go/types: crash in assignment between "unexported" named interface types

[remyoudompheng]

What steps will reproduce the problem?

Typechekck the follwoing pair of files:

$ cat main.go
package blah

import "testb/pkg"

type stringer interface {
    String() string
}

func F() {
      var t pkg.T
    var s stringer = t.Field
}

$ cat pkg/pkg.go
package pkg

type stringer interface {
    String() string
}

type T struct {
    Field stringer
}

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

Expected: no error

Instead:
$ gotype .
INTERNAL PANIC: runtime error: invalid memory address or nil pointer dereference
panic: runtime error: invalid memory address or nil pointer dereference [recovered]
    panic: runtime error: invalid memory address or nil pointer dereference [recovered]
    panic: runtime error: invalid memory address or nil pointer dereference
[signal 0xb code=0x1 addr=0x10 pc=0x487765]

goroutine 1 [running]:
main.func·002()
    /home/remy/travail/go/src/code.google.com/p/go.tools/gotype/gotype.go:185 +0xa2
code.google.com/p/go.tools/go/types.func·003()
    /home/remy/travail/go/src/code.google.com/p/go.tools/go/types/check.go:447 +0x175
code.google.com/p/go.tools/go/types.identicalMethods(0xc200087820, 0x1, 0x1,
0xc200087850, 0x1, ...)
    /home/remy/travail/go/src/code.google.com/p/go.tools/go/types/predicates.go:219 +0xe5
code.google.com/p/go.tools/go/types.IsIdentical(0xc200079b00, 0xc200064a00,
0xc200079b00, 0xc200064a40, 0x0, ...)
    /home/remy/travail/go/src/code.google.com/p/go.tools/go/types/predicates.go:165 +0x8de
code.google.com/p/go.tools/go/types.(*operand).isAssignable(0xc2000a5cc0, 0xc2000a5480,
0xc200079b40, 0xc2000a2840, 0x0, ...)
    /home/remy/travail/go/src/code.google.com/p/go.tools/go/types/operand.go:144 +0x172
code.google.com/p/go.tools/go/types.(*checker).assignment(0xc20008c0b0, 0xc2000a5cc0,
0xc200079b40, 0xc2000a2840, 0x1, ...)
    /home/remy/travail/go/src/code.google.com/p/go.tools/go/types/stmt.go:36 +0x1dd
code.google.com/p/go.tools/go/types.(*checker).assign1to1(0xc20008c0b0, 0xc2000a5040,
0xc200064660, 0xc2000a52c0, 0xc2000646e0, ...)
    /home/remy/travail/go/src/code.google.com/p/go.tools/go/types/stmt.go:139 +0x563
code.google.com/p/go.tools/go/types.(*checker).valueSpec(0xc20008c0b0, 0x73,
0xc20007d910, 0xc2000a5c40, 0xc200000228, ...)
    /home/remy/travail/go/src/code.google.com/p/go.tools/go/types/check.go:162 +0x3a9
code.google.com/p/go.tools/go/types.(*checker).object(0xc20008c0b0, 0xc20007d910,
0xc2000a5c40, 0xc2000a5c00)
    /home/remy/travail/go/src/code.google.com/p/go.tools/go/types/check.go:247 +0x3ca
code.google.com/p/go.tools/go/types.(*checker).decl(0xc20008c0b0, 0xc200079f80,
0xc2000a53c0)
    /home/remy/travail/go/src/code.google.com/p/go.tools/go/types/check.go:391 +0x44c
code.google.com/p/go.tools/go/types.(*checker).stmt(0xc20008c0b0, 0xc2000a5380,
0xc200087730)
    /home/remy/travail/go/src/code.google.com/p/go.tools/go/types/stmt.go:298 +0x3108
code.google.com/p/go.tools/go/types.(*checker).stmtList(0xc20008c0b0, 0xc200064700, 0x2,
0x2)
    /home/remy/travail/go/src/code.google.com/p/go.tools/go/types/stmt.go:247 +0x68
code.google.com/p/go.tools/go/types.check(0xc2000a5480, 0x5ce2a0, 0x1, 0xc200079e40,
0xc200000240, ...)
    /home/remy/travail/go/src/code.google.com/p/go.tools/go/types/check.go:485 +0x4cf
code.google.com/p/go.tools/go/types.(*Context).Check(0xc2000a5480, 0x5ce2a0, 0x1,
0xc200079e40, 0xc200000240, ...)
    /home/remy/travail/go/src/code.google.com/p/go.tools/go/types/api.go:112 +0x6c
main.processPackage(0xc200079e40, 0xc200000240, 0x1, 0x1)
    /home/remy/travail/go/src/code.google.com/p/go.tools/gotype/gotype.go:189 +0xd9
main.processFiles(0xc200086700, 0x2, 0x64, 0xc200000100)
    /home/remy/travail/go/src/code.google.com/p/go.tools/gotype/gotype.go:167 +0x178
main.processDirectory(0x7fff7b5d0923, 0x1)
    /home/remy/travail/go/src/code.google.com/p/go.tools/gotype/gotype.go:146 +0x24a
main.processFiles(0xc200064010, 0x1, 0x1, 0x417301)
    /home/remy/travail/go/src/code.google.com/p/go.tools/gotype/gotype.go:157 +0x1d9
main.main()
    /home/remy/travail/go/src/code.google.com/p/go.tools/gotype/gotype.go:200 +0xea

goroutine 2 [runnable]:


Please use labels and text to provide additional information.

[davecheney]

Comment 1:

Issue #5568 has been merged into this issue.

[remyoudompheng]

Comment 2:

The issue was fixed by the fix for issue #5675 (revision eeb58a9dd66a).
The first good revision is:
changeset:   42:eeb58a9dd66a
user:        Robert Griesemer <gri@golang.org>
date:        Tue Jun 11 10:00:00 2013 -0700
summary:     go.tools/go/types: fix isAssignable and IsIdentical
https://code.google.com/p/go/source/detail?r=eeb58a9dd66a&repo=tools

Status changed to Fixed.