[PATCH c++/86881] -Wshadow-local-compatible ICE

https://gcc.gnu.org/ml/gcc-patches/2018-09/msg00984.html
	PR c++/86881
	cp/
	* name-lookup.c (check_local_shadow): Ignore auto types.

	testsuite/
	* g++.dg/warn/pr86881.C: New.

From-SVN: r264391

gcc/cp/ChangeLog

+2018-09-18  Nathan Sidwell  <nathan@acm.org>
+
+	PR c++/86881
+	* name-lookup.c (check_local_shadow): Ignore auto types.
+
 2018-09-17  David Malcolm  <dmalcolm@redhat.com>
 
 	* error.c (range_label_for_type_mismatch::get_text): Update for

gcc/cp/name-lookup.c

@@ -2764,6 +2764,13 @@ check_local_shadow (tree decl)
 	       && (same_type_p (TREE_TYPE (old), TREE_TYPE (decl))
 		   || (!dependent_type_p (TREE_TYPE (decl))
 		       && !dependent_type_p (TREE_TYPE (old))
+		       /* If the new decl uses auto, we don't yet know
+			  its type (the old type cannot be using auto
+			  at this point, without also being
+			  dependent).  This is an indication we're
+			  (now) doing the shadow checking too
+			  early.  */
+		       && !type_uses_auto (TREE_TYPE (decl))
 		       && can_convert (TREE_TYPE (old), TREE_TYPE (decl),
 				       tf_none))))
 	warning_code = OPT_Wshadow_compatible_local;

gcc/testsuite/ChangeLog

+2018-09-18  Nathan Sidwell  <nathan@acm.org>
+
+	PR c++/86881
+	* g++.dg/warn/pr86881.C: New.
+
 2018-09-18  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
 
     * gcc.target/aarch64/spellcheck_1.c:

gcc/testsuite/g++.dg/warn/pr86881.C

+// PR c++/86881 ICE with shadow warning
+// { dg-do compile { c++11 } }
+// { dg-additional-options { -Wshadow-compatible-local } }}
+
+void a() {
+  auto b([] {});
+  {
+    auto b = 0;
+  }
+}
+
+struct Proxy { };
+
+void Two ()
+{
+  auto my = Proxy ();
+  {
+    auto my = Proxy (); // { dg-warning "shadows" "" { xfail *-*-* } }
+  };
+}