From 9db84ecedae899c04ac693d970120a065c58350e Mon Sep 17 00:00:00 2001
From: Nathan Sidwell <nathan@acm.org>
Date: Fri, 6 Oct 2017 16:02:13 +0000
Subject: [PATCH] [PR c++/82424] Dont convert dependent types

https://gcc.gnu.org/ml/gcc-patches/2017-10/msg00385.html
	cp/
	PR c++/82424
	* name-lookup.c (check_local_shadow): Don't try and convert
	dependent types.

	testsuite/
	PR c++/82424
	* g++.dg/warn/pr82424.C: New.

From-SVN: r253496
---
 gcc/cp/ChangeLog                    |  6 ++++++
 gcc/cp/name-lookup.c                |  6 +++++-
 gcc/testsuite/ChangeLog             |  5 +++++
 gcc/testsuite/g++.dg/warn/pr82424.C | 20 ++++++++++++++++++++
 4 files changed, 36 insertions(+), 1 deletion(-)
 create mode 100644 gcc/testsuite/g++.dg/warn/pr82424.C

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index ea0e8b6f9c8..b2813ebf211 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,9 @@
+2017-10-06  Nathan Sidwell  <nathan@acm.org>
+
+	PR c++/82424
+	* name-lookup.c (check_local_shadow): Don't try and convert
+	dependent types.
+
 2017-10-06  Jakub Jelinek  <jakub@redhat.com>
 
 	PR c++/82299
diff --git a/gcc/cp/name-lookup.c b/gcc/cp/name-lookup.c
index fb86310c884..a3da34d7549 100644
--- a/gcc/cp/name-lookup.c
+++ b/gcc/cp/name-lookup.c
@@ -2728,7 +2728,11 @@ check_local_shadow (tree decl)
       else if (warn_shadow_local)
 	warning_code = OPT_Wshadow_local;
       else if (warn_shadow_compatible_local
-	       && can_convert (TREE_TYPE (old), TREE_TYPE (decl), tf_none))
+	       && (same_type_p (TREE_TYPE (old), TREE_TYPE (decl))
+		   || (!dependent_type_p (TREE_TYPE (decl))
+		       && !dependent_type_p (TREE_TYPE (old))
+		       && can_convert (TREE_TYPE (old), TREE_TYPE (decl),
+				       tf_none))))
 	warning_code = OPT_Wshadow_compatible_local;
       else
 	return;
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index d7af2a93b5a..97825c3319c 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2017-10-06  Nathan Sidwell  <nathan@acm.org>
+
+	PR c++/82424
+	* g++.dg/warn/pr82424.C: New.
+
 2017-10-06  Jakub Jelinek  <jakub@redhat.com>
 
 	PR c++/82299
diff --git a/gcc/testsuite/g++.dg/warn/pr82424.C b/gcc/testsuite/g++.dg/warn/pr82424.C
new file mode 100644
index 00000000000..43dd5e4e3d2
--- /dev/null
+++ b/gcc/testsuite/g++.dg/warn/pr82424.C
@@ -0,0 +1,20 @@
+// { dg-additional-options "-Wshadow=compatible-local" }
+
+// pr c++/82424 we were trying to convert between dependent types.
+template <typename T> class a
+{
+  struct b;
+  template <typename, typename> void c ();
+};
+template <typename T>
+template <typename, typename>
+void
+a<T>::c ()
+{
+  typedef typename T::b b; // Don't go looking inside the typename
+  T thing;
+  {
+    T thing; // { dg-warning "shadows a previous local" }
+  }
+}
+
-- 
2.30.2