From 6b34716ba421d05190d66ab4660a48c0446f76c7 Mon Sep 17 00:00:00 2001
From: Nathan Sidwell <nathan@acm.org>
Date: Fri, 13 Jul 2018 15:33:27 +0000
Subject: [PATCH] [PR c++/86374] Name lookup failure in enclosing template

https://gcc.gnu.org/ml/gcc-patches/2018-07/msg00701.html
	PR c++/86374
	* pt.c (lookup_template_class_1): Use tsubst_aggr_type for
	contexts that are classes.
	* parser.c (cp_parser_template_id): Combine entering_scope decl &
	initializer.

	PR c++/86374
	* g++.dg/pr86374.C: New.

From-SVN: r262637
---
 gcc/cp/ChangeLog               |  8 ++++++++
 gcc/cp/parser.c                |  7 +++----
 gcc/cp/pt.c                    | 11 +++++++++--
 gcc/testsuite/ChangeLog        |  5 +++++
 gcc/testsuite/g++.dg/pr86374.C | 20 ++++++++++++++++++++
 5 files changed, 45 insertions(+), 6 deletions(-)
 create mode 100644 gcc/testsuite/g++.dg/pr86374.C

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index a640259193c..1d5d66946f6 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,11 @@
+2018-07-13  Nathan Sidwell  <nathan@acm.org>
+
+	PR c++/86374
+	* pt.c (lookup_template_class_1): Use tsubst_aggr_type for
+	contexts that are classes.
+	* parser.c (cp_parser_template_id): Combine entering_scope decl &
+	initializer.
+
 2018-07-12  Jakub Jelinek  <jakub@redhat.com>
 
 	* decl2.c (cplus_decl_attributes): Don't diagnose vars without mappable
diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c
index 366a0d89460..d0f1e1e9701 100644
--- a/gcc/cp/parser.c
+++ b/gcc/cp/parser.c
@@ -15973,15 +15973,14 @@ cp_parser_template_id (cp_parser *parser,
   else if (DECL_TYPE_TEMPLATE_P (templ)
 	   || DECL_TEMPLATE_TEMPLATE_PARM_P (templ))
     {
-      bool entering_scope;
       /* In "template <typename T> ... A<T>::", A<T> is the abstract A
 	 template (rather than some instantiation thereof) only if
 	 is not nested within some other construct.  For example, in
 	 "template <typename T> void f(T) { A<T>::", A<T> is just an
 	 instantiation of A.  */
-      entering_scope = (template_parm_scope_p ()
-			&& cp_lexer_next_token_is (parser->lexer,
-						   CPP_SCOPE));
+      bool entering_scope
+	= (template_parm_scope_p ()
+	   && cp_lexer_next_token_is (parser->lexer, CPP_SCOPE));
       template_id
 	= finish_template_type (templ, arguments, entering_scope);
     }
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index eae9e14d37d..9de9f500e2a 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -9368,8 +9368,15 @@ lookup_template_class_1 (tree d1, tree arglist, tree in_decl, tree context,
 	  return found;
 	}
 
-      context = tsubst (DECL_CONTEXT (gen_tmpl), arglist,
-			complain, in_decl);
+      context = DECL_CONTEXT (gen_tmpl);
+      if (context && TYPE_P (context))
+	{
+	  context = tsubst_aggr_type (context, arglist, complain, in_decl, true);
+	  context = complete_type (context);
+	}
+      else
+	context = tsubst (context, arglist, complain, in_decl);
+
       if (context == error_mark_node)
 	return error_mark_node;
 
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 0c61e976f73..1780ca0074a 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2018-07-13  Nathan Sidwell  <nathan@acm.org>
+
+	PR c++/86374
+	* g++.dg/pr86374.C: New.
+
 2018-07-13  Qing Zhao  <qing.zhao@oracle.com>
 
 	PR middle-end/78809
diff --git a/gcc/testsuite/g++.dg/pr86374.C b/gcc/testsuite/g++.dg/pr86374.C
new file mode 100644
index 00000000000..fd7115626e1
--- /dev/null
+++ b/gcc/testsuite/g++.dg/pr86374.C
@@ -0,0 +1,20 @@
+// pr C++/86374
+// bogus lookup error
+template<typename LIST>
+struct list {
+  static const int index = 1;
+  template <typename> struct addWithChecking {};
+};
+
+template<typename container, int ix = container::index>
+struct find {
+  static const int result = 0;
+};
+
+template <class LIST>
+template<class O>
+struct list<LIST>::addWithChecking<O*>
+{
+  static const int xres =
+    find<list<LIST> >::result; // bogus error about index here.
+};
-- 
2.30.2