Switch statement cleanups.

pkg/analyzer/lib/src/summary/link.dart

 // Copyright (c) 2016, 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.
 
 /**
  * This library is capable of producing linked summaries from unlinked
  * ones (or prelinked ones).  It functions by building a miniature
  * element model to represent the contents of the summaries, and then
  * scanning the element model to gather linked information and adding
  * it to the summary data structures.
@@ skipping 2682 matching lines @@
         return TokenType.BAR;
       case UnlinkedExprAssignOperator.prefixIncrement:
         return TokenType.PLUS_PLUS;
       case UnlinkedExprAssignOperator.prefixDecrement:
         return TokenType.MINUS_MINUS;
       case UnlinkedExprAssignOperator.postfixIncrement:
         return TokenType.PLUS_PLUS;
       case UnlinkedExprAssignOperator.postfixDecrement:
         return TokenType.MINUS_MINUS;
     }
+    return null;
   }
 }
 
 /**
  * Element representing a field resynthesized from a summary during
  * linking.
  */
 abstract class FieldElementForLink implements FieldElement {
   @override
   PropertyAccessorElementForLink get getter;
@@ skipping 1197 matching lines @@
   @override
   ParameterKind get parameterKind {
     switch (_unlinkedParam.kind) {
       case UnlinkedParamKind.required:
         return ParameterKind.REQUIRED;
       case UnlinkedParamKind.positional:
         return ParameterKind.POSITIONAL;
       case UnlinkedParamKind.named:
         return ParameterKind.NAMED;
     }
+    return null;
   }
 
   @override
   DartType get type {
     if (_inferredType != null) {
       return _inferredType;
     } else if (_declaredType == null) {
       if (_unlinkedParam.isFunctionTyped) {
         _declaredType = new FunctionTypeImpl(
             new FunctionElementForLink_FunctionTypedParam(
@@ skipping 1021 matching lines @@
    * there are no type parameters in scope.
    */
   TypeParameterizedElementMixin get _typeParameterContext;
 
   @override
   noSuchMethod(Invocation invocation) => super.noSuchMethod(invocation);
 
   @override
   String toString() => '$enclosingElement.$name';
 }