code review 88100048: reflect: correct type descriptor for call of interface ...

reflect: correct type descriptor for call of interface method

When preparing a call with an interface method, the argument
frame holds the receiver "iword", but funcLayout was being
asked to write a descriptor as if the receiver were a complete
interface value. This was originally caught by running a large
program with Debug=3 in runtime/mgc0.c, but the new panic
in funcLayout suffices to catch the mistake with the existing
tests.

Fixes issue 7748.

[rsc, 2014-04-16 02:39:02]

Hello golang-codereviews@googlegroups.com (cc: iant, khr),

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

[bradfitz, 2014-04-16 02:43:36]

LGTM

https://codereview.appspot.com/88100048/diff/60001/src/pkg/reflect/value.go
File src/pkg/reflect/value.go (right):

https://codereview.appspot.com/88100048/diff/60001/src/pkg/reflect/value.go#n...
src/pkg/reflect/value.go:672: func methodReceiver(op string, v Value,
methodIndex int) (rcvr, t *rtype, fn unsafe.Pointer) {
this is called rcvr here, but rcvrtype below, and below there's a rcvr that's
not a type.

little inconsistent.

[rsc, 2014-04-16 02:56:00]

Thanks. I renamed the result rcvrtype.

[iant, 2014-04-16 05:01:40]

LGTM

[rsc, 2014-04-16 15:52:32]

*** Submitted as https://code.google.com/p/go/source/detail?r=a0ba4e1b909d ***

reflect: correct type descriptor for call of interface method

When preparing a call with an interface method, the argument
frame holds the receiver "iword", but funcLayout was being
asked to write a descriptor as if the receiver were a complete
interface value. This was originally caught by running a large
program with Debug=3 in runtime/mgc0.c, but the new panic
in funcLayout suffices to catch the mistake with the existing
tests.

Fixes issue 7748.

LGTM=bradfitz, iant
R=golang-codereviews, bradfitz, iant
CC=golang-codereviews, khr
https://codereview.appspot.com/88100048