Modernize ElementAnnotationImpl.isX getters.

pkg/analyzer/lib/src/dart/element/element.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.element.element;
 
 import 'dart:collection';
 import 'dart:math' show min;
 
 import 'package:analyzer/dart/ast/ast.dart';
@@ skipping 1573 matching lines @@
    */
   static String PROXY_VARIABLE_NAME = "proxy";
 
   /**
    * The element representing the field, variable, or constructor being used as
    * an annotation.
    */
   Element element;
 
   /**
-   * The compliation unit in which this annotation appears.
+   * The compilation unit in which this annotation appears.
    */
   final CompilationUnitElementImpl compilationUnit;
 
   /**
    * The AST of the annotation itself, cloned from the resolved AST for the
    * source code.
    */
   Annotation annotationAst;
 
   /**
@@ skipping 10 matching lines @@
   ElementAnnotationImpl(this.compilationUnit);
 
   @override
   DartObject get constantValue => evaluationResult?.value;
 
   @override
   AnalysisContext get context => compilationUnit.library.context;
 
   @override
   bool get isDeprecated {
-    if (element != null) {
-      LibraryElement library = element.library;
-      if (library != null && library.isDartCore) {
-        if (element is ConstructorElement) {
-          ConstructorElement constructorElement = element as ConstructorElement;
-          if (constructorElement.enclosingElement.name ==
-              _DEPRECATED_CLASS_NAME) {
-            return true;
-          }
-        } else if (element is PropertyAccessorElement &&
-            element.name == _DEPRECATED_VARIABLE_NAME) {
-          return true;
-        }
+    if (element?.library?.isDartCore == true) {

[Brian Wilkerson, 2016/02/25 17:02:12]

I'm obviously not used to the null-aware operators yet; it took me a while to
figure out that this is equivalent.

It looks really weird to have a "== true" test in a condition, but I think I
like it better than the other option I can think of:

  element?.library?.isDartCore ?? false

+      if (element is ConstructorElement) {
+        return element.enclosingElement.name == _DEPRECATED_CLASS_NAME;
+      } else if (element is PropertyAccessorElement) {
+        return element.name == _DEPRECATED_VARIABLE_NAME;
       }
     }
     return false;
   }
 
   @override
-  bool get isOverride {
-    if (element != null) {
-      LibraryElement library = element.library;
-      if (library != null && library.isDartCore) {
-        if (element is PropertyAccessorElement &&
-            element.name == _OVERRIDE_VARIABLE_NAME) {
-          return true;
-        }
-      }
-    }
-    return false;
-  }
+  bool get isOverride =>
+      element is PropertyAccessorElement &&
+      element.name == _OVERRIDE_VARIABLE_NAME &&
+      element.library?.isDartCore == true;
 
   @override
-  bool get isProtected {
-    if (element != null) {
-      LibraryElement library = element.library;
-      if (library != null && library.name == _META_LIB_NAME) {
-        if (element is PropertyAccessorElement &&
-            element.name == _PROTECTED_VARIABLE_NAME) {
-          return true;
-        }
-      }
-    }
-    return false;
-  }
+  bool get isProtected =>
+      element is PropertyAccessorElement &&
+      element.name == _PROTECTED_VARIABLE_NAME &&
+      element.library?.name == _META_LIB_NAME;
 
   @override
-  bool get isProxy {
-    if (element != null) {
-      LibraryElement library = element.library;
-      if (library != null && library.isDartCore) {
-        if (element is PropertyAccessorElement &&
-            element.name == PROXY_VARIABLE_NAME) {
-          return true;
-        }
-      }
-    }
-    return false;
-  }
+  bool get isProxy =>
+      element is PropertyAccessorElement &&
+      element.name == PROXY_VARIABLE_NAME &&
+      element.library?.isDartCore == true;
 
   /**
    * Get the library containing this annotation.
    */
   Source get librarySource => compilationUnit.librarySource;
 
   @override
   Source get source => compilationUnit.source;
 
   @override
@@ skipping 3140 matching lines @@
 
   @override
   void visitElement(Element element) {
     int offset = element.nameOffset;
     if (offset != -1) {
       map[offset] = element;
     }
     super.visitElement(element);
   }
 }