https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84082
--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
To be precise, the CAST_EXPR doesn't have NULL TREE_TYPE initially, it has A
type, just NULL operand.
But then r245223 comes with:
if (processing_template_decl)
{
dependent_p = true;
scope = TREE_TYPE (postfix_expression) = NULL_TREE;
}
and clears the TREE_TYPE on the CAST_EXPR.
Slightly tweaked testcase that still ICEs:
struct A;
template<typename> void foo()
{
static int a[A().operator=(A())];
}
which is accepted fine with extra struct A { operator int (); }; before the
template.
So, either we shouldn't clear the type and use something different to mark such
CAST_EXPRs as dependent, or potential_constant_expression_p and similar code
needs to handle CAST_EXPR with NULL TREE_TYPE.
