P0409R2 - allow lambda capture [=, this]

	P0409R2 - allow lambda capture [=, this]
	* parser.c (cp_parser_lambda_introducer): For cxx2a don't pedwarn on
	redundant [=, this].

	* g++.dg/cpp1z/lambda-this1.C: Don't expect error for c++2a on [=, this]
	capture.  Add further tests.
	* g++.dg/cpp0x/lambda/lambda-capture-redundancy.C: Don't expect error
	for c++2a on [=, this] capture.

From-SVN: r253030

gcc/cp/ChangeLog

+2017-09-20  Jakub Jelinek  <jakub@redhat.com>
+
+	P0409R2 - allow lambda capture [=, this]
+	* parser.c (cp_parser_lambda_introducer): For cxx2a don't pedwarn on
+	redundant [=, this].
+
 2017-09-18  Jason Merrill  <jason@redhat.com>
 
 	PR c++/82069 - ICE with lambda in template

gcc/cp/parser.c

@@ -10183,7 +10183,8 @@ cp_parser_lambda_introducer (cp_parser* parser, tree lambda_expr)
       if (cp_lexer_next_token_is_keyword (parser->lexer, RID_THIS))
 	{
 	  location_t loc = cp_lexer_peek_token (parser->lexer)->location;
-	  if (LAMBDA_EXPR_DEFAULT_CAPTURE_MODE (lambda_expr) == CPLD_COPY)
+	  if (cxx_dialect < cxx2a
+	      && LAMBDA_EXPR_DEFAULT_CAPTURE_MODE (lambda_expr) == CPLD_COPY)
 	    pedwarn (loc, 0, "explicit by-copy capture of %<this%> redundant "
 		     "with by-copy capture default");
 	  cp_lexer_consume_token (parser->lexer);

gcc/testsuite/ChangeLog

 2017-09-20  Jakub Jelinek  <jakub@redhat.com>
 
+	P0409R2 - allow lambda capture [=, this]
+	* g++.dg/cpp1z/lambda-this1.C: Don't expect error for c++2a on [=, this]
+	capture.  Add further tests.
+	* g++.dg/cpp0x/lambda/lambda-capture-redundancy.C: Don't expect error
+	for c++2a on [=, this] capture.
+
 	* g++.dg/cpp1z/cplusplus.C: Test that __cplusplus is equal to 201703L.
 	* g++.dg/cpp1z/cplusplus_1z.C: New test.
 

gcc/testsuite/g++.dg/cpp0x/lambda/lambda-capture-redundancy.C

@@ -7,7 +7,7 @@ void S2::f(int i) {
   [&, i]{ };       // OK
   [&, &i]{ };	   // { dg-error "" } i preceded by & when & is the default
   [=, i]{ };       // { dg-error "" } i not preceded by & when = is the default
-  [=, this]{ };	   // { dg-error "" } this when = is the default
+  [=, this]{ };	   // { dg-error "" "" { target c++17_down } } this when = is the default
   [i, i]{ };	   // { dg-error "" } i repeated
   [this, this]{ }; // { dg-error "" } i repeated
 }

gcc/testsuite/g++.dg/cpp1z/lambda-this1.C

@@ -17,13 +17,31 @@ struct A {
     auto h = [*this] () mutable { a++; };// { dg-error "'*this' capture only available with" "" { target c++14_down } }
     auto i = [=] { return a; };
     auto j = [&] { return a; };
-    auto k = [=, this] { return a; };// { dg-error "explicit by-copy capture of 'this' redundant with by-copy capture default" }
+    // P0409R2 - C++2A lambda capture [=, this]
+    auto k = [=, this] { return a; };// { dg-error "explicit by-copy capture of 'this' redundant with by-copy capture default" "" { target c++17_down } }
     auto l = [&, this] { return a; };
     auto m = [=, *this] { return a; };// { dg-error "'*this' capture only available with" "" { target c++14_down } }
     auto n = [&, *this] { return a; };// { dg-error "'*this' capture only available with" "" { target c++14_down } }
     auto o = [*this, &v] { return a + v; };// { dg-error "'*this' capture only available with" "" { target c++14_down } }
     auto p = [*this] { this = 0; };	// { dg-error "lvalue required as left operand of assignment" }
 					// { dg-error "'*this' capture only available with" "" { target c++14_down } .-1 }
+    auto q = [=, this, *this] { return a; };// { dg-error "already captured 'this'" }
+					    // { dg-error "'*this' capture only available with" "" { target c++14_down } .-1 }
+					    // { dg-error "explicit by-copy capture of 'this' redundant with by-copy capture default" "" { target c++17_down } .-2 }
+    auto r = [=, this, this] { return a; };// { dg-error "already captured 'this'" }
+					   // { dg-error "explicit by-copy capture of 'this' redundant with by-copy capture default" "" { target c++17_down } .-1 }
+    auto s = [=, *this, this] { return a; };// { dg-error "already captured 'this'" }
+					    // { dg-error "'*this' capture only available with" "" { target c++14_down } .-1 }
+					    // { dg-error "explicit by-copy capture of 'this' redundant with by-copy capture default" "" { target c++17_down } .-2 }
+    auto t = [=, *this, *this] { return a; };// { dg-error "already captured 'this'" }
+					     // { dg-error "'*this' capture only available with" "" { target c++14_down } .-1 }
+    auto u = [&, this, *this] { return a; };// { dg-error "already captured 'this'" }
+					    // { dg-error "'*this' capture only available with" "" { target c++14_down } .-1 }
+    auto w = [&, this, this] { return a; };// { dg-error "already captured 'this'" }
+    auto x = [&, *this, this] { return a; };// { dg-error "already captured 'this'" }
+					    // { dg-error "'*this' capture only available with" "" { target c++14_down } .-1 }
+    auto y = [&, *this, *this] { return a; };// { dg-error "already captured 'this'" }
+					     // { dg-error "'*this' capture only available with" "" { target c++14_down } .-1 }
   }
 };
 struct B {