mirror of
https://github.com/golang/go.git
synced 2025-05-28 10:51:22 +00:00
cmd/cgo: use a named type to indicate syntactic context
We previously used bare strings, which made it difficult to see (and to cross-reference) the set of allowed context values. This change is purely cosmetic, but makes it easier for me to understand how to address #21878. updates #21878 Change-Id: I9027d94fd5997a0fe857c0055dea8719e1511f03 Reviewed-on: https://go-review.googlesource.com/63830 Run-TryBot: Bryan Mills <bcmills@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Ian Lance Taylor <iant@golang.org>
This commit is contained in:
parent
3066dbad52
commit
f2a5ed852b
@ -126,7 +126,7 @@ func (f *File) ParseGo(name string, src []byte) {
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if f.Ref == nil {
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f.Ref = make([]*Ref, 0, 8)
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}
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f.walk(ast2, "prog", (*File).saveExprs)
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f.walk(ast2, ctxProg, (*File).saveExprs)
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// Accumulate exported functions.
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// The comments are only on ast1 but we need to
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@ -134,8 +134,8 @@ func (f *File) ParseGo(name string, src []byte) {
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// The first walk fills in ExpFunc, and the
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// second walk changes the entries to
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// refer to ast2 instead.
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f.walk(ast1, "prog", (*File).saveExport)
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f.walk(ast2, "prog", (*File).saveExport2)
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f.walk(ast1, ctxProg, (*File).saveExport)
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f.walk(ast2, ctxProg, (*File).saveExport2)
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f.Comments = ast1.Comments
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f.AST = ast2
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@ -166,7 +166,7 @@ func commentText(g *ast.CommentGroup) string {
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}
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// Save various references we are going to need later.
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func (f *File) saveExprs(x interface{}, context string) {
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func (f *File) saveExprs(x interface{}, context astContext) {
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switch x := x.(type) {
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case *ast.Expr:
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switch (*x).(type) {
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@ -179,7 +179,7 @@ func (f *File) saveExprs(x interface{}, context string) {
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}
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// Save references to C.xxx for later processing.
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func (f *File) saveRef(n *ast.Expr, context string) {
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func (f *File) saveRef(n *ast.Expr, context astContext) {
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sel := (*n).(*ast.SelectorExpr)
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// For now, assume that the only instance of capital C is when
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// used as the imported package identifier.
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@ -189,10 +189,10 @@ func (f *File) saveRef(n *ast.Expr, context string) {
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if l, ok := sel.X.(*ast.Ident); !ok || l.Name != "C" {
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return
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}
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if context == "as2" {
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context = "expr"
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if context == ctxAssign2 {
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context = ctxExpr
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}
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if context == "embed-type" {
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if context == ctxEmbedType {
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error_(sel.Pos(), "cannot embed C type")
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}
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goname := sel.Sel.Name
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@ -223,7 +223,7 @@ func (f *File) saveRef(n *ast.Expr, context string) {
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}
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// Save calls to C.xxx for later processing.
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func (f *File) saveCall(call *ast.CallExpr, context string) {
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func (f *File) saveCall(call *ast.CallExpr, context astContext) {
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sel, ok := call.Fun.(*ast.SelectorExpr)
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if !ok {
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return
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@ -231,12 +231,12 @@ func (f *File) saveCall(call *ast.CallExpr, context string) {
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if l, ok := sel.X.(*ast.Ident); !ok || l.Name != "C" {
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return
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}
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c := &Call{Call: call, Deferred: context == "defer"}
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c := &Call{Call: call, Deferred: context == ctxDefer}
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f.Calls = append(f.Calls, c)
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}
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// If a function should be exported add it to ExpFunc.
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func (f *File) saveExport(x interface{}, context string) {
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func (f *File) saveExport(x interface{}, context astContext) {
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n, ok := x.(*ast.FuncDecl)
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if !ok {
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return
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@ -276,7 +276,7 @@ func (f *File) saveExport(x interface{}, context string) {
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}
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// Make f.ExpFunc[i] point at the Func from this AST instead of the other one.
