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cmd/compile: "invalid variable name x in type switch", where x is a name of a constant

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Small fix: looks like a short variable declaration with a type switch
checks to make sure the variable used had valid shape (ONAME, OTYPE, or
ONONAME) and rejects everything else. Then a new variable is declared.
If the symbol contained in the declaration was a named OLITERAL (still a
valid identifier obviously) it would be rejected, even though a new
variable would have been declared.

Fix adds this case to the check.

Added a test case from issue12413.

Fixes #12413

Change-Id: I150dadafa8ee5612c867d58031027f2dca8c6ebc
Reviewed-on: https://go-review.googlesource.com/15760
Reviewed-by: Minux Ma <minux@golang.org>
Run-TryBot: Minux Ma <minux@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This commit is contained in:
acanino 2015-10-10 21:35:22 -04:00 committed by Minux Ma
parent 3b000b3eae
commit b60c8203ea
3 changed files with 21 additions and 2 deletions
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2
src/cmd/compile/internal/gc/go.y
View file

@ -510,7 +510,7 @@ simple_stmt:
}
if $1.Next != nil {
Yyerror("argument count mismatch: %d = %d", count($1), 1);
} else if ($1.N.Op != ONAME && $1.N.Op != OTYPE && $1.N.Op != ONONAME) || isblank($1.N) {
} else if ($1.N.Op != ONAME && $1.N.Op != OTYPE && $1.N.Op != ONONAME && ($1.N.Op != OLITERAL || $1.N.Name == nil)) || isblank($1.N) {
Yyerror("invalid variable name %s in type switch", $1.N);
} else {
$$.Left = dclname($1.N.Sym);

2
src/cmd/compile/internal/gc/y.go
View file

@ -1586,7 +1586,7 @@ yydefault:
}
if yyDollar[1].list.Next != nil {
Yyerror("argument count mismatch: %d = %d", count(yyDollar[1].list), 1)
} else if (yyDollar[1].list.N.Op != ONAME && yyDollar[1].list.N.Op != OTYPE && yyDollar[1].list.N.Op != ONONAME) || isblank(yyDollar[1].list.N) {
} else if (yyDollar[1].list.N.Op != ONAME && yyDollar[1].list.N.Op != OTYPE && yyDollar[1].list.N.Op != ONONAME && (yyDollar[1].list.N.Op != OLITERAL || yyDollar[1].list.N.Name == nil)) || isblank(yyDollar[1].list.N) {
Yyerror("invalid variable name %s in type switch", yyDollar[1].list.N)
} else {
yyVAL.node.Left = dclname(yyDollar[1].list.N.Sym)

19
test/fixedbugs/issue12413.go Normal file
View file

@ -0,0 +1,19 @@
// compile
// Copyright 2015 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.
// issue 12413: invalid variable name x in type switch: code would fail
// to compile if the variable used in the short variable declaration was
// previously declared as a constant.
package main
func main() {
const x = 42
switch x := interface{}(nil).(type) {
default:
_ = x
}
}