unnecessary null comparison (#67525)

packages/flutter/lib/src/material/refresh_indicator.dart

@@ -378,7 +378,10 @@ class RefreshIndicatorState extends State<RefreshIndicator> with TickerProviderS
               ));
             return true;
           }());
-          if (refreshResult == null)
+          // `refreshResult` has a non-nullable type, but might be null when
+          // running with weak checking, so we need to null check it anyway (and
+          // ignore the warning that the null-handling logic is dead code).
+          if (refreshResult == null) // ignore: dead_code
             return;
           refreshResult.whenComplete(() {
             if (mounted && _mode == _RefreshIndicatorMode.refresh) {

packages/flutter/lib/src/material/scaffold.dart

@@ -3326,38 +3326,28 @@ class _StandardBottomSheetState extends State<_StandardBottomSheet> {
 
   @override
   Widget build(BuildContext context) {
-    if (widget.animationController != null) {
-      return AnimatedBuilder(
-        animation: widget.animationController,
-        builder: (BuildContext context, Widget? child) {
-          return Align(
-            alignment: AlignmentDirectional.topStart,
-            heightFactor: animationCurve.transform(widget.animationController.value),
-            child: child,
-          );
-        },
-        child: _wrapBottomSheet(
-          BottomSheet(
-            animationController: widget.animationController,
-            enableDrag: widget.enableDrag,
-            onDragStart: _handleDragStart,
-            onDragEnd: _handleDragEnd,
-            onClosing: widget.onClosing!,
-            builder: widget.builder,
-            backgroundColor: widget.backgroundColor,
-            elevation: widget.elevation,
-            shape: widget.shape,
-            clipBehavior: widget.clipBehavior,
-          ),
+    return AnimatedBuilder(
+      animation: widget.animationController,
+      builder: (BuildContext context, Widget? child) {
+        return Align(
+          alignment: AlignmentDirectional.topStart,
+          heightFactor: animationCurve.transform(widget.animationController.value),
+          child: child,
+        );
+      },
+      child: _wrapBottomSheet(
+        BottomSheet(
+          animationController: widget.animationController,
+          enableDrag: widget.enableDrag,
+          onDragStart: _handleDragStart,
+          onDragEnd: _handleDragEnd,
+          onClosing: widget.onClosing!,
+          builder: widget.builder,
+          backgroundColor: widget.backgroundColor,
+          elevation: widget.elevation,
+          shape: widget.shape,
+          clipBehavior: widget.clipBehavior,
         ),
-      );
-    }
-
-    return _wrapBottomSheet(
-      BottomSheet(
-        onClosing: widget.onClosing!,
-        builder: widget.builder,
-        backgroundColor: widget.backgroundColor,
       ),
     );
   }

packages/flutter/lib/src/services/binary_messenger.dart

@@ -10,7 +10,7 @@ import 'package:flutter/foundation.dart';
 import 'binding.dart';
 
 /// A function which takes a platform message and asynchronously returns an encoded response.
-typedef MessageHandler = Future<ByteData?> Function(ByteData? message);
+typedef MessageHandler = Future<ByteData?>? Function(ByteData? message);
 
 /// A messenger which sends binary data across the Flutter platform barrier.
 ///
@@ -31,7 +31,7 @@ abstract class BinaryMessenger {
   ///
   /// Returns a [Future] which completes to the received response, undecoded,
   /// in binary form.
-  Future<ByteData?> send(String channel, ByteData? message);
+  Future<ByteData?>? send(String channel, ByteData? message);
 
   /// Set a callback for receiving messages from the platform plugins on the
   /// given channel, without decoding them.

packages/flutter/lib/src/services/binding.dart

@@ -300,7 +300,7 @@ class _DefaultBinaryMessenger extends BinaryMessenger {
   }
 
   @override
-  Future<ByteData?> send(String channel, ByteData? message) {
+  Future<ByteData?>? send(String channel, ByteData? message) {
     final MessageHandler? handler = _mockHandlers[channel];
     if (handler != null)
       return handler(message);

packages/flutter/lib/src/services/platform_messages.dart

@@ -65,7 +65,7 @@ class BinaryMessages {
     'Use defaultBinaryMessenger.send instead. '
     'This feature was deprecated after v1.6.5.'
   )
-  static Future<ByteData?> send(String channel, ByteData? message) {
+  static Future<ByteData?>? send(String channel, ByteData? message) {
     return _binaryMessenger.send(channel, message);
   }
 

