From 84eb0f1a3bfc8007e8d6ecf4bf208682fbf5b4dd Mon Sep 17 00:00:00 2001
From: Jason Merrill <jason@redhat.com>
Date: Thu, 29 Jun 2017 11:30:11 -0400
Subject: [PATCH] PR c++/81164 - ICE with invalid inherited constructor.

	* search.c (binfo_direct_p): New.
	* name-lookup.c (do_class_using_decl): Use it.

From-SVN: r249797
---
 gcc/cp/ChangeLog                        |  6 ++++++
 gcc/cp/cp-tree.h                        |  1 +
 gcc/cp/name-lookup.c                    |  3 +--
 gcc/cp/search.c                         | 22 ++++++++++++++++++++++
 gcc/testsuite/g++.dg/cpp0x/inh-ctor28.C |  7 +++++++
 5 files changed, 37 insertions(+), 2 deletions(-)
 create mode 100644 gcc/testsuite/g++.dg/cpp0x/inh-ctor28.C

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 9281c6100f8..2c29f1e6d16 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,9 @@
+2017-06-29  Jason Merrill  <jason@redhat.com>
+
+	PR c++/81164 - ICE with invalid inherited constructor.
+	* search.c (binfo_direct_p): New.
+	* name-lookup.c (do_class_using_decl): Use it.
+
 2017-06-29  Nathan Sidwell  <nathan@acm.org>
 
 	* cp-tree.h (THIS_NAME, IN_CHARGE_NAME, VTBL_PTR_TYPE,
diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
index 435a23a3c4e..b3cff08805d 100644
--- a/gcc/cp/cp-tree.h
+++ b/gcc/cp/cp-tree.h
@@ -6598,6 +6598,7 @@ extern tree dfs_walk_all (tree, tree (*) (tree, void *),
 extern tree dfs_walk_once (tree, tree (*) (tree, void *),
 			   tree (*) (tree, void *), void *);
 extern tree binfo_via_virtual			(tree, tree);
+extern bool binfo_direct_p			(tree);
 extern tree build_baselink			(tree, tree, tree, tree);
 extern tree adjust_result_of_qualified_name_lookup
 						(tree, tree, tree);
diff --git a/gcc/cp/name-lookup.c b/gcc/cp/name-lookup.c
index 1f492a4898f..f15c8116959 100644
--- a/gcc/cp/name-lookup.c
+++ b/gcc/cp/name-lookup.c
@@ -4167,8 +4167,7 @@ do_class_using_decl (tree scope, tree name)
 	      return NULL_TREE;
 	    }
 	}
-      else if (name == ctor_identifier
-	       && BINFO_INHERITANCE_CHAIN (BINFO_INHERITANCE_CHAIN (binfo)))
+      else if (name == ctor_identifier && !binfo_direct_p (binfo))
 	{
 	  error ("cannot inherit constructors from indirect base %qT", scope);
 	  return NULL_TREE;
diff --git a/gcc/cp/search.c b/gcc/cp/search.c
index af7a0f169a1..7bcbcbfe535 100644
--- a/gcc/cp/search.c
+++ b/gcc/cp/search.c
@@ -2976,6 +2976,28 @@ binfo_via_virtual (tree binfo, tree limit)
   return NULL_TREE;
 }
 
+/* BINFO is for a base class in some hierarchy.  Return true iff it is a
+   direct base.  */
+
+bool
+binfo_direct_p (tree binfo)
+{
+  tree d_binfo = BINFO_INHERITANCE_CHAIN (binfo);
+  if (BINFO_INHERITANCE_CHAIN (d_binfo))
+    /* A second inheritance chain means indirect.  */
+    return false;
+  if (!BINFO_VIRTUAL_P (binfo))
+    /* Non-virtual, so only one inheritance chain means direct.  */
+    return true;
+  /* A virtual base looks like a direct base, so we need to look through the
+     direct bases to see if it's there.  */
+  tree b_binfo;
+  for (int i = 0; BINFO_BASE_ITERATE (d_binfo, i, b_binfo); ++i)
+    if (b_binfo == binfo)
+      return true;
+  return false;
+}
+
 /* BINFO is a base binfo in the complete type BINFO_TYPE (HERE).
    Find the equivalent binfo within whatever graph HERE is located.
    This is the inverse of original_binfo.  */
diff --git a/gcc/testsuite/g++.dg/cpp0x/inh-ctor28.C b/gcc/testsuite/g++.dg/cpp0x/inh-ctor28.C
new file mode 100644
index 00000000000..90a06c610f3
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/inh-ctor28.C
@@ -0,0 +1,7 @@
+// PR c++/81164
+// { dg-do compile { target c++11 } }
+
+struct A {};
+struct B : virtual A {};
+struct C : virtual A {};
+struct D : B,C { using A::A; };	// { dg-error "indirect" }
-- 
2.30.2