Remove unnecessary null checks in flutter/rendering (#118923)

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

@@ -82,11 +82,7 @@ class RenderAnimatedSize extends RenderAligningShiftedBox {
     super.textDirection,
     super.child,
     Clip clipBehavior = Clip.hardEdge,
-  }) : assert(vsync != null),
-       assert(duration != null),
-       assert(curve != null),
-       assert(clipBehavior != null),
-       _vsync = vsync,
+  }) : _vsync = vsync,
        _clipBehavior = clipBehavior {
     _controller = AnimationController(
       vsync: vsync,
@@ -119,7 +115,6 @@ class RenderAnimatedSize extends RenderAligningShiftedBox {
   /// The duration of the animation.
   Duration get duration => _controller.duration!;
   set duration(Duration value) {
-    assert(value != null);
     if (value == _controller.duration) {
       return;
     }
@@ -138,7 +133,6 @@ class RenderAnimatedSize extends RenderAligningShiftedBox {
   /// The curve of the animation.
   Curve get curve => _animation.curve;
   set curve(Curve value) {
-    assert(value != null);
     if (value == _animation.curve) {
       return;
     }
@@ -151,7 +145,6 @@ class RenderAnimatedSize extends RenderAligningShiftedBox {
   Clip get clipBehavior => _clipBehavior;
   Clip _clipBehavior = Clip.hardEdge;
   set clipBehavior(Clip value) {
-    assert(value != null);
     if (value != _clipBehavior) {
       _clipBehavior = value;
       markNeedsPaint();
@@ -169,7 +162,6 @@ class RenderAnimatedSize extends RenderAligningShiftedBox {
   TickerProvider get vsync => _vsync;
   TickerProvider _vsync;
   set vsync(TickerProvider value) {
-    assert(value != null);
     if (value == _vsync) {
       return;
     }
@@ -218,7 +210,6 @@ class RenderAnimatedSize extends RenderAligningShiftedBox {
 
     child!.layout(constraints, parentUsesSize: true);
 
-    assert(_state != null);
     switch (_state) {
       case RenderAnimatedSizeState.start:
         _layoutStart();
@@ -253,7 +244,6 @@ class RenderAnimatedSize extends RenderAligningShiftedBox {
     // size without modifying global state. See performLayout for comments
     // explaining the rational behind the implementation.
     final Size childSize = child!.getDryLayout(constraints);
-    assert(_state != null);
     switch (_state) {
       case RenderAnimatedSizeState.start:
         return constraints.constrain(childSize);

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

@@ -43,7 +43,6 @@ mixin RendererBinding on BindingBase, ServicesBinding, SchedulerBinding, Gesture
       ..onSemanticsAction = _handleSemanticsAction;
     initRenderView();
     _handleSemanticsEnabledChanged();
-    assert(renderView != null);
     addPersistentFrameCallback(_handlePersistentFrameCallback);
     initMouseTracker();
     if (kIsWeb) {
@@ -234,7 +233,6 @@ mixin RendererBinding on BindingBase, ServicesBinding, SchedulerBinding, Gesture
   /// Sets the given [RenderView] object (which must not be null), and its tree, to
   /// be the new render tree to display. The previous tree, if any, is detached.
   set renderView(RenderView value) {
-    assert(value != null);
     _pipelineOwner.rootNode = value;
   }
 
@@ -244,7 +242,6 @@ mixin RendererBinding on BindingBase, ServicesBinding, SchedulerBinding, Gesture
   @protected
   @visibleForTesting
   void handleMetricsChanged() {
-    assert(renderView != null);
     renderView.configuration = createViewConfiguration();
     if (renderView.child != null) {
       scheduleForcedFrame();
@@ -512,7 +509,6 @@ mixin RendererBinding on BindingBase, ServicesBinding, SchedulerBinding, Gesture
   // When editing the above, also update widgets/binding.dart's copy.
   @protected
   void drawFrame() {
-    assert(renderView != null);
     pipelineOwner.flushLayout();
     pipelineOwner.flushCompositingBits();
     pipelineOwner.flushPaint();
@@ -544,9 +540,6 @@ mixin RendererBinding on BindingBase, ServicesBinding, SchedulerBinding, Gesture
 
   @override
   void hitTest(HitTestResult result, Offset position) {
-    assert(renderView != null);
-    assert(result != null);
-    assert(position != null);
     renderView.hitTest(result, position: position);
     super.hitTest(result, position);
   }
@@ -620,7 +613,6 @@ class RenderingFlutterBinding extends BindingBase with GestureBinding, Scheduler
   /// This binding does not automatically schedule any frames. Callers are
   /// responsible for deciding when to first call [scheduleFrame].
   RenderingFlutterBinding({ RenderBox? root }) {
-    assert(renderView != null);
     renderView.child = root;
   }
 

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

@@ -96,10 +96,7 @@ class BoxConstraints extends Constraints {
     this.maxWidth = double.infinity,
     this.minHeight = 0.0,
     this.maxHeight = double.infinity,
-  }) : assert(minWidth != null),
-       assert(maxWidth != null),
-       assert(minHeight != null),
-       assert(maxHeight != null);
+  });
 
   /// Creates box constraints that is respected only by the given size.
   BoxConstraints.tight(Size size)
@@ -190,7 +187,6 @@ class BoxConstraints extends Constraints {
 
   /// Returns new box constraints that are smaller by the given edge dimensions.
   BoxConstraints deflate(EdgeInsets edges) {
-    assert(edges != null);
     assert(debugAssertIsValid());
     final double horizontal = edges.horizontal;
     final double vertical = edges.vertical;
@@ -472,7 +468,6 @@ class BoxConstraints extends Constraints {
   ///
   /// {@macro dart.ui.shadow.lerp}
   static BoxConstraints? lerp(BoxConstraints? a, BoxConstraints? b, double t) {
-    assert(t != null);
     if (a == null && b == null) {
       return null;
     }
@@ -762,8 +757,6 @@ class BoxHitTestResult extends HitTestResult {
     required Offset position,
     required BoxHitTest hitTest,
   }) {
-    assert(position != null);
-    assert(hitTest != null);
     if (transform != null) {
       transform = Matrix4.tryInvert(PointerEvent.removePerspectiveTransform(transform));
       if (transform == null) {
@@ -801,8 +794,6 @@ class BoxHitTestResult extends HitTestResult {
     required Offset position,
     required BoxHitTest hitTest,
   }) {
-    assert(position != null);
-    assert(hitTest != null);
     final Offset transformedPosition = offset == null ? position : position - offset;
     if (offset != null) {
       pushOffset(-offset);
@@ -838,9 +829,6 @@ class BoxHitTestResult extends HitTestResult {
     required Offset position,
     required BoxHitTest hitTest,
   }) {
-    assert(position != null);
-    assert(hitTest != null);
-    assert(position != null);
     final Offset transformedPosition = transform == null ?
         position : MatrixUtils.transformPoint(transform, position);
     if (transform != null) {
@@ -887,7 +875,6 @@ class BoxHitTestResult extends HitTestResult {
     Matrix4? rawTransform,
     required BoxHitTestWithOutOfBandPosition hitTest,
   }) {
-    assert(hitTest != null);
     assert(
       (paintOffset == null && paintTransform == null && rawTransform != null) ||
       (paintOffset == null && paintTransform != null && rawTransform == null) ||
@@ -915,8 +902,7 @@ class BoxHitTestEntry extends HitTestEntry<RenderBox> {
   /// Creates a box hit test entry.
   ///
   /// The [localPosition] argument must not be null.
-  BoxHitTestEntry(super.target, this.localPosition)
-    : assert(localPosition != null);
+  BoxHitTestEntry(super.target, this.localPosition);
 
   /// The position of the hit test in the local coordinates of [target].
   final Offset localPosition;
@@ -1452,13 +1438,6 @@ abstract class RenderBox extends RenderObject {
   @mustCallSuper
   double getMinIntrinsicWidth(double height) {
     assert(() {
-      if (height == null) {
-        throw FlutterError.fromParts(<DiagnosticsNode>[
-          ErrorSummary('The height argument to getMinIntrinsicWidth was null.'),
-          ErrorDescription('The argument to getMinIntrinsicWidth must not be negative or null.'),
-          ErrorHint('If you do not have a specific height in mind, then pass double.infinity instead.'),
-        ]);
-      }
       if (height < 0.0) {
         throw FlutterError.fromParts(<DiagnosticsNode>[
           ErrorSummary('The height argument to getMinIntrinsicWidth was negative.'),
@@ -1601,13 +1580,6 @@ abstract class RenderBox extends RenderObject {
   @mustCallSuper
   double getMaxIntrinsicWidth(double height) {
     assert(() {
-      if (height == null) {
-        throw FlutterError.fromParts(<DiagnosticsNode>[
-          ErrorSummary('The height argument to getMaxIntrinsicWidth was null.'),
-          ErrorDescription('The argument to getMaxIntrinsicWidth must not be negative or null.'),
-          ErrorHint('If you do not have a specific height in mind, then pass double.infinity instead.'),
-        ]);
-      }
       if (height < 0.0) {
         throw FlutterError.fromParts(<DiagnosticsNode>[
           ErrorSummary('The height argument to getMaxIntrinsicWidth was negative.'),
@@ -1684,13 +1656,6 @@ abstract class RenderBox extends RenderObject {
   @mustCallSuper
   double getMinIntrinsicHeight(double width) {
     assert(() {
-      if (width == null) {
-        throw FlutterError.fromParts(<DiagnosticsNode>[
-          ErrorSummary('The width argument to getMinIntrinsicHeight was null.'),
-          ErrorDescription('The argument to getMinIntrinsicHeight must not be negative or null.'),
-          ErrorHint('If you do not have a specific width in mind, then pass double.infinity instead.'),
-        ]);
-      }
       if (width < 0.0) {
         throw FlutterError.fromParts(<DiagnosticsNode>[
           ErrorSummary('The width argument to getMinIntrinsicHeight was negative.'),
@@ -1766,13 +1731,6 @@ abstract class RenderBox extends RenderObject {
   @mustCallSuper
   double getMaxIntrinsicHeight(double width) {
     assert(() {
-      if (width == null) {
-        throw FlutterError.fromParts(<DiagnosticsNode>[
-          ErrorSummary('The width argument to getMaxIntrinsicHeight was null.'),
-          ErrorDescription('The argument to getMaxIntrinsicHeight must not be negative or null.'),
-          ErrorHint('If you do not have a specific width in mind, then pass double.infinity instead.'),
-        ]);
-      }
       if (width < 0.0) {
         throw FlutterError.fromParts(<DiagnosticsNode>[
           ErrorSummary('The width argument to getMaxIntrinsicHeight was negative.'),
@@ -2253,7 +2211,6 @@ abstract class RenderBox extends RenderObject {
 
   @override
   void debugAssertDoesMeetConstraints() {
-    assert(constraints != null);
     assert(() {
       if (!hasSize) {
         final DiagnosticsNode contract;
@@ -2582,7 +2539,6 @@ abstract class RenderBox extends RenderObject {
   /// child's [parentData] in the [BoxParentData.offset] field.
   @override
   void applyPaintTransform(RenderObject child, Matrix4 transform) {
-    assert(child != null);
     assert(child.parent == this);
     assert(() {
       if (child.parentData is! BoxParentData) {

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

@@ -187,11 +187,6 @@ abstract class MultiChildLayoutDelegate {
           'There is no child with the id "$childId".',
         );
       }
-      if (offset == null) {
-        throw FlutterError(
-          'The $this custom multichild layout delegate provided a null position for the child with id "$childId".',
-        );
-      }
       return true;
     }());
     final MultiChildLayoutParentData childParentData = child!.parentData! as MultiChildLayoutParentData;
@@ -311,8 +306,7 @@ class RenderCustomMultiChildLayoutBox extends RenderBox
   RenderCustomMultiChildLayoutBox({
     List<RenderBox>? children,
     required MultiChildLayoutDelegate delegate,
-  }) : assert(delegate != null),
-       _delegate = delegate {
+  }) : _delegate = delegate {
     addAll(children);
   }
 
@@ -327,7 +321,6 @@ class RenderCustomMultiChildLayoutBox extends RenderBox
   MultiChildLayoutDelegate get delegate => _delegate;
   MultiChildLayoutDelegate _delegate;
   set delegate(MultiChildLayoutDelegate newDelegate) {
-    assert(newDelegate != null);
     if (_delegate == newDelegate) {
       return;
     }

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

@@ -294,8 +294,7 @@ class CustomPainterSemantics {
     required this.properties,
     this.transform,
     this.tags,
-  }) : assert(rect != null),
-       assert(properties != null);
+  });
 
   /// Identifies this object in a list of siblings.
   ///
@@ -371,8 +370,7 @@ class RenderCustomPaint extends RenderProxyBox {
     this.isComplex = false,
     this.willChange = false,
     RenderBox? child,
-  }) : assert(preferredSize != null),
-       _painter = painter,
+  }) : _painter = painter,
        _foregroundPainter = foregroundPainter,
        _preferredSize = preferredSize,
        super(child);
@@ -467,7 +465,6 @@ class RenderCustomPaint extends RenderProxyBox {
   Size get preferredSize => _preferredSize;
   Size _preferredSize;
   set preferredSize(Size value) {
-    assert(value != null);
     if (preferredSize == value) {
       return;
     }

