Elements. Use 'value' as the name of the formal parameter for a synthetic setter.

```
According to Gemini:
There is a very strong and widely followed recommendation.
The formal parameter for a setter in Dart should be named value.
```

So, it makes synthetic setters consistent with manually written setters.
These names sometimes are show in UI, e.g. in hover.

Change-Id: I4b53314aae63dce267906856d98a16ec22d38097
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/441827
Reviewed-by: Brian Wilkerson <[email protected]>
Commit-Queue: Konstantin Shcheglov <[email protected]>
Reviewed-by: Johnni Winther <[email protected]>

Author: scheglov

pkg/analysis_server/test/analysis/get_hover_test.dart

@@ -890,7 +890,7 @@ void f(A a) {
     // Synthetic getters are now shown as getters to avoid confusing
     // users by hiding them.
     // https://github.com/dart-lang/sdk/issues/55956
-    expect(hover.elementDescription, 'set fff(String _fff)');
+    expect(hover.elementDescription, 'set fff(String value)');
     expect(hover.elementKind, 'setter');
     // types
     expect(hover.staticType, 'String');

pkg/analysis_server/test/src/services/correction/fix/create_missing_overrides_test.dart

@@ -960,7 +960,7 @@ class B extends A {
   int get f => 0;
 
   @override
-  set f(int _f) {
+  set f(int value) {
     // TODO: implement f
   }
 }

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

@@ -6971,11 +6971,6 @@ class LocalVariableFragmentImpl extends NonParameterVariableFragmentImpl
   @override
   LocalVariableElementImpl get element => _element2;
 
-  @override
-  set enclosingFragment(FragmentImpl? value) {
-    super.enclosingFragment = value;
-  }
-
   @override
   LibraryFragmentImpl get libraryFragment => enclosingUnit;
 

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

@@ -335,8 +335,7 @@ class ElementBuilder {
       instanceFragment.addSetter(setterFragment);
 
       var valueFragment = FormalParameterFragmentImpl(
-        // TODO(scheglov): replace with null
-        name: '_${fieldFragment.name ?? ''}',
+        name: 'value',
         firstTokenOffset: null,
         nameOffset: null,
         parameterKind: ParameterKind.REQUIRED,
@@ -700,8 +699,7 @@ class ElementBuilder {
       libraryFragment.addSetter(setterFragment);
 
       var valueFragment = FormalParameterFragmentImpl(
-        // TODO(scheglov): replace with null
-        name: '_${variableFragment.name ?? ''}',
+        name: 'value',
         firstTokenOffset: null,
         nameOffset: null,
         parameterKind: ParameterKind.REQUIRED,

pkg/analyzer/test/src/dart/resolution/assignment_test.dart

@@ -378,7 +378,7 @@ AssignmentExpression
   operator: =
   rightHandSide: IntegerLiteral
     literal: 0
-    correspondingParameter: package:test/a.dart::@setter::v::@formalParameter::_v
+    correspondingParameter: package:test/a.dart::@setter::v::@formalParameter::value
     staticType: int
   readElement2: <null>
   readType: null
@@ -2453,7 +2453,7 @@ AssignmentExpression
   operator: =
   rightHandSide: IntegerLiteral
     literal: 1
-    correspondingParameter: <testLibrary>::@class::A::@setter::x::@formalParameter::_x
+    correspondingParameter: <testLibrary>::@class::A::@setter::x::@formalParameter::value
     staticType: int
   readElement2: <null>
   readType: null
@@ -4066,7 +4066,7 @@ AssignmentExpression
   operator: =
   rightHandSide: IntegerLiteral
     literal: 2
-    correspondingParameter: <testLibrary>::@class::C::@setter::x::@formalParameter::_x
+    correspondingParameter: <testLibrary>::@class::C::@setter::x::@formalParameter::value
     staticType: int
   readElement2: <null>
   readType: null
@@ -4099,7 +4099,7 @@ AssignmentExpression
   operator: =
   rightHandSide: IntegerLiteral
     literal: 2
-    correspondingParameter: <testLibrary>::@class::C::@setter::x::@formalParameter::_x
+    correspondingParameter: <testLibrary>::@class::C::@setter::x::@formalParameter::value
     staticType: int
   readElement2: <null>
   readType: null
@@ -4882,7 +4882,7 @@ AssignmentExpression
   operator: =
   rightHandSide: IntegerLiteral
     literal: 2
-    correspondingParameter: <testLibrary>::@class::A::@setter::x::@formalParameter::_x
+    correspondingParameter: <testLibrary>::@class::A::@setter::x::@formalParameter::value
     staticType: int
   readElement2: <null>
   readType: null
@@ -5176,7 +5176,7 @@ AssignmentExpression
   operator: =
   rightHandSide: IntegerLiteral
     literal: 2
-    correspondingParameter: <testLibrary>::@setter::x::@formalParameter::_x
+    correspondingParameter: <testLibrary>::@setter::x::@formalParameter::value
     staticType: int
   readElement2: <null>
   readType: null
@@ -5210,7 +5210,7 @@ AssignmentExpression
   operator: =
   rightHandSide: BooleanLiteral
     literal: true
-    correspondingParameter: <testLibrary>::@setter::x::@formalParameter::_x
+    correspondingParameter: <testLibrary>::@setter::x::@formalParameter::value
     staticType: bool
   readElement2: <null>
   readType: null

