Re-apply: Trace static tear-off closures.

sdk/lib/_internal/compiler/implementation/inferrer/closure_tracer.dart

Index: sdk/lib/_internal/compiler/implementation/inferrer/closure_tracer.dart
===================================================================
--- sdk/lib/_internal/compiler/implementation/inferrer/closure_tracer.dart	(revision 31273)
+++ sdk/lib/_internal/compiler/implementation/inferrer/closure_tracer.dart	(working copy)
@@ -5,17 +5,18 @@
 part of type_graph_inferrer;
 
 class ClosureTracerVisitor extends TracerVisitor {
-  ClosureTracerVisitor(tracedType, inferrer) : super(tracedType, inferrer);
+  final FunctionElement tracedElement;
 
+  ClosureTracerVisitor(this.tracedElement, tracedType, inferrer)
+      : super(tracedType, inferrer);
+
   void run() {
-    ClosureTypeInformation closure = tracedType;
-    FunctionElement element = closure.element;
-    element.functionSignature.forEachParameter((Element parameter) {
+    tracedElement.functionSignature.forEachParameter((Element parameter) {
       ElementTypeInformation info = inferrer.types.getInferredTypeOf(parameter);
       info.abandonInferencing = false;
     });
     analyze();
-    element.functionSignature.forEachParameter((Element parameter) {
+    tracedElement.functionSignature.forEachParameter((Element parameter) {
       ElementTypeInformation info = inferrer.types.getInferredTypeOf(parameter);
       if (continueAnalyzing) {
         info.disableHandleSpecialCases = true;
@@ -30,12 +31,10 @@
   }
 
   void analyzeCall(CallSiteTypeInformation info) {
-    ClosureTypeInformation closure = tracedType;
-    FunctionElement element = closure.element;
     Selector selector = info.selector;
-    if (!selector.signatureApplies(element, compiler)) return;
+    if (!selector.signatureApplies(tracedElement, compiler)) return;
     inferrer.updateParameterAssignments(
-        info, element, info.arguments, selector, remove: false,
+        info, tracedElement, info.arguments, selector, remove: false,
         addToQueue: false);
   }
 
@@ -51,10 +50,16 @@
   visitStaticCallSiteTypeInformation(StaticCallSiteTypeInformation info) {
     super.visitStaticCallSiteTypeInformation(info);
     Element called = info.calledElement;
-    if (called.isForeign(compiler) && called.name == 'JS') {
-      bailout('Used in JS ${info.call}');
+    if (called.isForeign(compiler)) {
+      String name = called.name;
+      if (name == 'JS' || name == 'DART_CLOSURE_TO_JS') {
+        bailout('Used in JS ${info.call}');
+      }
     }
-    if (inferrer.types.getInferredTypeOf(called) == currentUser) {
+    if (called.isGetter()
+        && info.selector != null
+        && info.selector.isCall()
+        && inferrer.types.getInferredTypeOf(called) == currentUser) {
       // This node can be a closure call as well. For example, `foo()`
       // where `foo` is a getter.
       analyzeCall(info);
@@ -77,3 +82,17 @@
     }
   }
 }
+
+class StaticTearOffClosureTracerVisitor extends ClosureTracerVisitor {
+  StaticTearOffClosureTracerVisitor(tracedElement, tracedType, inferrer)
+      : super(tracedElement, tracedType, inferrer);
+
+  visitStaticCallSiteTypeInformation(StaticCallSiteTypeInformation info) {
+    super.visitStaticCallSiteTypeInformation(info);
+    if (info.calledElement == tracedElement
+        && info.selector != null
+        && info.selector.isGetter()) {
+      addNewEscapeInformation(info);
+    }
+  }
+}