Add framework-side hitTestBehavior support for Semantics widget and apply to ModalRoute

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

diff --git a/packages/flutter/lib/src/rendering/custom_paint.dart b/packages/flutter/lib/src/rendering/custom_paint.dart
index ffd1a32..4bc5ae5 100644
--- a/packages/flutter/lib/src/rendering/custom_paint.dart
+++ b/packages/flutter/lib/src/rendering/custom_paint.dart
@@ -1039,6 +1039,9 @@
     if (config.validationResult != properties.validationResult) {
       config.validationResult = properties.validationResult;
     }
+    if (properties.hitTestBehavior != null) {
+      config.hitTestBehavior = properties.hitTestBehavior!;
+    }
     if (properties.inputType != null) {
       config.inputType = properties.inputType!;
     }

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

diff --git a/packages/flutter/lib/src/rendering/object.dart b/packages/flutter/lib/src/rendering/object.dart
index 12a9c61..089a259 100644
--- a/packages/flutter/lib/src/rendering/object.dart
+++ b/packages/flutter/lib/src/rendering/object.dart
@@ -4935,6 +4935,10 @@
       config.validationResult = _properties.validationResult;
     }
 
+    if (_properties.hitTestBehavior != null) {
+      config.hitTestBehavior = _properties.hitTestBehavior!;
+    }
+
     if (_properties.inputType != null) {
       config.inputType = _properties.inputType!;
     }

packages/flutter/lib/src/semantics/semantics.dart

diff --git a/packages/flutter/lib/src/semantics/semantics.dart b/packages/flutter/lib/src/semantics/semantics.dart
index d3c46b8..5ff42a7 100644
--- a/packages/flutter/lib/src/semantics/semantics.dart
+++ b/packages/flutter/lib/src/semantics/semantics.dart
@@ -12,6 +12,7 @@
 import 'dart:core';
 import 'dart:math' as math;
 import 'dart:ui'
+    as ui
     show
         CheckedState,
         Locale,
@@ -20,6 +21,7 @@
         SemanticsAction,
         SemanticsFlag,
         SemanticsFlags,
+        SemanticsHitTestBehavior,
         SemanticsInputType,
         SemanticsRole,
         SemanticsUpdate,
@@ -978,6 +980,7 @@
     required this.role,
     required this.controlsNodes,
     required this.validationResult,
+    required this.hitTestBehavior,
     required this.inputType,
     required this.locale,
     this.tags,
@@ -1240,6 +1243,9 @@
   /// {@macro flutter.semantics.SemanticsProperties.validationResult}
   final SemanticsValidationResult validationResult;
 
+  /// {@macro flutter.semantics.SemanticsProperties.hitTestBehavior}
+  final ui.SemanticsHitTestBehavior hitTestBehavior;
+
   /// {@macro flutter.semantics.SemanticsNode.inputType}
   final SemanticsInputType inputType;
 
@@ -1542,6 +1548,7 @@
     this.controlsNodes,
     this.inputType,
     this.validationResult = SemanticsValidationResult.none,
+    this.hitTestBehavior,
     this.onTap,
     this.onLongPress,
     this.onScrollLeft,
@@ -2434,6 +2441,13 @@
   /// {@endtemplate}
   final SemanticsValidationResult validationResult;
 
+  /// {@template flutter.semantics.SemanticsProperties.hitTestBehavior}
+  /// Describes how the semantic node should behave during hit testing.
+  ///
+  /// See [ui.SemanticsHitTestBehavior] for more details.
+  /// {@endtemplate}
+  final ui.SemanticsHitTestBehavior? hitTestBehavior;
+
   /// {@template flutter.semantics.SemanticsProperties.inputType}
   /// The input type for of a editable widget.
   ///
@@ -3063,7 +3077,8 @@
         _headingLevel != config._headingLevel ||
         _linkUrl != config._linkUrl ||
         _role != config.role ||
-        _validationResult != config.validationResult;
+        _validationResult != config.validationResult ||
+        _hitTestBehavior != config.hitTestBehavior;
   }
 
   // TAGS, LABELS, ACTIONS
@@ -3346,6 +3361,10 @@
   SemanticsValidationResult get validationResult => _validationResult;
   SemanticsValidationResult _validationResult = _kEmptyConfig.validationResult;
 
