Use synthetic elements to recover from errors in signatures.dart.

dart/pkg/compiler/lib/src/resolution/signatures.dart

 // Copyright (c) 2014, 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 resolution;
 
 /**
  * [SignatureResolver] resolves function signatures.
  */
 class SignatureResolver extends MappingVisitor<FormalElementX> {
@@ skipping 100 matching lines @@
       } else if (link.head.asSend() != null &&
                  link.head.asSend().selector.asFunctionExpression() != null) {
         // Inline function typed initializing formal or
         // parameter with default value, like `C(int this.f(String s))` or
         // `void m([int f(String s) = null])`.
         computeFunctionType(link.head.asSend().selector.asFunctionExpression());
       } else {
         assert(invariant(currentDefinitions,
             link.head.asIdentifier() != null || link.head.asSend() != null));
         if (fieldElement != null) {
           element.typeCache = fieldElement.computeType(compiler);

[ahe, 2015/01/12 10:25:32]

I added ErroneousFieldElementX.computeType to prevent a crash here.

         } else {
           element.typeCache = const DynamicType();
         }
       }
     }
   }
 
   Element visitIdentifier(Identifier node) {
     return createParameter(node, null);
   }
@@ skipping 33 matching lines @@
       parameter = new FormalElementX(
         ElementKind.PARAMETER, enclosingElement, currentDefinitions, name);
     }
     computeParameterType(parameter);
     return parameter;
   }
 
   InitializingFormalElementX createFieldParameter(Send node,
                                                   Expression initializer) {
     InitializingFormalElementX element;
-    if (node.receiver.asIdentifier() == null ||
-        !node.receiver.asIdentifier().isThis()) {
+    Identifier receiver = node.receiver.asIdentifier();
+    if (receiver == null || !receiver.isThis()) {
       error(node, MessageKind.INVALID_PARAMETER);
-    } else if (!identical(enclosingElement.kind,
-                          ElementKind.GENERATIVE_CONSTRUCTOR)) {
-      error(node, MessageKind.INITIALIZING_FORMAL_NOT_ALLOWED);
-      // TODO(ahe): Don't throw, recover from error.
-      throw new CompilerCancelledException(null);
+      return new ErroneousInitializingFormalElementX(
+          getParameterName(node), enclosingElement);
     } else {
+      if (!enclosingElement.isGenerativeConstructor) {
+        error(node, MessageKind.INITIALIZING_FORMAL_NOT_ALLOWED);
+        return new ErroneousInitializingFormalElementX(
+            getParameterName(node), enclosingElement);
+      }
       Identifier name = getParameterName(node);
       validateName(name);
       Element fieldElement =
           enclosingElement.enclosingClass.lookupLocalMember(name.source);
       if (fieldElement == null ||
           !identical(fieldElement.kind, ElementKind.FIELD)) {
         error(node, MessageKind.NOT_A_FIELD, {'fieldName': name});
-        // TODO(ahe): Don't throw, recover from error.
-        throw new CompilerCancelledException(null);
+        fieldElement = new ErroneousFieldElementX(
+            name, enclosingElement.enclosingClass);
       } else if (!fieldElement.isInstanceMember) {
         error(node, MessageKind.NOT_INSTANCE_FIELD, {'fieldName': name});
+        fieldElement = new ErroneousFieldElementX(
+            name, enclosingElement.enclosingClass);
       }
       element = new InitializingFormalElementX(enclosingElement,
           currentDefinitions, name, initializer, fieldElement);
       computeParameterType(element, fieldElement);
     }
     return element;
   }
 
   /// A [SendSet] node is an optional parameter with a default value.
   Element visitSendSet(SendSet node) {
@@ skipping 169 matching lines @@
 
   DartType resolveReturnType(TypeAnnotation annotation) {
     if (annotation == null) return const DynamicType();
     DartType result = resolver.resolveTypeAnnotation(annotation);
     if (result == null) {
       return const DynamicType();
     }
     return result;
   }
 }