[SelectionOverlay]Move the debug statement to the scope of the assertion. (#108508)

examples/api/lib/widgets/overlay/overlay.0.dart

@@ -132,7 +132,7 @@ class _OverlayExampleState extends State<OverlayExample> {
     );
 
     // Add the OverlayEntry to the Overlay.
-    Overlay.of(context)!.insert(overlayEntry!);
+    Overlay.of(context, debugRequiredFor: widget)!.insert(overlayEntry!);
   }
 
   // Remove the OverlayEntry.

packages/flutter/lib/src/cupertino/context_menu.dart

@@ -363,7 +363,7 @@ class _CupertinoContextMenuState extends State<CupertinoContextMenu> with Ticker
         );
       },
     );
-    Overlay.of(context, rootOverlay: true)!.insert(_lastOverlayEntry!);
+    Overlay.of(context, rootOverlay: true, debugRequiredFor: widget)!.insert(_lastOverlayEntry!);
     _openController.forward();
   }
 

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

@@ -1004,7 +1004,7 @@ class _BottomNavigationBarState extends State<BottomNavigationBar> with TickerPr
     assert(debugCheckHasDirectionality(context));
     assert(debugCheckHasMaterialLocalizations(context));
     assert(debugCheckHasMediaQuery(context));
-    assert(Overlay.of(context, debugRequiredFor: widget) != null);
+    assert(debugCheckHasOverlay(context));
 
     final BottomNavigationBarThemeData bottomTheme = BottomNavigationBarTheme.of(context);
     final BottomNavigationBarLandscapeLayout layout = widget.landscapeLayout

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

@@ -655,7 +655,7 @@ class _RangeSliderState extends State<RangeSlider> with TickerProviderStateMixin
           );
         },
       );
-      Overlay.of(context)!.insert(overlayEntry!);
+      Overlay.of(context, debugRequiredFor: widget)!.insert(overlayEntry!);
     }
   }
 }

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

@@ -842,7 +842,7 @@ class _SliderState extends State<Slider> with TickerProviderStateMixin {
           );
         },
       );
-      Overlay.of(context)!.insert(overlayEntry!);
+      Overlay.of(context, debugRequiredFor: widget)!.insert(overlayEntry!);
     }
   }
 }

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

@@ -698,7 +698,7 @@ class TooltipState extends State<Tooltip> with SingleTickerProviderStateMixin {
     if (_tooltipMessage.isEmpty) {
       return widget.child ?? const SizedBox();
     }
-    assert(Overlay.of(context, debugRequiredFor: widget) != null);
+    assert(debugCheckHasOverlay(context));
     final ThemeData theme = Theme.of(context);
     final TooltipThemeData tooltipTheme = TooltipTheme.of(context);
     final TextStyle defaultTextStyle;

packages/flutter/lib/src/widgets/autocomplete.dart

@@ -432,7 +432,7 @@ class _RawAutocompleteState<T extends Object> extends State<RawAutocomplete<T>>
           );
         },
       );
-      Overlay.of(context, rootOverlay: true)!.insert(newFloatingOptions);
+      Overlay.of(context, rootOverlay: true, debugRequiredFor: widget)!.insert(newFloatingOptions);
       _floatingOptions = newFloatingOptions;
     } else {
       _floatingOptions = null;

packages/flutter/lib/src/widgets/drag_target.dart

@@ -9,6 +9,7 @@ import 'package:flutter/services.dart';
 
 import 'basic.dart';
 import 'binding.dart';
+import 'debug.dart';
 import 'framework.dart';
 import 'media_query.dart';
 import 'overlay.dart';
@@ -598,7 +599,7 @@ class _DraggableState<T extends Object> extends State<Draggable<T>> {
 
   @override
   Widget build(BuildContext context) {
-    assert(Overlay.of(context, debugRequiredFor: widget, rootOverlay: widget.rootOverlay) != null);
+    assert(debugCheckHasOverlay(context));
     final bool canDrag = widget.maxSimultaneousDrags == null ||
                          _activeCount < widget.maxSimultaneousDrags!;
     final bool showChild = _activeCount == 0 || widget.childWhenDragging == null;

packages/flutter/lib/src/widgets/reorderable_list.dart

@@ -702,7 +702,7 @@ class SliverReorderableListState extends State<SliverReorderableList> with Ticke
     );
     _dragInfo!.startDrag();
 