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

@@ -199,7 +199,6 @@ enum CrossAxisAlignment {
 }
 
 bool? _startIsTopLeft(Axis direction, TextDirection? textDirection, VerticalDirection? verticalDirection) {
-  assert(direction != null);
   // If the relevant value of textDirection or verticalDirection is null, this returns null too.
   switch (direction) {
     case Axis.horizontal:
@@ -289,12 +288,7 @@ class RenderFlex extends RenderBox with ContainerRenderObjectMixin<RenderBox, Fl
     VerticalDirection verticalDirection = VerticalDirection.down,
     TextBaseline? textBaseline,
     Clip clipBehavior = Clip.none,
-  }) : assert(direction != null),
-       assert(mainAxisAlignment != null),
-       assert(mainAxisSize != null),
-       assert(crossAxisAlignment != null),
-       assert(clipBehavior != null),
-       _direction = direction,
+  }) : _direction = direction,
        _mainAxisAlignment = mainAxisAlignment,
        _mainAxisSize = mainAxisSize,
        _crossAxisAlignment = crossAxisAlignment,
@@ -309,7 +303,6 @@ class RenderFlex extends RenderBox with ContainerRenderObjectMixin<RenderBox, Fl
   Axis get direction => _direction;
   Axis _direction;
   set direction(Axis value) {
-    assert(value != null);
     if (_direction != value) {
       _direction = value;
       markNeedsLayout();
@@ -328,7 +321,6 @@ class RenderFlex extends RenderBox with ContainerRenderObjectMixin<RenderBox, Fl
   MainAxisAlignment get mainAxisAlignment => _mainAxisAlignment;
   MainAxisAlignment _mainAxisAlignment;
   set mainAxisAlignment(MainAxisAlignment value) {
-    assert(value != null);
     if (_mainAxisAlignment != value) {
       _mainAxisAlignment = value;
       markNeedsLayout();
@@ -348,7 +340,6 @@ class RenderFlex extends RenderBox with ContainerRenderObjectMixin<RenderBox, Fl
   MainAxisSize get mainAxisSize => _mainAxisSize;
   MainAxisSize _mainAxisSize;
   set mainAxisSize(MainAxisSize value) {
-    assert(value != null);
     if (_mainAxisSize != value) {
       _mainAxisSize = value;
       markNeedsLayout();
@@ -367,7 +358,6 @@ class RenderFlex extends RenderBox with ContainerRenderObjectMixin<RenderBox, Fl
   CrossAxisAlignment get crossAxisAlignment => _crossAxisAlignment;
   CrossAxisAlignment _crossAxisAlignment;
   set crossAxisAlignment(CrossAxisAlignment value) {
-    assert(value != null);
     if (_crossAxisAlignment != value) {
       _crossAxisAlignment = value;
       markNeedsLayout();
@@ -444,8 +434,6 @@ class RenderFlex extends RenderBox with ContainerRenderObjectMixin<RenderBox, Fl
   }
 
   bool get _debugHasNecessaryDirections {
-    assert(direction != null);
-    assert(crossAxisAlignment != null);
     if (firstChild != null && lastChild != firstChild) {
       // i.e. there's more than one child
       switch (direction) {
@@ -453,7 +441,6 @@ class RenderFlex extends RenderBox with ContainerRenderObjectMixin<RenderBox, Fl
           assert(textDirection != null, 'Horizontal $runtimeType with multiple children has a null textDirection, so the layout order is undefined.');
           break;
         case Axis.vertical:
-          assert(verticalDirection != null, 'Vertical $runtimeType with multiple children has a null verticalDirection, so the layout order is undefined.');
           break;
       }
     }
@@ -464,7 +451,6 @@ class RenderFlex extends RenderBox with ContainerRenderObjectMixin<RenderBox, Fl
           assert(textDirection != null, 'Horizontal $runtimeType with $mainAxisAlignment has a null textDirection, so the alignment cannot be resolved.');
           break;
         case Axis.vertical:
-          assert(verticalDirection != null, 'Vertical $runtimeType with $mainAxisAlignment has a null verticalDirection, so the alignment cannot be resolved.');
           break;
       }
     }
@@ -472,7 +458,6 @@ class RenderFlex extends RenderBox with ContainerRenderObjectMixin<RenderBox, Fl
         crossAxisAlignment == CrossAxisAlignment.end) {
       switch (direction) {
         case Axis.horizontal:
-          assert(verticalDirection != null, 'Horizontal $runtimeType with $crossAxisAlignment has a null verticalDirection, so the alignment cannot be resolved.');
           break;
         case Axis.vertical:
           assert(textDirection != null, 'Vertical $runtimeType with $crossAxisAlignment has a null textDirection, so the alignment cannot be resolved.');
@@ -494,7 +479,6 @@ class RenderFlex extends RenderBox with ContainerRenderObjectMixin<RenderBox, Fl
   Clip get clipBehavior => _clipBehavior;
   Clip _clipBehavior = Clip.none;
   set clipBehavior(Clip value) {
-    assert(value != null);
     if (value != _clipBehavior) {
       _clipBehavior = value;
       markNeedsPaint();
@@ -795,7 +779,6 @@ class RenderFlex extends RenderBox with ContainerRenderObjectMixin<RenderBox, Fl
 
   _LayoutSizes _computeSizes({required BoxConstraints constraints, required ChildLayouter layoutChild}) {
     assert(_debugHasNecessaryDirections);
-    assert(constraints != null);
 
     // Determine used flex factor, size inflexible items, calculate free space.
     int totalFlex = 0;
@@ -861,7 +844,6 @@ class RenderFlex extends RenderBox with ContainerRenderObjectMixin<RenderBox, Fl
               minChildExtent = 0.0;
               break;
           }
-          assert(minChildExtent != null);
           final BoxConstraints innerConstraints;
           if (crossAxisAlignment == CrossAxisAlignment.stretch) {
             switch (_direction) {

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

@@ -183,9 +183,7 @@ class RenderFlow extends RenderBox
     List<RenderBox>? children,
     required FlowDelegate delegate,
     Clip clipBehavior = Clip.hardEdge,
-  }) : assert(delegate != null),
-       assert(clipBehavior != null),
-       _delegate = delegate,
+  }) : _delegate = delegate,
        _clipBehavior = clipBehavior {
     addAll(children);
   }
@@ -209,7 +207,6 @@ class RenderFlow extends RenderBox
   /// to determine whether the new delegate requires this object to update its
   /// layout or painting.
   set delegate(FlowDelegate newDelegate) {
-    assert(newDelegate != null);
     if (_delegate == newDelegate) {
       return;
     }
@@ -234,7 +231,6 @@ class RenderFlow extends RenderBox
   Clip get clipBehavior => _clipBehavior;
   Clip _clipBehavior = Clip.hardEdge;
   set clipBehavior(Clip value) {
-    assert(value != null);
     if (value != _clipBehavior) {
       _clipBehavior = value;
       markNeedsPaint();

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

@@ -44,13 +44,7 @@ class RenderImage extends RenderBox {
     bool invertColors = false,
     bool isAntiAlias = false,
     FilterQuality filterQuality = FilterQuality.low,
-  }) : assert(scale != null),
-       assert(repeat != null),
-       assert(alignment != null),
-       assert(filterQuality != null),
-       assert(matchTextDirection != null),
-       assert(isAntiAlias != null),
-       _image = image,
+  }) : _image = image,
        _width = width,
        _height = height,
        _scale = scale,
@@ -144,7 +138,6 @@ class RenderImage extends RenderBox {
   double get scale => _scale;
   double _scale;
   set scale(double value) {
-    assert(value != null);
     if (value == _scale) {
       return;
     }
@@ -200,7 +193,6 @@ class RenderImage extends RenderBox {
   FilterQuality get filterQuality => _filterQuality;
   FilterQuality _filterQuality;
   set filterQuality(FilterQuality value) {
-    assert(value != null);
     if (value == _filterQuality) {
       return;
     }
@@ -249,7 +241,6 @@ class RenderImage extends RenderBox {
   AlignmentGeometry get alignment => _alignment;
   AlignmentGeometry _alignment;
   set alignment(AlignmentGeometry value) {
-    assert(value != null);
     if (value == _alignment) {
       return;
     }
@@ -261,7 +252,6 @@ class RenderImage extends RenderBox {
   ImageRepeat get repeat => _repeat;
   ImageRepeat _repeat;
   set repeat(ImageRepeat value) {
-    assert(value != null);
     if (value == _repeat) {
       return;
     }
@@ -318,7 +308,6 @@ class RenderImage extends RenderBox {
   bool get matchTextDirection => _matchTextDirection;
   bool _matchTextDirection;
   set matchTextDirection(bool value) {
-    assert(value != null);
     if (value == _matchTextDirection) {
       return;
     }
@@ -350,7 +339,6 @@ class RenderImage extends RenderBox {
     if (_isAntiAlias == value) {
       return;
     }
-    assert(value != null);
     _isAntiAlias = value;
     markNeedsPaint();
   }

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

@@ -24,7 +24,7 @@ class AnnotationEntry<T> {
   const AnnotationEntry({
     required this.annotation,
     required this.localPosition,
-  }) : assert(localPosition != null);
+  });
 
   /// The annotation object that is found.
   final T annotation;
@@ -891,8 +891,7 @@ class TextureLayer extends Layer {
     required this.textureId,
     this.freeze = false,
     this.filterQuality = ui.FilterQuality.low,
-  }) : assert(rect != null),
-       assert(textureId != null);
+  });
 
   /// Bounding rectangle of this layer.
   final Rect rect;
@@ -939,8 +938,7 @@ class PlatformViewLayer extends Layer {
   PlatformViewLayer({
     required this.rect,
     required this.viewId,
-  }) : assert(rect != null),
-       assert(viewId != null);
+  });
 
   /// Bounding rectangle of this layer in the global coordinate space.
   final Rect rect;
@@ -1027,7 +1025,6 @@ class PerformanceOverlayLayer extends Layer {
 
   @override
   void addToScene(ui.SceneBuilder builder) {
-    assert(optionsMask != null);
     builder.addPerformanceOverlay(optionsMask, overlayRect);
     builder.setRasterizerTracingThreshold(rasterizerThreshold);
     builder.setCheckerboardRasterCacheImages(checkerboardRasterCacheImages);
@@ -1255,7 +1252,6 @@ class ContainerLayer extends Layer {
       child._nextSibling = null;
       assert(child.attached == attached);
       dropChild(child);
-      assert(child._parentHandle != null);
       child._parentHandle.layer = null;
       child = next;
     }
@@ -1318,7 +1314,6 @@ class ContainerLayer extends Layer {
   /// position.
   void applyTransform(Layer? child, Matrix4 transform) {
     assert(child != null);
-    assert(transform != null);
   }
 
   /// Returns the descendants of this layer in depth first order.
@@ -1399,7 +1394,6 @@ class OffsetLayer extends ContainerLayer {
   @override
   void applyTransform(Layer? child, Matrix4 transform) {
     assert(child != null);
-    assert(transform != null);
     transform.translate(offset.dx, offset.dy);
   }
 
@@ -1426,8 +1420,6 @@ class OffsetLayer extends ContainerLayer {
   }
 
   ui.Scene _createSceneForImage(Rect bounds, { double pixelRatio = 1.0 }) {
-    assert(bounds != null);
-    assert(pixelRatio != null);
     final ui.SceneBuilder builder = ui.SceneBuilder();
     final Matrix4 transform = Matrix4.diagonal3Values(pixelRatio, pixelRatio, 1);
     transform.translate(-(bounds.left + offset.dx), -(bounds.top + offset.dy));
@@ -1521,7 +1513,6 @@ class ClipRectLayer extends ContainerLayer {
     Clip clipBehavior = Clip.hardEdge,
   }) : _clipRect = clipRect,
        _clipBehavior = clipBehavior,
-       assert(clipBehavior != null),
        assert(clipBehavior != Clip.none);
 
   /// The rectangle to clip in the parent's coordinate system.
@@ -1550,7 +1541,6 @@ class ClipRectLayer extends ContainerLayer {
   Clip get clipBehavior => _clipBehavior;
   Clip _clipBehavior;
   set clipBehavior(Clip value) {
-    assert(value != null);
     assert(value != Clip.none);
     if (value != _clipBehavior) {
       _clipBehavior = value;
@@ -1569,7 +1559,6 @@ class ClipRectLayer extends ContainerLayer {
   @override
   void addToScene(ui.SceneBuilder builder) {
     assert(clipRect != null);
-    assert(clipBehavior != null);
     bool enabled = true;
     assert(() {
       enabled = !debugDisableClipLayers;
@@ -1613,7 +1602,6 @@ class ClipRRectLayer extends ContainerLayer {
     Clip clipBehavior = Clip.antiAlias,
   }) : _clipRRect = clipRRect,
        _clipBehavior = clipBehavior,
-       assert(clipBehavior != null),
        assert(clipBehavior != Clip.none);
 
