Augment. When moving enum 'values' constants from augmentation to the introductory declaration, skip 'values' fragment of the augmentation.

This `values` fragment is a purely synthetic construct.

Change-Id: I795e6b2a92d8d5809c8107b41522e0d41c7d03bd
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/506220
Reviewed-by: Johnni Winther <johnniwinther@google.com>
Commit-Queue: Konstantin Shcheglov <scheglov@google.com>

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

@@ -120,9 +120,10 @@ class ElementBuilder {
             ? lastStaticFragments
             : lastInstanceFragments;
         var lastFragment = lastFragments[fragment.name];
+        var fragmentToTrack = fragment;
         switch (fragment) {
           case FieldFragmentImpl():
-            _handleInstanceFieldFragment(
+            fragmentToTrack = _handleInstanceFieldFragment(
               instanceElement,
               lastFragment,
               fragment,
@@ -154,7 +155,7 @@ class ElementBuilder {
           default:
             throw UnimplementedError('${fragment.runtimeType}');
         }
-        lastFragments[fragment.name] = fragment;
+        lastFragments[fragmentToTrack.name] = fragmentToTrack;
       }
 
       // Mark extension type members.
@@ -403,7 +404,15 @@ class ElementBuilder {
     interfaceElement.addConstructor(element);
   }
 
-  void _handleInstanceFieldFragment(
+  /// Adds [fieldFragment] into the element model for [instanceElement].
+  ///
+  /// The returned fragment is the one that should be tracked as the last
+  /// fragment with this name in its namespace. Usually this is [fieldFragment].
+  /// For a synthetic enum `values` field from an augmentation, the synthetic
+  /// field itself is discarded after its initializer elements are moved into
+  /// the introductory `values` field, so the introductory `values` fragment is
+  /// returned instead.
+  FieldFragmentImpl _handleInstanceFieldFragment(
     InstanceElementImpl instanceElement,
     FragmentImpl? lastFragment,
     FieldFragmentImpl fieldFragment,
@@ -411,7 +420,7 @@ class ElementBuilder {
     var instanceFragment = fieldFragment.enclosingFragment;
 
     // Move elements of `values` from augmentation to the first fragment.
-    if (fieldFragment.name == 'values' &&
+    if (fieldFragment.isOriginEnumValues &&
         instanceFragment is EnumFragmentImpl &&
         instanceFragment.previousFragment != null) {
       var implicitsMap = libraryBuilder.implicitEnumNodes;
@@ -421,7 +430,7 @@ class ElementBuilder {
       firstImplicit.valuesInitializer.addElements(
         augmentationImplicit.valuesInitializer.elements,
       );
-      return;
+      return firstImplicit.valuesFragment;
     }
 
     instanceFragment.addField(fieldFragment);
@@ -519,6 +528,8 @@ class ElementBuilder {
         setterElement.variable = fieldElement;
       }
     }
+
+    return fieldFragment;
   }
 
   void _handleInstanceGetterFragment(

pkg/analyzer/test/src/dart/parser/enum_test.dart

@@ -16,6 +16,24 @@ main() {
 
 @reflectiveTest
 class EnumDeclarationParserTest extends ParserDiagnosticsTest {
+  test_augment_blockBody_empty() {
+    var parseResult = parseTestCodeWithDiagnostics(r'''
+augment enum E {}
+''');
+
+    var node = parseResult.findNode.singleEnumDeclaration;
+    assertParsedNodeText(node, r'''
+EnumDeclaration
+  augmentKeyword: augment
+  enumKeyword: enum
+  namePart: NameWithTypeParameters
+    typeName: E
+  body: BlockEnumBody
+    leftBracket: {
+    rightBracket: }
+''');
+  }
+
   test_augment_constant_add() {
     var parseResult = parseTestCodeWithDiagnostics(r'''
 augment enum E {
@@ -95,6 +113,23 @@ EnumDeclaration
 ''');
   }
 
+  test_augment_emptyBody() {
+    var parseResult = parseTestCodeWithDiagnostics(r'''
+augment enum E;
+''');
+
+    var node = parseResult.findNode.singleEnumDeclaration;
+    assertParsedNodeText(node, r'''
+EnumDeclaration
+  augmentKeyword: augment
+  enumKeyword: enum
+  namePart: NameWithTypeParameters
+    typeName: E
+  body: EmptyEnumBody
+    semicolon: ;
+''');
+  }
+
   test_augment_implementsClause() {
     var parseResult = parseTestCodeWithDiagnostics(r'''
 augment enum E implements B {}
@@ -116,6 +151,25 @@ EnumDeclaration
 ''');
   }
 
+  test_augment_noConstants_semicolon() {
+    var parseResult = parseTestCodeWithDiagnostics(r'''
+augment enum E {;}
+''');
+
+    var node = parseResult.findNode.singleEnumDeclaration;
+    assertParsedNodeText(node, r'''
+EnumDeclaration
+  augmentKeyword: augment
+  enumKeyword: enum
+  namePart: NameWithTypeParameters
+    typeName: E
+  body: BlockEnumBody
+    leftBracket: {
+    semicolon: ;
+    rightBracket: }
+''');
+  }
+
   test_augment_noConstants_semicolon_method() {
     var parseResult = parseTestCodeWithDiagnostics(r'''
 augment enum E {;

