Support type variables on redirecting factory constructors.

sdk/lib/_internal/compiler/implementation/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;
 
 /**
  * A special element for the extra parameter taken by intercepted
  * methods. We need to override [Element.computeType] because our
  * optimizers may look at its declared type.
@@ skipping 3360 matching lines @@
     Selector selector = elements.getSelector(send);
     if (constructor.isForwardingConstructor) {
       compiler.unimplemented('forwarded constructor in named mixin application',
                              element: constructor.getEnclosingClass());
     }
     if (compiler.enqueuer.resolution.getCachedElements(constructor) == null) {
       compiler.internalError("Unresolved element: $constructor", node: send);
     }
     FunctionElement functionElement = constructor;
     constructor = functionElement.redirectionTarget;
+
     final bool isSymbolConstructor =
         functionElement == compiler.symbolConstructor;
 
     if (isSymbolConstructor) {
       constructor = compiler.symbolValidatedConstructor;
       assert(invariant(send, constructor != null,
                        message: 'Constructor Symbol.validated is missing'));
       selector = compiler.symbolValidatedConstructorSelector;
       assert(invariant(send, selector != null,
                        message: 'Constructor Symbol.validated is missing'));
     }
 
+    bool isRedirected = functionElement.isRedirectingFactory;
+    DartType expectedType = type;
+    if (isRedirected) {
+      FunctionExpression functionNode = functionElement.parseNode(compiler);
+      if (functionNode.isRedirectingFactory) {
+        // Lookup the type used in the redirection.
+        Return redirectionNode = functionNode.body;
+        TreeElements treeElements =
+            compiler.enqueuer.resolution.getCachedElements(
+                functionElement.declaration);
+        ClassElement targetClass = functionElement.getEnclosingClass();
+        type = treeElements.getType(redirectionNode)
+            .subst(type.typeArguments, targetClass.typeVariables);
+      }
+      functionElement = functionElement.redirectionTarget;
+    }
+
     var inputs = <HInstruction>[];
     // TODO(5347): Try to avoid the need for calling [implementation] before
     // calling [addStaticSendArgumentsToList].
     bool succeeded = addStaticSendArgumentsToList(selector, send.arguments,
                                                   constructor.implementation,
                                                   inputs);
     if (!succeeded) {
       generateWrongArgumentCountError(send, constructor, send.arguments);
       return;
     }
@@ skipping 24 matching lines @@
     pushInvokeStatic(node, constructor, inputs, elementType);
     HInstruction newInstance = stack.last;
 
     // The List constructor forwards to a Dart static method that does
     // not know about the type argument. Therefore we special case
     // this constructor to have the setRuntimeTypeInfo called where
     // the 'new' is done.
     if (isListConstructor && backend.needsRti(compiler.listClass)) {
       handleListConstructor(type, send, newInstance);
     }
+
+    // Finally, if we called a redirecting factory constructor, check the type.
+    if (isRedirected) {
+      HInstruction checked = potentiallyCheckType(newInstance, expectedType);
+      if (checked != newInstance) {
+        pop();
+        stack.add(checked);
+      }
+    }
   }
 
   visitStaticSend(Send node) {
     Selector selector = elements.getSelector(node);
     Element element = elements[node];
     if (element.isForeign(compiler)) {
       visitForeignSend(node);
       return;
     }
     if (element.isErroneous()) {
@@ skipping 1927 matching lines @@
           new HSubGraphBlockInformation(elseBranch.graph));
 
     HBasicBlock conditionStartBlock = conditionBranch.block;
     conditionStartBlock.setBlockFlow(info, joinBlock);
     SubGraph conditionGraph = conditionBranch.graph;
     HIf branch = conditionGraph.end.last;
     assert(branch is HIf);
     branch.blockInformation = conditionStartBlock.blockFlow;
   }
 }