   /// The rounded-rect to clip in the parent's coordinate system.
@@ -1638,7 +1626,6 @@ class ClipRRectLayer extends ContainerLayer {
   Clip get clipBehavior => _clipBehavior;
   Clip _clipBehavior;
   set clipBehavior(Clip value) {
-    assert(value != null);
     assert(value != Clip.none);
     if (value != _clipBehavior) {
       _clipBehavior = value;
@@ -1657,7 +1644,6 @@ class ClipRRectLayer extends ContainerLayer {
   @override
   void addToScene(ui.SceneBuilder builder) {
     assert(clipRRect != null);
-    assert(clipBehavior != null);
     bool enabled = true;
     assert(() {
       enabled = !debugDisableClipLayers;
@@ -1701,7 +1687,6 @@ class ClipPathLayer extends ContainerLayer {
     Clip clipBehavior = Clip.antiAlias,
   }) : _clipPath = clipPath,
        _clipBehavior = clipBehavior,
-       assert(clipBehavior != null),
        assert(clipBehavior != Clip.none);
 
   /// The path to clip in the parent's coordinate system.
@@ -1726,7 +1711,6 @@ class ClipPathLayer extends ContainerLayer {
   Clip get clipBehavior => _clipBehavior;
   Clip _clipBehavior;
   set clipBehavior(Clip value) {
-    assert(value != null);
     assert(value != Clip.none);
     if (value != _clipBehavior) {
       _clipBehavior = value;
@@ -1745,7 +1729,6 @@ class ClipPathLayer extends ContainerLayer {
   @override
   void addToScene(ui.SceneBuilder builder) {
     assert(clipPath != null);
-    assert(clipBehavior != null);
     bool enabled = true;
     assert(() {
       enabled = !debugDisableClipLayers;
@@ -1940,7 +1923,6 @@ class TransformLayer extends OffsetLayer {
   @override
   void applyTransform(Layer? child, Matrix4 transform) {
     assert(child != null);
-    assert(transform != null);
     assert(_lastEffectiveTransform != null || this.transform != null);
     if (_lastEffectiveTransform == null) {
       transform.multiply(this.transform!);
@@ -2250,7 +2232,6 @@ class PhysicalModelLayer extends ContainerLayer {
   Clip get clipBehavior => _clipBehavior;
   Clip _clipBehavior;
   set clipBehavior(Clip value) {
-    assert(value != null);
     if (value != _clipBehavior) {
       _clipBehavior = value;
       markNeedsAddToScene();
@@ -2310,7 +2291,6 @@ class PhysicalModelLayer extends ContainerLayer {
   @override
   void addToScene(ui.SceneBuilder builder) {
     assert(clipPath != null);
-    assert(clipBehavior != null);
     assert(elevation != null);
     assert(color != null);
     assert(shadowColor != null);
@@ -2437,7 +2417,7 @@ class LeaderLayer extends ContainerLayer {
   ///
   /// The [offset] property must be non-null before the compositing phase of the
   /// pipeline.
-  LeaderLayer({ required LayerLink link, Offset offset = Offset.zero }) : assert(link != null), _link = link, _offset = offset;
+  LeaderLayer({ required LayerLink link, Offset offset = Offset.zero }) : _link = link, _offset = offset;
 
   /// The object with which this layer should register.
   ///
@@ -2446,7 +2426,6 @@ class LeaderLayer extends ContainerLayer {
   LayerLink get link => _link;
   LayerLink _link;
   set link(LayerLink value) {
-    assert(value != null);
     if (_link == value) {
       return;
     }
@@ -2467,7 +2446,6 @@ class LeaderLayer extends ContainerLayer {
   Offset get offset => _offset;
   Offset _offset;
   set offset(Offset value) {
-    assert(value != null);
     if (value == _offset) {
       return;
     }
@@ -2496,7 +2474,6 @@ class LeaderLayer extends ContainerLayer {
 
   @override
   void addToScene(ui.SceneBuilder builder) {
-    assert(offset != null);
     if (offset != Offset.zero) {
       engineLayer = builder.pushTransform(
         Matrix4.translationValues(offset.dx, offset.dy, 0.0).storage,
@@ -2551,23 +2528,18 @@ class FollowerLayer extends ContainerLayer {
   /// The [unlinkedOffset], [linkedOffset], and [showWhenUnlinked] properties
   /// must be non-null before the compositing phase of the pipeline.
   FollowerLayer({
-    required LayerLink link,
+    required this.link,
     this.showWhenUnlinked = true,
     this.unlinkedOffset = Offset.zero,
     this.linkedOffset = Offset.zero,
-  }) : assert(link != null), _link = link;
+  });
 
   /// The link to the [LeaderLayer].
   ///
   /// The same object should be provided to a [LeaderLayer] that is earlier in
   /// the layer tree. When this layer is composited, it will apply a transform
   /// that moves its children to match the position of the [LeaderLayer].
-  LayerLink get link => _link;
-  set link(LayerLink value) {
-    assert(value != null);
-    _link = value;
-  }
-  LayerLink _link;
+  LayerLink link;
 
   /// Whether to show the layer's contents when the [link] does not point to a
   /// [LeaderLayer].
@@ -2631,7 +2603,7 @@ class FollowerLayer extends ContainerLayer {
 
   @override
   bool findAnnotations<S extends Object>(AnnotationResult<S> result, Offset localPosition, { required bool onlyFirst }) {
-    if (_link.leader == null) {
+    if (link.leader == null) {
       if (showWhenUnlinked!) {
         return super.findAnnotations(result, localPosition - unlinkedOffset!, onlyFirst: onlyFirst);
       }
@@ -2740,9 +2712,8 @@ class FollowerLayer extends ContainerLayer {
 
   /// Populate [_lastTransform] given the current state of the tree.
   void _establishTransform() {
-    assert(link != null);
     _lastTransform = null;
-    final LeaderLayer? leader = _link.leader;
+    final LeaderLayer? leader = link.leader;
     // Check to see if we are linked.
     if (leader == null) {
       return;
@@ -2806,9 +2777,8 @@ class FollowerLayer extends ContainerLayer {
 
   @override
   void addToScene(ui.SceneBuilder builder) {
-    assert(link != null);
     assert(showWhenUnlinked != null);
-    if (_link.leader == null && !showWhenUnlinked!) {
+    if (link.leader == null && !showWhenUnlinked!) {
       _lastTransform = null;
       _lastOffset = null;
       _inverseDirty = true;
@@ -2840,7 +2810,6 @@ class FollowerLayer extends ContainerLayer {
   @override
   void applyTransform(Layer? child, Matrix4 transform) {
     assert(child != null);
-    assert(transform != null);
     if (_lastTransform != null) {
       transform.multiply(_lastTransform!);
     } else {
@@ -2886,9 +2855,7 @@ class AnnotatedRegionLayer<T extends Object> extends ContainerLayer {
     this.size,
     Offset? offset,
     this.opaque = false,
-  }) : assert(value != null),
-       assert(opaque != null),
-       offset = offset ?? Offset.zero;
+  }) : offset = offset ?? Offset.zero;
 
   /// The annotated object, which is added to the result if all restrictions are
   /// met.

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

@@ -32,8 +32,7 @@ class RenderListBody extends RenderBox
   RenderListBody({
     List<RenderBox>? children,
     AxisDirection axisDirection = AxisDirection.down,
-  }) : assert(axisDirection != null),
-       _axisDirection = axisDirection {
+  }) : _axisDirection = axisDirection {
     addAll(children);
   }
 
@@ -51,7 +50,6 @@ class RenderListBody extends RenderBox
   AxisDirection get axisDirection => _axisDirection;
   AxisDirection _axisDirection;
   set axisDirection(AxisDirection value) {
-    assert(value != null);
     if (_axisDirection == value) {
       return;
     }
@@ -259,7 +257,6 @@ class RenderListBody extends RenderBox
 
   @override
   double computeMinIntrinsicWidth(double height) {
-    assert(mainAxis != null);
     switch (mainAxis) {
       case Axis.horizontal:
         return _getIntrinsicMainAxis((RenderBox child) => child.getMinIntrinsicWidth(height));
@@ -270,7 +267,6 @@ class RenderListBody extends RenderBox
 
   @override
   double computeMaxIntrinsicWidth(double height) {
-    assert(mainAxis != null);
     switch (mainAxis) {
       case Axis.horizontal:
         return _getIntrinsicMainAxis((RenderBox child) => child.getMaxIntrinsicWidth(height));
@@ -281,7 +277,6 @@ class RenderListBody extends RenderBox
 
   @override
   double computeMinIntrinsicHeight(double width) {
-    assert(mainAxis != null);
     switch (mainAxis) {
       case Axis.horizontal:
         return _getIntrinsicMainAxis((RenderBox child) => child.getMinIntrinsicHeight(width));
@@ -292,7 +287,6 @@ class RenderListBody extends RenderBox
 
   @override
   double computeMaxIntrinsicHeight(double width) {
-    assert(mainAxis != null);
     switch (mainAxis) {
       case Axis.horizontal:
         return _getIntrinsicMainAxis((RenderBox child) => child.getMaxIntrinsicHeight(width));

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

@@ -149,25 +149,13 @@ class RenderListWheelViewport
     bool renderChildrenOutsideViewport = false,
     Clip clipBehavior = Clip.none,
     List<RenderBox>? children,
-  }) : assert(childManager != null),
-       assert(offset != null),
-       assert(diameterRatio != null),
-       assert(diameterRatio > 0, diameterRatioZeroMessage),
-       assert(perspective != null),
+  }) : assert(diameterRatio > 0, diameterRatioZeroMessage),
        assert(perspective > 0),
        assert(perspective <= 0.01, perspectiveTooHighMessage),
-       assert(offAxisFraction != null),
-       assert(useMagnifier != null),
-       assert(magnification != null),
        assert(magnification > 0),
-       assert(overAndUnderCenterOpacity != null),
        assert(overAndUnderCenterOpacity >= 0 && overAndUnderCenterOpacity <= 1),
-       assert(itemExtent != null),
-       assert(squeeze != null),
        assert(squeeze > 0),
        assert(itemExtent > 0),
-       assert(renderChildrenOutsideViewport != null),
-       assert(clipBehavior != null),
        assert(
          !renderChildrenOutsideViewport || clipBehavior == Clip.none,
          clipBehaviorAndRenderChildrenOutsideViewportConflict,
@@ -225,7 +213,6 @@ class RenderListWheelViewport
   ViewportOffset get offset => _offset;
   ViewportOffset _offset;
   set offset(ViewportOffset value) {
-    assert(value != null);
     if (value == _offset) {
       return;
     }
@@ -270,7 +257,6 @@ class RenderListWheelViewport
   double get diameterRatio => _diameterRatio;
   double _diameterRatio;
   set diameterRatio(double value) {
-    assert(value != null);
     assert(
       value > 0,
       diameterRatioZeroMessage,
@@ -300,7 +286,6 @@ class RenderListWheelViewport
   double get perspective => _perspective;
   double _perspective;
   set perspective(double value) {
-    assert(value != null);
     assert(value > 0);
     assert(
       value <= 0.01,
@@ -342,7 +327,6 @@ class RenderListWheelViewport
   double get offAxisFraction => _offAxisFraction;
   double _offAxisFraction = 0.0;
   set offAxisFraction(double value) {
-    assert(value != null);
     if (value == _offAxisFraction) {
       return;
     }
@@ -356,7 +340,6 @@ class RenderListWheelViewport
   bool get useMagnifier => _useMagnifier;
   bool _useMagnifier = false;
   set useMagnifier(bool value) {
-    assert(value != null);
     if (value == _useMagnifier) {
       return;
     }
@@ -376,7 +359,6 @@ class RenderListWheelViewport
   double get magnification => _magnification;
   double _magnification = 1.0;
   set magnification(double value) {
-    assert(value != null);
     assert(value > 0);
     if (value == _magnification) {
       return;
@@ -396,7 +378,6 @@ class RenderListWheelViewport
   double get overAndUnderCenterOpacity => _overAndUnderCenterOpacity;
   double _overAndUnderCenterOpacity = 1.0;
   set overAndUnderCenterOpacity(double value) {
-    assert(value != null);
     assert(value >= 0 && value <= 1);
     if (value == _overAndUnderCenterOpacity) {
       return;
@@ -414,7 +395,6 @@ class RenderListWheelViewport
   double get itemExtent => _itemExtent;
   double _itemExtent;
   set itemExtent(double value) {
-    assert(value != null);
     assert(value > 0);
     if (value == _itemExtent) {
       return;
@@ -447,7 +427,6 @@ class RenderListWheelViewport
   double get squeeze => _squeeze;
   double _squeeze;
   set squeeze(double value) {
-    assert(value != null);
     assert(value > 0);
     if (value == _squeeze) {
       return;
@@ -470,7 +449,6 @@ class RenderListWheelViewport
   bool get renderChildrenOutsideViewport => _renderChildrenOutsideViewport;
   bool _renderChildrenOutsideViewport;
   set renderChildrenOutsideViewport(bool value) {
-    assert(value != null);
     assert(
       !renderChildrenOutsideViewport || clipBehavior == Clip.none,
       clipBehaviorAndRenderChildrenOutsideViewportConflict,
@@ -489,7 +467,6 @@ class RenderListWheelViewport
   Clip get clipBehavior => _clipBehavior;
   Clip _clipBehavior = Clip.hardEdge;
   set clipBehavior(Clip value) {
-    assert(value != null);
     if (value != _clipBehavior) {
       _clipBehavior = value;
       markNeedsPaint();
@@ -636,7 +613,6 @@ class RenderListWheelViewport
   ///
   /// This relies on the [childManager] maintaining [ListWheelParentData.index].
   int indexOf(RenderBox child) {
-    assert(child != null);
     final ListWheelParentData childParentData = child.parentData! as ListWheelParentData;
     assert(childParentData.index != null);
     return childParentData.index!;

