fix #27258, don't allow dynamic set of a final field

pkg/dev_compiler/tool/input_sdk/private/ddc_runtime/operations.dart

 // Copyright (c) 2015, 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.
 
 /// This library defines runtime operations on objects used by the code
 /// generator.
 part of dart._runtime;
 
 class InvocationImpl extends Invocation {
   final Symbol memberName;
@@ skipping 62 matching lines @@
 }
 
 // Version of dput that matches legacy Dart 1 type check rules and mirrors
 // behavior for JS types.
 // TODO(jacobr): remove the type checking rules workaround when mirrors based
 // PageLoader code can generate the correct reified generic types.
 dputMirror(obj, field, value) {
   var f = _canonicalMember(obj, field);
   _trackCall(obj);
   if (f != null) {
-    var objType = getType(obj);
-    var setterType = getSetterType(objType, f);
-    if (JS('bool', '# != void 0', setterType)) {
-      return JS(
-          '',
-          '#[#] = #',
-          obj,
-          f,
-          check(
-              value, _stripGenericArguments(JS('', '#.args[0]', setterType))));
-    } else {
-      var fieldType = getFieldType(objType, f);
-      // TODO(jacobr): add metadata tracking which fields are final and throw
-      // if a setter is called on a final field.
-      if (JS('bool', '# != void 0', fieldType)) {
-        return JS('', '#[#] = #', obj, f,
-            check(value, _stripGenericArguments(fieldType)));
-      }
-
-      // Do not support calls on JS interop objects to match Dart2JS behavior.
+    var setterType = getSetterType(getType(obj), f);
+    if (setterType != null) {
+      setterType = _stripGenericArguments(setterType);
+      return JS('', '#[#] = #', obj, f, check(value, setterType));
     }
   }
   return noSuchMethod(
       obj, new InvocationImpl(field, JS('', '[#]', value), isSetter: true));
 }
 
 dput(obj, field, value) {
   var f = _canonicalMember(obj, field);
   _trackCall(obj);
   if (f != null) {
-    var objType = getType(obj);
-    var setterType = getSetterType(objType, f);
-    if (JS('bool', '# != void 0', setterType)) {
-      return JS('', '#[#] = #', obj, f,
-          check(value, JS('', '#.args[0]', setterType)));
-    } else {
-      var fieldType = getFieldType(objType, f);
-      // TODO(jacobr): add metadata tracking which fields are final and throw
-      // if a setter is called on a final field.
-      if (JS('bool', '# != void 0', fieldType)) {
-        return JS('', '#[#] = #', obj, f, check(value, fieldType));
-      }
-      // Always allow for JS interop objects.
-      if (isJsInterop(obj)) {
-        return JS('', '#[#] = #', obj, f, value);
-      }
+    var setterType = getSetterType(getType(obj), f);
+    if (setterType != null) {
+      return JS('', '#[#] = #', obj, f, check(value, setterType));
+    }
+    // Always allow for JS interop objects.
+    if (isJsInterop(obj)) {
+      return JS('', '#[#] = #', obj, f, value);
     }
   }
   return noSuchMethod(
       obj, new InvocationImpl(field, JS('', '[#]', value), isSetter: true));
 }
 
 /// Check that a function of a given type can be applied to
 /// actuals.
 _checkApply(type, actuals) => JS(
     '',
@@ skipping 106 matching lines @@
       $ftype = $getMethodType($getType($f), 'call');
       $f = f.call ? $bind($f, 'call') : void 0;
     }
     if (!($f instanceof Function)) {
       return callNSM();
     }
   }
   // If f is a function, but not a method (no method type)
   // then it should have been a function valued field, so
   // get the type from the function.
-  if ($ftype === void 0) {
+  if ($ftype == null) {
     $ftype = $_getRuntimeType($f);
   }
 
-  if (!$ftype) {
+  if ($ftype == null) {
     // TODO(leafp): Allow JS objects to go through?
     if ($typeArgs != null) {
       // TODO(jmesserly): is there a sensible way to handle these?
       $throwStrongModeError('call to JS object `' + $obj +
           '` with type arguments <' + $typeArgs + '> is not supported.');
     }
     return $f.apply($obj, $args);
   }
 
   // Apply type arguments
@@ skipping 666 matching lines @@
     name = '+' + name;
   }
   return name;
 }
 
 /// Emulates the implicit "loadLibrary" function provided by a deferred library.
 ///
 /// Libraries are not actually deferred in DDC, so this just returns a future
 /// that completes immediately.
 Future loadLibrary() => new Future.value();