[gcc r17-2912] c++: early DMI and constructor default arg [PR126606]

https://gcc.gnu.org/g:4569067c6f5206e97a319ec6bfa4e3446b3a41d1

commit r17-2912-g4569067c6f5206e97a319ec6bfa4e3446b3a41d1
Author: Jason Merrill <[email protected]>
Date:   Sat Aug 1 00:17:45 2026 -0400

    c++: early DMI and constructor default arg [PR126606]
    
    This testcase demonstrates that the issue in 126481 was not the {} but
    the member of class type.
    
            PR c++/126606
            PR c++/126481
    
    gcc/cp/ChangeLog:
    
            * parser.cc (cp_parser_early_parsing_nsdmi): Check
            MAYBE_CLASS_TYPE_P instead of {}.
    
    gcc/testsuite/ChangeLog:
    
            * g++.dg/cpp0x/nsdmi-defer9.C: New test.

Diff:
---
 gcc/cp/parser.cc                          |  6 ++++--
 gcc/testsuite/g++.dg/cpp0x/nsdmi-defer9.C | 10 ++++++++++
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/gcc/cp/parser.cc b/gcc/cp/parser.cc
index 67a1696f0262..85c5030acbb4 100644
--- a/gcc/cp/parser.cc
+++ b/gcc/cp/parser.cc
@@ -37309,11 +37309,13 @@ cp_parser_early_parsing_nsdmi (cp_parser *parser, tree field)
   if (TREE_CODE (init) != DEFERRED_PARSE)
     return true;
 
+  /* Initializing a class might need other deferred parses.  */
+  if (MAYBE_CLASS_TYPE_P (strip_array_types (TREE_TYPE (field))))
+    return false;
+
   cp_token_cache *tokens = DEFPARSE_TOKENS (init);
   for (cp_token *p = tokens->first; p != tokens->last; ++p)
     if (p->type == CPP_NAME
-	/* = {} might depend on other DMI that haven't been parsed.  */
-	|| p->type == CPP_OPEN_BRACE
 	|| p->keyword == RID_THIS
 	|| p->keyword == RID_OPERATOR)
       /* There's a name to look up or 'this', give up.  */
diff --git a/gcc/testsuite/g++.dg/cpp0x/nsdmi-defer9.C b/gcc/testsuite/g++.dg/cpp0x/nsdmi-defer9.C
new file mode 100644
index 000000000000..74307188ff01
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/nsdmi-defer9.C
@@ -0,0 +1,10 @@
+// PR c++/126606
+// { dg-do compile { target c++11 } }
+
+struct s1 {
+  struct s2
+  {
+    s2(int a = 0, int b = 1){}
+  };
+  s2 a = 1;
+};