[Bug c++/95368] gcc things that a lambda capture is both const and mutable

[rafael at espindo dot la]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95368

--- Comment #2 from Rafael Avila de Espindola <rafael at espindo dot la> ---
I just tested a few compilers with the testcase from comment 1:

* clang version 11.0.0 (https://github.com/llvm/llvm-project.git
0796b170fb3bf38e6cc4e59746120b37c9a9cd9f):
  Accepts it.

* g++ (GCC) 10.1.1 20200507 (Red Hat 10.1.1-1):
  Rejects it:
  test.cc:17:14: error: passing ‘const foo’ as ‘this’ argument discards
qualifiers [-fpermissive]

* gcc (GCC) 9.3.1 20200528
  Rejects it:
  test.cc:17:14: error: passing ‘const foo’ as ‘this’ argument discards
qualifiers