C++ PATCH for c++/72764, ICE with invalid template typename

[Jason Merrill <jason at redhat dot com>]

The problem in this testcase is that when we first parse C<T> we look
up the canonical instantiation of C<T> which doesn't see inside A<T>
because it happens at global scope, but then in strip_typedefs we are
in the context of A<T>, so the call to make_typename_type in
strip_typedefs was finding the error and causing trouble, because we
don't expect strip_typedefs to change anything.

This is an oddity with the current semi-specification of alias
templates that I hope to address in the standard soon, but for now
this patch addresses the issue by rebuilding a TYPENAME_TYPE in
strip_typedefs, even if we could resolve it in the current scope.

Tested x86_64-pc-linux-gnu, applying to trunk.

Attachment: 72764.diff
Description: Text document