PR c++/60855 - ICE with sizeof VLA capture.

For normal captures we usually look through them within unevaluated context,
but that doesn't work here; trying to take the sizeof of the array in the
enclosing scope tries and fails to evaluate a SAVE_EXPR from the enclosing
scope.

	* lambda.c (is_lambda_ignored_entity): Don't look past VLA capture.

gcc/cp/ChangeLog

 2020-01-21  Jason Merrill  <jason@redhat.com>
 
+	PR c++/60855 - ICE with sizeof VLA capture.
+	* lambda.c (is_lambda_ignored_entity): Don't look past VLA capture.
+
 	PR c++/90732 - ICE with VLA capture and generic lambda.
 	* pt.c (tsubst_lambda_expr): Repeat add_capture for VLAs.
 

gcc/cp/lambda.c

@@ -1327,8 +1327,9 @@ lambda_static_thunk_p (tree fn)
 bool
 is_lambda_ignored_entity (tree val)
 {
-  /* Look past normal capture proxies.  */
-  if (is_normal_capture_proxy (val))
+  /* Look past normal, non-VLA capture proxies.  */
+  if (is_normal_capture_proxy (val)
+      && !variably_modified_type_p (TREE_TYPE (val), NULL_TREE))
     return true;
 
   /* Always ignore lambda fields, their names are only for debugging.  */

gcc/testsuite/g++.dg/cpp0x/lambda/lambda-vla4.C

+// PR c++/60855
+// { dg-do compile { target c++11 } }
+// { dg-additional-options "-Wno-vla" }
+
+int main() {
+  unsigned count = 5;
+  bool array[count];
+  [&array] () {
+    array[0] = sizeof(array) > 5;
+  }();
+  return 0;
+}