Fix hints in the analyzer package.

pkg/analyzer/lib/src/generated/ast.dart

 // Copyright (c) 2014, 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 code was auto-generated, is not intended to be edited, and is subject to
 // significant change. Please see the README file for more information.
 
 library engine.ast;
 
 import 'dart:collection';
@@ skipping 12387 matching lines @@
    * Search within the given AST [node] for an identifier representing an
    * element in the specified source range. Return the element that was found,
    * or `null` if no element was found.
    */
   AstNode searchWithin(AstNode node) {
     if (node == null) {
       return null;
     }
     try {
       node.accept(this);
-    } on NodeLocator_NodeFoundException catch (exception) {
+    } on NodeLocator_NodeFoundException {
       // A node with the right source position was found.
     } catch (exception, stackTrace) {
       AnalysisEngine.instance.logger.logInformation(
           "Unable to locate element at offset ($_startOffset - $_endOffset)",
           new CaughtException(exception, stackTrace));
       return null;
     }
     return _foundNode;
   }
 
   @override
   Object visitNode(AstNode node) {
     int start = node.offset;
     int end = start + node.length;
     if (end < _startOffset) {
       return null;
     }
     if (start > _endOffset) {
       return null;
     }
     try {
       node.visitChildren(this);
-    } on NodeLocator_NodeFoundException catch (exception) {
+    } on NodeLocator_NodeFoundException {
       rethrow;
     } catch (exception, stackTrace) {
       // Ignore the exception and proceed in order to visit the rest of the
       // structure.
       AnalysisEngine.instance.logger.logInformation(
           "Exception caught while traversing an AST structure.",
           new CaughtException(exception, stackTrace));
     }
     if (start <= _startOffset && _endOffset <= end) {
       _foundNode = node;
@@ skipping 4298 matching lines @@
  */
 abstract class StringLiteral extends Literal {
   /**
    * Return the value of the string literal, or `null` if the string is not a
    * constant string without any string interpolation.
    */
   String get stringValue {
     StringBuffer buffer = new StringBuffer();
     try {
       _appendStringValue(buffer);
-    } on IllegalArgumentException catch (exception) {
+    } on IllegalArgumentException {
       return null;
     }
     return buffer.toString();
   }
 
   /**
    * Append the value of this string literal to the given [buffer]. Throw an
    * [IllegalArgumentException] if the string is not a constant string without
    * any string interpolation.
    */
@@ skipping 2751 matching lines @@
     }
     String uriContent = this.uriContent;
     if (uriContent == null) {
       return UriValidationCode.INVALID_URI;
     }
     if (this is ImportDirective && uriContent.startsWith(_DART_EXT_SCHEME)) {
       return UriValidationCode.URI_WITH_DART_EXT_SCHEME;
     }
     try {
       parseUriWithException(Uri.encodeFull(uriContent));
-    } on URISyntaxException catch (exception) {
+    } on URISyntaxException {
       return UriValidationCode.INVALID_URI;
     }
     return null;
   }
 
   @override
   void visitChildren(AstVisitor visitor) {
     super.visitChildren(visitor);
     _safelyVisitChild(_uri, visitor);
   }
@@ skipping 563 matching lines @@
   }
 
   @override
   accept(AstVisitor visitor) => visitor.visitYieldStatement(this);
 
   @override
   void visitChildren(AstVisitor visitor) {
     _safelyVisitChild(_expression, visitor);
   }
 }