re PR c++/61636 (generic lambda: segfault / "cannot call member function without object")

	PR c++/61636
	* cp-tree.h (maybe_generic_this_capture): Declare.
	* lambda.c (resolvable_dummy_lambda): New, broken out of ...
	(maybe_resolve_dummy): ... here.  Call it.
	(maybe_generic_this_capture): New.
	* parser.c (cp_parser_postfix_expression): Speculatively capture
	this in generic lambda in unresolved member function call.
	* pt.c (tsubst_copy_and_build): Force hard error from failed
	member function lookup in generic lambda.

	PR c++/61636
	* g++.dg/cpp1y/pr61636-1.C: New.
	* g++.dg/cpp1y/pr61636-2.C: New.
	* g++.dg/cpp1y/pr61636-3.C: New.

From-SVN: r244544

1 files changed, 33 insertions, 12 deletions

diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index dec7d39..022ffda 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -17142,19 +17142,34 @@ tsubst_copy_and_build (tree t,
 
 		if (unq != function)
 		  {
-		    tree fn = unq;
-		    if (INDIRECT_REF_P (fn))
-		      fn = TREE_OPERAND (fn, 0);
-		    if (TREE_CODE (fn) == COMPONENT_REF)
-		      fn = TREE_OPERAND (fn, 1);
-		    if (is_overloaded_fn (fn))
-		      fn = get_first_fn (fn);
-		    if (permerror (EXPR_LOC_OR_LOC (t, input_location),
-				   "%qD was not declared in this scope, "
-				   "and no declarations were found by "
-				   "argument-dependent lookup at the point "
-				   "of instantiation", function))
+		    /* In a lambda fn, we have to be careful to not
+		       introduce new this captures.  Legacy code can't
+		       be using lambdas anyway, so it's ok to be
+		       stricter.  */
+		    bool in_lambda = (current_class_type
+				      && LAMBDA_TYPE_P (current_class_type));
+		    char const *msg = "%qD was not declared in this scope, "
+		      "and no declarations were found by "
+		      "argument-dependent lookup at the point "
+		      "of instantiation";
+
+		    bool diag = true;
+		    if (in_lambda)
+		      error_at (EXPR_LOC_OR_LOC (t, input_location),
+				msg, function);
+		    else
+		      diag = permerror (EXPR_LOC_OR_LOC (t, input_location),
+					msg, function);
+		    if (diag)
 		      {
+			tree fn = unq;
+			if (INDIRECT_REF_P (fn))
+			  fn = TREE_OPERAND (fn, 0);
+			if (TREE_CODE (fn) == COMPONENT_REF)
+			  fn = TREE_OPERAND (fn, 1);
+			if (is_overloaded_fn (fn))
+			  fn = get_first_fn (fn);
+
 			if (!DECL_P (fn))
 			  /* Can't say anything more.  */;
 			else if (DECL_CLASS_SCOPE_P (fn))
@@ -17177,7 +17192,13 @@ tsubst_copy_and_build (tree t,
 			  inform (DECL_SOURCE_LOCATION (fn),
 				  "%qD declared here, later in the "
 				  "translation unit", fn);
+			if (in_lambda)
+			  {
+			    release_tree_vector (call_args);
+			    RETURN (error_mark_node);
+			  }
 		      }
+
 		    function = unq;
 		  }
 	      }