[PR c++/84835] ICE with generic lambda in extern "C"

https://gcc.gnu.org/ml/gcc-patches/2018-03/msg00890.html
	PR c++/84835
	* lambda.c (maybe_add_lambda_conv_op): Force C++ linkage.
	* pt.c (build_template_decl): Propagate language linkage.

	PR c++/84835
	* g++.dg/cpp1y/pr84835.C: New.

From-SVN: r258655

gcc/cp/ChangeLog

 2018-03-19  Nathan Sidwell  <nathan@acm.org>
 
+	PR c++/84835
+	* lambda.c (maybe_add_lambda_conv_op): Force C++ linkage.
+	* pt.c (build_template_decl): Propagate language linkage.
+
 	PR c++/84812
 	* name-lookup.c (set_local_extern_decl_linkage): Defend against
 	ambiguous lookups.

gcc/cp/lambda.c

@@ -1176,6 +1176,7 @@ maybe_add_lambda_conv_op (tree type)
   tree thistype = cp_build_qualified_type (type, TYPE_QUAL_CONST);
   tree fntype = build_method_type_directly (thistype, rettype, void_list_node);
   tree convfn = build_lang_decl (FUNCTION_DECL, name, fntype);
+  SET_DECL_LANGUAGE (convfn, lang_cplusplus);
   tree fn = convfn;
   DECL_SOURCE_LOCATION (fn) = DECL_SOURCE_LOCATION (callop);
   SET_DECL_ALIGN (fn, MINIMUM_METHOD_BOUNDARY);
@@ -1208,6 +1209,7 @@ maybe_add_lambda_conv_op (tree type)
 
   name = get_identifier ("_FUN");
   tree statfn = build_lang_decl (FUNCTION_DECL, name, stattype);
+  SET_DECL_LANGUAGE (statfn, lang_cplusplus);
   fn = statfn;
   DECL_SOURCE_LOCATION (fn) = DECL_SOURCE_LOCATION (callop);
   grokclassfn (type, fn, NO_SPECIAL);

gcc/cp/pt.c

@@ -4677,6 +4677,7 @@ tree
 build_template_decl (tree decl, tree parms, bool member_template_p)
 {
   tree tmpl = build_lang_decl (TEMPLATE_DECL, DECL_NAME (decl), NULL_TREE);
+  SET_DECL_LANGUAGE (tmpl, DECL_LANGUAGE (decl));
   DECL_TEMPLATE_PARMS (tmpl) = parms;
   DECL_CONTEXT (tmpl) = DECL_CONTEXT (decl);
   DECL_SOURCE_LOCATION (tmpl) = DECL_SOURCE_LOCATION (decl);

gcc/testsuite/ChangeLog

+2018-03-19  Nathan Sidwell  <nathan@acm.org>
+
+	PR c++/84835
+	* g++.dg/cpp1y/pr84835.C: New.
+
 2018-03-19  Sudakshina Das  <sudi.das@arm.com>
 
 	PR target/81647

gcc/testsuite/g++.dg/cpp1y/pr84835.C

+// { dg-do compile { target c++14 } }
+// PR c++/84835
+// ICE with generic lambda inside extern "C"
+
+extern "C" 
+{
+  auto r = [] (auto x) 
+  {
+    void baz (); // extern "C"
+    baz ();
+  };
+  
+}
+
+void g ()
+{
+  r (0);
+}
+
+//  { dg-final { scan-assembler "\[^0-9\]baz" } }