325,8 @@ func (g *genInst) dictPass(info *instInfo) {
mce := m.(*ir.ConvExpr)
// Note: x's argument is still typed as a type parameter.
// m's argument now has an instantiated type.
if mce.X.Type().HasShape() || (mce.X.Type().IsInterface() && m.Type().HasShape()) {
m = convertUsingDictionary(info, info.dictParam, m.Pos(), m.(*ir.ConvExpr).X, m, m.Type())
if mce.X.Type().HasShape() || m.Type().HasShape() {
m = convertUsingDictionary(info, info.dictParam, m.Pos(), mce.X, m, m.Type())
}
case ir.ODOTTYPE, ir.ODOTTYPE2:
if !m.Type().HasShape() {
@ -1420,7 +1420,7 @@ func findDictType(info *instInfo, t *types.Type) int {
// instantiated node of the CONVIFACE node or XDOT node (for a bound method call) that is causing the
// conversion.
func convertUsingDictionary(info *instInfo, dictParam *ir.Name, pos src.XPos, v ir.Node, in ir.Node, dst *types.Type) ir.Node {
assert(v.Type().HasShape() || v.Type().IsInterface() && in.Type().HasShape())
assert(v.Type().HasShape() || in.Type().HasShape())
assert(dst.IsInterface())
if v.Type().IsInterface() {
@ -1799,6 +1799,7 @@ func (g *genInst) finalizeSyms() {
g.instantiateMethods()
itabLsym := reflectdata.ITabLsym(srctype, dsttype)
d.off = objw.SymPtr(lsym, d.off, itabLsym, 0)
markTypeUsed(srctype, lsym)
infoPrint(" + Itab for (%v,%v)\n", srctype, dsttype)
}
}
@ -1974,7 +1975,7 @@ func (g *genInst) getInstInfo(st *ir.Func, shapes []*types.Type, instInfo *instI
}
case ir.OCONVIFACE:
if n.Type().IsInterface() && !n.Type().IsEmptyInterface() &&
n.(*ir.ConvExpr).X.Type().HasShape() {
(n.Type().HasShape() || n.(*ir.ConvExpr).X.Type().HasShape()) {
infoPrint(" Itab for interface conv: %v\n", n)
info.itabConvs = append(info.itabConvs, n)
}

50
test/typeparam/issue52026.go Normal file
View File

@ -0,0 +1,50 @@
// run
// Copyright 2022 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 main
func returnOption[T any](n int) Option[T] {
if n == 1 {
return Some[T]{}
} else {
return None{}
}
}
type Option[T any] interface {
sealedOption()
}
type Some[T any] struct {
val T
}
func (s Some[T]) Value() T {
return s.val
}
func (s Some[T]) sealedOption() {}
type None struct{}
func (s None) sealedOption() {}
func main() {
s := returnOption[int](1)
_ = s.(Some[int])
s = returnOption[int](0)
_ = s.(None)
switch (any)(s).(type) {
case Some[int]:
panic("s is a Some[int]")
case None:
// ok
default:
panic("oops")
}
}