cmd/compile: don't crash on invalid labeled statement

Fixes #14006.

Change-Id: Ia819073677ad6993c02255e23760ee21598427b4
Reviewed-on: https://go-review.googlesource.com/18736
Run-TryBot: Robert Griesemer <gri@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This commit is contained in:
Robert Griesemer 2016-01-19 13:14:03 -08:00
parent 92ba69d216
commit 7ce2402bae
2 changed files with 70 additions and 1 deletions

View file

@ -668,9 +668,14 @@ func (p *parser) simple_stmt(labelOk, rangeOk bool) *Node {
if labelOk {
// If we have a labelname, it was parsed by operand
// (calling p.name()) and given an ONAME, ONONAME, OTYPE, OPACK, or OLITERAL node.
// We only have a labelname if there is a symbol (was issue 14006).
switch lhs.Op {
case ONAME, ONONAME, OTYPE, OPACK, OLITERAL:
lhs = newname(lhs.Sym)
if lhs.Sym != nil {
lhs = newname(lhs.Sym)
break
}
fallthrough
default:
p.syntax_error("expecting semicolon or newline or }")
// we already progressed, no need to advance

View file

@ -0,0 +1,64 @@
// errorcheck
// Copyright 2016 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.
// Literals that happen to resolve to named constants
// may be used as label names (see issue 13684). Make
// sure that other literals don't crash the compiler.
package main
const labelname = 1
func main() {
goto labelname
labelname:
}
func f() {
var x int
switch x {
case 1:
2: // ERROR "unexpected :"
case 2:
}
switch x {
case 1:
2: ; // ERROR "unexpected :"
case 2:
}
var y string
switch y {
case "foo":
"bar": // ERROR "unexpected :"
case "bar":
}
switch y {
case "foo":
"bar": ; // ERROR "unexpected :"
case "bar":
}
var z bool
switch {
case z:
labelname: // ERROR "missing statement after label"
case false:
}
switch {
case z:
labelname:
}
switch {
case z:
labelname: ;
case false:
}
}