Only do the declaring of parameters in a non-bailout version. The bailout version has different set…

lib/compiler/implementation/ssa/codegen.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 SsaCodeGeneratorTask extends CompilerTask {
   final JavaScriptBackend backend;
   SsaCodeGeneratorTask(JavaScriptBackend backend)
       : this.backend = backend,
         super(backend.compiler);
   String get name() => 'SSA code generator';
@@ skipping 197 matching lines @@
       generateAtUseSite = new Set<HInstruction>(),
       controlFlowOperators = new Set<HInstruction>(),
       breakAction = new Map<Element, ElementAction>(),
       continueAction = new Map<Element, ElementAction>(),
       unsignedShiftPrecedences = JSPrecedence.binary['>>>'] {
 
     Interceptors interceptors = backend.builder.interceptors;
     equalsNullElement = interceptors.getEqualsNullInterceptor();
     boolifiedEqualsNullElement =
         interceptors.getBoolifiedVersionOf(equalsNullElement);
-    parameterNames.forEach((Element element, String name) {
-      declaredVariables.add(name);
-    });
   }
 
   abstract visitTypeGuard(HTypeGuard node);
 
   abstract beginGraph(HGraph graph);
   abstract endGraph(HGraph graph);
 
   abstract beginLoop(HBasicBlock block);
   abstract endLoop(HBasicBlock block);
   abstract handleLoopCondition(HLoopBranch node);
@@ skipping 2230 matching lines @@
       buffer.add(')');
       endExpression(JSPrecedence.CALL_PRECEDENCE);
     } else {
       use(node.checkedInput, expectedPrecedence);
     }
   }
 }
 
 class SsaOptimizedCodeGenerator extends SsaCodeGenerator {
   SsaOptimizedCodeGenerator(backend, work, parameters, parameterNames)
-    : super(backend, work, parameters, parameterNames);
+    : super(backend, work, parameters, parameterNames) {
+    // Declare the parameter names only for the optimized version. The
+    // unoptimized version has different parameters.
+    parameterNames.forEach((Element element, String name) {
+      declaredVariables.add(name);
+    });
+  }
 
   int maxBailoutParameters;
 
   HBasicBlock beginGraph(HGraph graph) => graph.entry;
   void endGraph(HGraph graph) {}
 
   void bailout(HTypeGuard guard, String reason) {
     if (maxBailoutParameters === null) {
       maxBailoutParameters = 0;
       work.guards.forEach((HTypeGuard guard) {
@@ skipping 211 matching lines @@
     }
     assert(variableNames.hasName(argument));
     return argument;
   }
 
   void endGraph(HGraph graph) {
     // TODO(ngeoffray): We could avoid generating the state at the
     // call site for non-complex bailout methods.
     newParameters.add('state');
 
+    // TODO(ngeoffray): We should declare the parameters in
+    // beginGraph, to avoid potentially redeclaring them with 'var'
+    // in the method body.
     if (!propagator.hasComplexTypeGuards) {
       propagator.firstTypeGuard.block.first = savedFirstInstruction;
       for (HInstruction input in propagator.firstTypeGuard.inputs) {
         input = unwrap(input);
         newParameters.add(', ${variableNames.getName(input)}');
       }
     } else {
       for (int i = 0; i < maxBailoutParameters; i++) {
         newParameters.add(', env$i');
       }
@@ skipping 175 matching lines @@
       startBailoutSwitch();
     }
   }
 
   void endLabeledBlock(HLabeledBlockInformation labeledBlockInfo) {
     if (labeledBlockInfo.body.start.hasGuards()) {
       endBailoutSwitch();
     }
   }
 }