c: Avoid clobbering TREE_TYPE (error_mark_node) [PR99990]

The following testcase ICEs during error recovery, because finish_decl
overwrites TREE_TYPE (error_mark_node), which better should stay always
to be error_mark_node.

2021-04-10  Jakub Jelinek  <jakub@redhat.com>

	PR c/99990
	* c-decl.c (finish_decl): Don't overwrite TREE_TYPE of
	error_mark_node.

	* gcc.dg/pr99990.c: New test.

diff --git a/gcc/c/c-decl.c b/gcc/c/c-decl.c
index 3b2241b..3c25451 100644 (file)
--- a/gcc/c/c-decl.c
+++ b/gcc/c/c-decl.c
@@ -5402,7 +5402,7 @@ finish_decl (tree decl, location_t init_loc, tree init,
          gcc_unreachable ();
        }
 
-      if (DECL_INITIAL (decl))
+      if (DECL_INITIAL (decl) && DECL_INITIAL (decl) != error_mark_node)
        TREE_TYPE (DECL_INITIAL (decl)) = type;
 
       relayout_decl (decl);

diff --git a/gcc/testsuite/gcc.dg/pr99990.c b/gcc/testsuite/gcc.dg/pr99990.c
new file mode 100644 (file)
index 0000000..6878b00
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr99990.c
@@ -0,0 +1,12 @@
+/* PR c/99990 */
+/* { dg-do compile } */
+/* { dg-options "" } */
+
+#include <stdarg.h>
+
+void
+foo ()
+{
+  va_arg (0, long);    /* { dg-error "first argument to 'va_arg' not of type 'va_list'" } */
+  void *b[] = 0;       /* { dg-error "invalid initializer" } */
+}