Hello,

in this PR, we end up with 3 types A, B and C such that 
TYPE_CANONICAL(A)=B and TYPE_CANONICAL(B)=C. I don't think that is 
supposed to happen. Here, build_qualified_type fills in TYPE_CANONICAL(A) 
by calling build_qualified_type (so get_qualified_type), which afaics 
isn't guaranteed to return a canonical type.

I doubt the patch can be wrong, but it may be that this is a situation 
that is not supposed to happen and should be fixed elsewhere?

Bootstrap+testsuite on x86_64-linux-gnu.

2014-06-09  Marc Glisse  <marc.glisse@inria.fr>

 	PR c++/54442
gcc/
 	* tree.c (build_qualified_type): Use a canonical type for
 	TYPE_CANONICAL.
gcc/testsuite/
 	* g++.dg/pr54442.C: New file.

-- 
Marc Glisse