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

@@ -30,8 +30,7 @@ typedef MouseDetectorAnnotationFinder = HitTestResult Function(Offset offset);
 class _MouseState {
   _MouseState({
     required PointerEvent initialEvent,
-  }) : assert(initialEvent != null),
-       _latestEvent = initialEvent;
+  }) : _latestEvent = initialEvent;
 
   // The list of annotations that contains this device.
   //
@@ -40,7 +39,6 @@ class _MouseState {
   LinkedHashMap<MouseTrackerAnnotation, Matrix4> _annotations = LinkedHashMap<MouseTrackerAnnotation, Matrix4>();
 
   LinkedHashMap<MouseTrackerAnnotation, Matrix4> replaceAnnotations(LinkedHashMap<MouseTrackerAnnotation, Matrix4> value) {
-    assert(value != null);
     final LinkedHashMap<MouseTrackerAnnotation, Matrix4> previous = _annotations;
     _annotations = value;
     return previous;
@@ -51,7 +49,6 @@ class _MouseState {
   PointerEvent _latestEvent;
 
   PointerEvent replaceLatestEvent(PointerEvent value) {
-    assert(value != null);
     assert(value.device == _latestEvent.device);
     final PointerEvent previous = _latestEvent;
     _latestEvent = value;
@@ -83,10 +80,7 @@ class _MouseTrackerUpdateDetails with Diagnosticable {
     required this.lastAnnotations,
     required this.nextAnnotations,
     required PointerEvent this.previousEvent,
-  }) : assert(previousEvent != null),
-       assert(lastAnnotations != null),
-       assert(nextAnnotations != null),
-       triggeringEvent = null;
+  }) : triggeringEvent = null;
 
   /// When device update is triggered by a pointer event.
   ///
@@ -97,9 +91,7 @@ class _MouseTrackerUpdateDetails with Diagnosticable {
     required this.nextAnnotations,
     this.previousEvent,
     required PointerEvent this.triggeringEvent,
-  }) : assert(triggeringEvent != null),
-       assert(lastAnnotations != null),
-       assert(nextAnnotations != null);
+  });
 
   /// The annotations that the device is hovering before the update.
   ///
@@ -129,7 +121,6 @@ class _MouseTrackerUpdateDetails with Diagnosticable {
   /// The pointing device of this update.
   int get device {
     final int result = (previousEvent ?? triggeringEvent)!.device;
-    assert(result != null);
     return result;
   }
 
@@ -138,7 +129,6 @@ class _MouseTrackerUpdateDetails with Diagnosticable {
   /// The [latestEvent] is never null.
   PointerEvent get latestEvent {
     final PointerEvent result = triggeringEvent ?? previousEvent!;
-    assert(result != null);
     return result;
   }
 
@@ -219,7 +209,6 @@ class MouseTracker extends ChangeNotifier {
     if (state == null) {
       return true;
     }
-    assert(event != null);
     final PointerEvent lastEvent = state.latestEvent;
     assert(event.device == lastEvent.device);
     // An Added can only follow a Removed, and a Removed can only be followed
@@ -236,7 +225,6 @@ class MouseTracker extends ChangeNotifier {
   }
 
   LinkedHashMap<MouseTrackerAnnotation, Matrix4> _hitTestResultToAnnotations(HitTestResult result) {
-    assert(result != null);
     final LinkedHashMap<MouseTrackerAnnotation, Matrix4> annotations = LinkedHashMap<MouseTrackerAnnotation, Matrix4>();
     for (final HitTestEntry entry in result.path) {
       final Object target = entry.target;
@@ -253,8 +241,6 @@ class MouseTracker extends ChangeNotifier {
   // If the device is not connected or not a mouse, an empty map is returned
   // without calling `hitTest`.
   LinkedHashMap<MouseTrackerAnnotation, Matrix4> _findAnnotations(_MouseState state, MouseDetectorAnnotationFinder hitTest) {
-    assert(state != null);
-    assert(hitTest != null);
     final Offset globalPosition = state.latestEvent.position;
     final int device = state.device;
     if (!_mouseStates.containsKey(device)) {

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

@@ -83,9 +83,7 @@ class PaintingContext extends ClipContext {
   /// Typically only called by [PaintingContext.repaintCompositedChild]
   /// and [pushLayer].
   @protected
-  PaintingContext(this._containerLayer, this.estimatedBounds)
-    : assert(_containerLayer != null),
-      assert(estimatedBounds != null);
+  PaintingContext(this._containerLayer, this.estimatedBounds);
 
   final ContainerLayer _containerLayer;
 
@@ -462,7 +460,6 @@ class PaintingContext extends ClipContext {
   ///  * [addLayer], for pushing a layer without painting further contents
   ///    within it.
   void pushLayer(ContainerLayer childLayer, PaintingContextCallback painter, Offset offset, { Rect? childPaintBounds }) {
-    assert(painter != null);
     // If a layer is being reused, it may already contain children. We remove
     // them so that `painter` can add children that are relevant for this frame.
     if (childLayer.hasChildren) {
@@ -560,7 +557,6 @@ class PaintingContext extends ClipContext {
   ///
   /// {@macro flutter.rendering.PaintingContext.pushClipRect.oldLayer}
   ClipRRectLayer? pushClipRRect(bool needsCompositing, Offset offset, Rect bounds, RRect clipRRect, PaintingContextCallback painter, { Clip clipBehavior = Clip.antiAlias, ClipRRectLayer? oldLayer }) {
-    assert(clipBehavior != null);
     if (clipBehavior == Clip.none) {
       painter(this, offset);
       return null;
@@ -600,7 +596,6 @@ class PaintingContext extends ClipContext {
   ///
   /// {@macro flutter.rendering.PaintingContext.pushClipRect.oldLayer}
   ClipPathLayer? pushClipPath(bool needsCompositing, Offset offset, Rect bounds, Path clipPath, PaintingContextCallback painter, { Clip clipBehavior = Clip.antiAlias, ClipPathLayer? oldLayer }) {
-    assert(clipBehavior != null);
     if (clipBehavior == Clip.none) {
       painter(this, offset);
       return null;
@@ -637,7 +632,6 @@ class PaintingContext extends ClipContext {
   /// ancestor render objects that this render object will include a composited
   /// layer, which, for example, causes them to use composited clips.
   ColorFilterLayer pushColorFilter(Offset offset, ColorFilter colorFilter, PaintingContextCallback painter, { ColorFilterLayer? oldLayer }) {
-    assert(colorFilter != null);
     final ColorFilterLayer layer = oldLayer ?? ColorFilterLayer();
     layer.colorFilter = colorFilter;
     pushLayer(layer, painter, offset);
@@ -831,8 +825,7 @@ typedef LayoutCallback<T extends Constraints> = void Function(T constraints);
 /// You can obtain the [PipelineOwner] using the [RenderObject.owner] property.
 class SemanticsHandle {
   SemanticsHandle._(PipelineOwner owner, this.listener)
-      : assert(owner != null),
-        _owner = owner {
+      : _owner = owner {
     if (listener != null) {
       _owner.semanticsOwner!.addListener(listener!);
     }
@@ -1510,7 +1503,6 @@ abstract class RenderObject extends AbstractNode with DiagnosticableTreeMixin im
   @override
   void adoptChild(RenderObject child) {
     assert(_debugCanPerformMutations);
-    assert(child != null);
     setupParentData(child);
     markNeedsLayout();
     markNeedsCompositingBitsUpdate();
@@ -1525,7 +1517,6 @@ abstract class RenderObject extends AbstractNode with DiagnosticableTreeMixin im
   @override
   void dropChild(RenderObject child) {
     assert(_debugCanPerformMutations);
-    assert(child != null);
     assert(child.parentData != null);
     child._cleanRelayoutBoundary();
     child.parentData!.detach();
@@ -2079,7 +2070,6 @@ abstract class RenderObject extends AbstractNode with DiagnosticableTreeMixin im
         arguments: debugTimelineArguments,
       );
     }
-    assert(constraints != null);
     assert(constraints.debugAssertIsValid(
       isAppliedConstraint: true,
       informationCollector: () {
@@ -3249,7 +3239,6 @@ abstract class RenderObject extends AbstractNode with DiagnosticableTreeMixin im
   _SemanticsFragment _getSemanticsForParent({
     required bool mergeIntoParent,
   }) {
-    assert(mergeIntoParent != null);
     assert(!_needsLayout, 'Updated layout information required for $this to calculate semantics.');
 
     final SemanticsConfiguration config = _semanticsConfiguration;
@@ -3975,7 +3964,6 @@ mixin ContainerRenderObjectMixin<ChildType extends RenderObject, ParentDataType
 
   /// The previous child before the given child in the child list.
   ChildType? childBefore(ChildType child) {
-    assert(child != null);
     assert(child.parent == this);
     final ParentDataType childParentData = child.parentData! as ParentDataType;
     return childParentData.previousSibling;
@@ -3983,7 +3971,6 @@ mixin ContainerRenderObjectMixin<ChildType extends RenderObject, ParentDataType
 
   /// The next child after the given child in the child list.
   ChildType? childAfter(ChildType child) {
-    assert(child != null);
     assert(child.parent == this);
     final ParentDataType childParentData = child.parentData! as ParentDataType;
     return childParentData.nextSibling;
@@ -4088,7 +4075,7 @@ mixin RelayoutWhenSystemFontsChangeMixin on RenderObject {
 abstract class _SemanticsFragment {
   _SemanticsFragment({
     required this.dropsSemanticsOfPreviousSiblings,
-  }) : assert (dropsSemanticsOfPreviousSiblings != null);
+  });
 
   /// Incorporate the fragments of children into this fragment.
   void addAll(Iterable<_InterestingSemanticsFragment> fragments);
@@ -4139,8 +4126,7 @@ abstract class _InterestingSemanticsFragment extends _SemanticsFragment {
   _InterestingSemanticsFragment({
     required RenderObject owner,
     required super.dropsSemanticsOfPreviousSiblings,
-  }) : assert(owner != null),
-       _ancestorChain = <RenderObject>[owner];
+  }) : _ancestorChain = <RenderObject>[owner];
 
   /// The [RenderObject] that owns this fragment (and any new [SemanticsNode]
   /// introduced by it).
@@ -4322,9 +4308,7 @@ class _SwitchableSemanticsFragment extends _InterestingSemanticsFragment {
     required super.dropsSemanticsOfPreviousSiblings,
   }) : _siblingMergeGroups = siblingMergeGroups,
        _mergeIntoParent = mergeIntoParent,
-       _config = config,
-       assert(mergeIntoParent != null),
-       assert(config != null);
+       _config = config;
 
   final bool _mergeIntoParent;
   SemanticsConfiguration _config;
@@ -4679,7 +4663,6 @@ class _SemanticsGeometry {
 
   /// From parent to child coordinate system.
   static Rect? _transformRect(Rect? rect, Matrix4 transform) {
-    assert(transform != null);
     if (rect == null) {
       return null;
     }
@@ -4700,18 +4683,12 @@ class _SemanticsGeometry {
     Matrix4 transform,
     Matrix4 clipRectTransform,
   ) {
-    assert(ancestor != null);
-    assert(child != null);
-    assert(transform != null);
-    assert(clipRectTransform != null);
     assert(clipRectTransform.isIdentity());
     RenderObject intermediateParent = child.parent! as RenderObject;
-    assert(intermediateParent != null);
     while (intermediateParent != ancestor) {
       intermediateParent.applyPaintTransform(child, transform);
       intermediateParent = intermediateParent.parent! as RenderObject;
       child = child.parent! as RenderObject;
-      assert(intermediateParent != null);
     }
     ancestor.applyPaintTransform(child, transform);
     ancestor.applyPaintTransform(child, clipRectTransform);
@@ -4757,8 +4734,7 @@ class DiagnosticsDebugCreator extends DiagnosticsProperty<Object> {
   /// Create a [DiagnosticsProperty] with its [value] initialized to input
   /// [RenderObject.debugCreator].
   DiagnosticsDebugCreator(Object value)
-    : assert(value != null),
-      super(
+    : super(
         'debugCreator',
         value,
         level: DiagnosticLevel.hidden,

