Fix null receiver guard an uncached site.

pkg/compiler/lib/src/cps_ir/inline.dart

Index: pkg/compiler/lib/src/cps_ir/inline.dart
diff --git a/pkg/compiler/lib/src/cps_ir/inline.dart b/pkg/compiler/lib/src/cps_ir/inline.dart
index f348ce295701b5250026b50ae3a178c8f10fc0f4..aa6cd4b9f4fa8e2fa9c124a8e819b7ee2293f6de 100644
--- a/pkg/compiler/lib/src/cps_ir/inline.dart
+++ b/pkg/compiler/lib/src/cps_ir/inline.dart
@@ -380,11 +380,10 @@ class InliningVisitor extends TrampolineRecursiveVisitor {
     // Negative inlining result in the cache.
     if (cachedResult == InliningCache.NO_INLINE) return null;
 
-    // Positive inlining result in the cache.
-    if (cachedResult is FunctionDefinition) {
-      FunctionDefinition function = cachedResult;
+    Primitive finish(FunctionDefinition function) {
       _fragment = new CpsFragment(invoke.sourceInformation);
       Primitive receiver = invoke.receiver?.definition;
+      Reference<Primitive> dartReceiver = invoke.dartReceiverReference;

[Kevin Millikin (Google), 2016/01/07 18:15:08]

This is already in scope, isn't it?

[sra1, 2016/01/07 18:23:14]

Yes, thanks.

       List<Primitive> arguments =
           invoke.arguments.map((Reference ref) => ref.definition).toList();
       // Add a null check to the inlined function body if necessary.  The
@@ -402,6 +401,11 @@ class InliningVisitor extends TrampolineRecursiveVisitor {
           hint: invoke.hint);
     }
 
+    // Positive inlining result in the cache.
+    if (cachedResult is FunctionDefinition) {
+      return finish(cachedResult);
+    }
+
     // We have not seen this combination of target and abstract arguments
     // before.  Make an inlining decision.
     assert(cachedResult == InliningCache.ABSENT);
@@ -445,23 +449,7 @@ class InliningVisitor extends TrampolineRecursiveVisitor {
 
     _inliner.cache.putPositive(target, callStructure, abstractReceiver,
         abstractArguments, function);
-    _fragment = new CpsFragment(invoke.sourceInformation);
-    Primitive receiver = invoke.receiver?.definition;
-    List<Primitive> arguments =
-        invoke.arguments.map((Reference ref) => ref.definition).toList();
-    if (dartReceiver != null && abstractReceiver.isNullable) {
-      Primitive check =
-          _fragment.letPrim(new NullCheck(dartReceiver.definition,
-              invoke.sourceInformation));
-      check.type = abstractReceiver.nonNullable();
-      if (invoke.callingConvention == CallingConvention.Intercepted) {
-        arguments[0] = check;
-      } else {
-        receiver = check;
-      }
-    }
-    return _fragment.inlineFunction(function, receiver, arguments,
-        hint: invoke.hint);
+    return finish(function);
   }
 
   Primitive nullReceiverGuard(InvocationPrimitive invoke,