[Android/iOS] Fix Rectangle Width broken

src/Controls/src/Core/Shapes/Shape.cs

@@ -406,12 +406,12 @@ protected override Size MeasureOverride(double widthConstraint, double heightCon
 				case Stretch.Fill:
 					if (!double.IsInfinity(heightConstraint))
 					{
-						result.Height = heightConstraint;
+						result.Height = HeightRequest < 0 ? heightConstraint : HeightRequest;
 					}
 
 					if (!double.IsInfinity(widthConstraint))
 					{
-						result.Width = widthConstraint;
+						result.Width = WidthRequest < 0 ? widthConstraint : WidthRequest;
 					}
 					break;
 

src/Controls/tests/TestCases.HostApp/Issues/Issue18628.cs

@@ -0,0 +1,60 @@
+using Microsoft.Maui.Controls.Shapes;
+
+namespace Maui.Controls.Sample.Issues
+{
+
+	[Issue(IssueTracker.Github, 18628, "[Android/iOS] Rectangle rendering is broken")]
+	public class Issue18628 : ContentPage
+	{
+		public Issue18628()
+		{
+			var grid = new Grid
+			{
+				WidthRequest = 600,
+				HeightRequest = 250,
+				RowDefinitions = new RowDefinitionCollection
+				{
+					new RowDefinition { Height = new GridLength(1, GridUnitType.Auto) },
+					new RowDefinition { Height = new GridLength(1, GridUnitType.Star) },
+					new RowDefinition { Height = new GridLength(1, GridUnitType.Star) }
+				}
+			};
+
+			var label = new Label
+			{
+				Text = "RectangleWidth Test",
+				HorizontalOptions = LayoutOptions.Center,
+				HorizontalTextAlignment = TextAlignment.Center,
+				VerticalTextAlignment = TextAlignment.Start,
+				HeightRequest = 100,
+				AutomationId = "Label"
+			};
+
+			grid.Children.Add(label);
+			Grid.SetRow(label, 0);
+
+			var rectangle = new Rectangle
+			{
+				Fill = Colors.Red, 
+				AutomationId="Rectangle",
+				WidthRequest = 10,
+				VerticalOptions = LayoutOptions.Fill
+			};
+
+			grid.Children.Add(rectangle);
+			Grid.SetRow(rectangle, 1);
+
+			var ellipse = new Ellipse
+			{
+				Fill = Colors.Blue,
+				VerticalOptions = LayoutOptions.Fill,
+				WidthRequest = 300
+			};
+
+			grid.Children.Add(ellipse);
+			Grid.SetRow(ellipse, 2);
+
+			Content = grid;
+		}
+	}
+}			

src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue18628.cs

@@ -0,0 +1,23 @@
+using NUnit.Framework;
+using UITest.Appium;
+using UITest.Core;
+
+namespace Microsoft.Maui.TestCases.Tests.Issues
+{
+	public class Issue18628 : _IssuesUITest
+	{
+		public Issue18628(TestDevice testDevice) : base(testDevice)
+		{
+		}
+
+		public override string Issue => "[Android/iOS] Rectangle rendering is broken";
+
+		[Test]
+		[Category(UITestCategories.Shape)]
+		public void VerifyRectangleWidth()
+		{
+			App.WaitForElement("Label");
+			VerifyScreenshot();
+		}
+	}
+}