fixes #27586, prefer context type in generic inference

pkg/dev_compiler/lib/js/legacy/dart_sdk.js

Index: pkg/dev_compiler/lib/js/legacy/dart_sdk.js
diff --git a/pkg/dev_compiler/lib/js/legacy/dart_sdk.js b/pkg/dev_compiler/lib/js/legacy/dart_sdk.js
index 5a352a1aacf60cb43bbdaf0fa728a3d0de48afaf..9f92653bc17f5212841522a343d9c30782ae9b11 100644
--- a/pkg/dev_compiler/lib/js/legacy/dart_sdk.js
+++ b/pkg/dev_compiler/lib/js/legacy/dart_sdk.js
@@ -335,7 +335,6 @@ dart_library.library('dart_sdk', null, /* Imports */[
   let _SplayTreeNodeIterator = () => (_SplayTreeNodeIterator = dart.constFn(collection._SplayTreeNodeIterator$()))();
   let SplayTreeSet = () => (SplayTreeSet = dart.constFn(collection.SplayTreeSet$()))();
   let dynamicAnddynamicTodynamic = () => (dynamicAnddynamicTodynamic = dart.constFn(dart.functionType(dart.dynamic, [dart.dynamic, dart.dynamic])))();
-  let MappedIterableOfString$dynamic = () => (MappedIterableOfString$dynamic = dart.constFn(_internal.MappedIterable$(core.String, dart.dynamic)))();
   let SinkOfObject = () => (SinkOfObject = dart.constFn(core.Sink$(core.Object)))();
   let Codec = () => (Codec = dart.constFn(convert.Codec$()))();
   let ComparableOfString = () => (ComparableOfString = dart.constFn(core.Comparable$(core.String)))();
@@ -403,7 +402,6 @@ dart_library.library('dart_sdk', null, /* Imports */[
   let FutureOfint = () => (FutureOfint = dart.constFn(async.Future$(core.int)))();
   let CompleterOfDatabase = () => (CompleterOfDatabase = dart.constFn(async.Completer$(indexed_db.Database)))();
   let ListOfEventTarget = () => (ListOfEventTarget = dart.constFn(core.List$(html$.EventTarget)))();
-  let RectangleOfint = () => (RectangleOfint = dart.constFn(math.Rectangle$(core.int)))();
   let IterableOfNode = () => (IterableOfNode = dart.constFn(core.Iterable$(html$.Node)))();
   let ListOfNode = () => (ListOfNode = dart.constFn(core.List$(html$.Node)))();
   let ListOfElement = () => (ListOfElement = dart.constFn(core.List$(html$.Element)))();
@@ -675,6 +673,7 @@ dart_library.library('dart_sdk', null, /* Imports */[
   let IterableAndListTovoid = () => (IterableAndListTovoid = dart.constFn(dart.definiteFunctionType(dart.void, [core.Iterable, core.List])))();
   let _SplayTreeMapNodeTobool = () => (_SplayTreeMapNodeTobool = dart.constFn(dart.definiteFunctionType(core.bool, [collection._SplayTreeMapNode])))();
   let dynamicAndFnTodynamic = () => (dynamicAndFnTodynamic = dart.constFn(dart.definiteFunctionType(dart.dynamic, [dart.dynamic, dynamicAnddynamicTodynamic()])))();
+  let EventSinkTo_ConverterStreamEventSink = () => (EventSinkTo_ConverterStreamEventSink = dart.constFn(dart.definiteFunctionType(convert._ConverterStreamEventSink, [async.EventSink])))();
   let Uint8ListAndintAndintTovoid$ = () => (Uint8ListAndintAndintTovoid$ = dart.constFn(dart.definiteFunctionType(dart.void, [typed_data.Uint8List, core.int, core.int])))();
   let StringAndFnTodynamic = () => (StringAndFnTodynamic = dart.constFn(dart.definiteFunctionType(dart.dynamic, [core.String, dynamicAnddynamicTodynamic()])))();
   let EventSinkOfStringTo_LineSplitterEventSink = () => (EventSinkOfStringTo_LineSplitterEventSink = dart.constFn(dart.definiteFunctionType(convert._LineSplitterEventSink, [EventSinkOfString()])))();
@@ -10491,7 +10490,7 @@ dart_library.library('dart_sdk', null, /* Imports */[
             let wrapper = new async._ControllerEventSinkWrapper(null);
             timeout = dart.fn(() => {
               wrapper[_sink] = controller;
-              zone.runUnaryGuarded(dart.dynamic, EventSinkOfT())(registeredOnTimeout, wrapper);
+              zone.runUnaryGuarded(dart.dynamic, async._ControllerEventSinkWrapper)(registeredOnTimeout, wrapper);
               wrapper[_sink] = null;
             }, VoidTovoid$());
           }
@@ -13843,7 +13842,7 @@ dart_library.library('dart_sdk', null, /* Imports */[
       this[_symbol] = symbol;
       this[_name$] = _js_mirrors.getName(symbol);
       this.type = _js_mirrors.reflectType(t);
-      this.metadata = ListOfInstanceMirror().unmodifiable(annotations[dartx.map](mirrors.InstanceMirror)(dart.fn(a => _js_mirrors.reflect(a), dynamicToInstanceMirror())));
+      this.metadata = ListOfInstanceMirror().unmodifiable(annotations[dartx.map](dart.dynamic)(dart.fn(a => _js_mirrors.reflect(a), dynamicToInstanceMirror())));
       this.isStatic = false;
       this.isFinal = false;
     }
@@ -28714,7 +28713,7 @@ dart_library.library('dart_sdk', null, /* Imports */[
     }
     get values() {
       if (dart.test(this[_isUpgraded])) return this[_upgradedMap][dartx.values];
