diff --git a/packages/flutter/lib/src/material/bottom_navigation_bar.dart b/packages/flutter/lib/src/material/bottom_navigation_bar.dart
index aca0a99..bb3595d 100644
--- a/packages/flutter/lib/src/material/bottom_navigation_bar.dart
+++ b/packages/flutter/lib/src/material/bottom_navigation_bar.dart
@@ -985,8 +985,7 @@
         unselectedLabelStyle: effectiveUnselectedLabelStyle,
         enableFeedback: widget.enableFeedback ?? bottomTheme.enableFeedback ?? true,
         onTap: () {
-          if (widget.onTap != null)
-            widget.onTap!(i);
+          widget.onTap?.call(i);
         },
         colorTween: colorTween,
         flex: _evaluateFlex(_animations[i]),
diff --git a/packages/flutter/lib/src/material/data_table.dart b/packages/flutter/lib/src/material/data_table.dart
index 2987e12..9c20486 100644
--- a/packages/flutter/lib/src/material/data_table.dart
+++ b/packages/flutter/lib/src/material/data_table.dart
@@ -1018,7 +1018,7 @@
         tableRows[rowIndex].children![0] = _buildCheckbox(
           context: context,
           checked: row.selected,
-          onRowTap: () => row.onSelectChanged != null ? row.onSelectChanged!(!row.selected) : null ,
+          onRowTap: () => row.onSelectChanged?.call(!row.selected),
           onCheckboxChanged: row.onSelectChanged,
           overlayColor: row.color ?? effectiveDataRowColor,
           tristate: false,
@@ -1084,7 +1084,7 @@
           onLongPress: cell.onLongPress,
           onTapCancel: cell.onTapCancel,
           onTapDown: cell.onTapDown,
-          onSelectChanged: () => row.onSelectChanged != null ? row.onSelectChanged!(!row.selected) : null,
+          onSelectChanged: () => row.onSelectChanged?.call(!row.selected),
           overlayColor: row.color ?? effectiveDataRowColor,
         );
         rowIndex += 1;
diff --git a/packages/flutter/lib/src/material/drawer.dart b/packages/flutter/lib/src/material/drawer.dart
index 56cb976..cf9d1b0 100644
--- a/packages/flutter/lib/src/material/drawer.dart
+++ b/packages/flutter/lib/src/material/drawer.dart
@@ -460,13 +460,11 @@
       switch (Directionality.of(context)) {
         case TextDirection.rtl:
           _controller.fling(velocity: -visualVelocity);
-          if (widget.drawerCallback != null)
-            widget.drawerCallback!(visualVelocity < 0.0);
+          widget.drawerCallback?.call(visualVelocity < 0.0);
           break;
         case TextDirection.ltr:
           _controller.fling(velocity: visualVelocity);
-          if (widget.drawerCallback != null)
-            widget.drawerCallback!(visualVelocity > 0.0);
+          widget.drawerCallback?.call(visualVelocity > 0.0);
           break;
       }
     } else if (_controller.value < 0.5) {
@@ -481,15 +479,13 @@
   /// Typically called by [ScaffoldState.openDrawer].
   void open() {
     _controller.fling(velocity: 1.0);
-    if (widget.drawerCallback != null)
-      widget.drawerCallback!(true);
+    widget.drawerCallback?.call(true);
   }
 
   /// Starts an animation to close the drawer.
   void close() {
     _controller.fling(velocity: -1.0);
-    if (widget.drawerCallback != null)
-      widget.drawerCallback!(false);
+    widget.drawerCallback?.call(false);
   }
 
   late ColorTween _scrimColorTween;
diff --git a/packages/flutter/lib/src/material/ink_well.dart b/packages/flutter/lib/src/material/ink_well.dart
index 7c54573..a13f7e9 100644
--- a/packages/flutter/lib/src/material/ink_well.dart
+++ b/packages/flutter/lib/src/material/ink_well.dart
@@ -865,12 +865,11 @@
 
