2017-05-29  Nathan Sidwell  <nathan@acm.org>

	PR c++/80891 (#3)
	* cp-tree.h (build_min_nt_call_vec): Declare.
	* decl.c (build_offset_ref_call_from_tree): Call it.
	* parser.c (cp_parser_postfix_expression): Likewise.
	* pt.c (tsubst_copy_and_build): Likewise.
	* semantics.c (finish_call_expr): Likewise.
	* tree.c (build_min_nt_loc): Keep unresolved lookups.
	(build_min): Likewise.
	(build_min_non_dep): Likewise.
	(build_min_non_dep_call_vec): Likewise.
	(build_min_nt_call_vec): New.

	PR c++/80891 (#3)
	* g++.dg/lookup/pr80891-3.C: New.

Index: cp/cp-tree.h
===================================================================
--- cp/cp-tree.h	(revision 248569)
+++ cp/cp-tree.h	(working copy)
@@ -6891,6 +6891,7 @@ extern tree build_min_nt_loc			(location
 						 ...);
 extern tree build_min_non_dep			(enum tree_code, tree, ...);
 extern tree build_min_non_dep_op_overload	(enum tree_code, tree, tree, ...);
+extern tree build_min_nt_call_vec (tree, vec<tree, va_gc> *);
 extern tree build_min_non_dep_call_vec		(tree, tree, vec<tree, va_gc> *);
 extern vec<tree, va_gc>* vec_copy_and_insert    (vec<tree, va_gc>*, tree, unsigned);
 extern tree build_cplus_new			(tree, tree, tsubst_flags_t);
Index: cp/decl2.c
===================================================================
--- cp/decl2.c	(revision 248569)
+++ cp/decl2.c	(working copy)
@@ -4891,7 +4891,7 @@ build_offset_ref_call_from_tree (tree fn
 		  || TREE_CODE (fn) == MEMBER_REF);
       if (type_dependent_expression_p (fn)
 	  || any_type_dependent_arguments_p (*args))
-	return build_nt_call_vec (fn, *args);
+	return build_min_nt_call_vec (fn, *args);
 
       orig_args = make_tree_vector_copy (*args);
 
Index: cp/parser.c
===================================================================
--- cp/parser.c	(revision 248569)
+++ cp/parser.c	(working copy)
@@ -6952,7 +6952,7 @@ cp_parser_postfix_expression (cp_parser
 		  {
 		    maybe_generic_this_capture (instance, fn);
 		    postfix_expression
-		      = build_nt_call_vec (postfix_expression, args);
+		      = build_min_nt_call_vec (postfix_expression, args);
 		    release_tree_vector (args);
 		    break;
 		  }
Index: cp/pt.c
===================================================================
--- cp/pt.c	(revision 248569)
+++ cp/pt.c	(working copy)
@@ -17389,7 +17389,7 @@ tsubst_copy_and_build (tree t,
 			&& TREE_CODE (fn) != FIELD_DECL)
 		    || type_dependent_expression_p (fn)
 		    || any_type_dependent_arguments_p (call_args)))
-	      ret = build_nt_call_vec (function, call_args);
+	      ret = build_min_nt_call_vec (function, call_args);
 	    else if (!BASELINK_P (fn))
 	      ret = finish_call_expr (function, &call_args,
 				       /*disallow_virtual=*/false,
Index: cp/semantics.c
===================================================================
--- cp/semantics.c	(revision 248569)
+++ cp/semantics.c	(working copy)
@@ -2322,7 +2322,7 @@ finish_call_expr (tree fn, vec<tree, va_
       if (type_dependent_expression_p (fn)
 	  || any_type_dependent_arguments_p (*args))
 	{
-	  result = build_nt_call_vec (fn, *args);
+	  result = build_min_nt_call_vec (fn, *args);
 	  SET_EXPR_LOCATION (result, EXPR_LOC_OR_LOC (fn, input_location));
 	  KOENIG_LOOKUP_P (result) = koenig_p;
 	  if (is_overloaded_fn (fn))
Index: cp/tree.c
===================================================================
--- cp/tree.c	(revision 248570)
+++ cp/tree.c	(working copy)
@@ -3216,13 +3216,14 @@ build_min_nt_loc (location_t loc, enum t
     {
       tree x = va_arg (p, tree);
       TREE_OPERAND (t, i) = x;
+      if (x && TREE_CODE (x) == OVERLOAD)
+	lookup_keep (x, true);
     }
 
