code review 7305080: go/types: len(((*T)(nil)).X) is const if X is an array

go/types: len(((*T)(nil)).X) is const if X is an array

Fixes issue 4744.

[gri, 2013-02-12 01:53:10]

Hello adonovan@google.com (cc: golang-dev@googlegroups.com),

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

[adonovan, 2013-02-12 02:59:53]

LGTM.

There's a typo in the bug number in your CL description though.

What's the significance of containsCallsOrReceives?  Are they really the only
two syntactic expression forms that can have side effects?  What about failure
effects?  Most expressions can have those.  It seems odd to me that this
predicate exists.

PS. welcome back!  We should catch up via video when you have a chance.

[gri, 2013-02-12 06:03:33]

On Feb 11, 2013 6:59 PM, <adonovan@google.com> wrote:
>
> LGTM.
>
> There's a typo in the bug number in your CL description though.

Will fix before submitting.

>
> What's the significance of containsCallsOrReceives?  Are they really the
> only two syntactic expression forms that can have side effects?  What
> about failure effects?  Most expressions can have those.  It seems odd
> to me that this predicate exists.

It's exactly the condition as specified by the spec for the cap and len
argument. Only unusual as far as the spec might be unusual for specifying
this exception.

>
> PS. welcome back!  We should catch up via video when you have a chance.
>
>
>
>
>
> https://codereview.appspot.com/7305080/

[gri, 2013-02-12 06:40:02]

*** Submitted as https://code.google.com/p/go/source/detail?r=9e8eec6e3239 ***

go/types: len(((*T)(nil)).X) is const if X is an array

Fixes issue 4744.

R=adonovan
CC=golang-dev
https://codereview.appspot.com/7305080