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func (f *File) saveExport2(x interface{}, context string) {
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func (f *File) saveExport2(x interface{}, context astContext) {
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n, ok := x.(*ast.FuncDecl)
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if !ok {
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return
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@ -290,8 +290,30 @@ func (f *File) saveExport2(x interface{}, context string) {
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}
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}
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type astContext int
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const (
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ctxProg astContext = iota
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ctxEmbedType
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ctxType
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ctxStmt
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ctxExpr
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ctxField
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ctxParam
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ctxAssign2 // assignment of a single expression to two variables
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ctxSwitch
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ctxTypeSwitch
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ctxFile
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ctxDecl
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ctxSpec
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ctxDefer
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ctxCall // any function call other than ctxCall2
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ctxCall2 // function call whose result is assigned to two variables
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ctxSelector
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)
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// walk walks the AST x, calling visit(f, x, context) for each node.
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func (f *File) walk(x interface{}, context string, visit func(*File, interface{}, string)) {
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func (f *File) walk(x interface{}, context astContext, visit func(*File, interface{}, astContext)) {
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visit(f, x, context)
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switch n := x.(type) {
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case *ast.Expr:
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@ -306,10 +328,10 @@ func (f *File) walk(x interface{}, context string, visit func(*File, interface{}
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// These are ordered and grouped to match ../../go/ast/ast.go
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case *ast.Field:
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if len(n.Names) == 0 && context == "field" {
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f.walk(&n.Type, "embed-type", visit)
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if len(n.Names) == 0 && context == ctxField {
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f.walk(&n.Type, ctxEmbedType, visit)
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} else {
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f.walk(&n.Type, "type", visit)
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f.walk(&n.Type, ctxType, visit)
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}
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case *ast.FieldList:
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for _, field := range n.List {
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@ -320,163 +342,163 @@ func (f *File) walk(x interface{}, context string, visit func(*File, interface{}
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case *ast.Ellipsis:
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case *ast.BasicLit:
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case *ast.FuncLit:
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f.walk(n.Type, "type", visit)
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f.walk(n.Body, "stmt", visit)
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f.walk(n.Type, ctxType, visit)
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f.walk(n.Body, ctxStmt, visit)
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case *ast.CompositeLit:
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f.walk(&n.Type, "type", visit)
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f.walk(n.Elts, "expr", visit)
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f.walk(&n.Type, ctxType, visit)
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f.walk(n.Elts, ctxExpr, visit)
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case *ast.ParenExpr:
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f.walk(&n.X, context, visit)
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case *ast.SelectorExpr:
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f.walk(&n.X, "selector", visit)
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f.walk(&n.X, ctxSelector, visit)
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case *ast.IndexExpr:
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f.walk(&n.X, "expr", visit)
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f.walk(&n.Index, "expr", visit)
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f.walk(&n.X, ctxExpr, visit)
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f.walk(&n.Index, ctxExpr, visit)
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case *ast.SliceExpr:
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f.walk(&n.X, "expr", visit)
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f.walk(&n.X, ctxExpr, visit)
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if n.Low != nil {
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f.walk(&n.Low, "expr", visit)
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f.walk(&n.Low, ctxExpr, visit)
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}
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if n.High != nil {
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f.walk(&n.High, "expr", visit)
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f.walk(&n.High, ctxExpr, visit)
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}
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if n.Max != nil {
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f.walk(&n.Max, "expr", visit)
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f.walk(&n.Max, ctxExpr, visit)
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}
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case *ast.TypeAssertExpr:
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f.walk(&n.X, "expr", visit)
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f.walk(&n.Type, "type", visit)
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f.walk(&n.X, ctxExpr, visit)
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f.walk(&n.Type, ctxType, visit)
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case *ast.CallExpr:
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if context == "as2" {
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f.walk(&n.Fun, "call2", visit)
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if context == ctxAssign2 {
