Include an empty body when suggesting a name for a top-level declaration that does not have a body

Change-Id: I92875fdb80b0541eaa5505b507e822915181ee52
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/370980
Reviewed-by: Keerti Parthasarathy <keertip@google.com>
Commit-Queue: Brian Wilkerson <brianwilkerson@google.com>

pkg/analysis_server/lib/src/services/completion/dart/candidate_suggestion.dart

@@ -258,12 +258,25 @@ final class IdentifierSuggestion extends CandidateSuggestion {
   /// The identifier to be inserted.
   final String identifier;
 
+  /// Whether an empty body should be included in the completion string.
+  final bool includeBody;
+
   /// Initialize a newly created candidate suggestion to suggest the
   /// [identifier].
-  IdentifierSuggestion({required this.identifier, required super.matcherScore});
+  ///
+  /// If [includeBody] is `true`, then empty curly braces will be included in
+  /// the suggestion.
+  IdentifierSuggestion(
+      {required this.identifier,
+      required this.includeBody,
+      required super.matcherScore});
 
   @override
-  String get completion => identifier;
+  String get completion => identifier + (includeBody ? ' {}' : '');
+
+  /// The offset, from the beginning of the inserted text, where the cursor
+  /// should be positioned.
+  int get selectionOffset => identifier.length + (includeBody ? 2 : 0);
 }
 
 /// The information about a candidate suggestion based on a declaration that can
@@ -843,7 +856,10 @@ extension SuggestionBuilderExtension on SuggestionBuilder {
       case FunctionCall():
         suggestFunctionCall();
       case IdentifierSuggestion():
-        suggestName(suggestion.identifier);
+        suggestName(
+          suggestion.completion,
+          selectionOffset: suggestion.selectionOffset,
+        );
       case ImportPrefixSuggestion():
         suggestPrefix(
           suggestion.libraryElement,

pkg/analysis_server/lib/src/services/completion/dart/identifier_helper.dart

@@ -51,7 +51,7 @@ class IdentifierHelper {
 
   /// Adds any suggestions for the name of a top-level declaration (class, enum,
   /// mixin, function, etc.).
-  void addTopLevelName() {
+  void addTopLevelName({required bool includeBody}) {
     var context = state.request.analysisSession.resourceProvider.pathContext;
     var path = state.request.path;
     var candidateName = context.basenameWithoutExtension(path).toUpperCamelCase;
@@ -69,7 +69,10 @@ class IdentifierHelper {
     var matcherScore = state.matcher.score(candidateName);
     if (matcherScore != -1) {
       collector.addSuggestion(IdentifierSuggestion(
-          identifier: candidateName, matcherScore: matcherScore));
+        identifier: candidateName,
+        includeBody: includeBody,
+        matcherScore: matcherScore,
+      ));
     }
   }
 
@@ -85,8 +88,11 @@ class IdentifierHelper {
     if (name.isNotEmpty) {
       var matcherScore = state.matcher.score(name);
       if (matcherScore != -1) {
-        collector.addSuggestion(
-            IdentifierSuggestion(identifier: name, matcherScore: matcherScore));
+        collector.addSuggestion(IdentifierSuggestion(
+          identifier: name,
+          includeBody: false,
+          matcherScore: matcherScore,
+        ));
       }
     }
   }

pkg/analysis_server/lib/src/services/completion/dart/in_scope_completion_pass.dart