packages/flutter/test/rendering/mock_canvas.dart

@@ -821,10 +821,6 @@ class _TestRecordingCanvasPatternMatcher extends _TestRecordingCanvasMatcher imp
     final Iterator<RecordedInvocation> call = calls.iterator..moveNext();
     try {
       while (predicate.moveNext()) {
-        if (call.current == null) {
-          throw 'It painted less on its canvas than the paint pattern expected. '
-                'The first missing paint call was: ${predicate.current}';
-        }
         predicate.current.match(call);
       }
       assert(predicate.current == null);
@@ -836,11 +832,7 @@ class _TestRecordingCanvasPatternMatcher extends _TestRecordingCanvasMatcher imp
       return false;
     } on String catch (s) {
       description.writeln(s);
-      if (call.current != null) {
-        description.write('The stack of the offending call was:\n${call.current.stackToString(indent: "  ")}\n');
-      } else {
-        description.write('The stack of the first call was:\n${calls.first.stackToString(indent: "  ")}\n');
-      }
+      description.write('The stack of the offending call was:\n${call.current.stackToString(indent: "  ")}\n');
       return false;
     }
     return true;
@@ -1390,8 +1382,6 @@ class _SomethingPaintPredicate extends _PaintPredicate {
     RecordedInvocation currentCall;
     do {
       currentCall = call.current;
-      if (currentCall == null)
-        throw 'It did not call anything that was matched by the predicate passed to a "something" step of the paint pattern.';
       if (!currentCall.invocation.isMethod)
         throw 'It called $currentCall, which was not a method, when the paint pattern expected a method call';
       call.moveNext();

packages/flutter_driver/lib/src/common/find.dart

@@ -42,8 +42,7 @@ DriverError _createInvalidKeyValueTypeError(String invalidType) {
 abstract class CommandWithTarget extends Command {
   /// Constructs this command given a [finder].
   CommandWithTarget(this.finder, {Duration timeout}) : super(timeout: timeout) {
-    if (finder == null)
-      throw DriverError('$runtimeType target cannot be null');
+    assert(finder != null, '$runtimeType target cannot be null');
   }
 
   /// Deserializes this command from the value generated by [serialize].

packages/flutter_driver/lib/src/extension/wait_conditions.dart

@@ -164,13 +164,7 @@ class _InternalCombinedCondition implements WaitCondition {
     if (condition.conditionName != 'CombinedCondition')
       throw SerializationException('Error occurred during deserializing from the given condition: ${condition.serialize()}');
     final CombinedCondition combinedCondition = condition as CombinedCondition;
-    if (combinedCondition.conditions == null) {
-      return const _InternalCombinedCondition(<WaitCondition>[]);
-    }
-
-    final List<WaitCondition> conditions = combinedCondition.conditions.map(
-        (SerializableWaitCondition serializableCondition) => deserializeCondition(serializableCondition)
-      ).toList();
+    final List<WaitCondition> conditions = combinedCondition.conditions.map(deserializeCondition).toList();
     return _InternalCombinedCondition(conditions);
   }
 

packages/flutter_test/lib/src/binding.dart

@@ -101,11 +101,11 @@ class TestDefaultBinaryMessenger extends BinaryMessenger {
   int get pendingMessageCount => _pendingMessages.length;
 
   @override
-  Future<ByteData?> send(String channel, ByteData? message) {
-    final Future<ByteData?> resultFuture = delegate.send(channel, message);
-    // Removes the future itself from the [_pendingMessages] list when it
-    // completes.
+  Future<ByteData?>? send(String channel, ByteData? message) {
+    final Future<ByteData?>? resultFuture = delegate.send(channel, message);
     if (resultFuture != null) {
+      // Removes the future itself from the [_pendingMessages] list when it
+      // completes.
       _pendingMessages.add(resultFuture);
       resultFuture.whenComplete(() => _pendingMessages.remove(resultFuture));
     }
@@ -1780,8 +1780,7 @@ class _LiveTestRenderView extends RenderView {
     _label ??= TextPainter(textAlign: TextAlign.left, textDirection: TextDirection.ltr);
     _label!.text = TextSpan(text: value, style: _labelStyle);
     _label!.layout();
-    if (onNeedPaint != null)
-      onNeedPaint();
+    onNeedPaint();
   }
 
   @override

packages/flutter_test/lib/src/widget_tester.dart

@@ -1072,8 +1072,7 @@ class _TestTicker extends Ticker {
 
   @override
   void dispose() {
-    if (_onDispose != null)
-      _onDispose(this);
+    _onDispose(this);
     super.dispose();
   }
 }