diff options
| -rw-r--r-- | src/cmd/compile/internal/syntax/parser.go | 17 | ||||
| -rw-r--r-- | src/cmd/compile/internal/syntax/testdata/issue46558.src | 14 |
2 files changed, 30 insertions, 1 deletions
diff --git a/src/cmd/compile/internal/syntax/parser.go b/src/cmd/compile/internal/syntax/parser.go index 0e711a0113..503dea7fae 100644 --- a/src/cmd/compile/internal/syntax/parser.go +++ b/src/cmd/compile/internal/syntax/parser.go @@ -1100,7 +1100,7 @@ loop: complit_ok = true } case *IndexExpr: - if p.xnest >= 0 { + if p.xnest >= 0 && !isValue(t) { // x is possibly a composite literal type complit_ok = true } @@ -1127,6 +1127,21 @@ loop: return x } +// isValue reports whether x syntactically must be a value (and not a type) expression. +func isValue(x Expr) bool { + switch x := x.(type) { + case *BasicLit, *CompositeLit, *FuncLit, *SliceExpr, *AssertExpr, *TypeSwitchGuard, *CallExpr: + return true + case *Operation: + return x.Op != Mul || x.Y != nil // *T may be a type + case *ParenExpr: + return isValue(x.X) + case *IndexExpr: + return isValue(x.X) || isValue(x.Index) + } + return false +} + // Element = Expression | LiteralValue . func (p *parser) bare_complitexpr() Expr { if trace { diff --git a/src/cmd/compile/internal/syntax/testdata/issue46558.src b/src/cmd/compile/internal/syntax/testdata/issue46558.src new file mode 100644 index 0000000000..a22b600825 --- /dev/null +++ b/src/cmd/compile/internal/syntax/testdata/issue46558.src @@ -0,0 +1,14 @@ +// Copyright 2021 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 p + +func F(s string) { + switch s[0] { + case 'a': + case s[2] { // ERROR unexpected { + case 'b': + } + } +} // ERROR non-declaration statement |