@@ -618,7 +618,10 @@ class InScopeCompletionPass extends SimpleAstVisitor<void> {
     } else if (offset <= node.classKeyword.end) {
       keywordHelper.addKeyword(Keyword.CLASS);
     } else if (offset <= node.name.end) {
-      identifierHelper(includePrivateIdentifiers: false).addTopLevelName();
+      var hasSyntheticBody =
+          node.leftBracket.isSynthetic && node.rightBracket.isSynthetic;
+      identifierHelper(includePrivateIdentifiers: false)
+          .addTopLevelName(includeBody: hasSyntheticBody);
     } else if (offset <= node.leftBracket.offset) {
       keywordHelper.addClassDeclarationKeywords(node);
     } else if (offset >= node.leftBracket.end &&
@@ -944,7 +947,10 @@ class InScopeCompletionPass extends SimpleAstVisitor<void> {
       return;
     }
     if (offset <= node.name.end) {
-      identifierHelper(includePrivateIdentifiers: false).addTopLevelName();
+      var hasSyntheticBody =
+          node.leftBracket.isSynthetic && node.rightBracket.isSynthetic;
+      identifierHelper(includePrivateIdentifiers: false)
+          .addTopLevelName(includeBody: hasSyntheticBody);
       return;
     }
     if (offset <= node.leftBracket.offset) {
@@ -1103,10 +1109,16 @@ class InScopeCompletionPass extends SimpleAstVisitor<void> {
       if (featureSet.isEnabled(Feature.inline_class)) {
         keywordHelper.addText('type');
       }
-      identifierHelper(includePrivateIdentifiers: false).addTopLevelName();
+      // TODO(brianwilkerson): Consider adding both an `on` keyword and a body
+      //  when none of them already exist.
+      identifierHelper(includePrivateIdentifiers: false)
+          .addTopLevelName(includeBody: false);
       return;
     } else {
-      identifierHelper(includePrivateIdentifiers: false).addTopLevelName();
+      // TODO(brianwilkerson): Consider adding both an `on` keyword and a body
+      //  when none of them already exist.
+      identifierHelper(includePrivateIdentifiers: false)
+          .addTopLevelName(includeBody: false);
     }
     if (offset <= node.leftBracket.offset) {
       collector.completionLocation = 'ExtensionDeclaration_onClause';
@@ -1144,7 +1156,10 @@ class InScopeCompletionPass extends SimpleAstVisitor<void> {
     if (offset == node.offset) {
       _forCompilationUnitMemberBefore(node);
     } else if (offset <= node.name.end) {
-      identifierHelper(includePrivateIdentifiers: false).addTopLevelName();
+      var hasSyntheticBody =
+          node.leftBracket.isSynthetic && node.rightBracket.isSynthetic;
+      identifierHelper(includePrivateIdentifiers: false)
+          .addTopLevelName(includeBody: hasSyntheticBody);
     } else if (offset >= node.representation.end &&
         (offset <= node.leftBracket.offset || node.leftBracket.isSynthetic)) {
       keywordHelper.addKeyword(Keyword.IMPLEMENTS);
@@ -1838,7 +1853,10 @@ class InScopeCompletionPass extends SimpleAstVisitor<void> {
       return;
     }
     if (offset <= node.name.end) {
-      identifierHelper(includePrivateIdentifiers: false).addTopLevelName();
+      var hasSyntheticBody =
+          node.leftBracket.isSynthetic && node.rightBracket.isSynthetic;
+      identifierHelper(includePrivateIdentifiers: false)
+          .addTopLevelName(includeBody: hasSyntheticBody);
       return;
     }
     if (offset <= node.leftBracket.offset) {

pkg/analysis_server/lib/src/services/completion/dart/suggestion_builder.dart

@@ -834,11 +834,11 @@ class SuggestionBuilder {
   }
 
   /// Add a suggestion to use the [name] at a declaration site.
-  void suggestName(String name) {
+  void suggestName(String name, {int? selectionOffset}) {
     // TODO(brianwilkerson): Explore whether there are any features of the name
     //  that can be used to provide better relevance scores.
     _addSuggestion(CompletionSuggestion(CompletionSuggestionKind.IDENTIFIER,
-        500, name, name.length, 0, false, false));
+        500, name, selectionOffset ?? name.length, 0, false, false));
   }
 
   /// Add a suggestion to add a named argument corresponding to the [parameter].

pkg/analysis_server/test/services/completion/dart/location/class_declaration_test.dart

@@ -125,10 +125,11 @@ suggestions
 ''');
   }
 
-  Future<void> test_name() async {
-    allowedIdentifiers = {'Test'};
+  Future<void> test_name_withBody() async {
+    allowedIdentifiers = {'Test', 'Test {}'};
+    printerConfiguration.withSelection = true;
     await computeSuggestions('''
-class ^
+class ^ {}
 ''');
     assertResponse(r'''
 suggestions
@@ -137,6 +138,20 @@ suggestions
 ''');
   }
 
+  Future<void> test_name_withoutBody() async {
+    allowedIdentifiers = {'Test', 'Test {}'};
+    printerConfiguration.withSelection = true;
+    await computeSuggestions('''
+class ^
+''');
+    assertResponse(r'''
+suggestions
+  Test {}
+    kind: identifier
+    selection: 6
+''');
+  }
+
   Future<void> test_noBody() async {
     await computeSuggestions('''
 class A ^

pkg/analysis_server/test/services/completion/dart/location/enum_declaration_test.dart

