[patch c++]: Fix PR/61198: Crash when selecting specializations through aliases.

[Jason Merrill]

On 12/18/2014 01:16 PM, Kai Tietz wrote:
> Well, in general I would have assumed to be able to get alias decl of
> tmpl. Wasn't able to find a simple way to get it. So, by looking into
> source I found that most cases handling args > tmpl-args by using
> inner_most_template_args instead. Defaulting to
> innermost_template_args looks indeed a bit wrong, but seemed to work.

It's wrong, it just papers over the bug.  There shouldn't be a mismatch 
at this point.

The problem seems to be that most_general_template isn't actually 
returning the most general template, so we're trying to instantiate the 
partially-instantiated alias template with a full set of arguments: thus 
the mismatch.

Jason