Emit diagnostics for bad NSM implementations

pkg/compiler/lib/src/compiler.dart

Index: pkg/compiler/lib/src/compiler.dart
diff --git a/pkg/compiler/lib/src/compiler.dart b/pkg/compiler/lib/src/compiler.dart
index dcaea5943a723310bc0c5df3746f21a74b4a9248..5bd9aeede472827a81b4c4bdc8de544f97cde059 100644
--- a/pkg/compiler/lib/src/compiler.dart
+++ b/pkg/compiler/lib/src/compiler.dart
@@ -291,6 +291,7 @@ abstract class Backend {
   bool get canHandleCompilationFailed;
 
   void onResolutionComplete() {}
+  void onTypeInferenceComplete() {}
 
   ItemCompilationContext createItemCompilationContext() {
     return new ItemCompilationContext();
@@ -362,7 +363,7 @@ abstract class Backend {
   void registerRuntimeType(Enqueuer enqueuer, Registry registry) {}
 
   /// Call this to register a `noSuchMethod` implementation.
-  void registerNoSuchMethod(Element noSuchMethodElement) {}
+  void registerNoSuchMethod(FunctionElement noSuchMethodElement) {}
 
   /// Call this method to enable support for `noSuchMethod`.
   void enableNoSuchMethod(Enqueuer enqueuer) {}
@@ -1611,6 +1612,8 @@ abstract class Compiler implements DiagnosticListener {
 
     if (stopAfterTypeInference) return;
 
+    backend.onTypeInferenceComplete();
+
     log('Compiling...');
     phase = PHASE_COMPILING;
     // TODO(johnniwinther): Move these to [CodegenEnqueuer].