[analysis_server] Include types in closure completions when always_specify_types is enabled

Fixes https://github.com/Dart-Code/Dart-Code/issues/5149

Change-Id: Ic212e13d9fe90b4c728f92ecdf8fd5ca519047ed
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/372426
Reviewed-by: Konstantin Shcheglov <scheglov@google.com>
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>
Commit-Queue: Brian Wilkerson <brianwilkerson@google.com>

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

@@ -351,13 +351,16 @@ class SuggestionBuilder {
   /// If [includeTrailingComma] is `true` then the completion text will include
   /// a trailing comma, such as when the closure is part of an argument list.
   void suggestClosure(FunctionType type, {bool includeTrailingComma = false}) {
+    var includeTypes =
+        request.fileState.analysisOptions.codeStyleOptions.specifyTypes;
     var indent = getRequestLineIndent(request);
-    var parametersString = buildClosureParameters(type);
-    // Build a version of the parameter string without keywords for the
-    // completion label because `required` is less useful and may push the
-    // end of the completion (`=>` vs `() {}`) off the end.
-    var parametersDisplayString =
-        buildClosureParameters(type, includeKeywords: false);
+    var parametersString = buildClosureParameters(type,
+        includeTypes: includeTypes, includeKeywords: true);
+    // Build a short version of the parameter string without keywords or types
+    // for the completion label because they're less useful there and may push
+    // the end of the completion (`=>` vs `() {}`) off the end.
+    var parametersDisplayString = buildClosureParameters(type,
+        includeKeywords: false, includeTypes: false);
 
     var blockBuffer = StringBuffer(parametersString);
     blockBuffer.writeln(' {');

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

@@ -31,8 +31,11 @@ Comparator<CompletionSuggestionBuilder> completionComparator = (a, b) {
   return b.relevance.compareTo(a.relevance);
 };
 
-String buildClosureParameters(FunctionType type,
-    {bool includeKeywords = true}) {
+String buildClosureParameters(
+  FunctionType type, {
+  required bool includeTypes,
+  required bool includeKeywords,
+}) {
   var buffer = StringBuffer();
   buffer.write('(');
 
@@ -52,6 +55,10 @@ String buildClosureParameters(FunctionType type,
       hasOptionalPositional = true;
       buffer.write('[');
     }
+    if (includeTypes) {
+      buffer.write(parameter.type);
+      buffer.write(' ');
+    }
     var name = parameter.name;
     if (name.isEmpty) {
       name = 'p$i';

pkg/analysis_server/test/services/completion/dart/declaration/closure_test.dart

@@ -1,5 +1,8 @@
+import 'package:analysis_server/src/services/linter/lint_names.dart';
+import 'package:linter/src/rules.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
+import '../../../../analysis_server_base.dart';
 import '../../../../client/completion_driver_test.dart';
 
 void main() {
@@ -116,6 +119,29 @@ ${' ' * 4}
 ''');
   }
 
+  Future<void> test_lint_alwaysSpecifyTypes() async {
+    registerLintRules();
+    writeTestPackageAnalysisOptionsFile(
+      AnalysisOptionsFileConfig(lints: [LintNames.always_specify_types]),
+    );
+
+    await computeSuggestions('''
+void Function(List<int> a, Object? b, [dynamic c]) v = ^;
+''');
+    assertResponse('''
+suggestions
+  |(List<int> a, Object? b, [dynamic c]) => |
+    kind: invocation
+    displayText: (a, b, [c]) =>
+  (List<int> a, Object? b, [dynamic c]) {
+${' ' * 2}
+}
+    kind: invocation
+    displayText: (a, b, [c]) {}
+    selection: 42
+''');
+  }
+
   Future<void> test_parameters_optionalNamed() async {
     await computeSuggestions('''
 void f({void Function(int a, {int b, int c}) closure}) {}