fixes to anticipate next Dart linter release

dev/benchmarks/macrobenchmarks/lib/src/web/bench_mouse_region_grid_hover.dart

@@ -123,7 +123,7 @@ abstract final class _UntilNextFrame {
     if (_UntilNextFrame._completer == null) {
       _UntilNextFrame._completer = Completer<void>();
       SchedulerBinding.instance.addPostFrameCallback((_) {
-        _UntilNextFrame._completer!.complete(null);
+        _UntilNextFrame._completer!.complete();
         _UntilNextFrame._completer = null;
       });
     }

dev/benchmarks/macrobenchmarks/lib/src/web/bench_mouse_region_grid_scroll.dart

@@ -95,7 +95,7 @@ abstract final class _UntilNextFrame {
     if (_UntilNextFrame._completer == null) {
       _UntilNextFrame._completer = Completer<void>();
       SchedulerBinding.instance.addPostFrameCallback((_) {
-        _UntilNextFrame._completer!.complete(null);
+        _UntilNextFrame._completer!.complete();
         _UntilNextFrame._completer = null;
       });
     }

dev/benchmarks/macrobenchmarks/lib/src/web/bench_mouse_region_mixed_grid_hover.dart

@@ -147,7 +147,7 @@ class _UntilNextFrame {
     if (_UntilNextFrame._completer == null) {
       _UntilNextFrame._completer = Completer<void>();
       SchedulerBinding.instance.addPostFrameCallback((_) {
-        _UntilNextFrame._completer!.complete(null);
+        _UntilNextFrame._completer!.complete();
         _UntilNextFrame._completer = null;
       });
     }

packages/flutter/lib/src/painting/image_provider.dart

@@ -448,7 +448,7 @@ abstract class ImageProvider<T extends Object> {
             exception: exception,
             stack: stack,
           ));
-          completer.complete(null);
+          completer.complete();
         }
       },
     );

packages/flutter/test/material/scaffold_test.dart

@@ -2569,7 +2569,7 @@ void main() {
                             ),
                             TextButton(
                               onPressed: () {
-                                Navigator.pop(context, null);
+                                Navigator.pop(context);
                               },
                               child: const Text('Pop route'),
                             ),

packages/flutter/test/widgets/root_restoration_scope_test.dart

@@ -319,7 +319,7 @@ void main() {
     expect(binding.restorationManager.rootBucketAccessed, 1);
     expect(find.text('Hello'), findsNothing);
 
-    completer.complete(null);
+    completer.complete();
     await tester.pump(const Duration(milliseconds: 100));
 
     expect(binding.restorationManager.rootBucketAccessed, 1);

packages/flutter_test/lib/src/matchers.dart

@@ -1624,10 +1624,10 @@ class _MatchAnythingExceptClip extends _FailWithDescriptionMatcher {
     final RenderObject renderObject = nodes.single.renderObject!;
 
     switch (renderObject.runtimeType) {
-      case RenderClipPath:
-      case RenderClipOval:
-      case RenderClipRect:
-      case RenderClipRRect:
+      case const (RenderClipPath):
+      case const (RenderClipOval):
+      case const (RenderClipRect):
+      case const (RenderClipRRect):
         return failWithDescription(matchState, 'had a root render object of type: ${renderObject.runtimeType}');
       default:
         return true;

packages/flutter_test/lib/src/test_pointer.dart

@@ -100,11 +100,11 @@ class TestPointer {
       _buttons = buttons;
     }
     switch (event.runtimeType) {
-      case PointerDownEvent:
+      case const (PointerDownEvent):
         assert(!isDown);
         _isDown = true;
-      case PointerUpEvent:
-      case PointerCancelEvent:
+      case const (PointerUpEvent):
+      case const (PointerCancelEvent):
         assert(isDown);
         _isDown = false;
       default:

packages/flutter_tools/lib/src/compile.dart

@@ -114,7 +114,7 @@ class StdoutHandler {
         }
       }
       if (message.length <= messageBoundaryKey.length) {
-        compilerOutput?.complete(null);
+        compilerOutput?.complete();
         return;
       }
       final int spaceDelimiter = message.lastIndexOf(' ');
@@ -809,7 +809,7 @@ class DefaultResidentCompiler implements ResidentCompiler {
           // when outputFilename future is not completed, but stdout is closed
           // process has died unexpectedly.
           if (_stdoutHandler.compilerOutput?.isCompleted == false) {
-            _stdoutHandler.compilerOutput?.complete(null);
+            _stdoutHandler.compilerOutput?.complete();
             throwToolExit('the Dart compiler exited unexpectedly.');
           }
         });

packages/flutter_tools/lib/src/custom_devices/custom_device.dart

@@ -184,7 +184,7 @@ class CustomDevicePortForwarder extends DevicePortForwarder {
     // a port forwarding failure and we complete with a null value.
     unawaited(process.exitCode.whenComplete(() {
       if (!completer.isCompleted) {
-        completer.complete(null);
+        completer.complete();
       }
     }));
 

packages/flutter_tools/test/commands.shard/hermetic/doctor_test.dart

@@ -368,7 +368,7 @@ void main() {
       await FakeAsync().run((FakeAsync time) {
         unawaited(FakeAsyncCrashingDoctor(time, logger).diagnose(verbose: false).then((bool r) {
           expect(r, isFalse);
-          completer.complete(null);
+          completer.complete();
         }));
         time.elapse(const Duration(seconds: 1));
         time.flushMicrotasks();

packages/flutter_tools/test/general.shard/base/async_guard_test.dart

@@ -176,12 +176,12 @@ void main() {
           caughtByHandler = true;
         }
         if (!completer.isCompleted) {
-          completer.complete(null);
+          completer.complete();
         }
       }, (Object e, StackTrace s) {
         caughtByZone = true;
         if (!completer.isCompleted) {
-          completer.complete(null);
+          completer.complete();
         }
       }));
       time.elapse(const Duration(seconds: 1));
@@ -214,12 +214,12 @@ void main() {
           caughtByHandler = true;
         }
         if (!completer.isCompleted) {
-          completer.complete(null);
+          completer.complete();
         }
       }, (Object e, StackTrace s) {
         caughtByZone = true;
         if (!completer.isCompleted) {
-          completer.complete(null);
+          completer.complete();
         }
       }));
       time.elapse(const Duration(seconds: 1));
@@ -252,12 +252,12 @@ void main() {
           caughtByHandler = true;
         }
         if (!completer.isCompleted) {
-          completer.complete(null);
+          completer.complete();
         }
       }, (Object e, StackTrace s) {
         caughtByZone = true;
         if (!completer.isCompleted) {
-          completer.complete(null);
+          completer.complete();
         }
       }));
       time.elapse(const Duration(seconds: 1));
@@ -292,12 +292,12 @@ void main() {
           caughtByHandler = true;
         }
         if (!completer.isCompleted) {
-          completer.complete(null);
+          completer.complete();
         }
       }, (Object e, StackTrace s) {
         caughtByZone = true;
         if (!completer.isCompleted) {
-          completer.complete(null);
+          completer.complete();
         }
       }));
       time.elapse(const Duration(seconds: 1));

packages/flutter_tools/test/general.shard/compile_batch_test.dart

@@ -126,7 +126,7 @@ void main() {
       packageConfig: PackageConfig.empty,
       packagesPath: '.packages',
     );
-    stdoutHandler.compilerOutput?.complete(null);
+    stdoutHandler.compilerOutput?.complete();
     completer.complete();
 
     expect(await output, null);