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f.walk(&n.Fun, ctxCall2, visit)
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} else {
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f.walk(&n.Fun, "call", visit)
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f.walk(&n.Fun, ctxCall, visit)
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}
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f.walk(n.Args, "expr", visit)
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f.walk(n.Args, ctxExpr, visit)
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case *ast.StarExpr:
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f.walk(&n.X, context, visit)
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case *ast.UnaryExpr:
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f.walk(&n.X, "expr", visit)
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f.walk(&n.X, ctxExpr, visit)
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case *ast.BinaryExpr:
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f.walk(&n.X, "expr", visit)
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f.walk(&n.Y, "expr", visit)
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f.walk(&n.X, ctxExpr, visit)
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f.walk(&n.Y, ctxExpr, visit)
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case *ast.KeyValueExpr:
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f.walk(&n.Key, "expr", visit)
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f.walk(&n.Value, "expr", visit)
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f.walk(&n.Key, ctxExpr, visit)
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f.walk(&n.Value, ctxExpr, visit)
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case *ast.ArrayType:
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f.walk(&n.Len, "expr", visit)
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f.walk(&n.Elt, "type", visit)
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f.walk(&n.Len, ctxExpr, visit)
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f.walk(&n.Elt, ctxType, visit)
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case *ast.StructType:
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f.walk(n.Fields, "field", visit)
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f.walk(n.Fields, ctxField, visit)
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case *ast.FuncType:
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f.walk(n.Params, "param", visit)
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f.walk(n.Params, ctxParam, visit)
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if n.Results != nil {
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f.walk(n.Results, "param", visit)
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f.walk(n.Results, ctxParam, visit)
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}
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case *ast.InterfaceType:
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f.walk(n.Methods, "field", visit)
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f.walk(n.Methods, ctxField, visit)
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case *ast.MapType:
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f.walk(&n.Key, "type", visit)
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f.walk(&n.Value, "type", visit)
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f.walk(&n.Key, ctxType, visit)
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f.walk(&n.Value, ctxType, visit)
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case *ast.ChanType:
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f.walk(&n.Value, "type", visit)
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f.walk(&n.Value, ctxType, visit)
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case *ast.BadStmt:
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case *ast.DeclStmt:
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f.walk(n.Decl, "decl", visit)
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f.walk(n.Decl, ctxDecl, visit)
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case *ast.EmptyStmt:
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case *ast.LabeledStmt:
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f.walk(n.Stmt, "stmt", visit)
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f.walk(n.Stmt, ctxStmt, visit)
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case *ast.ExprStmt:
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f.walk(&n.X, "expr", visit)
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f.walk(&n.X, ctxExpr, visit)
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case *ast.SendStmt:
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f.walk(&n.Chan, "expr", visit)
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f.walk(&n.Value, "expr", visit)
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f.walk(&n.Chan, ctxExpr, visit)
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f.walk(&n.Value, ctxExpr, visit)
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case *ast.IncDecStmt:
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f.walk(&n.X, "expr", visit)
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f.walk(&n.X, ctxExpr, visit)
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case *ast.AssignStmt:
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f.walk(n.Lhs, "expr", visit)
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f.walk(n.Lhs, ctxExpr, visit)
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if len(n.Lhs) == 2 && len(n.Rhs) == 1 {
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f.walk(n.Rhs, "as2", visit)
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f.walk(n.Rhs, ctxAssign2, visit)
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} else {
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f.walk(n.Rhs, "expr", visit)
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f.walk(n.Rhs, ctxExpr, visit)
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}
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case *ast.GoStmt:
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f.walk(n.Call, "expr", visit)
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f.walk(n.Call, ctxExpr, visit)
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case *ast.DeferStmt:
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f.walk(n.Call, "defer", visit)
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f.walk(n.Call, ctxDefer, visit)
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case *ast.ReturnStmt:
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f.walk(n.Results, "expr", visit)
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f.walk(n.Results, ctxExpr, visit)
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case *ast.BranchStmt:
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case *ast.BlockStmt:
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f.walk(n.List, context, visit)
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case *ast.IfStmt:
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f.walk(n.Init, "stmt", visit)
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f.walk(&n.Cond, "expr", visit)
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f.walk(n.Body, "stmt", visit)
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f.walk(n.Else, "stmt", visit)
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f.walk(n.Init, ctxStmt, visit)
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f.walk(&n.Cond, ctxExpr, visit)
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f.walk(n.Body, ctxStmt, visit)
