Start work on a non-complete type inferrer. Currently only analyzes return types.

sdk/lib/_internal/compiler/implementation/resolution/members.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 resolution;
 
 abstract class TreeElements {
   Element operator[](Node node);
   Selector getSelector(Send send);
   DartType getType(Node node);
@@ skipping 1819 matching lines @@
     SourceString name;
     if (node.name == null) {
       name = const SourceString("");
     } else {
       name = node.name.asIdentifier().source;
     }
 
     FunctionElement function = new FunctionElementX.node(
         name, node, ElementKind.FUNCTION, Modifiers.EMPTY,
         enclosingElement);
+    // [function] and its enclosing method share the same
+    // [TreeElementMapping].
+    compiler.enqueuer.resolution.resolvedElements[function] = mapping;
     Scope oldScope = scope; // The scope is modified by [setupFunction].
     setupFunction(node, function);
     defineElement(node, function, doAddToScope: node.name != null);
 
     Element previousEnclosingElement = enclosingElement;
     enclosingElement = function;
     // Run the body in a fresh statement scope.
     StatementScope oldStatementScope = statementScope;
     statementScope = new StatementScope();
     visit(node.body);
@@ skipping 1804 matching lines @@
     return e;
   }
 
   /// Assumed to be called by [resolveRedirectingFactory].
   Element visitReturn(Return node) {
     Node expression = node.expression;
     return finishConstructorReference(visit(expression),
                                       expression, expression);
   }
 }