[Bug libstdc++/58025] Cannot use std::hash without setting off -Wmismatched-tags

[whatmannerofburgeristhis at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58025

--- Comment #1 from Matt Arsenault <whatmannerofburgeristhis at gmail dot com> 
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Created attachment 30570
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=30570&action=edit
Testcase