[Bug c++/84231] [8 Regression] cannot bind non-const lvalue reference of type ‘const char*&’ to an rvalue of type ‘const char*’

[aoliva at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84231

--- Comment #3 from Alexandre Oliva <aoliva at gcc dot gnu.org> ---
The difference arises because, when resolving the % overload in
normal_function, the result operands of the ternary operator have gained
rvalue-forcing NOP_EXPRs, which makes their lvalue_kind clk_none, so the
ref-binding is a bad conversion and the non-const template is not viable, but
within function_template, the rvalue-forcing casts aren't there, so lvalue_kind
for the ternary operator results is clk_ordinary, and reference_binding is
regarded as acceptable, and so both operator%s are viable, and the one without
const is later selected as a better match.
I suppose the parsing of the ternary operator should behave the same way, given
that nothing is dependent in the expression.  But when
processing_template_decl, build_x_conditional_expr creates a COND_EXPR node
with the original operands.  Oops.