[Bug c++/42082] New: [C++0x] ICE on probably invalid with "canonical types differ for identical types"

["lloyd at randombit dot net" <gcc-bugzilla at gcc dot gnu dot org>]

The attached code causes an ICE with gcc 4.5 20091112. I'm somewhat certain but
not positive that it is not valid code.

$ g++-4.5-20091112 -std=c++0x decl.cpp -o decl
decl.cpp: In function 'std::unique_future<_Res> async(F) [with T = int, F =
main()::<lambda()>]':
decl.cpp:16:30:   instantiated from here
decl.cpp:7:46: internal compiler error: canonical types differ for identical
types int() and int()
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://gcc.gnu.org/bugs.html> for instructions.


-- 
           Summary: [C++0x] ICE on probably invalid with "canonical types
                    differ for identical types"
           Product: gcc
           Version: 4.5.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: lloyd at randombit dot net
 GCC build triplet: x86_64-unknown-linux-gnu
  GCC host triplet: x86_64-unknown-linux-gnu
GCC target triplet: x86_64-unknown-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42082