[Bug c++/83020] [7 Regression] ('17) Class template constructor call skipped with no error when substitution fails in default argument

[paolo.carlini at oracle dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83020

Paolo Carlini <paolo.carlini at oracle dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|('17) Class template        |[7 Regression] ('17) Class
                   |constructor call skipped    |template constructor call
                   |with no error when          |skipped with no error when
                   |substitution fails in       |substitution fails in
                   |default argument            |default argument

--- Comment #2 from Paolo Carlini <paolo.carlini at oracle dot com> ---
Thus, for -std=c++17, this is a 7 Regression. First of all, I think I'm going
to add the testcase to trunk.