-      return MappedIterableOfString$dynamic().new(this[_computeKeys$](), dart.fn(each => this._get(each), dynamicTodynamic$()));
+      return _internal.MappedIterable.new(this[_computeKeys$](), dart.fn(each => this._get(each), dynamicTodynamic$()));
     }
     _set(key, value) {
       if (dart.test(this[_isUpgraded])) {
@@ -29278,11 +29277,9 @@ dart_library.library('dart_sdk', null, /* Imports */[
   const _subsetMask = Symbol('_subsetMask');
   convert.Converter$ = dart.generic((S, T) => {
     let StreamOfS = () => (StreamOfS = dart.constFn(async.Stream$(S)))();
-    let _ConverterStreamEventSinkOfS$dynamic = () => (_ConverterStreamEventSinkOfS$dynamic = dart.constFn(convert._ConverterStreamEventSink$(S, dart.dynamic)))();
     let StreamTransformerOfS$T = () => (StreamTransformerOfS$T = dart.constFn(async.StreamTransformer$(S, T)))();
     let SinkOfT = () => (SinkOfT = dart.constFn(core.Sink$(T)))();
     let StreamOfT = () => (StreamOfT = dart.constFn(async.Stream$(T)))();
-    let EventSinkTo_ConverterStreamEventSinkOfS$dynamic = () => (EventSinkTo_ConverterStreamEventSinkOfS$dynamic = dart.constFn(dart.definiteFunctionType(_ConverterStreamEventSinkOfS$dynamic(), [async.EventSink])))();
     class Converter extends core.Object {
       new() {
       }
@@ -29298,7 +29295,7 @@ dart_library.library('dart_sdk', null, /* Imports */[
       }
       bind(stream) {
         StreamOfS()._check(stream);
-        return StreamOfT().eventTransformed(stream, dart.fn(sink => new (_ConverterStreamEventSinkOfS$dynamic())(this, sink), EventSinkTo_ConverterStreamEventSinkOfS$dynamic()));
+        return StreamOfT().eventTransformed(stream, dart.fn(sink => new convert._ConverterStreamEventSink(this, sink), EventSinkTo_ConverterStreamEventSink()));
       }
     }
     dart.addTypeTests(Converter);
@@ -35031,7 +35028,7 @@ dart_library.library('dart_sdk', null, /* Imports */[
       if (dart.test(pathToSplit[dartx.isNotEmpty]) && pathToSplit[dartx.codeUnitAt](0) == core.Uri._SLASH) {
         pathToSplit = pathToSplit[dartx.substring](1);
       }
-      result = pathToSplit == "" ? const$51 || (const$51 = dart.constList([], core.String)) : ListOfString().unmodifiable(pathToSplit[dartx.split]("/")[dartx.map](core.String)(core.Uri.decodeComponent));
+      result = pathToSplit == "" ? const$51 || (const$51 = dart.constList([], core.String)) : ListOfString().unmodifiable(pathToSplit[dartx.split]("/")[dartx.map](dart.dynamic)(core.Uri.decodeComponent));
       this[_pathSegments] = result;
       return result;
     }
@@ -41258,10 +41255,10 @@ dart_library.library('dart_sdk', null, /* Imports */[
       return html$.window[_getComputedStyle](this, pseudoElement);
     }
     get [dartx.client]() {
-      return new (RectangleOfint())(this[dartx.clientLeft], this[dartx.clientTop], this[dartx.clientWidth], this[dartx.clientHeight]);
+      return new (RectangleOfnum())(this[dartx.clientLeft], this[dartx.clientTop], this[dartx.clientWidth], this[dartx.clientHeight]);
     }
     get [dartx.offset]() {
-      return new (RectangleOfint())(this[dartx.offsetLeft], this[dartx.offsetTop], this[dartx.offsetWidth], this[dartx.offsetHeight]);
+      return new (RectangleOfnum())(this[dartx.offsetLeft], this[dartx.offsetTop], this[dartx.offsetWidth], this[dartx.offsetHeight]);
     }
     [dartx.appendText](text) {
       this[dartx.append](html$.Text.new(text));
@@ -66070,7 +66067,7 @@ dart_library.library('dart_sdk', null, /* Imports */[
     }
     static new(callback) {
       0;
-      return new (window.MutationObserver || window.WebKitMutationObserver || window.MozMutationObserver)(_js_helper.convertDartClosureToJS(html$._wrapZoneBinaryCallback)(html$._wrapBinaryZone(dart.dynamic, dart.dynamic, dart.dynamic)(callback), 2));
+      return new (window.MutationObserver || window.WebKitMutationObserver || window.MozMutationObserver)(_js_helper.convertDartClosureToJS(dynamicAnddynamicTodynamic())(html$._wrapBinaryZone(dart.dynamic, dart.dynamic, dart.dynamic)(callback), 2));
     }
   };
   dart.setSignature(html$.MutationObserver, {
@@ -70536,7 +70533,7 @@ dart_library.library('dart_sdk', null, /* Imports */[
   ]);
   html$.Screen = class Screen extends _interceptors.Interceptor {
     get [dartx.available]() {
-      return new (RectangleOfint())(this[_availLeft], this[_availTop], this[_availWidth], this[_availHeight]);
+      return new (RectangleOfnum())(this[_availLeft], this[_availTop], this[_availWidth], this[_availHeight]);
     }
     static _() {
       dart.throw(new core.UnsupportedError("Not supported"));