Elements. Improve types of enclosingElement, remove some casts.

Change-Id: I594a7d650eac56d0d54e34578600d979bf7119d4
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/445322
Commit-Queue: Konstantin Shcheglov <[email protected]>
Reviewed-by: Johnni Winther <[email protected]>

Author: scheglov

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

@@ -2626,8 +2626,9 @@ class FieldElementImpl extends PropertyInducingElementImpl
   FieldElementImpl get baseElement => this;
 
   @override
-  InstanceElement get enclosingElement =>
-      (firstFragment.enclosingFragment as InstanceFragment).element;
+  InstanceElementImpl get enclosingElement {
+    return firstFragment.enclosingFragment.element;
+  }
 
   @Deprecated('Use enclosingElement instead')
   @override
@@ -2854,6 +2855,11 @@ class FieldFragmentImpl extends PropertyInducingFragmentImpl
   @override
   FieldFragmentImpl get declaration => this;
 
+  @override
+  InstanceFragmentImpl get enclosingFragment {
+    return super.enclosingFragment as InstanceFragmentImpl;
+  }
+
   /// Whether the type of this fragment references a type parameter of the
   /// enclosing element. This includes not only explicitly specified type
   /// annotations, but also inferred types.
@@ -7391,8 +7397,9 @@ class MethodElementImpl extends ExecutableElementImpl
   }
 
   @override
-  Element? get enclosingElement =>
-      (firstFragment.enclosingFragment as InstanceFragment).element;
+  InstanceElementImpl get enclosingElement {
+    return firstFragment.enclosingFragment.element;
+  }
 
   @Deprecated('Use enclosingElement instead')
   @override

pkg/analyzer/lib/src/summary2/bundle_reader.dart

@@ -352,8 +352,7 @@ class LibraryReader {
       // TODO(scheglov): formal parameters
       element.deferReadResolution(
         _createDeferredReadResolutionCallback((reader) {
-          var enclosingElement =
-              element.enclosingElement as InstanceElementImpl;
+          var enclosingElement = element.enclosingElement;
           reader._addTypeParameters2(enclosingElement.typeParameters);
           element.returnType = reader.readRequiredType();
           element.superConstructor = reader.readConstructorElementMixin();
@@ -379,8 +378,7 @@ class LibraryReader {
           return fragment;
         },
         readResolution: (fragment, reader) {
-          var enclosingElement =
-              fragment.element.enclosingElement as InstanceElementImpl;
+          var enclosingElement = fragment.element.enclosingElement;
           reader._addTypeParameters2(enclosingElement.typeParameters);
 
           _readTypeParameters2(
@@ -689,8 +687,7 @@ class LibraryReader {
 
       element.deferReadResolution(
         _createDeferredReadResolutionCallback((reader) {
-          var enclosingElement =
-              element.enclosingElement as InstanceElementImpl;
+          var enclosingElement = element.enclosingElement;
           reader._addTypeParameters2(enclosingElement.typeParameters);
           element.type = reader.readRequiredType();
         }),
@@ -709,8 +706,7 @@ class LibraryReader {
           return fragment;
         },
         readResolution: (fragment, reader) {
-          var enclosingElement =
-              fragment.element.enclosingElement as InstanceElementImpl;
+          var enclosingElement = fragment.element.enclosingElement;
           reader._addTypeParameters2(enclosingElement.typeParameters);
 
           fragment.metadata = reader._readMetadata();
@@ -903,8 +899,7 @@ class LibraryReader {
       // TODO(scheglov): formal parameters
       element.deferReadResolution(
         _createDeferredReadResolutionCallback((reader) {
-          var enclosingElement =
-              element.enclosingElement as InstanceElementImpl;
+          var enclosingElement = element.enclosingElement;
           reader._addTypeParameters2(enclosingElement.typeParameters);
 
           reader._addTypeParameters2(element.typeParameters);
@@ -929,8 +924,7 @@ class LibraryReader {
           return fragment;
         },
         readResolution: (fragment, reader) {
-          var enclosingElement =
-              fragment.element.enclosingElement as InstanceElementImpl;
+          var enclosingElement = fragment.element.enclosingElement;
           reader._addTypeParameters2(enclosingElement.typeParameters);
 
           _readTypeParameters2(

pkg/analyzer/lib/src/summary2/element_builder.dart

@@ -292,8 +292,7 @@ class ElementBuilder {
     FragmentImpl? lastFieldFragment,
     FieldFragmentImpl fieldFragment,
   ) {
-    var instanceFragment =
-        fieldFragment.enclosingFragment as InstanceFragmentImpl;
+    var instanceFragment = fieldFragment.enclosingFragment;
     instanceFragment.addField(fieldFragment);
 
     if (fieldFragment.isAugmentation &&