Handle more unqualified SendSets

pkg/compiler/lib/src/ssa/builder.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of ssa;
 
 class SsaFunctionCompiler implements FunctionCompiler {
   final SsaCodeGeneratorTask generator;
   final SsaBuilderTask builder;
   final SsaOptimizerTask optimizer;
@@ skipping 3558 matching lines @@
       _) {
     generateStaticGetterGet(node, getter);
   }
 
   void generateInstanceSetterWithCompiledReceiver(ast.Send send,
                                                   HInstruction receiver,
                                                   HInstruction value,
                                                   {Selector selector,
                                                    TypeMask mask,
                                                    ast.Node location}) {
-    assert(send == null || Elements.isInstanceSend(send, elements));
+    assert(invariant(
+        send == null ? location : send,
+        send == null || Elements.isInstanceSend(send, elements),
+        message: "Unexpected instance setter"
+                 "${send != null ? " element: ${elements[send]}" : ""}"));
     if (selector == null) {
       assert(send != null);
       selector = elements.getSelector(send);
       if (mask == null) {
         mask = elements.getTypeMask(send);
       }
     }
     if (location == null) {
       assert(send != null);
       location = send;
@@ skipping 5245 matching lines @@
     if (unaliased is TypedefType) throw 'unable to unalias $type';
     unaliased.accept(this, builder);
   }
 
   void visitDynamicType(DynamicType type, SsaBuilder builder) {
     JavaScriptBackend backend = builder.compiler.backend;
     ClassElement cls = backend.findHelper('DynamicRuntimeType');
     builder.push(new HDynamicType(type, new TypeMask.exact(cls, classWorld)));
   }
 }