[Bug c++/92031] New: Incorrect "taking address of r-value" error

[bugzilla at myosotissp dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92031

            Bug ID: 92031
           Summary: Incorrect "taking address of r-value" error
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: bugzilla at myosotissp dot com
  Target Milestone: ---

In the following code, starting with gcc-9.1 gcc incorrectly fails to compile
the template function f ("error: taking address of rvalue [-fpermissive]").
clang, icc and gcc-8.3 and earlier all accept it. Also, gcc-9.1 has no problem
with the exact same code in a non-template function (see g() in the repro).

---------------------------
struct x { const int& l; };
void a(const x&) {}
template<class E>                          
void f() {
  a(x { 0 });
}
auto g() {
  a(x { 0 });
}
---------------------------

Also, godbolt link: https://godbolt.org/z/YWLM5i