[gcc r15-7825] c++: Fix checking assert upon invalid class definition [PR116740]

[Simon Martin]

https://gcc.gnu.org/g:b3d078220d202094a2b4eaef9b4a5ad1b84d30e6

commit r15-7825-gb3d078220d202094a2b4eaef9b4a5ad1b84d30e6
Author: Simon Martin <simon@nasilyan.com>
Date:   Wed Mar 5 09:08:57 2025 +0100

    c++: Fix checking assert upon invalid class definition [PR116740]
    
    A checking assert triggers upon the following invalid code since
    GCC 11:
    
    === cut here ===
    class { a (struct b;
    } struct b
    === cut here ===
    
    The problem is that during error recovery, we call
    set_identifier_type_value_with_scope for B in the global namespace, and
    the checking assert added via r11-7228-g8f93e1b892850b fails.
    
    This patch relaxes that assert to not fail if we've seen a parser error
    (it a generalization of another fix done to that checking assert via
    r11-7266-g24bf79f1798ad1).
    
            PR c++/116740
    
    gcc/cp/ChangeLog:
    
            * name-lookup.cc (set_identifier_type_value_with_scope): Don't
            fail assert with ill-formed input.
    
    gcc/testsuite/ChangeLog:
    
            * g++.dg/parse/crash80.C: New test.

Diff:
---
 gcc/cp/name-lookup.cc                | 6 ++----
 gcc/testsuite/g++.dg/parse/crash80.C | 7 +++++++
 2 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/gcc/cp/name-lookup.cc b/gcc/cp/name-lookup.cc
index d1abb205bc7f..742e5d289dc9 100644
--- a/gcc/cp/name-lookup.cc
+++ b/gcc/cp/name-lookup.cc
@@ -5101,10 +5101,8 @@ set_identifier_type_value_with_scope (tree id, tree decl, cp_binding_level *b)
   if (b->kind == sk_namespace)
     /* At namespace scope we should not see an identifier type value.  */
     gcc_checking_assert (!REAL_IDENTIFIER_TYPE_VALUE (id)
-			 /* We could be pushing a friend underneath a template
-			    parm (ill-formed).  */
-			 || (TEMPLATE_PARM_P
-			     (TYPE_NAME (REAL_IDENTIFIER_TYPE_VALUE (id)))));
+			 /* But we might end up here with ill-formed input.  */
+			 || seen_error ());
   else
     {
       /* Push the current type value, so we can restore it later  */
diff --git a/gcc/testsuite/g++.dg/parse/crash80.C b/gcc/testsuite/g++.dg/parse/crash80.C
new file mode 100644
index 000000000000..cd9216adf5c9
--- /dev/null
+++ b/gcc/testsuite/g++.dg/parse/crash80.C
@@ -0,0 +1,7 @@
+// PR c++/116740
+// { dg-do "compile" }
+
+class K {
+  int a(struct b; // { dg-error "expected '\\)'" }
+};
+struct b {};