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

@@ -34,6 +34,208 @@ enum E {
 ''');
   }
 
+  test_constant_augmentation_add() async {
+    var result = await resolveTestCodeWithDiagnostics(r'''
+enum A {
+  v1
+}
+
+augment enum A {
+  v2
+}
+
+void f() {
+  A.v2;
+}
+''');
+
+    assertResolvedNodeText(result.unit, r'''
+CompilationUnit
+  declarations
+    EnumDeclaration
+      enumKeyword: enum
+      namePart: NameWithTypeParameters
+        typeName: A
+      body: BlockEnumBody
+        leftBracket: {
+        constants
+          EnumConstantDeclaration
+            name: v1
+            constructorElement: <testLibrary>::@enum::A::@constructor::new
+            declaredFragment: <testLibraryFragment> v1@11
+        rightBracket: }
+      declaredFragment: <testLibraryFragment> A@5
+    EnumDeclaration
+      augmentKeyword: augment
+      enumKeyword: enum
+      namePart: NameWithTypeParameters
+        typeName: A
+      body: BlockEnumBody
+        leftBracket: {
+        constants
+          EnumConstantDeclaration
+            name: v2
+            constructorElement: <testLibrary>::@enum::A::@constructor::new
+            declaredFragment: <testLibraryFragment> v2@36
+        rightBracket: }
+      declaredFragment: <testLibraryFragment> A@30
+    FunctionDeclaration
+      returnType: NamedType
+        name: void
+        element: <null>
+        type: void
+      name: f
+      functionExpression: FunctionExpression
+        parameters: FormalParameterList
+          leftParenthesis: (
+          rightParenthesis: )
+        body: BlockFunctionBody
+          block: Block
+            leftBracket: {
+            statements
+              ExpressionStatement
+                expression: PrefixedIdentifier
+                  prefix: SimpleIdentifier
+                    token: A
+                    element: <testLibrary>::@enum::A
+                    staticType: null
+                  period: .
+                  identifier: SimpleIdentifier
+                    token: v2
+                    element: <testLibrary>::@enum::A::@getter::v2
+                    staticType: A
+                  element: <testLibrary>::@enum::A::@getter::v2
+                  staticType: A
+                semicolon: ;
+            rightBracket: }
+        declaredFragment: <testLibraryFragment> f@47
+          element: <testLibrary>::@function::f
+            type: void Function()
+        staticType: void Function()
+      declaredFragment: <testLibraryFragment> f@47
+        element: <testLibrary>::@function::f
+          type: void Function()
+''');
+  }
+
+  test_constant_augmentation_valuesGetter_recovery() async {
+    var result = await resolveTestCodeWithDiagnostics(r'''
+enum A {
+  v1
+}
+
+augment enum A {;
+  static int get values => 0;
+//               ^^^^^^
+// [diag.valuesDeclarationInEnum] A member named 'values' can't be declared in an enum.
+}
+
+augment enum A {
+  v2
+}
+
+void f() {
+  A.values;
+}
+''');
+
+    assertResolvedNodeText(result.unit, r'''
+CompilationUnit
+  declarations
+    EnumDeclaration
+      enumKeyword: enum
+      namePart: NameWithTypeParameters
+        typeName: A
+      body: BlockEnumBody
+        leftBracket: {
+        constants
+          EnumConstantDeclaration
+            name: v1
+            constructorElement: <testLibrary>::@enum::A::@constructor::new
+            declaredFragment: <testLibraryFragment> v1@11
+        rightBracket: }
+      declaredFragment: <testLibraryFragment> A@5
+    EnumDeclaration
+      augmentKeyword: augment
+      enumKeyword: enum
+      namePart: NameWithTypeParameters
+        typeName: A
+      body: BlockEnumBody
+        leftBracket: {
+        semicolon: ;
+        members
+          MethodDeclaration
+            modifierKeyword: static
+            returnType: NamedType
+              name: int
+              element: dart:core::@class::int
+              type: int
+            propertyKeyword: get
+            name: values
+            body: ExpressionFunctionBody
+              functionDefinition: =>
+              expression: IntegerLiteral
+                literal: 0
+                staticType: int
+              semicolon: ;
+            declaredFragment: <testLibraryFragment> values@52
+              element: <testLibrary>::@enum::A::@getter::values#1
+                type: int Function()
+        rightBracket: }
+      declaredFragment: <testLibraryFragment> A@30
+    EnumDeclaration
+      augmentKeyword: augment
+      enumKeyword: enum
+      namePart: NameWithTypeParameters
+        typeName: A
+      body: BlockEnumBody
+        leftBracket: {
+        constants
+          EnumConstantDeclaration
+            name: v2
+            constructorElement: <testLibrary>::@enum::A::@constructor::new
+            declaredFragment: <testLibraryFragment> v2@87
+        rightBracket: }
+      declaredFragment: <testLibraryFragment> A@81
+    FunctionDeclaration
+      returnType: NamedType
+        name: void
+        element: <null>
+        type: void
+      name: f
+      functionExpression: FunctionExpression
+        parameters: FormalParameterList
+          leftParenthesis: (
+          rightParenthesis: )
+        body: BlockFunctionBody
+          block: Block
+            leftBracket: {
+            statements
+              ExpressionStatement
+                expression: PrefixedIdentifier
+                  prefix: SimpleIdentifier
+                    token: A
+                    element: <testLibrary>::@enum::A
+                    staticType: null
+                  period: .
+                  identifier: SimpleIdentifier
+                    token: values
+                    element: <testLibrary>::@enum::A::@getter::values
+                    staticType: List<A>
+                  element: <testLibrary>::@enum::A::@getter::values
+                  staticType: List<A>
+                semicolon: ;
+            rightBracket: }
+        declaredFragment: <testLibraryFragment> f@98
+          element: <testLibrary>::@function::f
+            type: void Function()
+        staticType: void Function()
+      declaredFragment: <testLibraryFragment> f@98
+        element: <testLibrary>::@function::f
+          type: void Function()
+''');
+  }
+
   test_constructor_argumentList_contextType() async {
     var result = await resolveTestCodeWithDiagnostics(r'''
 enum E {