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Commit aa25f6c

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authored
Merge pull request #1208 from nevkontakte/composite-lit
Fix compiler panic when handling composite literals representing named pointer types.
2 parents c3dcfaf + 6e3de82 commit aa25f6c
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‎compiler/expressions.go

Copy file name to clipboardExpand all lines: compiler/expressions.go
+29-3Lines changed: 29 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -100,8 +100,34 @@ func (fc *funcContext) translateExpr(expr ast.Expr) *expression {
100100

101101
switch e := expr.(type) {
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case *ast.CompositeLit:
103-
if ptrType, isPointer := exprType.(*types.Pointer); isPointer {
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exprType = ptrType.Elem()
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if ptrType, isPointer := exprType.Underlying().(*types.Pointer); isPointer {
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// Go automatically treats `[]*T{{}}` as `[]*T{&T{}}`, in which case the
105+
// inner composite literal `{}` would has a pointer type. To make sure the
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// type conversion is handled correctly, we generate the explicit AST for
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// this.
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var rewritten ast.Expr = fc.setType(&ast.UnaryExpr{
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OpPos: e.Pos(),
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Op: token.AND,
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X: fc.setType(&ast.CompositeLit{
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Elts: e.Elts,
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}, ptrType.Elem()),
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}, ptrType)
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if exprType, ok := exprType.(*types.Named); ok {
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// Handle a special case when the pointer type is named, e.g.:
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// type PS *S
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// _ = []PS{{}}
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// In that case the value corresponding to the inner literal `{}` is
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// initialized as `&S{}` and then converted to `PS`: `[]PS{PS(&S{})}`.
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typeCast := fc.setType(&ast.CallExpr{
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Fun: fc.newTypeIdent(exprType.String(), exprType.Obj()),
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Lparen: e.Lbrace,
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Args: []ast.Expr{rewritten},
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Rparen: e.Rbrace,
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}, exprType)
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rewritten = typeCast
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}
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return fc.translateExpr(rewritten)
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}
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collectIndexedElements := func(elementType types.Type) []string {
@@ -173,7 +199,7 @@ func (fc *funcContext) translateExpr(expr ast.Expr) *expression {
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}
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return fc.formatExpr("new %s.ptr(%s)", fc.typeName(exprType), strings.Join(elements, ", "))
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default:
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panic(fmt.Sprintf("Unhandled CompositeLit type: %T\n", t))
202+
panic(fmt.Sprintf("Unhandled CompositeLit type: %[1]T %[1]v\n", t))
177203
}
178204

179205
case *ast.FuncLit:

‎compiler/utils.go

Copy file name to clipboardExpand all lines: compiler/utils.go
+6Lines changed: 6 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -282,6 +282,12 @@ func (fc *funcContext) newIdent(name string, t types.Type) *ast.Ident {
282282
return ident
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}
284284

285+
func (fc *funcContext) newTypeIdent(name string, obj types.Object) *ast.Ident {
286+
ident := ast.NewIdent(name)
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fc.pkgCtx.Info.Uses[ident] = obj
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return ident
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}
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func (fc *funcContext) setType(e ast.Expr, t types.Type) ast.Expr {
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fc.pkgCtx.Types[e] = types.TypeAndValue{Type: t}
287293
return e

‎tests/misc_test.go

Copy file name to clipboardExpand all lines: tests/misc_test.go
+15Lines changed: 15 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -920,3 +920,18 @@ func TestAssignImplicitConversion(t *testing.T) {
920920
}
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})
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}
923+
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func TestCompositeLiterals(t *testing.T) {
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type S struct{}
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type SP *S
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s1 := []*S{{}}
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if got := reflect.TypeOf(s1[0]); got.String() != "*tests.S" {
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t.Errorf("Got: reflect.TypeOf(s1[0]) = %v. Want: *tests.S", got)
931+
}
932+
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s2 := []SP{{}}
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if got := reflect.TypeOf(s2[0]); got.String() != "tests.SP" {
935+
t.Errorf("Got: reflect.TypeOf(s2[0]) = %v. Want: tests.SP", got)
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}
937+
}

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