Some preliminary support for quasi-generics

tool/sdk_expected_errors.txt

Index: tool/sdk_expected_errors.txt
diff --git a/tool/sdk_expected_errors.txt b/tool/sdk_expected_errors.txt
index 6af1a26cfe7fe4e5f12b6f5872a4dbbabaa2673c..8063ccb9e2ea4bdc85ab93a63ae410dd53a22d10 100644
--- a/tool/sdk_expected_errors.txt
+++ b/tool/sdk_expected_errors.txt
@@ -223,7 +223,6 @@ warning: [DownCastComposite] _first.encoder.fuse(_second.encoder) (Converter<S,
 warning: [DownCastComposite] _second.decoder.fuse(_first.decoder) (Converter<T, dynamic>) will need runtime check to cast to type Converter<T, S> (dart:convert/codec.dart, line 88, col 34)
 warning: [DownCastComposite] JS('JSExtendableArray', '#', keys) (dynamic) will need runtime check to cast to type List<String> (dart:convert, line 311, col 12)
 warning: [DownCastComposite] _second.convert(_first.convert(input)) (dynamic) will need runtime check to cast to type T (dart:convert/converter.dart, line 58, col 25)
-warning: [DownCastComposite] byteStream.transform(decoder).fold(new StringBuffer(), (buffer, string) => buffer..write(string)).then((buffer) => buffer.toString()) (Future<dynamic>) will need runtime check to cast to type Future<String> (dart:convert/encoding.dart, line 14, col 12)
 warning: [DownCastComposite] toEncodable ((dynamic) → dynamic) will need runtime check to cast to type (Object) → Object (dart:convert/json.dart, line 142, col 28)
 warning: [DownCastComposite] _toEncodable ((dynamic) → dynamic) will need runtime check to cast to type (Object) → Object (dart:convert/json.dart, line 147, col 28)
 warning: [DownCastComposite] _toEncodable (Function) will need runtime check to cast to type (Object) → dynamic (dart:convert/json.dart, line 270, col 42)
@@ -264,8 +263,6 @@ warning: [DownCastComposite] test ((dynamic) → bool) will need runtime check t
 warning: [DownCastComposite] list (List<dynamic>) will need runtime check to cast to type Iterable<T> (dart:_internal/iterable.dart, line 997, col 40)
 warning: [DownCastComposite] list (List<dynamic>) will need runtime check to cast to type Iterable<T> (dart:_internal/iterable.dart, line 1033, col 35)
 warning: [DownCastComposite] l (List<dynamic>) will need runtime check to cast to type List<T> (dart:_internal/iterable.dart, line 1115, col 31)
-warning: [DownCastComposite] IsolateNatives.spawnFunction(entryPoint, message, paused).then((msg) => new Isolate(msg[1], pauseCapability: msg[2], terminateCapability: msg[3])) (Future<dynamic>) will need runtime check to cast to type Future<Isolate> (dart:isolate, line 168, col 14)
-warning: [DownCastComposite] IsolateNatives.spawnUri(uri, args, message, paused).then((msg) => new Isolate(msg[1], pauseCapability: msg[2], terminateCapability: msg[3])) (Future<dynamic>) will need runtime check to cast to type Future<Isolate> (dart:isolate, line 234, col 14)
 warning: [DownCastComposite] _convertToJS ((dynamic) → dynamic) will need runtime check to cast to type (E) → dynamic (dart:js, line 325, col 44)
 warning: [DownCastComposite] super[index] (dynamic) will need runtime check to cast to type E (dart:js, line 358, col 12)
 warning: [DownCastComposite] callMethod('splice', [index, 1])[0] (dynamic) will need runtime check to cast to type E (dart:js, line 404, col 12)