[Bug c++/127196] [contracts] redeclaration of function with type dependent param used in postcondition accepts non-const param

[waffl3x at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=127196

--- Comment #3 from Waffl3x <waffl3x at gcc dot gnu.org> ---
Agreed, my mistake. Had my second comment ODR-used 'a' it would just be
a more verbose example of the original bug. Otherwise it's just a
garden variety ODR-violation.