Elements. Deprecate ParameterElement.

Change-Id: Ie74ab5beee915e7b875067803ec1c0db422dd1c2
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/418961
Reviewed-by: Paul Berry <[email protected]>
Commit-Queue: Konstantin Shcheglov <[email protected]>

Author: scheglov

pkg/analyzer/api.txt

@@ -3434,7 +3434,7 @@ package:analyzer/dart/element/element.dart:
   NamespaceCombinator (class extends Object):
     end (getter: int)
     offset (getter: int)
-  ParameterElement (class extends Object implements PromotableElement, ConstantEvaluationTarget):
+  ParameterElement (class extends Object implements PromotableElement, ConstantEvaluationTarget, deprecated):
     new (constructor: ParameterElement Function())
     declaration (getter: ParameterElement)
     defaultValueCode (getter: String?)

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

@@ -1893,6 +1893,7 @@ sealed class NamespaceCombinator {
 /// A parameter defined within an executable element.
 ///
 /// Clients may not extend, implement or mix-in this class.
+@Deprecated('Use FormalParameterElement instead')
 abstract class ParameterElement
     implements PromotableElement, ConstantEvaluationTarget {
   @override

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

@@ -475,7 +475,7 @@ class ClassElementImpl extends ClassOrMixinElementImpl
       if (count > 0) {
         var implicitParameters = <ParameterElementImpl>[];
         for (int i = 0; i < count; i++) {
-          ParameterElement superParameter = superParameters[i];
+          var superParameter = superParameters[i];
           ParameterElementImpl implicitParameter;
           if (superParameter is ConstVariableElement) {
             var constVariable = superParameter as ConstVariableElement;
@@ -484,7 +484,6 @@ class ClassElementImpl extends ClassOrMixinElementImpl
               nameOffset: -1,
               name2: superParameter.name.nullIfEmpty,
               nameOffset2: null,
-              // ignore: deprecated_member_use_from_same_package
               parameterKind: superParameter.parameterKind,
             )..constantInitializer = constVariable.constantInitializer;
             if (superParameter.isNamed) {
@@ -500,7 +499,6 @@ class ClassElementImpl extends ClassOrMixinElementImpl
               nameOffset: -1,
               name2: superParameter.name.nullIfEmpty,
               nameOffset2: null,
-              // ignore: deprecated_member_use_from_same_package
               parameterKind: superParameter.parameterKind,
             );
           }
@@ -1725,7 +1723,7 @@ mixin ConstructorElementMixin
       return false;
     }
     // no required parameters
-    for (ParameterElement parameter in parameters) {
+    for (var parameter in parameters) {
       if (parameter.isRequired) {
         return false;
       }
@@ -1854,7 +1852,7 @@ class DefaultFieldFormalParameterElementImpl
   }
 }
 
-/// A [ParameterElement] for parameters that have an initializer.
+/// A [ParameterElementImpl] for parameters that have an initializer.
 class DefaultParameterElementImpl extends ParameterElementImpl
     with ConstVariableElement {
   /// Initialize a newly created parameter element to have the given [name] and
@@ -9310,10 +9308,13 @@ abstract class NonParameterVariableElementImpl extends VariableElementImpl
   }
 }
 
-/// A concrete implementation of a [ParameterElement].
 class ParameterElementImpl extends VariableElementImpl
-    with ParameterElementMixin
-    implements ParameterElement, FormalParameterFragment {
+    with
+        ParameterElementMixin
+    implements
+        // ignore:deprecated_member_use_from_same_package
+        ParameterElement,
+        FormalParameterFragment {
   @override
   String? name2;
 
@@ -9568,9 +9569,12 @@ class ParameterElementImpl_ofImplicitSetter extends ParameterElementImpl {
 }
 
 /// A mixin that provides a common implementation for methods defined in
-/// [ParameterElement].
+/// `ParameterElement`.
 mixin ParameterElementMixin
-    implements ParameterElement, VariableElementOrMember {
+    implements
+        // ignore:deprecated_member_use_from_same_package
+        ParameterElement,
+        VariableElementOrMember {
   @override
   ParameterElementImpl get declaration;
 

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

@@ -1116,8 +1116,12 @@ class MethodMember extends ExecutableMember
 /// A parameter element defined in a parameterized type where the values of the
 /// type parameters are known.
 class ParameterMember extends VariableMember
-    with ParameterElementMixin, FormalParameterElementMixin
-    implements ParameterElement {
+    with
+        ParameterElementMixin,
+        FormalParameterElementMixin
+    implements
+        // ignore:deprecated_member_use_from_same_package
+        ParameterElement {
   @override
   final List<TypeParameterElementImpl> typeParameters;
 
@@ -1561,7 +1565,7 @@ class SuperFormalParameterMember extends ParameterMember
   bool get isCovariant => declaration.isCovariant;
 
   @override
-  ParameterElement? get superConstructorParameter {
+  ParameterElementMixin? get superConstructorParameter {
     var superConstructorParameter = declaration.superConstructorParameter;
     if (superConstructorParameter == null) {
       return null;

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

@@ -385,13 +385,6 @@ extension FieldElementOrMemberExtension on FieldElementOrMember {
 }
 
 extension FormalParameterElementExtension on FormalParameterElement {
-  ParameterElement get asElement {
-    if (this case ParameterMember member) {
-      return member;
-    }
-    return firstFragment as ParameterElement;
-  }
-
   void appendToWithoutDelimiters(
     StringBuffer buffer, {
     @Deprecated('Only non-nullable by default mode is supported')
@@ -574,24 +567,20 @@ extension MixinElementImplExtension on MixinElementImpl {
   }
 }
 
-extension ParameterElementExtension on ParameterElement {
+extension ParameterElementImplExtension on ParameterElementImpl {
+  FormalParameterElementImpl get asElement2 {
+    return element;
+  }
+}
+
+extension ParameterElementMixinExtension on ParameterElementMixin {
   FormalParameterElementMixin get asElement2 {
     return switch (this) {
       ParameterElementImpl(:var element) => element,
       ParameterMember member => member,
       _ => throw UnsupportedError('Unsupported type: $runtimeType'),
     };
   }
-
-  ParameterElementImpl get declarationImpl {
-    return declaration as ParameterElementImpl;
-  }
-}
-
-extension ParameterElementImplExtension on ParameterElementImpl {
-  FormalParameterElementImpl get asElement2 {
-    return element;
-  }
 }
 
 extension PatternVariableElementImpl2Extension on PatternVariableElementImpl2 {