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go/test/fixedbugs/issue8042.go
Robert Griesemer 912a638b0c cmd/compile: check labels and branches during parse time
Instead of a separate check control flow pass (checkcfg.go)
operating on nodes, perform this check at parse time on the
new syntax tree. Permits this check to be done concurrently,
and doesn't depend on the specifics of the symbol's dclstack
implementation anymore. The remaining dclstack uses will be
removed in a follow-up change.

- added CheckBranches Mode flag (so we can turn off the check
  if we only care about syntactic correctness, e.g. for tests)

- adjusted test/goto.go error messages: the new branches
  checker only reports if a goto jumps into a block, but not
  which block (we may want to improve this again, eventually)

- also, the new branches checker reports one variable that
  is being jumped over by a goto, but it may not be the first
  one declared (this is fine either way)

- the new branches checker reports additional errors for
  fixedbugs/issue14006.go (not crucial to avoid those errors)

- the new branches checker now correctly reports only
  variable declarations being jumped over, rather than
  all declarations (issue 8042). Added respective tests.

Fixes #8042.

Change-Id: I53b6e1bda189748e1e1fb5b765a8a64337c27d40
Reviewed-on: https://go-review.googlesource.com/39998
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
2017-04-19 00:36:34 +00:00

67 lines
688 B
Go

// compile
// Copyright 2017 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.
// Verify that gotos across non-variable declarations
// are accepted.
package p
func _() {
goto L1
const x = 0
L1:
goto L2
type T int
L2:
}
func _() {
{
goto L1
}
const x = 0
L1:
{
goto L2
}
type T int
L2:
}
func _(d int) {
if d > 0 {
goto L1
} else {
goto L2
}
const x = 0
L1:
switch d {
case 1:
goto L3
case 2:
default:
goto L4
}
type T1 int
L2:
const y = 1
L3:
for d > 0 {
if d < 10 {
goto L4
}
}
type T2 int
L4:
select {
default:
goto L5
}
type T3 int
L5:
}