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

@@ -88,15 +88,8 @@ class RenderParagraph extends RenderBox
     List<RenderBox>? children,
     Color? selectionColor,
     SelectionRegistrar? registrar,
-  }) : assert(text != null),
-       assert(text.debugAssertIsValid()),
-       assert(textAlign != null),
-       assert(textDirection != null),
-       assert(softWrap != null),
-       assert(overflow != null),
-       assert(textScaleFactor != null),
+  }) : assert(text.debugAssertIsValid()),
        assert(maxLines == null || maxLines > 0),
-       assert(textWidthBasis != null),
        _softWrap = softWrap,
        _overflow = overflow,
        _selectionColor = selectionColor,
@@ -132,7 +125,6 @@ class RenderParagraph extends RenderBox
   /// The text to display.
   InlineSpan get text => _textPainter.text!;
   set text(InlineSpan value) {
-    assert(value != null);
     switch (_textPainter.text!.compareTo(value)) {
       case RenderComparison.identical:
         return;
@@ -279,7 +271,6 @@ class RenderParagraph extends RenderBox
   /// How the text should be aligned horizontally.
   TextAlign get textAlign => _textPainter.textAlign;
   set textAlign(TextAlign value) {
-    assert(value != null);
     if (_textPainter.textAlign == value) {
       return;
     }
@@ -302,7 +293,6 @@ class RenderParagraph extends RenderBox
   /// This must not be null.
   TextDirection get textDirection => _textPainter.textDirection!;
   set textDirection(TextDirection value) {
-    assert(value != null);
     if (_textPainter.textDirection == value) {
       return;
     }
@@ -320,7 +310,6 @@ class RenderParagraph extends RenderBox
   bool get softWrap => _softWrap;
   bool _softWrap;
   set softWrap(bool value) {
-    assert(value != null);
     if (_softWrap == value) {
       return;
     }
@@ -332,7 +321,6 @@ class RenderParagraph extends RenderBox
   TextOverflow get overflow => _overflow;
   TextOverflow _overflow;
   set overflow(TextOverflow value) {
-    assert(value != null);
     if (_overflow == value) {
       return;
     }
@@ -347,7 +335,6 @@ class RenderParagraph extends RenderBox
   /// the specified font size.
   double get textScaleFactor => _textPainter.textScaleFactor;
   set textScaleFactor(double value) {
-    assert(value != null);
     if (_textPainter.textScaleFactor == value) {
       return;
     }
@@ -405,7 +392,6 @@ class RenderParagraph extends RenderBox
   /// {@macro flutter.painting.textPainter.textWidthBasis}
   TextWidthBasis get textWidthBasis => _textPainter.textWidthBasis;
   set textWidthBasis(TextWidthBasis value) {
-    assert(value != null);
     if (_textPainter.textWidthBasis == value) {
       return;
     }
@@ -490,7 +476,6 @@ class RenderParagraph extends RenderBox
   @override
   double computeDistanceToActualBaseline(TextBaseline baseline) {
     assert(!debugNeedsLayout);
-    assert(constraints != null);
     assert(constraints.debugAssertIsValid());
     _layoutTextWithConstraints(constraints);
     // TODO(garyq): Since our metric for ideographic baseline is currently
@@ -813,7 +798,6 @@ class RenderParagraph extends RenderBox
           _overflowShader = null;
           break;
         case TextOverflow.fade:
-          assert(textDirection != null);
           _needsClipping = true;
           final TextPainter fadeSizePainter = TextPainter(
             text: TextSpan(style: _textPainter.text!.style, text: '\u2026'),
@@ -975,8 +959,6 @@ class RenderParagraph extends RenderBox
     ui.BoxWidthStyle boxWidthStyle = ui.BoxWidthStyle.tight,
   }) {
     assert(!debugNeedsLayout);
-    assert(boxHeightStyle != null);
-    assert(boxWidthStyle != null);
     _layoutTextWithConstraints(constraints);
     return _textPainter.getBoxesForSelection(
       selection,

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

@@ -67,11 +67,7 @@ class RenderPerformanceOverlay extends RenderBox {
     int rasterizerThreshold = 0,
     bool checkerboardRasterCacheImages = false,
     bool checkerboardOffscreenLayers = false,
-  }) : assert(optionsMask != null),
-       assert(rasterizerThreshold != null),
-       assert(checkerboardRasterCacheImages != null),
-       assert(checkerboardOffscreenLayers != null),
-       _optionsMask = optionsMask,
+  }) : _optionsMask = optionsMask,
        _rasterizerThreshold = rasterizerThreshold,
        _checkerboardRasterCacheImages = checkerboardRasterCacheImages,
        _checkerboardOffscreenLayers = checkerboardOffscreenLayers;
@@ -81,7 +77,6 @@ class RenderPerformanceOverlay extends RenderBox {
   int get optionsMask => _optionsMask;
   int _optionsMask;
   set optionsMask(int value) {
-    assert(value != null);
     if (value == _optionsMask) {
       return;
     }
@@ -95,7 +90,6 @@ class RenderPerformanceOverlay extends RenderBox {
   int get rasterizerThreshold => _rasterizerThreshold;
   int _rasterizerThreshold;
   set rasterizerThreshold(int value) {
-    assert(value != null);
     if (value == _rasterizerThreshold) {
       return;
     }
@@ -107,7 +101,6 @@ class RenderPerformanceOverlay extends RenderBox {
   bool get checkerboardRasterCacheImages => _checkerboardRasterCacheImages;
   bool _checkerboardRasterCacheImages;
   set checkerboardRasterCacheImages(bool value) {
-    assert(value != null);
     if (value == _checkerboardRasterCacheImages) {
       return;
     }
@@ -119,7 +112,6 @@ class RenderPerformanceOverlay extends RenderBox {
   bool get checkerboardOffscreenLayers => _checkerboardOffscreenLayers;
   bool _checkerboardOffscreenLayers;
   set checkerboardOffscreenLayers(bool value) {
-    assert(value != null);
     if (value == _checkerboardOffscreenLayers) {
       return;
     }

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

@@ -80,11 +80,7 @@ class RenderAndroidView extends PlatformViewRenderBox {
     required PlatformViewHitTestBehavior hitTestBehavior,
     required Set<Factory<OneSequenceGestureRecognizer>> gestureRecognizers,
     Clip clipBehavior = Clip.hardEdge,
-  }) : assert(viewController != null),
-       assert(hitTestBehavior != null),
-       assert(gestureRecognizers != null),
-       assert(clipBehavior != null),
-       _viewController = viewController,
+  }) : _viewController = viewController,
        _clipBehavior = clipBehavior,
        super(controller: viewController, hitTestBehavior: hitTestBehavior, gestureRecognizers: gestureRecognizers) {
     _viewController.pointTransformer = (Offset offset) => globalToLocal(offset);
@@ -110,8 +106,6 @@ class RenderAndroidView extends PlatformViewRenderBox {
   @override
   set controller(AndroidViewController controller) {
     assert(!_isDisposed);
-    assert(_viewController != null);
-    assert(controller != null);
     if (_viewController == controller) {
       return;
     }
@@ -132,7 +126,6 @@ class RenderAndroidView extends PlatformViewRenderBox {
   Clip get clipBehavior => _clipBehavior;
   Clip _clipBehavior = Clip.hardEdge;
   set clipBehavior(Clip value) {
-    assert(value != null);
     if (value != _clipBehavior) {
       _clipBehavior = value;
       markNeedsPaint();
@@ -299,10 +292,7 @@ class RenderUiKitView extends RenderBox {
     required UiKitViewController viewController,
     required this.hitTestBehavior,
     required Set<Factory<OneSequenceGestureRecognizer>> gestureRecognizers,
-  }) : assert(viewController != null),
-       assert(hitTestBehavior != null),
-       assert(gestureRecognizers != null),
-       _viewController = viewController {
+  }) : _viewController = viewController {
     updateGestureRecognizers(gestureRecognizers);
   }
 
@@ -314,7 +304,6 @@ class RenderUiKitView extends RenderBox {
   UiKitViewController get viewController => _viewController;
   UiKitViewController _viewController;
   set viewController(UiKitViewController value) {
-    assert(value != null);
     if (_viewController == value) {
       return;
     }
@@ -333,7 +322,6 @@ class RenderUiKitView extends RenderBox {
 
   /// {@macro flutter.rendering.PlatformViewRenderBox.updateGestureRecognizers}
   void updateGestureRecognizers(Set<Factory<OneSequenceGestureRecognizer>> gestureRecognizers) {
-    assert(gestureRecognizers != null);
     assert(
       _factoriesTypeSet(gestureRecognizers).length == gestureRecognizers.length,
       'There were multiple gesture recognizer factories for the same type, there must only be a single '
@@ -632,9 +620,7 @@ class PlatformViewRenderBox extends RenderBox with _PlatformViewGestureMixin {
     required PlatformViewController controller,
     required PlatformViewHitTestBehavior hitTestBehavior,
     required Set<Factory<OneSequenceGestureRecognizer>> gestureRecognizers,
-  }) :  assert(controller != null && controller.viewId != null && controller.viewId > -1),
-        assert(hitTestBehavior != null),
-        assert(gestureRecognizers != null),
+  }) :  assert(controller.viewId > -1),
         _controller = controller {
     this.hitTestBehavior = hitTestBehavior;
     updateGestureRecognizers(gestureRecognizers);
@@ -645,8 +631,7 @@ class PlatformViewRenderBox extends RenderBox with _PlatformViewGestureMixin {
   PlatformViewController _controller;
   /// This value must not be null, and setting it to a new value will result in a repaint.
   set controller(covariant PlatformViewController controller) {
-    assert(controller != null);
-    assert(controller.viewId != null && controller.viewId > -1);
+    assert(controller.viewId > -1);
 
     if (_controller == controller) {
       return;
@@ -695,7 +680,6 @@ class PlatformViewRenderBox extends RenderBox with _PlatformViewGestureMixin {
 
   @override
   void paint(PaintingContext context, Offset offset) {
-    assert(_controller.viewId != null);
     context.addLayer(PlatformViewLayer(
       rect: offset & size,
       viewId: _controller.viewId,
@@ -705,7 +689,6 @@ class PlatformViewRenderBox extends RenderBox with _PlatformViewGestureMixin {
   @override
   void describeSemanticsConfiguration(SemanticsConfiguration config) {
     super.describeSemanticsConfiguration(config);
-    assert(_controller.viewId != null);
     config.isSemanticBoundary = true;
     config.platformViewId = _controller.viewId;
   }
@@ -733,7 +716,6 @@ mixin _PlatformViewGestureMixin on RenderBox implements MouseTrackerAnnotation {
   /// Any active gesture arena the `PlatformView` participates in is rejected when the
   /// set of gesture recognizers is changed.
   void _updateGestureRecognizersWithCallBack(Set<Factory<OneSequenceGestureRecognizer>> gestureRecognizers, _HandlePointerEvent handlePointerEvent) {
-    assert(gestureRecognizers != null);
     assert(
       _factoriesTypeSet(gestureRecognizers).length == gestureRecognizers.length,
       'There were multiple gesture recognizer factories for the same type, there must only be a single '

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

@@ -74,14 +74,12 @@ abstract class RenderProxySliver extends RenderSliver with RenderObjectWithChild
 
   @override
   double childMainAxisPosition(RenderSliver child) {
-    assert(child != null);
     assert(child == this.child);
     return 0.0;
   }
 
   @override
   void applyPaintTransform(RenderObject child, Matrix4 transform) {
-    assert(child != null);
     final SliverPhysicalParentData childParentData = child.parentData! as SliverPhysicalParentData;
     childParentData.applyPaintTransform(transform);
   }
@@ -105,8 +103,7 @@ class RenderSliverOpacity extends RenderProxySliver {
     double opacity = 1.0,
     bool alwaysIncludeSemantics = false,
     RenderSliver? sliver,
-  }) : assert(opacity != null && opacity >= 0.0 && opacity <= 1.0),
-       assert(alwaysIncludeSemantics != null),
+  }) : assert(opacity >= 0.0 && opacity <= 1.0),
        _opacity = opacity,
        _alwaysIncludeSemantics = alwaysIncludeSemantics,
        _alpha = ui.Color.getAlphaFromOpacity(opacity) {
@@ -131,7 +128,6 @@ class RenderSliverOpacity extends RenderProxySliver {
   double get opacity => _opacity;
   double _opacity;
   set opacity(double value) {
-    assert(value != null);
     assert(value >= 0.0 && value <= 1.0);
     if (_opacity == value) {
       return;
@@ -220,8 +216,7 @@ class RenderSliverIgnorePointer extends RenderProxySliver {
     RenderSliver? sliver,
     bool ignoring = true,
     bool? ignoringSemantics,
-  }) : assert(ignoring != null),
-       _ignoring = ignoring,
+  }) : _ignoring = ignoring,
        _ignoringSemantics = ignoringSemantics {
     child = sliver;
   }
@@ -233,7 +228,6 @@ class RenderSliverIgnorePointer extends RenderProxySliver {
   bool get ignoring => _ignoring;
   bool _ignoring;
   set ignoring(bool value) {
-    assert(value != null);
     if (value == _ignoring) {
       return;
     }
@@ -297,8 +291,7 @@ class RenderSliverOffstage extends RenderProxySliver {
   RenderSliverOffstage({
     bool offstage = true,
     RenderSliver? sliver,
-  }) : assert(offstage != null),
-       _offstage = offstage {
+  }) : _offstage = offstage {
     child = sliver;
   }
 
@@ -313,7 +306,6 @@ class RenderSliverOffstage extends RenderProxySliver {
   bool _offstage;
 
   set offstage(bool value) {
-    assert(value != null);
     if (value == _offstage) {
       return;
     }
@@ -401,8 +393,7 @@ class RenderSliverAnimatedOpacity extends RenderProxySliver with RenderAnimatedO
     required Animation<double> opacity,
     bool alwaysIncludeSemantics = false,
     RenderSliver? sliver,
-  }) : assert(opacity != null),
-       assert(alwaysIncludeSemantics != null) {
+  }) {
     this.opacity = opacity;
     this.alwaysIncludeSemantics = alwaysIncludeSemantics;
     child = sliver;

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

@@ -24,8 +24,7 @@ class RenderRotatedBox extends RenderBox with RenderObjectWithChildMixin<RenderB
   RenderRotatedBox({
     required int quarterTurns,
     RenderBox? child,
-  }) : assert(quarterTurns != null),
-       _quarterTurns = quarterTurns {
+  }) : _quarterTurns = quarterTurns {
     this.child = child;
   }
 
@@ -33,7 +32,6 @@ class RenderRotatedBox extends RenderBox with RenderObjectWithChildMixin<RenderB
   int get quarterTurns => _quarterTurns;
   int _quarterTurns;
   set quarterTurns(int value) {
-    assert(value != null);
     if (_quarterTurns == value) {
       return;
     }

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

@@ -687,9 +687,7 @@ class SelectionPoint {
     required this.localPosition,
     required this.lineHeight,
     required this.handleType,
-  }) : assert(localPosition != null),
-       assert(lineHeight != null),
-       assert(handleType != null);
+  });
 
   /// The position of the selection point in the local coordinates of the
   /// containing [Selectable].

