[gcc r15-4026] c++: Fix regression introduced by r15-3796 [PR116722]

[Simon Martin via Gcc-cvs]

https://gcc.gnu.org/g:3a528386571fffbb41703a238aee950043af3f3c

commit r15-4026-g3a528386571fffbb41703a238aee950043af3f3c
Author: Simon Martin <si...@nasilyan.com>
Date:   Wed Oct 2 15:32:37 2024 +0200

    c++: Fix regression introduced by r15-3796 [PR116722]
    
    Jason pointed out that the fix I made for PR116722 via r15-3796
    introduces a regression when running constexpr-dynamic10.C with
    -fimplicit-constexpr.
    
    The problem is that my change makes us leave cxx_eval_call_expression
    early, and bypass the call to cxx_eval_thunk_call (through a recursive
    call to cxx_eval_call_expression) that used to emit an error for that
    testcase with -fimplicit-constexpr.
    
    This patch emits the error if !ctx->quiet before bailing out because the
    {con,de}structor belongs to a class with virtual bases.
    
            PR c++/116722
    
    gcc/cp/ChangeLog:
    
            * constexpr.cc (cxx_bind_parameters_in_call): When !ctx->quiet,
            emit error before bailing out due to a call to {con,de}structor
            for a class with virtual bases.

Diff:
---
 gcc/cp/constexpr.cc | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/gcc/cp/constexpr.cc b/gcc/cp/constexpr.cc
index 5c6696740fc9..4e4df94f4206 100644
--- a/gcc/cp/constexpr.cc
+++ b/gcc/cp/constexpr.cc
@@ -1867,6 +1867,12 @@ cxx_bind_parameters_in_call (const constexpr_ctx *ctx, 
tree t, tree fun,
      with virtual bases.  */
   if (DECL_HAS_IN_CHARGE_PARM_P (fun) || DECL_HAS_VTT_PARM_P (fun))
     {
+      if (!ctx->quiet)
+       {
+         error_at (cp_expr_loc_or_input_loc (t),
+                   "call to non-%<constexpr%> function %qD", fun);
+         explain_invalid_constexpr_fn (fun);
+       }
       *non_constant_p = true;
       return binds;
     }