   va_end (p);
   return t;
 }
 
-
 /* Similar to `build', but for template definitions.  */
 
 tree
@@ -3245,8 +3246,13 @@ build_min (enum tree_code code, tree tt,
     {
       tree x = va_arg (p, tree);
       TREE_OPERAND (t, i) = x;
-      if (x && !TYPE_P (x) && TREE_SIDE_EFFECTS (x))
-	TREE_SIDE_EFFECTS (t) = 1;
+      if (x)
+	{
+	  if (!TYPE_P (x) && TREE_SIDE_EFFECTS (x))
+	    TREE_SIDE_EFFECTS (t) = 1;
+	  if (TREE_CODE (x) == OVERLOAD)
+	    lookup_keep (x, true);
+	}
     }
 
   va_end (p);
@@ -3281,6 +3287,8 @@ build_min_non_dep (enum tree_code code,
     {
       tree x = va_arg (p, tree);
       TREE_OPERAND (t, i) = x;
+      if (x && TREE_CODE (x) == OVERLOAD)
+	lookup_keep (x, true);
     }
 
   if (code == COMPOUND_EXPR && TREE_CODE (non_dep) != COMPOUND_EXPR)
@@ -3292,14 +3300,34 @@ build_min_non_dep (enum tree_code code,
   return convert_from_reference (t);
 }
 
-/* Similar to `build_nt_call_vec', but for template definitions of
+/* Similar to build_min_nt, but call expressions  */
+
+tree
+build_min_nt_call_vec (tree fn, vec<tree, va_gc> *args)
+{
+  tree ret, t;
+  unsigned int ix;
+
+  ret = build_vl_exp (CALL_EXPR, vec_safe_length (args) + 3);
+  CALL_EXPR_FN (ret) = fn;
+  CALL_EXPR_STATIC_CHAIN (ret) = NULL_TREE;
+  FOR_EACH_VEC_SAFE_ELT (args, ix, t)
+    {
+      CALL_EXPR_ARG (ret, ix) = t;
+      if (TREE_CODE (t) == OVERLOAD)
+	lookup_keep (t, true);
+    }
+  return ret;
+}
+
+/* Similar to `build_min_nt_call_vec', but for template definitions of
    non-dependent expressions. NON_DEP is the non-dependent expression
    that has been built.  */
 
 tree
 build_min_non_dep_call_vec (tree non_dep, tree fn, vec<tree, va_gc> *argvec)
 {
-  tree t = build_nt_call_vec (fn, argvec);
+  tree t = build_min_nt_call_vec (fn, argvec);
   if (REFERENCE_REF_P (non_dep))
     non_dep = TREE_OPERAND (non_dep, 0);
   TREE_TYPE (t) = TREE_TYPE (non_dep);
Index: testsuite/g++.dg/lookup/pr80891-3.C
===================================================================
--- testsuite/g++.dg/lookup/pr80891-3.C	(revision 0)
+++ testsuite/g++.dg/lookup/pr80891-3.C	(working copy)
@@ -0,0 +1,26 @@
+// PR c++/80891 part 3
+// We were failing to mark OVERLOADS held in template definitions as
+// immutable in non-call contexts.
+
+namespace std {
+  int endl();
+}
+
+using std::endl;
+
+template <class RealType> void test_spots(RealType)
+{
+  using namespace std;
+  RealType a;
+  a << endl;
+}
+
+template <typename T>
+void operator<< (T, int (&)());
+
+struct Q {};
+void test_maintest_method()
+{
+  Q q;
+  test_spots(q);
+}
