Remove more type casts

pkg/analyzer/lib/src/dart/ast/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.
 
 library analyzer.src.dart.ast.ast;
 
 import 'dart:collection';
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/token.dart';
@@ skipping 748 matching lines @@
    * If the AST structure has been resolved, and the function being invoked is
    * known based on propagated type information, then return the parameter
    * element representing the parameter to which the value of the right operand
    * will be bound. Otherwise, return `null`.
    */
   ParameterElement get _propagatedParameterElementForRightHandSide {
     ExecutableElement executableElement = null;
     if (propagatedElement != null) {
       executableElement = propagatedElement;
     } else {
-      if (_leftHandSide is Identifier) {
-        Identifier identifier = _leftHandSide as Identifier;
-        Element leftElement = identifier.propagatedElement;
+      Expression left = _leftHandSide;
+      if (left is Identifier) {
+        Element leftElement = left.propagatedElement;
         if (leftElement is ExecutableElement) {
           executableElement = leftElement;
         }
-      } else if (_leftHandSide is PropertyAccess) {
-        SimpleIdentifier identifier =
-            (_leftHandSide as PropertyAccess).propertyName;
-        Element leftElement = identifier.propagatedElement;
+      } else if (left is PropertyAccess) {
+        Element leftElement = left.propertyName.propagatedElement;
         if (leftElement is ExecutableElement) {
           executableElement = leftElement;
         }
       }
     }
     if (executableElement == null) {
       return null;
     }
     List<ParameterElement> parameters = executableElement.parameters;
     if (parameters.length < 1) {
       return null;
     }
     return parameters[0];
   }
 
   /**
    * If the AST structure has been resolved, and the function being invoked is
    * known based on static type information, then return the parameter element
    * representing the parameter to which the value of the right operand will be
    * bound. Otherwise, return `null`.
    */
   ParameterElement get _staticParameterElementForRightHandSide {
     ExecutableElement executableElement = null;
     if (staticElement != null) {
       executableElement = staticElement;
     } else {
-      if (_leftHandSide is Identifier) {
-        Element leftElement = (_leftHandSide as Identifier).staticElement;
+      Expression left = _leftHandSide;
+      if (left is Identifier) {
+        Element leftElement = left.staticElement;
         if (leftElement is ExecutableElement) {
           executableElement = leftElement;
         }
-      } else if (_leftHandSide is PropertyAccess) {
-        Element leftElement =
-            (_leftHandSide as PropertyAccess).propertyName.staticElement;
+      } else if (left is PropertyAccess) {
+        Element leftElement = left.propertyName.staticElement;
         if (leftElement is ExecutableElement) {
           executableElement = leftElement;
         }
       }
     }
     if (executableElement == null) {
       return null;
     }
     List<ParameterElement> parameters = executableElement.parameters;
     if (parameters.length < 1) {
@@ skipping 7405 matching lines @@
   SimpleIdentifier get identifier => _identifier;
 
   @override
   void set identifier(SimpleIdentifier identifier) {
     _identifier = _becomeParentOf(identifier);
   }
 
   @override
   bool get isDeferred {
     Element element = _prefix.staticElement;
-    if (element is! PrefixElement) {
-      return false;
+    if (element is PrefixElement) {
+      List<ImportElement> imports =
+          element.enclosingElement.getImportsWithPrefix(element);
+      if (imports.length != 1) {
+        return false;
+      }
+      return imports[0].isDeferred;
     }
-    PrefixElement prefixElement = element as PrefixElement;
-    List<ImportElement> imports =
-        prefixElement.enclosingElement.getImportsWithPrefix(prefixElement);
-    if (imports.length != 1) {
-      return false;
-    }
-    return imports[0].isDeferred;
+    return false;
   }
 
   @override
   String get name => "${_prefix.name}.${_identifier.name}";
 
   @override
   int get precedence => 15;
 
   @override
   SimpleIdentifier get prefix => _prefix;
@@ skipping 692 matching lines @@
   @override
   dynamic/*=E*/ accept/*<E>*/(AstVisitor/*<E>*/ visitor) =>
       visitor.visitSimpleIdentifier(this);
 
   @override
   bool inDeclarationContext() => false;
 
   @override
   bool inGetterContext() {
     // TODO(brianwilkerson) Convert this to a getter.
-    AstNode parent = this.parent;
+    AstNode initialParent = this.parent;
+    AstNode parent = initialParent;
     AstNode target = this;
     // skip prefix
-    if (parent is PrefixedIdentifier) {
-      PrefixedIdentifier prefixed = parent as PrefixedIdentifier;
-      if (identical(prefixed.prefix, this)) {
+    if (initialParent is PrefixedIdentifier) {
+      if (identical(initialParent.prefix, this)) {
         return true;
       }
-      parent = prefixed.parent;
-      target = prefixed;
-    } else if (parent is PropertyAccess) {
-      PropertyAccess access = parent as PropertyAccess;
-      if (identical(access.target, this)) {
+      parent = initialParent.parent;
+      target = initialParent;
+    } else if (initialParent is PropertyAccess) {
+      if (identical(initialParent.target, this)) {
         return true;
       }
-      parent = access.parent;
-      target = access;
+      parent = initialParent.parent;
+      target = initialParent;
     }
     // skip label
     if (parent is Label) {
       return false;
     }
     // analyze usage
     if (parent is AssignmentExpression) {
       if (identical(parent.leftHandSide, target) &&
           parent.operator.type == TokenType.EQ) {
         return false;
       }
     }
     if (parent is ForEachStatement) {
       if (identical(parent.identifier, target)) {
         return false;
       }
     }
     return true;
   }
 
   @override
   bool inSetterContext() {
     // TODO(brianwilkerson) Convert this to a getter.
-    AstNode parent = this.parent;
+    AstNode initialParent = this.parent;
+    AstNode parent = initialParent;
     AstNode target = this;
     // skip prefix
-    if (parent is PrefixedIdentifier) {
-      PrefixedIdentifier prefixed = parent as PrefixedIdentifier;
+    if (initialParent is PrefixedIdentifier) {
       // if this is the prefix, then return false
-      if (identical(prefixed.prefix, this)) {
+      if (identical(initialParent.prefix, this)) {
         return false;
       }
-      parent = prefixed.parent;
-      target = prefixed;
-    } else if (parent is PropertyAccess) {
-      PropertyAccess access = parent as PropertyAccess;
-      if (identical(access.target, this)) {
+      parent = initialParent.parent;
+      target = initialParent;
+    } else if (initialParent is PropertyAccess) {
+      if (identical(initialParent.target, this)) {
         return false;
       }
-      parent = access.parent;
-      target = access;
+      parent = initialParent.parent;
+      target = initialParent;
     }
     // analyze usage
     if (parent is PrefixExpression) {
       return parent.operator.type.isIncrementOperator;
     } else if (parent is PostfixExpression) {
       return true;
     } else if (parent is AssignmentExpression) {
       return identical(parent.leftHandSide, target);
     } else if (parent is ForEachStatement) {
       return identical(parent.identifier, target);
@@ skipping 1949 matching lines @@
 
   @override
   dynamic/*=E*/ accept/*<E>*/(AstVisitor/*<E>*/ visitor) =>
       visitor.visitYieldStatement(this);
 
   @override
   void visitChildren(AstVisitor visitor) {
     _expression?.accept(visitor);
   }
 }