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

@@ -107,8 +107,7 @@ class RenderPadding extends RenderShiftedBox {
     required EdgeInsetsGeometry padding,
     TextDirection? textDirection,
     RenderBox? child,
-  }) : assert(padding != null),
-       assert(padding.isNonNegative),
+  }) : assert(padding.isNonNegative),
        _textDirection = textDirection,
        _padding = padding,
        super(child);
@@ -135,7 +134,6 @@ class RenderPadding extends RenderShiftedBox {
   EdgeInsetsGeometry get padding => _padding;
   EdgeInsetsGeometry _padding;
   set padding(EdgeInsetsGeometry value) {
-    assert(value != null);
     assert(value.isNonNegative);
     if (_padding == value) {
       return;
@@ -277,8 +275,7 @@ abstract class RenderAligningShiftedBox extends RenderShiftedBox {
     AlignmentGeometry alignment = Alignment.center,
     required TextDirection? textDirection,
     RenderBox? child,
-  }) : assert(alignment != null),
-       _alignment = alignment,
+  }) : _alignment = alignment,
        _textDirection = textDirection,
        super(child);
 
@@ -314,7 +311,6 @@ abstract class RenderAligningShiftedBox extends RenderShiftedBox {
   ///
   /// The new alignment must not be null.
   set alignment(AlignmentGeometry value) {
-    assert(value != null);
     if (_alignment == value) {
       return;
     }
@@ -697,10 +693,7 @@ class RenderConstraintsTransformBox extends RenderAligningShiftedBox with DebugO
     required BoxConstraintsTransform constraintsTransform,
     super.child,
     Clip clipBehavior = Clip.none,
-  }) : assert(alignment != null),
-       assert(clipBehavior != null),
-       assert(constraintsTransform != null),
-       _constraintsTransform = constraintsTransform,
+  }) : _constraintsTransform = constraintsTransform,
        _clipBehavior = clipBehavior;
 
   /// {@macro flutter.widgets.constraintsTransform}
@@ -729,7 +722,6 @@ class RenderConstraintsTransformBox extends RenderAligningShiftedBox with DebugO
   Clip get clipBehavior => _clipBehavior;
   Clip _clipBehavior;
   set clipBehavior(Clip value) {
-    assert(value != null);
     if (value != _clipBehavior) {
       _clipBehavior = value;
       markNeedsPaint();
@@ -783,7 +775,6 @@ class RenderConstraintsTransformBox extends RenderAligningShiftedBox with DebugO
     final RenderBox? child = this.child;
     if (child != null) {
       final BoxConstraints childConstraints = constraintsTransform(constraints);
-      assert(childConstraints != null);
       assert(childConstraints.isNormalized, '$childConstraints is not normalized');
       _childConstraints = childConstraints;
       child.layout(childConstraints, parentUsesSize: true);
@@ -896,14 +887,12 @@ class RenderSizedOverflowBox extends RenderAligningShiftedBox {
     required Size requestedSize,
     super.alignment,
     super.textDirection,
-  }) : assert(requestedSize != null),
-       _requestedSize = requestedSize;
+  }) : _requestedSize = requestedSize;
 
   /// The size this render box should attempt to be.
   Size get requestedSize => _requestedSize;
   Size _requestedSize;
   set requestedSize(Size value) {
-    assert(value != null);
     if (_requestedSize == value) {
       return;
     }
@@ -1212,15 +1201,13 @@ class RenderCustomSingleChildLayoutBox extends RenderShiftedBox {
   RenderCustomSingleChildLayoutBox({
     RenderBox? child,
     required SingleChildLayoutDelegate delegate,
-  }) : assert(delegate != null),
-       _delegate = delegate,
+  }) : _delegate = delegate,
        super(child);
 
   /// A delegate that controls this object's layout.
   SingleChildLayoutDelegate get delegate => _delegate;
   SingleChildLayoutDelegate _delegate;
   set delegate(SingleChildLayoutDelegate newDelegate) {
-    assert(newDelegate != null);
     if (_delegate == newDelegate) {
       return;
     }
@@ -1333,9 +1320,7 @@ class RenderBaseline extends RenderShiftedBox {
     RenderBox? child,
     required double baseline,
     required TextBaseline baselineType,
-  }) : assert(baseline != null),
-       assert(baselineType != null),
-       _baseline = baseline,
+  }) : _baseline = baseline,
        _baselineType = baselineType,
        super(child);
 
@@ -1344,7 +1329,6 @@ class RenderBaseline extends RenderShiftedBox {
   double get baseline => _baseline;
   double _baseline;
   set baseline(double value) {
-    assert(value != null);
     if (_baseline == value) {
       return;
     }
@@ -1356,7 +1340,6 @@ class RenderBaseline extends RenderShiftedBox {
   TextBaseline get baselineType => _baselineType;
   TextBaseline _baselineType;
   set baselineType(TextBaseline value) {
-    assert(value != null);
     if (_baselineType == value) {
       return;
     }

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

@@ -32,8 +32,7 @@ class RenderSliverFillViewport extends RenderSliverFixedExtentBoxAdaptor {
   RenderSliverFillViewport({
     required super.childManager,
     double viewportFraction = 1.0,
-  }) : assert(viewportFraction != null),
-       assert(viewportFraction > 0.0),
+  }) : assert(viewportFraction > 0.0),
        _viewportFraction = viewportFraction;
 
   @override
@@ -47,7 +46,6 @@ class RenderSliverFillViewport extends RenderSliverFixedExtentBoxAdaptor {
   double get viewportFraction => _viewportFraction;
   double _viewportFraction;
   set viewportFraction(double value) {
-    assert(value != null);
     if (_viewportFraction == value) {
       return;
     }

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

@@ -257,7 +257,6 @@ abstract class RenderSliverFixedExtentBoxAdaptor extends RenderSliverMultiBoxAda
         child.layout(childConstraints);
       }
       trailingChildWithLayout = child;
-      assert(child != null);
       final SliverMultiBoxAdaptorParentData childParentData = child.parentData! as SliverMultiBoxAdaptorParentData;
       assert(childParentData.index == index);
       childParentData.layoutOffset = indexToLayoutOffset(itemExtent, childParentData.index!);
@@ -351,7 +350,6 @@ class RenderSliverFixedExtentList extends RenderSliverFixedExtentBoxAdaptor {
   double get itemExtent => _itemExtent;
   double _itemExtent;
   set itemExtent(double value) {
-    assert(value != null);
     if (_itemExtent == value) {
       return;
     }

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

@@ -155,12 +155,11 @@ class SliverGridRegularTileLayout extends SliverGridLayout {
     required this.childMainAxisExtent,
     required this.childCrossAxisExtent,
     required this.reverseCrossAxis,
-  }) : assert(crossAxisCount != null && crossAxisCount > 0),
-       assert(mainAxisStride != null && mainAxisStride >= 0),
-       assert(crossAxisStride != null && crossAxisStride >= 0),
-       assert(childMainAxisExtent != null && childMainAxisExtent >= 0),
-       assert(childCrossAxisExtent != null && childCrossAxisExtent >= 0),
-       assert(reverseCrossAxis != null);
+  }) : assert(crossAxisCount > 0),
+       assert(mainAxisStride >= 0),
+       assert(crossAxisStride >= 0),
+       assert(childMainAxisExtent >= 0),
+       assert(childCrossAxisExtent >= 0);
 
   /// The number of children in the cross axis.
   final int crossAxisCount;
@@ -226,7 +225,6 @@ class SliverGridRegularTileLayout extends SliverGridLayout {
 
   @override
   double computeMaxScrollOffset(int childCount) {
-    assert(childCount != null);
     final int mainAxisCount = ((childCount - 1) ~/ crossAxisCount) + 1;
     final double mainAxisSpacing = mainAxisStride - childMainAxisExtent;
     return mainAxisStride * mainAxisCount - mainAxisSpacing;
@@ -317,10 +315,10 @@ class SliverGridDelegateWithFixedCrossAxisCount extends SliverGridDelegate {
     this.crossAxisSpacing = 0.0,
     this.childAspectRatio = 1.0,
     this.mainAxisExtent,
-  }) : assert(crossAxisCount != null && crossAxisCount > 0),
-       assert(mainAxisSpacing != null && mainAxisSpacing >= 0),
-       assert(crossAxisSpacing != null && crossAxisSpacing >= 0),
-       assert(childAspectRatio != null && childAspectRatio > 0);
+  }) : assert(crossAxisCount > 0),
+       assert(mainAxisSpacing >= 0),
+       assert(crossAxisSpacing >= 0),
+       assert(childAspectRatio > 0);
 
   /// The number of children in the cross axis.
   final int crossAxisCount;
@@ -416,10 +414,10 @@ class SliverGridDelegateWithMaxCrossAxisExtent extends SliverGridDelegate {
     this.crossAxisSpacing = 0.0,
     this.childAspectRatio = 1.0,
     this.mainAxisExtent,
-  }) : assert(maxCrossAxisExtent != null && maxCrossAxisExtent > 0),
-       assert(mainAxisSpacing != null && mainAxisSpacing >= 0),
-       assert(crossAxisSpacing != null && crossAxisSpacing >= 0),
-       assert(childAspectRatio != null && childAspectRatio > 0);
+  }) : assert(maxCrossAxisExtent > 0),
+       assert(mainAxisSpacing >= 0),
+       assert(crossAxisSpacing >= 0),
+       assert(childAspectRatio > 0);
 
   /// The maximum extent of tiles in the cross axis.
   ///
@@ -525,8 +523,7 @@ class RenderSliverGrid extends RenderSliverMultiBoxAdaptor {
   RenderSliverGrid({
     required super.childManager,
     required SliverGridDelegate gridDelegate,
-  }) : assert(gridDelegate != null),
-       _gridDelegate = gridDelegate;
+  }) : _gridDelegate = gridDelegate;
 
   @override
   void setupParentData(RenderObject child) {
@@ -539,7 +536,6 @@ class RenderSliverGrid extends RenderSliverMultiBoxAdaptor {
   SliverGridDelegate get gridDelegate => _gridDelegate;
   SliverGridDelegate _gridDelegate;
   set gridDelegate(SliverGridDelegate value) {
-    assert(value != null);
     if (_gridDelegate == value) {
       return;
     }
@@ -640,7 +636,6 @@ class RenderSliverGrid extends RenderSliverMultiBoxAdaptor {
         child.layout(childConstraints);
       }
       trailingChildWithLayout = child;
-      assert(child != null);
       final SliverGridParentData childParentData = child.parentData! as SliverGridParentData;
       childParentData.layoutOffset = gridGeometry.scrollOffset;
       childParentData.crossAxisOffset = gridGeometry.crossAxisOffset;

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

@@ -188,8 +188,7 @@ abstract class RenderSliverMultiBoxAdaptor extends RenderSliver
   /// The [childManager] argument must not be null.
   RenderSliverMultiBoxAdaptor({
     required RenderSliverBoxChildManager childManager,
-  }) : assert(childManager != null),
-       _childManager = childManager {
+  }) : _childManager = childManager {
     assert(() {
       _debugDanglingKeepAlives = <RenderBox>[];
       return true;
@@ -229,7 +228,6 @@ abstract class RenderSliverMultiBoxAdaptor extends RenderSliver
   bool get debugChildIntegrityEnabled => _debugChildIntegrityEnabled;
   bool _debugChildIntegrityEnabled = true;
   set debugChildIntegrityEnabled(bool enabled) {
-    assert(enabled != null);
     assert(() {
       _debugChildIntegrityEnabled = enabled;
       return _debugVerifyChildOrder() &&
@@ -536,7 +534,6 @@ abstract class RenderSliverMultiBoxAdaptor extends RenderSliver
   /// Returns the index of the given child, as given by the
   /// [SliverMultiBoxAdaptorParentData.index] field of the child's [parentData].
   int indexOf(RenderBox child) {
-    assert(child != null);
     final SliverMultiBoxAdaptorParentData childParentData = child.parentData! as SliverMultiBoxAdaptorParentData;
     assert(childParentData.index != null);
     return childParentData.index!;
@@ -546,7 +543,6 @@ abstract class RenderSliverMultiBoxAdaptor extends RenderSliver
   /// child's [RenderBox.size] property. This is only valid after layout.
   @protected
   double paintExtentOf(RenderBox child) {
-    assert(child != null);
     assert(child.hasSize);
     switch (constraints.axis) {
       case Axis.horizontal:
@@ -576,7 +572,6 @@ abstract class RenderSliverMultiBoxAdaptor extends RenderSliver
 
