[PATCH] Fix a C++ crash with may_alias type attribute

[Jonathan Wakely]

On 04/04/17 12:39 +0000, Bernd Edlinger wrote:
>Hi,
>
>I noticed that the already created reference and pointer types
>are left in an inconsistent state if the may_alias attribute
>is added to a class, in some cases.
>
>The attached patch fixes this by adding another loop over
>all type variants of each pointer and reference type.
>
>The new test case 20_util/any/assign/2a.cc is just a
>clone of 20_util/any/assign/2.cc with the may_alias
>attribute at the right place.

The new test doesn't really belong in the libstdc++, does it?

If this is a bug in the front-end then a reduced version of the test
belongs in the g++ testsuite.