remove unnecessary String.toString() (#81859)

dev/benchmarks/test_apps/stocks/lib/i18n/stock_strings.dart

@@ -66,7 +66,7 @@ import 'stock_strings_es.dart';
 /// be consistent with the languages listed in the StockStrings.supportedLocales
 /// property.
 abstract class StockStrings {
-  StockStrings(String locale) : localeName = intl.Intl.canonicalizedLocale(locale.toString());
+  StockStrings(String locale) : localeName = intl.Intl.canonicalizedLocale(locale);
 
   final String localeName;
 

dev/integration_tests/flutter_gallery/lib/demo/material/slider_demo.dart

@@ -282,7 +282,7 @@ class _SlidersState extends State<_Sliders> {
                 ),
               ),
               Slider.adaptive(
-                label: _continuousValue.toStringAsFixed(6).toString(),
+                label: _continuousValue.toStringAsFixed(6),
                 value: _continuousValue,
                 min: 0.0,
                 max: 100.0,

packages/flutter/lib/src/rendering/editable.dart

@@ -727,7 +727,7 @@ class RenderEditable extends RenderBox with RelayoutWhenSystemFontsChangeMixin {
     int? lastNonWhitespace;
     for (final String currentString in string.characters) {
       if (!includeWhitespace &&
-          !_isWhitespace(currentString.characters.first.toString().codeUnitAt(0))) {
+          !_isWhitespace(currentString.characters.first.codeUnitAt(0))) {
         lastNonWhitespace = count;
       }
       if (count + currentString.length >= index) {

packages/flutter_goldens_client/lib/skia_client.dart

@@ -376,7 +376,7 @@ class SkiaGoldClient {
   /// Removes the file extension from the [fileName] to represent the test name
   /// properly.
   String cleanTestName(String fileName) {
-    return fileName.split(path.extension(fileName.toString()))[0];
+    return fileName.split(path.extension(fileName))[0];
   }
 
   /// Returns a boolean value to prevent the client from re-authorizing itself

packages/flutter_test/lib/src/_goldens_web.dart

@@ -64,7 +64,7 @@ class DefaultWebGoldenComparator extends WebGoldenComparator {
       method: 'POST',
       sendData: json.encode(<String, Object>{
         'testUri': testUri.toString(),
-        'key': key.toString(),
+        'key': key,
         'width': width.round(),
         'height': height.round(),
       }),

packages/flutter_tools/lib/src/android/gradle_utils.dart

@@ -235,7 +235,7 @@ void updateLocalProperties({
       buildInfo.buildNumber ?? project.manifest.buildNumber,
       globals.logger,
     );
-    changeIfNecessary('flutter.versionCode', buildNumber?.toString());
+    changeIfNecessary('flutter.versionCode', buildNumber);
   }
 
   if (changed) {

packages/flutter_tools/lib/src/compile.dart

@@ -662,7 +662,7 @@ class DefaultResidentCompiler implements ResidentCompiler {
           toMultiRootPath(fileUri, fileSystemScheme, fileSystemRoots, _platform.isWindows);
       }
       _server.stdin.writeln(message);
-      _logger.printTrace(message.toString());
+      _logger.printTrace(message);
     }
     _server.stdin.writeln(inputKey);
     _logger.printTrace('<- $inputKey');

packages/flutter_tools/lib/src/ios/migrations/project_base_configuration_migration.dart

@@ -86,7 +86,7 @@ class ProjectBaseConfigurationMigration extends ProjectMigrator {
     newProjectContents = newProjectContents.replaceAll(releaseBaseConfigurationOriginal, releaseBaseConfigurationReplacement);
     if (originalProjectContents != newProjectContents) {
       logger.printStatus('Project base configurations detected, removing.');
-      _xcodeProjectInfoFile.writeAsStringSync(newProjectContents.toString());
+      _xcodeProjectInfoFile.writeAsStringSync(newProjectContents);
     }
     return true;
   }

packages/flutter_tools/lib/src/ios/simulators.dart

@@ -130,7 +130,7 @@ class SimControl {
       return <String, Map<String, dynamic>>{};
     }
     try {
-      final Object decodeResult = json.decode(results.stdout?.toString())[section.name];
+      final Object decodeResult = json.decode(results.stdout)[section.name];
       if (decodeResult is Map<String, dynamic>) {
         return decodeResult;
       }

packages/flutter_tools/lib/src/migrations/cmake_custom_command_migration.dart

@@ -70,7 +70,7 @@ class CmakeCustomCommandMigration extends ProjectMigrator {
     }
     if (originalProjectContents != newProjectContents) {
       logger.printStatus('add_custom_command() missing VERBATIM or FLUTTER_TARGET_PLATFORM, updating.');
-      _cmakeFile.writeAsStringSync(newProjectContents.toString());
+      _cmakeFile.writeAsStringSync(newProjectContents);
     }
     return true;
   }