-    final OverlayState overlay = Overlay.of(context)!;
+    final OverlayState overlay = Overlay.of(context, debugRequiredFor: widget)!;
     assert(_overlayEntry == null);
     _overlayEntry = OverlayEntry(builder: _dragInfo!.createProxy);
     overlay.insert(_overlayEntry!);
@@ -897,7 +897,7 @@ class SliverReorderableListState extends State<SliverReorderableList> with Ticke
     }
     final Widget child = widget.itemBuilder(context, index);
     assert(child.key != null, 'All list items must have a key');
-    final OverlayState overlay = Overlay.of(context)!;
+    final OverlayState overlay = Overlay.of(context, debugRequiredFor: widget)!;
     return _ReorderableItem(
       key: _ReorderableItemGlobalKey(child.key!, index, this),
       index: index,
@@ -1284,7 +1284,7 @@ class _DragInfo extends Drag {
 }
 
 Offset _overlayOrigin(BuildContext context) {
-  final OverlayState overlay = Overlay.of(context)!;
+  final OverlayState overlay = Overlay.of(context, debugRequiredFor: context.widget)!;
   final RenderBox overlayBox = overlay.context.findRenderObject()! as RenderBox;
   return overlayBox.localToGlobal(Offset.zero);
 }

packages/flutter/lib/src/widgets/selectable_region.dart

@@ -12,6 +12,7 @@ import 'package:flutter/services.dart';
 
 import 'actions.dart';
 import 'basic.dart';
+import 'debug.dart';
 import 'focus_manager.dart';
 import 'focus_scope.dart';
 import 'framework.dart';
@@ -804,7 +805,7 @@ class _SelectableRegionState extends State<SelectableRegion> with TextSelectionD
 
   @override
   Widget build(BuildContext context) {
-    assert(Overlay.of(context, debugRequiredFor: widget) != null);
+    assert(debugCheckHasOverlay(context));
     return CompositedTransformTarget(
       link: _toolbarLayerLink,
       child: RawGestureDetector(

packages/flutter/lib/src/widgets/text_selection.dart

@@ -16,6 +16,7 @@ import 'basic.dart';
 import 'binding.dart';
 import 'constants.dart';
 import 'container.dart';
+import 'debug.dart';
 import 'editable_text.dart';
 import 'framework.dart';
 import 'gesture_detector.dart';
@@ -616,15 +617,8 @@ class SelectionOverlay {
        _endHandleType = endHandleType,
        _lineHeightAtEnd = lineHeightAtEnd,
        _selectionEndpoints = selectionEndpoints,
-       _toolbarLocation = toolbarLocation {
-    final OverlayState? overlay = Overlay.of(context, rootOverlay: true);
-    assert(
-      overlay != null,
-      'No Overlay widget exists above $context.\n'
-      'Usually the Navigator created by WidgetsApp provides the overlay. Perhaps your '
-      'app content was created above the Navigator with the WidgetsApp builder parameter.',
-    );
-  }
+       _toolbarLocation = toolbarLocation,
+       assert(debugCheckHasOverlay(context));
 
   /// The context in which the selection handles should appear.
   ///

packages/flutter/test/widgets/selectable_text_test.dart

@@ -176,6 +176,37 @@ void main() {
     );
   }
 
+  testWidgets('throw if no Overlay widget exists above', (WidgetTester tester) async {
+    await tester.pumpWidget(
+      const Directionality(
+        textDirection: TextDirection.ltr,
+        child: MediaQuery(
+          data: MediaQueryData(size: Size(800.0, 600.0)),
+          child: Center(
+            child: Material(
+              child: SelectableText('I love Flutter!'),
+            ),
+          ),
+        ),
+      ),
+    );
+
+    final Offset textFieldStart = tester.getTopLeft(find.byType(SelectableText));
+    final TestGesture gesture = await tester.startGesture(textFieldStart, kind: PointerDeviceKind.mouse);
+    await tester.pump(const Duration(seconds: 2));
+    await gesture.up();
+    await tester.pumpAndSettle();
+
+    final FlutterError error = tester.takeException() as FlutterError;
+    expect(
+      error.message,
+      contains('EditableText widgets require an Overlay widget ancestor'),
+    );
+
+    await tester.pumpWidget(const SizedBox.shrink());
+    expect(tester.takeException(), isNotNull);  // side effect exception
+  });
+
   testWidgets('Do not crash when remove SelectableText during handle drag', (WidgetTester tester) async {
     // Regression test https://github.com/flutter/flutter/issues/108242
     bool isShow = true;