Elements. Make PropertyAccessorElement2.enclosingElement2 non-nullable.

Change-Id: If54f6428cbf8e96cb84e9eb2e989104b2f56cbce
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/406689
Reviewed-by: Brian Wilkerson <[email protected]>

Author: scheglov

pkg/analysis_server/lib/src/services/correction/fix/data_driven/element_matcher.dart

@@ -549,7 +549,7 @@ class _MatcherBuilder {
           var enclosingElement = element.enclosingElement2;
           if (enclosingElement is! LibraryElement2) {
             _addMatcher(
-              components: [node.name, (enclosingElement?.displayName)!],
+              components: [node.name, enclosingElement.displayName],
               kinds: [],
             );
             return;

pkg/analyzer/lib/dart/element/element2.dart

@@ -2322,6 +2322,9 @@ abstract class PropertyAccessorElement2 implements ExecutableElement2 {
   @override
   PropertyAccessorElement2 get baseElement;
 
+  @override
+  Element2 get enclosingElement2;
+
   @override
   PropertyAccessorFragment get firstFragment;
 

pkg/analyzer/lib/src/dart/element/element.dart

@@ -10056,7 +10056,7 @@ class PropertyAccessorElementImpl extends ExecutableElementImpl
   set element(PropertyAccessorElementImpl2 element) => _element = element;
 
   @override
-  Fragment? get enclosingFragment {
+  Fragment get enclosingFragment {
     var enclosing = enclosingElement3;
     if (enclosing is InstanceFragment) {
       return enclosing as InstanceFragment;
@@ -10158,7 +10158,7 @@ abstract class PropertyAccessorElementImpl2 extends ExecutableElementImpl2
   PropertyAccessorElement2 get baseElement => this;
 
   @override
-  Element2? get enclosingElement2 => firstFragment.enclosingFragment?.element;
+  Element2 get enclosingElement2 => firstFragment.enclosingFragment.element;
 
   @override
   PropertyAccessorElementImpl get firstFragment;
@@ -10585,7 +10585,7 @@ class SetterElementImpl extends PropertyAccessorElementImpl2
       firstFragment.correspondingGetter2?.element as GetterElement?;
 
   @override
-  Element2? get enclosingElement2 => firstFragment.enclosingFragment?.element;
+  Element2 get enclosingElement2 => firstFragment.enclosingFragment.element;
 
   @override
   List<PropertyAccessorElementImpl> get fragments {

pkg/analyzer/lib/src/dart/element/member.dart

@@ -1444,6 +1444,11 @@ abstract class PropertyAccessorMember extends ExecutableMember
   PropertyAccessorElementImpl get declaration =>
       super.declaration as PropertyAccessorElementImpl;
 
+  @override
+  Element2 get enclosingElement2 {
+    return super.enclosingElement2!;
+  }
+
   @override
   Element get enclosingElement3 => declaration.enclosingElement3;
 

pkg/linter/lib/src/rules/overridden_fields.dart

@@ -49,12 +49,10 @@ class _Visitor extends SimpleAstVisitor<void> {
         );
         if (overriddenMember is GetterElement && overriddenMember.isSynthetic) {
           var definingInterface = overriddenMember.enclosingElement2;
-          if (definingInterface != null) {
-            rule.reportLintForToken(
-              variable.name,
-              arguments: [definingInterface.displayName],
-            );
-          }
+          rule.reportLintForToken(
+            variable.name,
+            arguments: [definingInterface.displayName],
+          );
         }
       }
     }