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f.walk(n.Else, ctxStmt, visit)
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case *ast.CaseClause:
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if context == "typeswitch" {
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context = "type"
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if context == ctxTypeSwitch {
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context = ctxType
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} else {
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context = "expr"
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context = ctxExpr
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}
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f.walk(n.List, context, visit)
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f.walk(n.Body, "stmt", visit)
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f.walk(n.Body, ctxStmt, visit)
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case *ast.SwitchStmt:
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f.walk(n.Init, "stmt", visit)
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f.walk(&n.Tag, "expr", visit)
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f.walk(n.Body, "switch", visit)
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f.walk(n.Init, ctxStmt, visit)
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f.walk(&n.Tag, ctxExpr, visit)
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f.walk(n.Body, ctxSwitch, visit)
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case *ast.TypeSwitchStmt:
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f.walk(n.Init, "stmt", visit)
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f.walk(n.Assign, "stmt", visit)
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f.walk(n.Body, "typeswitch", visit)
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f.walk(n.Init, ctxStmt, visit)
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f.walk(n.Assign, ctxStmt, visit)
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f.walk(n.Body, ctxTypeSwitch, visit)
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case *ast.CommClause:
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f.walk(n.Comm, "stmt", visit)
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f.walk(n.Body, "stmt", visit)
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f.walk(n.Comm, ctxStmt, visit)
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f.walk(n.Body, ctxStmt, visit)
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case *ast.SelectStmt:
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f.walk(n.Body, "stmt", visit)
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f.walk(n.Body, ctxStmt, visit)
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case *ast.ForStmt:
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f.walk(n.Init, "stmt", visit)
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f.walk(&n.Cond, "expr", visit)
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f.walk(n.Post, "stmt", visit)
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f.walk(n.Body, "stmt", visit)
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f.walk(n.Init, ctxStmt, visit)
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f.walk(&n.Cond, ctxExpr, visit)
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f.walk(n.Post, ctxStmt, visit)
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f.walk(n.Body, ctxStmt, visit)
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case *ast.RangeStmt:
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f.walk(&n.Key, "expr", visit)
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f.walk(&n.Value, "expr", visit)
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f.walk(&n.X, "expr", visit)
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f.walk(n.Body, "stmt", visit)
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f.walk(&n.Key, ctxExpr, visit)
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f.walk(&n.Value, ctxExpr, visit)
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f.walk(&n.X, ctxExpr, visit)
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f.walk(n.Body, ctxStmt, visit)
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case *ast.ImportSpec:
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case *ast.ValueSpec:
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f.walk(&n.Type, "type", visit)
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f.walk(&n.Type, ctxType, visit)
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if len(n.Names) == 2 && len(n.Values) == 1 {
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f.walk(&n.Values[0], "as2", visit)
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f.walk(&n.Values[0], ctxAssign2, visit)
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} else {
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f.walk(n.Values, "expr", visit)
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f.walk(n.Values, ctxExpr, visit)
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}
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case *ast.TypeSpec:
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f.walk(&n.Type, "type", visit)
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f.walk(&n.Type, ctxType, visit)
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|
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case *ast.BadDecl:
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case *ast.GenDecl:
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f.walk(n.Specs, "spec", visit)
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f.walk(n.Specs, ctxSpec, visit)
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case *ast.FuncDecl:
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if n.Recv != nil {
|
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f.walk(n.Recv, "param", visit)
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f.walk(n.Recv, ctxParam, visit)
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}
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f.walk(n.Type, "type", visit)
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f.walk(n.Type, ctxType, visit)
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if n.Body != nil {
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f.walk(n.Body, "stmt", visit)
|
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f.walk(n.Body, ctxStmt, visit)
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||||
}
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|
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case *ast.File:
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f.walk(n.Decls, "decl", visit)
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f.walk(n.Decls, ctxDecl, visit)
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||||
|
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case *ast.Package:
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for _, file := range n.Files {
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f.walk(file, "file", visit)
|
||||
f.walk(file, ctxFile, visit)
|
||||
}
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||||
|
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case []ast.Decl:
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|
@ -748,7 +748,7 @@ func (p *Package) rewriteCall(f *File, call *Call, name *Name) bool {
|
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|
||||
// If this call expects two results, we have to
|
||||
// adjust the results of the function we generated.
