Support multiline location messages and use signature for function spans.

pkg/compiler/lib/src/elements/modelx.dart

 // Copyright (c) 2013, 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.
 
 library elements.modelx;
 
 import '../common.dart';
 import '../common/resolution.dart' show
     Resolution,
     Parsing;
@@ skipping 2034 matching lines @@
     with AnalyzableElementX implements MethodElement {
 
   FunctionElementX(String name,
                    ElementKind kind,
                    Modifiers modifiers,
                    Element enclosing)
       : super(name, kind, modifiers, enclosing);
 
   MemberElement get memberContext => this;
 
+  @override
+  SourceSpan get sourcePosition {
+    SourceSpan span = super.sourcePosition;
+    if (span != null && hasNode) {
+      FunctionExpression functionExpression = node.asFunctionExpression();
+      if (functionExpression != null) {
+        Token begin = functionExpression.getBeginToken();
+        Token end;
+        if (functionExpression.parameters != null) {
+          end = functionExpression.parameters.getEndToken();
+        } else {
+          end = functionExpression.name.getEndToken();
+        }
+        span = new SourceSpan.fromTokens(span.uri, begin, end);
+      }
+    }
+    return span;
+  }
+
   void reuseElement() {
     super.reuseElement();
     nestedClosures.clear();
     _functionSignatureCache = null;
     typeCache = null;
   }
 }
 
 abstract class MethodElementX extends FunctionElementX {
   final bool hasBody;
@@ skipping 1036 matching lines @@
   AstElement get definingElement;
 
   bool get hasResolvedAst => definingElement.hasTreeElements;
 
   ResolvedAst get resolvedAst {
     return new ResolvedAst(declaration,
         definingElement.node, definingElement.treeElements);
   }
 
 }