[Bug c++/61370] New: decltype, enable_if, previous arguments

[patrick.a.moran at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61370

            Bug ID: 61370
           Summary: decltype, enable_if, previous arguments
           Product: gcc
           Version: 4.9.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: patrick.a.moran at gmail dot com

Created attachment 32878
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=32878&action=edit
minimal reproduction

SFINAE that depednds on the decltype of a previous argument fails to funciton
in a member function if the definition is external to the class.  The
out-of-class definition is reported as having a prototype that does not match
any in the class.

In the attached test case you can see the error.  If you define WORKAROUND, you
will see the same code with the definition moved into the class and the error
will not recur.