|
||||
if ref.Context == "call2" {
|
||||
if ref.Context == ctxCall2 {
|
||||
if ftype.Results == nil {
|
||||
// An explicit void argument
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||||
// looks odd but it seems to
|
||||
@ -940,8 +940,8 @@ func (p *Package) checkAddrArgs(f *File, args []ast.Expr, x ast.Expr) []ast.Expr
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// effect is a function call.
|
||||
func (p *Package) hasSideEffects(f *File, x ast.Expr) bool {
|
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found := false
|
||||
f.walk(x, "expr",
|
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func(f *File, x interface{}, context string) {
|
||||
f.walk(x, ctxExpr,
|
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func(f *File, x interface{}, context astContext) {
|
||||
switch x.(type) {
|
||||
case *ast.CallExpr:
|
||||
found = true
|
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@ -1080,10 +1080,10 @@ func (p *Package) rewriteRef(f *File) {
|
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}
|
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var expr ast.Expr = ast.NewIdent(r.Name.Mangle) // default
|
||||
switch r.Context {
|
||||
case "call", "call2":
|
||||
case ctxCall, ctxCall2:
|
||||
if r.Name.Kind != "func" {
|
||||
if r.Name.Kind == "type" {
|
||||
r.Context = "type"
|
||||
r.Context = ctxType
|
||||
if r.Name.Type == nil {
|
||||
error_(r.Pos(), "invalid conversion to C.%s: undefined C type '%s'", fixGo(r.Name.Go), r.Name.C)
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||||
break
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@ -1095,7 +1095,7 @@ func (p *Package) rewriteRef(f *File) {
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||||
break
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||||
}
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functions[r.Name.Go] = true
|
||||
if r.Context == "call2" {
|
||||
if r.Context == ctxCall2 {
|
||||
if r.Name.Go == "_CMalloc" {
|
||||
error_(r.Pos(), "no two-result form for C.malloc")
|
||||
break
|
||||
@ -1113,7 +1113,7 @@ func (p *Package) rewriteRef(f *File) {
|
||||
r.Name = n
|
||||
break
|
||||
}
|
||||
case "expr":
|
||||
case ctxExpr:
|
||||
switch r.Name.Kind {
|
||||
case "func":
|
||||
if builtinDefs[r.Name.C] != "" {
|
||||
@ -1154,13 +1154,13 @@ func (p *Package) rewriteRef(f *File) {
|
||||
case "macro":
|
||||
expr = &ast.CallExpr{Fun: expr}
|
||||
}
|
||||
case "selector":
|
||||
case ctxSelector:
|
||||
if r.Name.Kind == "var" {
|
||||
expr = &ast.StarExpr{Star: (*r.Expr).Pos(), X: expr}
|
||||
} else {
|
||||
error_(r.Pos(), "only C variables allowed in selector expression %s", fixGo(r.Name.Go))
|
||||
}
|
||||
case "type":
|
||||
case ctxType:
|
||||
if r.Name.Kind != "type" {
|
||||
error_(r.Pos(), "expression C.%s used as type", fixGo(r.Name.Go))
|
||||
} else if r.Name.Type == nil {
|
||||
|
@ -76,7 +76,7 @@ type Call struct {
|
||||
type Ref struct {
|
||||
Name *Name
|
||||
Expr *ast.Expr
|
||||
Context string // "type", "expr", "call", or "call2"
|
||||
Context astContext
|
||||
}
|
||||
|
||||
func (r *Ref) Pos() token.Pos {
|
||||
@ -301,7 +301,7 @@ func main() {
|
||||
p.Translate(f)
|
||||
for _, cref := range f.Ref {
|
||||
switch cref.Context {
|
||||
case "call", "call2":
|
||||
case ctxCall, ctxCall2:
|
||||
if cref.Name.Kind != "type" {
|
||||
break
|
||||
}
|
||||
|
Loading…
x
Reference in New Issue
Block a user