cmd/go: reject adding methods in _test.go file

[remyoudompheng]

What steps will reproduce the problem?
1. Extract bug.tar.gz into $GOPATH/src
2. Run "go test p2"

What is the expected output? What do you see instead?

Expected: "PASS"

Instead:

# testmain
/opt/remy/go/pkg/tool/linux_amd64/6l: conflicting definitions for @"p2".Secret
/tmp/go-build276558121/p2/_test/p2_test.a(_go_.6):  type @"p2".Secret struct {
@"p2".field []uint64 }
    func (@"p2".f·2 *@"p2".Secret "esc:0x0") Bits () (? []uint64) { return @"p2".f·2.@"p2".field }
/tmp/go-build276558121/p1.a(_go_.6):    type @"p2".Secret struct {
@"p2".field []uint64 }
FAIL    p2 [build failed]

The example combines:
- a export_test.go to add an exported method to a type for tests
- a p2_test package that depends on p1 which depends on p2.

Attachments:

1. bug.tar.gz (606 bytes)

[remyoudompheng]

Comment 1:

I've encountered this issue with Go 1.0, Go 1.1 (and 1.1.2) and tip.

[rsc]

Comment 2:

This use case is not supported: you cannot add methods in _test.go files.
In Go 1.3 maybe we can build a better error message.

Labels changed: added go1.3, removed go1.2maybe.

[rsc]

Comment 3:

Labels changed: added release-go1.3.

[rsc]

Comment 4:

Labels changed: removed go1.3.

[rsc]

Comment 5:

Labels changed: added repo-main.

[rsc]

Comment 7:

I have no good ideas about how to diagnose this.

Labels changed: added priority-later, release-none, suggested, removed priority-triage, release-go1.3.