code review 6443109: cmd/gc: string conversion for surrogates

cmd/gc: string conversion for surrogates
This is required by the spec to produce the replacement char.
The fix lies in lib9's rune code.

[r, 2012-08-09 23:20:14]

Hello golang-dev@googlegroups.com,

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

[nigeltao, 2012-08-09 23:36:39]

LGTM.

[rsc, 2012-08-10 00:34:49]

I am surprised that string(-1) and string(0x110000) are not
compile-time errors, but the spec is definitely clear. It is strange
that string(0x110000) is okay but "\U00110000" is not. Oh well.

This test file has, to date, only tested runtime conversions, hence
the otherwise unnecessary variable r. I think it's fine to add some
compile-time tests here, but please do it in a way that the same
inputs are being tested in both situations.

Russ

[r, 2012-08-10 00:53:25]

Oh well indeed. We might lock this down better in a post-Go-1 Go. That
said, I do believe there is room in the current spec to forbid
"\U00110000".

I'll beef up the test file.

-rob

[r, 2012-08-10 18:10:40]

Hello golang-dev@googlegroups.com, nigeltao@golang.org, rsc@golang.org (cc:
golang-dev@googlegroups.com),

Please take another look.

[rsc, 2012-08-30 17:34:33]

LGTM

[r, 2012-08-30 18:16:58]

*** Submitted as http://code.google.com/p/go/source/detail?r=38b71d522589 ***

cmd/gc: string conversion for surrogates
This is required by the spec to produce the replacement char.
The fix lies in lib9's rune code.

R=golang-dev, nigeltao, rsc
CC=golang-dev
http://codereview.appspot.com/6443109