   @override
   double? childScrollOffset(RenderObject child) {
-    assert(child != null);
     assert(child.parent == this);
     final SliverMultiBoxAdaptorParentData childParentData = child.parentData! as SliverMultiBoxAdaptorParentData;
     return childParentData.layoutOffset;
@@ -640,8 +635,6 @@ abstract class RenderSliverMultiBoxAdaptor extends RenderSliver
         addExtent = true;
         break;
     }
-    assert(mainAxisUnit != null);
-    assert(addExtent != null);
     RenderBox? child = firstChild;
     while (child != null) {
       final double mainAxisDelta = childMainAxisPosition(child);

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

@@ -35,9 +35,6 @@ abstract class RenderSliverEdgeInsetsPadding extends RenderSliver with RenderObj
   /// Only valid after layout has started, since before layout the render object
   /// doesn't know what direction it will be laid out in.
   double get beforePadding {
-    assert(constraints != null);
-    assert(constraints.axisDirection != null);
-    assert(constraints.growthDirection != null);
     assert(resolvedPadding != null);
     switch (applyGrowthDirectionToAxisDirection(constraints.axisDirection, constraints.growthDirection)) {
       case AxisDirection.up:
@@ -56,9 +53,6 @@ abstract class RenderSliverEdgeInsetsPadding extends RenderSliver with RenderObj
   /// Only valid after layout has started, since before layout the render object
   /// doesn't know what direction it will be laid out in.
   double get afterPadding {
-    assert(constraints != null);
-    assert(constraints.axisDirection != null);
-    assert(constraints.growthDirection != null);
     assert(resolvedPadding != null);
     switch (applyGrowthDirectionToAxisDirection(constraints.axisDirection, constraints.growthDirection)) {
       case AxisDirection.up:
@@ -79,8 +73,6 @@ abstract class RenderSliverEdgeInsetsPadding extends RenderSliver with RenderObj
   /// Only valid after layout has started, since before layout the render object
   /// doesn't know what direction it will be laid out in.
   double get mainAxisPadding {
-    assert(constraints != null);
-    assert(constraints.axis != null);
     assert(resolvedPadding != null);
     return resolvedPadding!.along(constraints.axis);
   }
@@ -92,8 +84,6 @@ abstract class RenderSliverEdgeInsetsPadding extends RenderSliver with RenderObj
   /// Only valid after layout has started, since before layout the render object
   /// doesn't know what direction it will be laid out in.
   double get crossAxisPadding {
-    assert(constraints != null);
-    assert(constraints.axis != null);
     assert(resolvedPadding != null);
     switch (constraints.axis) {
       case Axis.horizontal:
@@ -201,8 +191,6 @@ abstract class RenderSliverEdgeInsetsPadding extends RenderSliver with RenderObj
     );
 
     final SliverPhysicalParentData childParentData = child!.parentData! as SliverPhysicalParentData;
-    assert(constraints.axisDirection != null);
-    assert(constraints.growthDirection != null);
     switch (applyGrowthDirectionToAxisDirection(constraints.axisDirection, constraints.growthDirection)) {
       case AxisDirection.up:
         childParentData.paintOffset = Offset(resolvedPadding!.left, calculatePaintOffset(constraints, from: resolvedPadding!.bottom + childLayoutGeometry.scrollExtent, to: resolvedPadding!.bottom + childLayoutGeometry.scrollExtent + resolvedPadding!.top));
@@ -217,7 +205,6 @@ abstract class RenderSliverEdgeInsetsPadding extends RenderSliver with RenderObj
         childParentData.paintOffset = Offset(calculatePaintOffset(constraints, from: resolvedPadding!.right + childLayoutGeometry.scrollExtent, to: resolvedPadding!.right + childLayoutGeometry.scrollExtent + resolvedPadding!.left), resolvedPadding!.top);
         break;
     }
-    assert(childParentData.paintOffset != null);
     assert(beforePadding == this.beforePadding);
     assert(afterPadding == this.afterPadding);
     assert(mainAxisPadding == this.mainAxisPadding);
@@ -242,18 +229,13 @@ abstract class RenderSliverEdgeInsetsPadding extends RenderSliver with RenderObj
 
   @override
   double childMainAxisPosition(RenderSliver child) {
-    assert(child != null);
     assert(child == this.child);
     return calculatePaintOffset(constraints, from: 0.0, to: beforePadding);
   }
 
   @override
   double childCrossAxisPosition(RenderSliver child) {
-    assert(child != null);
     assert(child == this.child);
-    assert(constraints != null);
-    assert(constraints.axisDirection != null);
-    assert(constraints.growthDirection != null);
     assert(resolvedPadding != null);
     switch (applyGrowthDirectionToAxisDirection(constraints.axisDirection, constraints.growthDirection)) {
       case AxisDirection.up:
@@ -273,7 +255,6 @@ abstract class RenderSliverEdgeInsetsPadding extends RenderSliver with RenderObj
 
   @override
   void applyPaintTransform(RenderObject child, Matrix4 transform) {
-    assert(child != null);
     assert(child == this.child);
     final SliverPhysicalParentData childParentData = child.parentData! as SliverPhysicalParentData;
     childParentData.applyPaintTransform(transform);
@@ -326,8 +307,7 @@ class RenderSliverPadding extends RenderSliverEdgeInsetsPadding {
     required EdgeInsetsGeometry padding,
     TextDirection? textDirection,
     RenderSliver? child,
-  }) : assert(padding != null),
-       assert(padding.isNonNegative),
+  }) : assert(padding.isNonNegative),
        _padding = padding,
        _textDirection = textDirection {
     this.child = child;
@@ -357,7 +337,6 @@ class RenderSliverPadding extends RenderSliverEdgeInsetsPadding {
   EdgeInsetsGeometry get padding => _padding;
   EdgeInsetsGeometry _padding;
   set padding(EdgeInsetsGeometry value) {
-    assert(value != null);
     assert(padding.isNonNegative);
     if (_padding == value) {
       return;

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

@@ -37,7 +37,7 @@ class OverScrollHeaderStretchConfiguration {
   OverScrollHeaderStretchConfiguration({
     this.stretchTriggerOffset = 100.0,
     this.onStretchTrigger,
-  }) : assert(stretchTriggerOffset != null);
+  });
 
   /// The offset of overscroll required to trigger the [onStretchTrigger].
   final double stretchTriggerOffset;
@@ -152,7 +152,6 @@ abstract class RenderSliverPersistentHeader extends RenderSliver with RenderObje
       return 0.0;
     }
     assert(child!.hasSize);
-    assert(constraints.axis != null);
     switch (constraints.axis) {
       case Axis.vertical:
         return child!.size.height;
@@ -217,7 +216,6 @@ abstract class RenderSliverPersistentHeader extends RenderSliver with RenderObje
   /// The `overlapsContent` argument is passed to [updateChild].
   @protected
   void layoutChild(double scrollOffset, double maxExtent, { bool overlapsContent = false }) {
-    assert(maxExtent != null);
     final double shrinkOffset = math.min(scrollOffset, maxExtent);
     if (_needsUpdateChild || _lastShrinkOffset != shrinkOffset || _lastOverlapsContent != overlapsContent) {
       invokeLayoutCallback<SliverConstraints>((SliverConstraints constraints) {
@@ -228,7 +226,6 @@ abstract class RenderSliverPersistentHeader extends RenderSliver with RenderObje
       _lastOverlapsContent = overlapsContent;
       _needsUpdateChild = false;
     }
-    assert(minExtent != null);
     assert(() {
       if (minExtent <= maxExtent) {
         return true;
@@ -294,7 +291,6 @@ abstract class RenderSliverPersistentHeader extends RenderSliver with RenderObje
 
   @override
   void applyPaintTransform(RenderObject child, Matrix4 transform) {
-    assert(child != null);
     assert(child == this.child);
     applyPaintTransformForBoxChild(child as RenderBox, transform);
   }
@@ -302,7 +298,6 @@ abstract class RenderSliverPersistentHeader extends RenderSliver with RenderObje
   @override
   void paint(PaintingContext context, Offset offset) {
     if (child != null && geometry!.visible) {
-      assert(constraints.axisDirection != null);
       switch (applyGrowthDirectionToAxisDirection(constraints.axisDirection, constraints.growthDirection)) {
         case AxisDirection.up:
           offset += Offset(0.0, geometry!.paintExtent - childMainAxisPosition(child!) - childExtent);
@@ -496,8 +491,7 @@ class FloatingHeaderSnapConfiguration {
   FloatingHeaderSnapConfiguration({
     this.curve = Curves.ease,
     this.duration = const Duration(milliseconds: 300),
-  }) : assert(curve != null),
-       assert(duration != null);
+  });
 
   /// The snap animation curve.
   final Curve curve;
@@ -607,9 +601,6 @@ abstract class RenderSliverFloatingPersistentHeader extends RenderSliverPersiste
   }
 
   void _updateAnimation(Duration duration, double endValue, Curve curve) {
-    assert(duration != null);
-    assert(endValue != null);
-    assert(curve != null);
     assert(
       vsync != null,
       'vsync must not be null if the floating header changes size animatedly.',

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

@@ -25,8 +25,7 @@ class RelativeRect {
   /// Creates a RelativeRect with the given values.
   ///
   /// The arguments must not be null.
-  const RelativeRect.fromLTRB(this.left, this.top, this.right, this.bottom)
-    : assert(left != null && top != null && right != null && bottom != null);
+  const RelativeRect.fromLTRB(this.left, this.top, this.right, this.bottom);
 
   /// Creates a RelativeRect from a Rect and a Size. The Rect (first argument)
   /// and the RelativeRect (the output) are in the coordinate space of the
@@ -166,7 +165,6 @@ class RelativeRect {
   ///
   /// {@macro dart.ui.shadow.lerp}
   static RelativeRect? lerp(RelativeRect? a, RelativeRect? b, double t) {
-    assert(t != null);
     if (a == null && b == null) {
       return null;
     }
@@ -354,10 +352,7 @@ class RenderStack extends RenderBox
     TextDirection? textDirection,
     StackFit fit = StackFit.loose,
     Clip clipBehavior = Clip.hardEdge,
-  }) : assert(alignment != null),
-       assert(fit != null),
-       assert(clipBehavior != null),
-       _alignment = alignment,
+  }) : _alignment = alignment,
        _textDirection = textDirection,
        _fit = fit,
        _clipBehavior = clipBehavior {
@@ -405,7 +400,6 @@ class RenderStack extends RenderBox
   AlignmentGeometry get alignment => _alignment;
   AlignmentGeometry _alignment;
   set alignment(AlignmentGeometry value) {
-    assert(value != null);
     if (_alignment == value) {
       return;
     }
@@ -435,7 +429,6 @@ class RenderStack extends RenderBox
   StackFit get fit => _fit;
   StackFit _fit;
   set fit(StackFit value) {
-    assert(value != null);
     if (_fit != value) {
       _fit = value;
       markNeedsLayout();
@@ -448,7 +441,6 @@ class RenderStack extends RenderBox
   Clip get clipBehavior => _clipBehavior;
   Clip _clipBehavior = Clip.hardEdge;
   set clipBehavior(Clip value) {
-    assert(value != null);
     if (value != _clipBehavior) {
       _clipBehavior = value;
       markNeedsPaint();
@@ -571,7 +563,6 @@ class RenderStack extends RenderBox
     double height = constraints.minHeight;
 
     final BoxConstraints nonPositionedConstraints;
-    assert(fit != null);
     switch (fit) {
       case StackFit.loose:
         nonPositionedConstraints = constraints.loosen();
@@ -583,7 +574,6 @@ class RenderStack extends RenderBox
         nonPositionedConstraints = constraints;
         break;
     }
-    assert(nonPositionedConstraints != null);
 
     RenderBox? child = firstChild;
     while (child != null) {
@@ -755,7 +745,6 @@ class RenderIndexedStack extends RenderStack {
     if (firstChild == null || index == null) {
       return false;
     }
-    assert(position != null);
     final RenderBox child = _childAtIndex();
     final StackParentData childParentData = child.parentData! as StackParentData;
     return result.addWithPaintOffset(

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

@@ -134,7 +134,7 @@ class FixedColumnWidth extends TableColumnWidth {
   /// Creates a column width based on a fixed number of logical pixels.
   ///
   /// The [value] argument must not be null.
-  const FixedColumnWidth(this.value) : assert(value != null);
+  const FixedColumnWidth(this.value);
 
   /// The width the column should occupy in logical pixels.
   final double value;
@@ -161,7 +161,7 @@ class FractionColumnWidth extends TableColumnWidth {
   /// maxWidth.
   ///
   /// The [value] argument must not be null.
-  const FractionColumnWidth(this.value) : assert(value != null);
+  const FractionColumnWidth(this.value);
 
   /// The fraction of the table's constraints' maxWidth that this column should
   /// occupy.
@@ -199,7 +199,7 @@ class FlexColumnWidth extends TableColumnWidth {
   /// the other columns have been laid out.
   ///
   /// The [value] argument must not be null.
-  const FlexColumnWidth([this.value = 1.0]) : assert(value != null);
+  const FlexColumnWidth([this.value = 1.0]);
 