+  /// {@macro flutter.semantics.SemanticsProperties.hitTestBehavior}
+  ui.SemanticsHitTestBehavior get hitTestBehavior => _hitTestBehavior;
+  ui.SemanticsHitTestBehavior _hitTestBehavior = ui.SemanticsHitTestBehavior.defer;
+
   /// {@template flutter.semantics.SemanticsNode.inputType}
   /// The input type for of a editable node.
   ///
@@ -3424,6 +3443,7 @@
     _role = config._role;
     _controlsNodes = config._controlsNodes;
     _validationResult = config._validationResult;
+    _hitTestBehavior = config._hitTestBehavior;
     _inputType = config._inputType;
     _locale = config.locale;
 
@@ -3476,6 +3496,7 @@
     SemanticsRole role = _role;
     Set<String>? controlsNodes = _controlsNodes;
     SemanticsValidationResult validationResult = _validationResult;
+    ui.SemanticsHitTestBehavior hitTestBehavior = _hitTestBehavior;
     SemanticsInputType inputType = _inputType;
     final Locale? locale = _locale;
     final Set<int> customSemanticsActionIds = <int>{};
@@ -3627,6 +3648,7 @@
       role: role,
       controlsNodes: controlsNodes,
       validationResult: validationResult,
+      hitTestBehavior: hitTestBehavior,
       inputType: inputType,
       locale: locale,
     );
@@ -3714,6 +3736,7 @@
       role: data.role,
       controlsNodes: data.controlsNodes?.toList(),
       validationResult: data.validationResult,
+      hitTestBehavior: data.hitTestBehavior,
       inputType: data.inputType,
       locale: data.locale,
     );
@@ -5947,6 +5970,14 @@
     _hasBeenAnnotated = true;
   }
 
+  /// {@macro flutter.semantics.SemanticsProperties.hitTestBehavior}
+  ui.SemanticsHitTestBehavior get hitTestBehavior => _hitTestBehavior;
+  ui.SemanticsHitTestBehavior _hitTestBehavior = ui.SemanticsHitTestBehavior.defer;
+  set hitTestBehavior(ui.SemanticsHitTestBehavior value) {
+    _hitTestBehavior = value;
+    _hasBeenAnnotated = true;
+  }
+
   /// {@macro flutter.semantics.SemanticsProperties.inputType}
   SemanticsInputType get inputType => _inputType;
   SemanticsInputType _inputType = SemanticsInputType.none;

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

diff --git a/packages/flutter/lib/src/widgets/basic.dart b/packages/flutter/lib/src/widgets/basic.dart
index f583d04..b13f74c 100644
--- a/packages/flutter/lib/src/widgets/basic.dart
+++ b/packages/flutter/lib/src/widgets/basic.dart
@@ -9,7 +9,9 @@
 library;
 
 import 'dart:math' as math;
-import 'dart:ui' as ui show Image, ImageFilter, SemanticsInputType, TextHeightBehavior;
+import 'dart:ui'
+    as ui
+    show Image, ImageFilter, SemanticsHitTestBehavior, SemanticsInputType, TextHeightBehavior;
 
 import 'package:flutter/animation.dart';
 import 'package:flutter/foundation.dart';
@@ -4045,6 +4047,7 @@
     required SemanticsRole? role,
     required Set<String>? controlsNodes,
     required SemanticsValidationResult validationResult,
+    required ui.SemanticsHitTestBehavior? hitTestBehavior,
     required ui.SemanticsInputType? inputType,
     required Locale? localeForSubtree,
   }) : this.fromProperties(
@@ -4127,6 +4130,7 @@
            role: role,
            controlsNodes: controlsNodes,
            validationResult: validationResult,
+           hitTestBehavior: hitTestBehavior,
            inputType: inputType,
          ),
        );
@@ -7948,6 +7952,7 @@
     super.role,
     super.controlsNodes,
     super.validationResult = SemanticsValidationResult.none,
+    super.hitTestBehavior,
     super.inputType,
     super.localeForSubtree,
   });

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

diff --git a/packages/flutter/lib/src/widgets/routes.dart b/packages/flutter/lib/src/widgets/routes.dart
index 48927ea..a64b610 100644
--- a/packages/flutter/lib/src/widgets/routes.dart
+++ b/packages/flutter/lib/src/widgets/routes.dart
@@ -2313,6 +2313,7 @@
     // To be sorted before the _modalBarrier.
     return _modalScopeCache ??= Semantics(
       sortKey: const OrdinalSortKey(0.0),
+      hitTestBehavior: ui.SemanticsHitTestBehavior.opaque,
       child: _ModalScope<T>(
         key: _scopeKey,
         route: this,