@@ -353,15 +353,30 @@ suggestions
 ''');
   }
 
-  Future<void> test_name() async {
-    allowedIdentifiers = {'Test'};
+  Future<void> test_name_withBody() async {
+    allowedIdentifiers = {'Test', 'Test {}'};
+    printerConfiguration.withSelection = true;
     await computeSuggestions('''
-enum ^
+enum ^ {}
 ''');
     assertResponse(r'''
 suggestions
   Test
     kind: identifier
+''');
+  }
+
+  Future<void> test_name_withoutBody() async {
+    allowedIdentifiers = {'Test', 'Test {}'};
+    printerConfiguration.withSelection = true;
+    await computeSuggestions('''
+enum ^
+''');
+    assertResponse(r'''
+suggestions
+  Test {}
+    kind: identifier
+    selection: 6
 ''');
   }
 }

pkg/analysis_server/test/services/completion/dart/location/extension_declaration_test.dart

@@ -54,24 +54,9 @@ suggestions
 ''');
   }
 
-  Future<void> test_name() async {
-    allowedIdentifiers = {'Test'};
-    await computeSuggestions('''
-extension ^
-''');
-    assertResponse(r'''
-suggestions
-  Test
-    kind: identifier
-  on
-    kind: keyword
-  type
-    kind: keyword
-''');
-  }
-
   Future<void> test_name_partial() async {
-    allowedIdentifiers = {'Test'};
+    allowedIdentifiers = {'Test', 'Test {}'};
+    printerConfiguration.withSelection = true;
     await computeSuggestions('''
 extension T^
 ''');
@@ -83,6 +68,40 @@ suggestions
     kind: identifier
   type
     kind: keyword
+''');
+  }
+
+  Future<void> test_name_withBody() async {
+    allowedIdentifiers = {'Test', 'Test {}'};
+    printerConfiguration.withSelection = true;
+    await computeSuggestions('''
+extension ^ {}
+''');
+    assertResponse(r'''
+suggestions
+  Test
+    kind: identifier
+  on
+    kind: keyword
+  type
+    kind: keyword
+''');
+  }
+
+  Future<void> test_name_withoutBody() async {
+    allowedIdentifiers = {'Test', 'Test {}'};
+    printerConfiguration.withSelection = true;
+    await computeSuggestions('''
+extension ^
+''');
+    assertResponse(r'''
+suggestions
+  Test
+    kind: identifier
+  on
+    kind: keyword
+  type
+    kind: keyword
 ''');
   }
 }

pkg/analysis_server/test/services/completion/dart/location/extension_type_declaration_test.dart

@@ -122,10 +122,11 @@ suggestions
 ''');
   }
 
-  Future<void> test_name() async {
-    allowedIdentifiers = {'Test'};
+  Future<void> test_name_withBody() async {
+    allowedIdentifiers = {'Test', 'Test {}'};
+    printerConfiguration.withSelection = true;
     await computeSuggestions('''
-extension type ^
+extension type ^ {}
 ''');
     assertResponse(r'''
 suggestions
@@ -134,6 +135,20 @@ suggestions
 ''');
   }
 
+  Future<void> test_name_withoutBody() async {
+    allowedIdentifiers = {'Test', 'Test {}'};
+    printerConfiguration.withSelection = true;
+    await computeSuggestions('''
+extension type ^
+''');
+    assertResponse(r'''
+suggestions
+  Test {}
+    kind: identifier
+    selection: 6
+''');
+  }
+
   Future<void> test_representationField_annotation() async {
     await computeSuggestions('''
 extension type E(@^)

pkg/analysis_server/test/services/completion/dart/location/mixin_declaration_test.dart

@@ -43,15 +43,30 @@ suggestions
 ''');
   }
 
-  Future<void> test_name() async {
-    allowedIdentifiers = {'Test'};
+  Future<void> test_name_withBody() async {
+    allowedIdentifiers = {'Test', 'Test {}'};
+    printerConfiguration.withSelection = true;
     await computeSuggestions('''
-mixin ^
+mixin ^ {}
 ''');
     assertResponse(r'''
 suggestions
   Test
     kind: identifier
+''');
+  }
+
+  Future<void> test_name_withoutBody() async {
+    allowedIdentifiers = {'Test', 'Test {}'};
+    printerConfiguration.withSelection = true;
+    await computeSuggestions('''
+mixin ^
+''');
+    assertResponse(r'''
+suggestions
+  Test {}
+    kind: identifier
+    selection: 6
 ''');
   }
 }