Parse argument definition test expressions.

dart/lib/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.
 
 class Interceptors {
   Compiler compiler;
   Interceptors(Compiler this.compiler);
 
   SourceString mapOperatorToMethodName(Operator op) {
     String name = op.source.stringValue;
@@ skipping 1761 matching lines @@
 
 
   void visitLogicalNot(Send node) {
     assert(node.argumentsNode is Prefix);
     visit(node.receiver);
     HNot not = new HNot(popBoolified());
     pushWithPosition(not, node);
   }
 
   void visitUnary(Send node, Operator op) {
+    String value = op.source.stringValue;
+    if (value === '?') {
+      // TODO(ahe): Implement argument definition test.
+      stack.add(graph.addConstantBool(true));
+      return;
+    }
     assert(node.argumentsNode is Prefix);
     visit(node.receiver);
     assert(op.token.kind !== PLUS_TOKEN);
     HInstruction operand = pop();
 
     HInstruction target =
         new HStatic(interceptors.getPrefixOperatorInterceptor(op));
     add(target);
     HInvokeUnary result;
-    String value = op.source.stringValue;
     switch (value) {
       case "-": result = new HNegate(target, operand); break;
       case "~": result = new HBitNot(target, operand); break;
       default:
         compiler.internalError('Unexpected unary operator: $value.', node: op);
         break;
     }
     // See if we can constant-fold right away. This avoids rewrites later on.
     if (operand is HConstant) {
       HConstant constant = operand;
@@ skipping 2137 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;
   }
 }