Fix ICE with -g and -std=c23 when forming composite types [PR113438]

[Martin Uecker <uecker@tugraz.at>]

Debug output ICEs when we do not set TYPE_STUB_DECL, fix this.


    Fix ICE with -g and -std=c23 when forming composite types [PR113438]
    
    Set TYPE_STUB_DECL to an artificial decl when creating a new structure
    as a composite type.
    
            PR c/113438
    
    gcc/c/
            * c-typeck.cc (composite_type_internal): Set TYPE_STUB_DECL.
    
    gcc/testsuite/
            * gcc.dg/pr113438.c: New test.

diff --git a/gcc/c/c-typeck.cc b/gcc/c/c-typeck.cc
index 66c6abc9f07..cfa3b7ab10f 100644
--- a/gcc/c/c-typeck.cc
+++ b/gcc/c/c-typeck.cc
@@ -585,6 +585,11 @@ composite_type_internal (tree t1, tree t2, struct composite_cache* cache)
 	  /* Setup the struct/union type.  Because we inherit all variably
 	     modified components, we can ignore the size expression.  */
 	  tree expr = NULL_TREE;
+
+	  /* Set TYPE_STUB_DECL for debugging symbols.  */
+	  TYPE_STUB_DECL (n) = pushdecl (build_decl (input_location, TYPE_DECL,
+						     NULL_TREE, n));
+
 	  n = finish_struct(input_location, n, fields, attributes, NULL, &expr);
 
 	  n = qualify_type (n, t1);
diff --git a/gcc/testsuite/gcc.dg/pr113438.c b/gcc/testsuite/gcc.dg/pr113438.c
new file mode 100644
index 00000000000..5612ee4fa38
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr113438.c
@@ -0,0 +1,7 @@
+/* PR113438
+ * { dg-do compile }
+ * { dg-options "-std=c23 -g" } */
+
+void g(struct foo { int x; } a);
+void g(struct foo { int x; } a);
+