DoubleTap recognizer support and improved error message (#56328)

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

@@ -916,10 +916,13 @@ class RenderParagraph extends RenderBox
           if (recognizer is TapGestureRecognizer) {
             configuration.onTap = recognizer.onTap;
             configuration.isLink = true;
+          } else if (recognizer is DoubleTapGestureRecognizer) {
+            configuration.onTap = recognizer.onDoubleTap;
+            configuration.isLink = true;
           } else if (recognizer is LongPressGestureRecognizer) {
             configuration.onLongPress = recognizer.onLongPress;
           } else {
-            assert(false);
+            assert(false, '${recognizer.runtimeType} is not supported.');
           }
         }
         final SemanticsNode newChild = (_cachedChildNodes?.isNotEmpty == true)

packages/flutter/test/rendering/paragraph_test.dart

@@ -417,4 +417,37 @@ void main() {
     expect(boxes[8], const TextBox.fromLTRBD(14.0, 28.0, 28.0, 42.0 , TextDirection.ltr));
   // Ahem-based tests don't yet quite work on Windows or some MacOS environments
   }, skip: isWindows || isMacOS || isBrowser);
+
+  test('Supports gesture recognizer semantics', () {
+    final RenderParagraph paragraph = RenderParagraph(
+      TextSpan(text: _kText, children: <InlineSpan>[
+        TextSpan(text: 'one', recognizer: TapGestureRecognizer()..onTap = () {}),
+        TextSpan(text: 'two', recognizer: LongPressGestureRecognizer()..onLongPress = () {}),
+        TextSpan(text: 'three', recognizer: DoubleTapGestureRecognizer()..onDoubleTap = () {}),
+      ]),
+      textDirection: TextDirection.rtl,
+    );
+    layout(paragraph);
+
+    paragraph.assembleSemanticsNode(SemanticsNode(), SemanticsConfiguration(), <SemanticsNode>[]);
+  });
+
+  test('Asserts on unsupported gesture recognizer', () {
+    final RenderParagraph paragraph = RenderParagraph(
+      TextSpan(text: _kText, children: <InlineSpan>[
+        TextSpan(text: 'three', recognizer: MultiTapGestureRecognizer()..onTap = (int id) {}),
+      ]),
+      textDirection: TextDirection.rtl,
+    );
+    layout(paragraph);
+
+    bool failed = false;
+    try {
+      paragraph.assembleSemanticsNode(SemanticsNode(), SemanticsConfiguration(), <SemanticsNode>[]);
+    } catch(e) {
+      failed = true;
+      expect(e.message, 'MultiTapGestureRecognizer is not supported.');
+    }
+    expect(failed, true);
+  });
 }