[Bug c++/124252] New: Accepts invalid cast (X0&&){} from braced-init-list

[suyuchang at whu dot edu.cn via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=124252

            Bug ID: 124252
           Summary: Accepts invalid cast (X0&&){} from braced-init-list
           Product: gcc
           Version: 15.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: suyuchang at whu dot edu.cn
  Target Milestone: ---

The code uses a C-style cast to an rvalue reference type with a
braced-init-list operand: (X0&&){}. Clang rejects it, but GCC accepts it.

Code:
struct X0 { } X1 = ( X0 && ) { } ;


clang++ test.cpp
<source>:1:20: error: reference to type 'X0' cannot bind to an initializer list
    1 | struct X0 { } X1 = ( X0 && ) { } ; 
      |                    ^         ~~~
1 error generated.
Compiler returned: 1

g++ -c test.cpp
Compiler returned: 0

Regression since GCC 6.1

The test case was generated by a fuzzer.