     switch (type) {
       case _HighlightType.pressed:
-        if (widget.onHighlightChanged != null)
-          widget.onHighlightChanged!(value);
+        widget.onHighlightChanged?.call(value);
         break;
       case _HighlightType.hover:
-        if (callOnHover && widget.onHover != null)
-          widget.onHover!(value);
+        if (callOnHover)
+          widget.onHover?.call(value);
         break;
       case _HighlightType.focus:
         break;
@@ -951,18 +950,14 @@
   void _handleFocusUpdate(bool hasFocus) {
     _hasFocus = hasFocus;
     _updateFocusHighlights();
-    if (widget.onFocusChange != null) {
-      widget.onFocusChange!(hasFocus);
-    }
+    widget.onFocusChange?.call(hasFocus);
   }
 
   void _handleTapDown(TapDownDetails details) {
     if (_anyChildInkResponsePressed)
       return;
     _startSplash(details: details);
-    if (widget.onTapDown != null) {
-      widget.onTapDown!(details);
-    }
+    widget.onTapDown?.call(details);
   }
 
   void _startSplash({TapDownDetails? details, BuildContext? context}) {
@@ -991,24 +986,21 @@
     if (widget.onTap != null) {
       if (widget.enableFeedback)
         Feedback.forTap(context);
-      widget.onTap!();
+      widget.onTap?.call();
     }
   }
 
   void _handleTapCancel() {
     _currentSplash?.cancel();
     _currentSplash = null;
-    if (widget.onTapCancel != null) {
-      widget.onTapCancel!();
-    }
+    widget.onTapCancel?.call();
     updateHighlight(_HighlightType.pressed, value: false);
   }
 
   void _handleDoubleTap() {
     _currentSplash?.confirm();
     _currentSplash = null;
-    if (widget.onDoubleTap != null)
-      widget.onDoubleTap!();
+    widget.onDoubleTap?.call();
   }
 
   void _handleLongPress() {
diff --git a/packages/flutter/lib/src/material/selectable_text.dart b/packages/flutter/lib/src/material/selectable_text.dart
index 2088be8..5b846d4 100644
--- a/packages/flutter/lib/src/material/selectable_text.dart
+++ b/packages/flutter/lib/src/material/selectable_text.dart
@@ -94,8 +94,7 @@
           break;
       }
     }
-    if (_state.widget.onTap != null)
-      _state.widget.onTap!();
+    _state.widget.onTap?.call();
   }
 
   @override
diff --git a/packages/flutter/lib/src/rendering/object.dart b/packages/flutter/lib/src/rendering/object.dart
index 6afdfe0..4208bb3 100644
--- a/packages/flutter/lib/src/rendering/object.dart
+++ b/packages/flutter/lib/src/rendering/object.dart
@@ -176,8 +176,7 @@
     assert(() {
       if (debugProfilePaintsEnabled)
         Timeline.startSync('${child.runtimeType}', arguments: timelineArgumentsIndicatingLandmarkEvent);
-      if (debugOnProfilePaint != null)
-        debugOnProfilePaint!(child);
+      debugOnProfilePaint?.call(child);
       return true;
     }());
 
@@ -830,8 +829,7 @@
   /// Used to notify the pipeline owner that an associated render object wishes
   /// to update its visual appearance.
   void requestVisualUpdate() {
-    if (onNeedVisualUpdate != null)
-      onNeedVisualUpdate!();
+    onNeedVisualUpdate?.call();
   }
 
   /// The unique object managed by this pipeline that has no parent.
@@ -1029,8 +1027,7 @@
     if (_outstandingSemanticsHandles == 1) {
       assert(_semanticsOwner == null);
       _semanticsOwner = SemanticsOwner();
-      if (onSemanticsOwnerCreated != null)
-        onSemanticsOwnerCreated!();
+      onSemanticsOwnerCreated?.call();
     }
     return SemanticsHandle._(this, listener);
   }
@@ -1041,8 +1038,7 @@
     if (_outstandingSemanticsHandles == 0) {
       _semanticsOwner!.dispose();
       _semanticsOwner = null;
-      if (onSemanticsOwnerDisposed != null)
-        onSemanticsOwnerDisposed!();
+      onSemanticsOwnerDisposed?.call();
     }
   }