pkg/analyzer/test/src/dart/resolution/ast_rewrite_test.dart

@@ -1642,7 +1642,7 @@ ConstructorReference
       element: <testLibrary>::@class::C::@constructor::new
       staticType: null
     element: <testLibrary>::@class::C::@constructor::new
-  correspondingParameter: <testLibrary>::@setter::f::@formalParameter::_f
+  correspondingParameter: <testLibrary>::@setter::f::@formalParameter::value
   staticType: C Function()
 ''');
   }

pkg/analyzer/test/src/dart/resolution/function_reference_test.dart

@@ -4151,7 +4151,7 @@ FunctionReference
     operator: =
     rightHandSide: SimpleIdentifier
       token: f
-      correspondingParameter: <testLibrary>::@setter::g::@formalParameter::_g
+      correspondingParameter: <testLibrary>::@setter::g::@formalParameter::value
       element: <testLibrary>::@function::foo::@formalParameter::f
       staticType: void Function<T>(T)
     readElement2: <null>

pkg/analyzer/test/src/dart/resolution/prefixed_identifier_test.dart

@@ -198,7 +198,7 @@ AssignmentExpression
   operator: =
   rightHandSide: IntegerLiteral
     literal: 1
-    correspondingParameter: <testLibrary>::@class::A::@setter::foo::@formalParameter::_foo
+    correspondingParameter: <testLibrary>::@class::A::@setter::foo::@formalParameter::value
     staticType: int
   readElement2: <null>
   readType: null

pkg/analyzer/test/src/dart/resolution/property_access_test.dart

@@ -669,7 +669,7 @@ AssignmentExpression
   operator: =
   rightHandSide: IntegerLiteral
     literal: 1
-    correspondingParameter: <testLibrary>::@class::A::@setter::foo::@formalParameter::_foo
+    correspondingParameter: <testLibrary>::@class::A::@setter::foo::@formalParameter::value
     staticType: int
   readElement2: <null>
   readType: null
@@ -2533,7 +2533,7 @@ AssignmentExpression
   operator: =
   rightHandSide: IntegerLiteral
     literal: 1
-    correspondingParameter: <testLibrary>::@class::A::@setter::foo::@formalParameter::_foo
+    correspondingParameter: <testLibrary>::@class::A::@setter::foo::@formalParameter::value
     staticType: int
   readElement2: <null>
   readType: null

pkg/analyzer/test/src/diagnostics/private_setter_test.dart

@@ -50,7 +50,7 @@ AssignmentExpression
   operator: =
   rightHandSide: IntegerLiteral
     literal: 0
-    correspondingParameter: package:test/a.dart::@class::A::@setter::_foo::@formalParameter::__foo
+    correspondingParameter: package:test/a.dart::@class::A::@setter::_foo::@formalParameter::value
     staticType: int
   readElement2: <null>
   readType: null