code review 13326045: cmd/gc: make method names for function scoped types unique

cmd/gc: make method names for function scoped types unique

Types in function scope can have methods on them if they embed another type, but we didn't make the name unique, meaning that 2 identically named types in different functions would conflict with eachother.

Fixes issue 6269.

[DMorsing, 2013-08-28 21:35:27]

Hello golang-dev@googlegroups.com,

I'd like you to review this change to
https://code.google.com/p/go/

[bradfitz, 2013-08-28 21:43:21]

LGTM



On Wed, Aug 28, 2013 at 2:35 PM, <daniel.morsing@gmail.com> wrote:

> Reviewers: golang-dev1,
>
> Message:
> Hello golang-dev@googlegroups.com,
>
> I'd like you to review this change to
> https://code.google.com/p/go/
>
>
> Description:
> cmd/gc: make method names for function scoped types unique
>
> Types in function scope can have methods on them if they embed another
> type, but we didn't the name unique, meaning that 2 identically named
> types in different functions would conflict with eachother.
>
> Fixes issue 6269.
>
> Please review this at
https://codereview.appspot.**com/13326045/<https://codereview.appspot.com/133...
>
> Affected files:
>   M src/cmd/gc/fmt.c
>   A test/fixedbugs/issue6269.go
>
>
> Index: src/cmd/gc/fmt.c
> ==============================**==============================**=======
> --- a/src/cmd/gc/fmt.c
> +++ b/src/cmd/gc/fmt.c
> @@ -604,8 +604,11 @@
>         if(!(fp->flags&FmtLong) && t->sym && t->etype != TFIELD && t !=
> types[t->etype]) {
>                 switch(fmtmode) {
>                 case FTypeId:
> -                       if(fp->flags&FmtShort)
> +                       if(fp->flags&FmtShort) {
> +                               if(t->vargen)
> +                                       return fmtprint(fp, "%hS·%d",
> t->sym, t->vargen);
>                                 return fmtprint(fp, "%hS", t->sym);
> +                       }
>                         if(fp->flags&FmtUnsigned)
>                                 return fmtprint(fp, "%uS", t->sym);
>                         // fallthrough
> Index: test/fixedbugs/issue6269.go
> ==============================**==============================**=======
> new file mode 100644
> --- /dev/null
> +++ b/test/fixedbugs/issue6269.go
> @@ -0,0 +1,39 @@
> +// run
> +
> +// Copyright 2013 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 6269: name collision on method names for function local types.
> +
> +package main
> +
> +type foo struct{}
> +
> +func (foo) Error() string {
> +       return "ok"
> +}
> +
> +type bar struct{}
> +
> +func (bar) Error() string {
> +       return "fail"
> +}
> +
> +func unused() {
> +       type collision struct {
> +               bar
> +       }
> +       _ = collision{}
> +}
> +
> +func main() {
> +       type collision struct {
> +               foo
> +       }
> +       s := error(collision{})
> +       if str := s.Error(); str != "ok" {
> +               println("s.Error() ==", str)
> +               panic(`s.Error() != "ok"`)
> +       }
> +}
>
>
> --
>
> ---You received this message because you are subscribed to the Google
> Groups "golang-dev" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to
golang-dev+unsubscribe@**googlegroups.com<golang-dev%2Bunsubscribe@googlegrou...
> .
> For more options, visit
https://groups.google.com/**groups/opt_out<https://groups.google.com/groups/o...
> .
>

[DMorsing, 2013-08-29 14:48:49]

*** Submitted as https://code.google.com/p/go/source/detail?r=84a92114983d ***

cmd/gc: make method names for function scoped types unique

Types in function scope can have methods on them if they embed another type, but
we didn't make the name unique, meaning that 2 identically named types in
different functions would conflict with eachother.

Fixes issue 6269.

R=golang-dev, bradfitz
CC=golang-dev
https://codereview.appspot.com/13326045

[rsc, 2013-09-05 14:44:59]

Nice.