   /// The fraction of the remaining space once all the other columns have
   /// been laid out that this column should occupy.
@@ -388,9 +388,6 @@ class RenderTable extends RenderBox {
   }) : assert(columns == null || columns >= 0),
        assert(rows == null || rows >= 0),
        assert(rows == null || children == null),
-       assert(defaultColumnWidth != null),
-       assert(textDirection != null),
-       assert(configuration != null),
        _textDirection = textDirection,
        _columns = columns ?? (children != null && children.isNotEmpty ? children.first.length : 0),
        _rows = rows ?? 0,
@@ -419,7 +416,6 @@ class RenderTable extends RenderBox {
   int get columns => _columns;
   int _columns;
   set columns(int value) {
-    assert(value != null);
     assert(value >= 0);
     if (value == columns) {
       return;
@@ -454,7 +450,6 @@ class RenderTable extends RenderBox {
   int get rows => _rows;
   int _rows;
   set rows(int value) {
-    assert(value != null);
     assert(value >= 0);
     if (value == rows) {
       return;
@@ -513,7 +508,6 @@ class RenderTable extends RenderBox {
   TableColumnWidth get defaultColumnWidth => _defaultColumnWidth;
   TableColumnWidth _defaultColumnWidth;
   set defaultColumnWidth(TableColumnWidth value) {
-    assert(value != null);
     if (defaultColumnWidth == value) {
       return;
     }
@@ -525,7 +519,6 @@ class RenderTable extends RenderBox {
   TextDirection get textDirection => _textDirection;
   TextDirection _textDirection;
   set textDirection(TextDirection value) {
-    assert(value != null);
     if (_textDirection == value) {
       return;
     }
@@ -573,7 +566,6 @@ class RenderTable extends RenderBox {
   ImageConfiguration get configuration => _configuration;
   ImageConfiguration _configuration;
   set configuration(ImageConfiguration value) {
-    assert(value != null);
     if (value == _configuration) {
       return;
     }
@@ -585,7 +577,6 @@ class RenderTable extends RenderBox {
   TableCellVerticalAlignment get defaultVerticalAlignment => _defaultVerticalAlignment;
   TableCellVerticalAlignment _defaultVerticalAlignment;
   set defaultVerticalAlignment(TableCellVerticalAlignment value) {
-    assert(value != null);
     if (_defaultVerticalAlignment == value) {
       return;
     }
@@ -626,7 +617,7 @@ class RenderTable extends RenderBox {
     assert(columns >= 0);
     // consider the case of a newly empty table
     if (columns == 0 || cells.isEmpty) {
-      assert(cells == null || cells.isEmpty);
+      assert(cells.isEmpty);
       _columns = columns;
       if (_children.isEmpty) {
         assert(_rows == 0);
@@ -642,7 +633,6 @@ class RenderTable extends RenderBox {
       markNeedsLayout();
       return;
     }
-    assert(cells != null);
     assert(cells.length % columns == 0);
     // fill a set with the cells that are moving (it's important not
     // to dropChild a child that's remaining with us, because that
@@ -722,8 +712,6 @@ class RenderTable extends RenderBox {
   /// does not modify the table. Otherwise, the given child must not already
   /// have a parent.
   void setChild(int x, int y, RenderBox? value) {
-    assert(x != null);
-    assert(y != null);
     assert(x >= 0 && x < columns && y >= 0 && y < rows);
     assert(_children.length == rows * columns);
     final int xy = x + y * columns;
@@ -864,7 +852,6 @@ class RenderTable extends RenderBox {
   }
 
   List<double> _computeColumnWidths(BoxConstraints constraints) {
-    assert(constraints != null);
     assert(_children.length == rows * columns);
     // We apply the constraints to the column widths in the order of
     // least important to most important:
@@ -1061,7 +1048,6 @@ class RenderTable extends RenderBox {
         final RenderBox? child = _children[xy];
         if (child != null) {
           final TableCellParentData childParentData = child.parentData! as TableCellParentData;
-          assert(childParentData != null);
           switch (childParentData.verticalAlignment ?? defaultVerticalAlignment) {
             case TableCellVerticalAlignment.baseline:
               assert(debugCannotComputeDryLayout(
@@ -1133,7 +1119,6 @@ class RenderTable extends RenderBox {
         final RenderBox? child = _children[xy];
         if (child != null) {
           final TableCellParentData childParentData = child.parentData! as TableCellParentData;
-          assert(childParentData != null);
           childParentData.x = x;
           childParentData.y = y;
           switch (childParentData.verticalAlignment ?? defaultVerticalAlignment) {

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

@@ -89,12 +89,6 @@ class TableBorder {
   /// Whether all the sides of the border (outside and inside) are identical.
   /// Uniform borders are typically more efficient to paint.
   bool get isUniform {
-    assert(top != null);
-    assert(right != null);
-    assert(bottom != null);
-    assert(left != null);
-    assert(horizontalInside != null);
-    assert(verticalInside != null);
 
     final Color topColor = top.color;
     if (right.color != topColor ||
@@ -159,7 +153,6 @@ class TableBorder {
   ///
   /// {@macro dart.ui.shadow.lerp}
   static TableBorder? lerp(TableBorder? a, TableBorder? b, double t) {
-    assert(t != null);
     if (a == null && b == null) {
       return null;
     }
@@ -212,19 +205,9 @@ class TableBorder {
     required Iterable<double> columns,
   }) {
     // properties can't be null
-    assert(top != null);
-    assert(right != null);
-    assert(bottom != null);
-    assert(left != null);
-    assert(horizontalInside != null);
-    assert(verticalInside != null);
 
     // arguments can't be null
-    assert(canvas != null);
-    assert(rect != null);
-    assert(rows != null);
     assert(rows.isEmpty || (rows.first >= 0.0 && rows.last <= rect.height));
-    assert(columns != null);
     assert(columns.isEmpty || (columns.first >= 0.0 && columns.last <= rect.width));
 
     if (columns.isNotEmpty || rows.isNotEmpty) {

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

@@ -40,8 +40,7 @@ class TextureBox extends RenderBox {
     required int textureId,
     bool freeze = false,
     FilterQuality filterQuality = FilterQuality.low,
-  }) : assert(textureId != null),
-      _textureId = textureId,
+  }) : _textureId = textureId,
       _freeze = freeze,
       _filterQuality = filterQuality;
 
@@ -49,7 +48,6 @@ class TextureBox extends RenderBox {
   int get textureId => _textureId;
   int _textureId;
   set textureId(int value) {
-    assert(value != null);
     if (value != _textureId) {
       _textureId = value;
       markNeedsPaint();
@@ -60,7 +58,6 @@ class TextureBox extends RenderBox {
   bool get freeze => _freeze;
   bool _freeze;
   set freeze(bool value) {
-    assert(value != null);
     if (value != _freeze) {
       _freeze = value;
       markNeedsPaint();
@@ -71,7 +68,6 @@ class TextureBox extends RenderBox {
   FilterQuality get filterQuality => _filterQuality;
   FilterQuality _filterQuality;
   set filterQuality(FilterQuality value) {
-    assert(value != null);
     if (value != _filterQuality) {
       _filterQuality = value;
       markNeedsPaint();

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

@@ -69,8 +69,7 @@ class RenderView extends RenderObject with RenderObjectWithChildMixin<RenderBox>
     RenderBox? child,
     required ViewConfiguration configuration,
     required ui.FlutterView window,
-  }) : assert(configuration != null),
-       _configuration = configuration,
+  }) : _configuration = configuration,
        _window = window {
     this.child = child;
   }
@@ -88,7 +87,6 @@ class RenderView extends RenderObject with RenderObjectWithChildMixin<RenderBox>
   ///
   /// Always call [prepareInitialFrame] before changing the configuration.
   set configuration(ViewConfiguration value) {
-    assert(value != null);
     if (configuration == value) {
       return;
     }
@@ -201,7 +199,6 @@ class RenderView extends RenderObject with RenderObjectWithChildMixin<RenderBox>
   ///  * [Layer.findAllAnnotations], which is used by this method to find all
   ///    [AnnotatedRegionLayer]s annotated for mouse tracking.
   HitTestResult hitTestMouseTrackers(Offset position) {
-    assert(position != null);
     final BoxHitTestResult result = BoxHitTestResult();
     hitTest(result, position: position);
     return result;

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

@@ -196,7 +196,6 @@ abstract class ViewportOffset extends ChangeNotifier {
     Curve? curve,
     bool? clamp,
   }) {
-    assert(to != null);
     if (duration == null || duration == Duration.zero) {
       jumpTo(to);
       return Future<void>.value();

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

@@ -121,14 +121,7 @@ class RenderWrap extends RenderBox
     TextDirection? textDirection,
     VerticalDirection verticalDirection = VerticalDirection.down,
     Clip clipBehavior = Clip.none,
-  }) : assert(direction != null),
-       assert(alignment != null),
-       assert(spacing != null),
-       assert(runAlignment != null),
-       assert(runSpacing != null),
-       assert(crossAxisAlignment != null),
-       assert(clipBehavior != null),
-       _direction = direction,
+  }) : _direction = direction,
        _alignment = alignment,
        _spacing = spacing,
        _runAlignment = runAlignment,
@@ -149,7 +142,6 @@ class RenderWrap extends RenderBox
   Axis get direction => _direction;
   Axis _direction;
   set direction (Axis value) {
-    assert(value != null);
     if (_direction == value) {
       return;
     }
@@ -173,7 +165,6 @@ class RenderWrap extends RenderBox
   WrapAlignment get alignment => _alignment;
   WrapAlignment _alignment;
   set alignment (WrapAlignment value) {
-    assert(value != null);
     if (_alignment == value) {
       return;
     }
@@ -195,7 +186,6 @@ class RenderWrap extends RenderBox
   double get spacing => _spacing;
   double _spacing;
   set spacing (double value) {
-    assert(value != null);
     if (_spacing == value) {
       return;
     }
@@ -220,7 +210,6 @@ class RenderWrap extends RenderBox
   WrapAlignment get runAlignment => _runAlignment;
   WrapAlignment _runAlignment;
   set runAlignment (WrapAlignment value) {
-    assert(value != null);
     if (_runAlignment == value) {
       return;
     }
@@ -241,7 +230,6 @@ class RenderWrap extends RenderBox
   double get runSpacing => _runSpacing;
   double _runSpacing;
   set runSpacing (double value) {
-    assert(value != null);
     if (_runSpacing == value) {
       return;
     }
@@ -267,7 +255,6 @@ class RenderWrap extends RenderBox
   WrapCrossAlignment get crossAxisAlignment => _crossAxisAlignment;
   WrapCrossAlignment _crossAxisAlignment;
   set crossAxisAlignment (WrapCrossAlignment value) {
-    assert(value != null);
     if (_crossAxisAlignment == value) {
       return;
     }
@@ -344,7 +331,6 @@ class RenderWrap extends RenderBox
   Clip get clipBehavior => _clipBehavior;
   Clip _clipBehavior = Clip.none;
   set clipBehavior(Clip value) {
-    assert(value != null);
     if (value != _clipBehavior) {
       _clipBehavior = value;
       markNeedsPaint();
@@ -353,10 +339,6 @@ class RenderWrap extends RenderBox
   }
 
   bool get _debugHasNecessaryDirections {
-    assert(direction != null);
-    assert(alignment != null);
-    assert(runAlignment != null);
-    assert(crossAxisAlignment != null);
     if (firstChild != null && lastChild != firstChild) {
       // i.e. there's more than one child
       switch (direction) {
@@ -364,7 +346,6 @@ class RenderWrap extends RenderBox
           assert(textDirection != null, 'Horizontal $runtimeType with multiple children has a null textDirection, so the layout order is undefined.');
           break;
         case Axis.vertical:
-          assert(verticalDirection != null, 'Vertical $runtimeType with multiple children has a null verticalDirection, so the layout order is undefined.');
           break;
       }
     }
@@ -374,14 +355,12 @@ class RenderWrap extends RenderBox
           assert(textDirection != null, 'Horizontal $runtimeType with alignment $alignment has a null textDirection, so the alignment cannot be resolved.');
           break;
         case Axis.vertical:
-          assert(verticalDirection != null, 'Vertical $runtimeType with alignment $alignment has a null verticalDirection, so the alignment cannot be resolved.');
           break;
       }
     }
     if (runAlignment == WrapAlignment.start || runAlignment == WrapAlignment.end) {
       switch (direction) {
         case Axis.horizontal:
-          assert(verticalDirection != null, 'Horizontal $runtimeType with runAlignment $runAlignment has a null verticalDirection, so the alignment cannot be resolved.');
           break;
         case Axis.vertical:
           assert(textDirection != null, 'Vertical $runtimeType with runAlignment $runAlignment has a null textDirection, so the alignment cannot be resolved.');
@@ -391,7 +370,6 @@ class RenderWrap extends RenderBox
     if (crossAxisAlignment == WrapCrossAlignment.start || crossAxisAlignment == WrapCrossAlignment.end) {
       switch (direction) {
         case Axis.horizontal:
-          assert(verticalDirection != null, 'Horizontal $runtimeType with crossAxisAlignment $crossAxisAlignment has a null verticalDirection, so the alignment cannot be resolved.');
           break;
         case Axis.vertical:
           assert(textDirection != null, 'Vertical $runtimeType with crossAxisAlignment $crossAxisAlignment has a null textDirection, so the alignment cannot be resolved.');
@@ -610,8 +588,6 @@ class RenderWrap extends RenderBox
         }
         break;
     }
-    assert(childConstraints != null);
-    assert(mainAxisLimit != null);
     final double spacing = this.spacing;
     final double runSpacing = this.runSpacing;
     final List<_RunMetrics> runMetrics = <_RunMetrics>[];