Detect total switches to prevent type pollution by default cases.

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 4985 matching lines @@
           ast.CaseMatch match = labelOrCase;
           Constant constant = getConstantForNode(match.expression);
           constants[labelOrCase] = constant;
         }
       }
     }
     return constants;
   }
 
   visitSwitchStatement(ast.SwitchStatement node) {
-    Map<ast.CaseMatch,Constant> constants = buildSwitchCaseConstants(node);
+    Map<ast.CaseMatch, Constant> constants = buildSwitchCaseConstants(node);
 
     // The switch case indices must match those computed in
     // [SwitchCaseJumpHandler].
     bool hasContinue = false;
     Map<ast.SwitchCase, int> caseIndex = new Map<ast.SwitchCase, int>();
     int switchIndex = 1;
     bool hasDefault = false;
     for (ast.SwitchCase switchCase in node.cases) {
       for (ast.Node labelOrCase in switchCase.labelsAndCases) {
         ast.Node label = labelOrCase.asLabel();
@@ skipping 1093 matching lines @@
     DartType unaliased = type.unalias(builder.compiler);
     if (unaliased is TypedefType) throw 'unable to unalias $type';
     unaliased.accept(this, builder);
   }
 
   void visitDynamicType(DynamicType type, SsaBuilder builder) {
     ClassElement cls = builder.compiler.findHelper('DynamicRuntimeType');
     builder.push(new HDynamicType(type, new TypeMask.exact(cls)));
   }
 }