[cfe] Fix missing comma between type parameters in function types

Change-Id: I90f7d1665a93414ed89799b3f564fdb7d2114e20
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/119324
Commit-Queue: Aske Simon Christensen <askesc@google.com>
Auto-Submit: Aske Simon Christensen <askesc@google.com>
Reviewed-by: Dmitry Stefantsov <dmitryas@google.com>

pkg/front_end/lib/src/fasta/kernel/type_labeler.dart

@@ -178,6 +178,7 @@ class TypeLabeler implements DartTypeVisitor<void>, ConstantVisitor<void> {
           result.add(" extends ");
           param.bound.accept(this);
         }
+        first = false;
       }
       result.add(">");
     }

pkg/front_end/testcases/general/generic_function_type_in_message.dart

@@ -0,0 +1,13 @@
+// Copyright (c) 2019, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+num add<A extends num, B extends num>(A a, B b) => a + b;
+
+test() {
+  int x = add;
+}
+
+main() {
+  if (add(1,2) < 3) test();
+}

pkg/front_end/testcases/general/generic_function_type_in_message.dart.outline.expect

@@ -0,0 +1,10 @@
+library;
+import self as self;
+import "dart:core" as core;
+
+static method add<A extends core::num* = core::num*, B extends core::num* = core::num*>(self::add::A* a, self::add::B* b) → core::num*
+  ;
+static method test() → dynamic
+  ;
+static method main() → dynamic
+  ;

pkg/front_end/testcases/general/generic_function_type_in_message.dart.strong.expect

@@ -0,0 +1,26 @@
+library;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/general/generic_function_type_in_message.dart:8:11: Error: A value of type 'num Function<A extends num, B extends num>(A, B)' can't be assigned to a variable of type 'int'.
+//   int x = add;
+//           ^
+//
+import self as self;
+import "dart:core" as core;
+
+static method add<A extends core::num* = core::num*, B extends core::num* = core::num*>(self::add::A* a, self::add::B* b) → core::num*
+  return a.{core::num::+}(b);
+static method test() → dynamic {
+  core::int* x = let final<BottomType> #t1 = invalid-expression "pkg/front_end/testcases/general/generic_function_type_in_message.dart:8:11: Error: A value of type 'num Function<A extends num, B extends num>(A, B)' can't be assigned to a variable of type 'int'.
+  int x = add;
+          ^" in (#C1) as{TypeError} core::int*;
+}
+static method main() → dynamic {
+  if(self::add<core::int*, core::int*>(1, 2).{core::num::<}(3))
+    self::test();
+}
+
+constants  {
+  #C1 = tearoff self::add
+}

pkg/front_end/testcases/general/generic_function_type_in_message.dart.strong.transformed.expect

@@ -0,0 +1,26 @@
+library;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/general/generic_function_type_in_message.dart:8:11: Error: A value of type 'num Function<A extends num, B extends num>(A, B)' can't be assigned to a variable of type 'int'.
+//   int x = add;
+//           ^
+//
+import self as self;
+import "dart:core" as core;
+
+static method add<A extends core::num* = core::num*, B extends core::num* = core::num*>(self::add::A* a, self::add::B* b) → core::num*
+  return a.{core::num::+}(b);
+static method test() → dynamic {
+  core::int* x = let final<BottomType> #t1 = invalid-expression "pkg/front_end/testcases/general/generic_function_type_in_message.dart:8:11: Error: A value of type 'num Function<A extends num, B extends num>(A, B)' can't be assigned to a variable of type 'int'.
+  int x = add;
+          ^" in (#C1) as{TypeError} core::int*;
+}
+static method main() → dynamic {
+  if(self::add<core::int*, core::int*>(1, 2).{core::num::<}(3))
+    self::test();
+}
+
+constants  {
+  #C1 = tearoff self::add
+}

pkg/front_end/testcases/text_serialization.status

@@ -160,6 +160,7 @@ general/function_type_is_check: TextSerializationFailure # Was: Pass
 general/function_type_recovery: TextSerializationFailure # Was: Pass
 general/functions: TextSerializationFailure # Was: Pass
 general/future_or_test: TextSerializationFailure # Was: Pass
+general/generic_function_type_in_message: TextSerializationFailure
 general/having_part_with_part_and_annotation: TextSerializationFailure
 general/having_part_with_parts_and_annotation: TextSerializationFailure
 general/hello: TextSerializationFailure # Was: Pass