[XamlC] use op_implicit where we should (#580)

* [XamlC] (passing) test for 48242

* [XamlC] (failing) test for 48242

* [XamlC] more op_implicit conversions

* additional test

* fix rebase

10 files changed, 187 insertions, 7 deletions

diff --git a/Xamarin.Forms.Build.Tasks/SetPropertiesVisitor.cs b/Xamarin.Forms.Build.Tasks/SetPropertiesVisitor.cs
index 4523a49d..d4765511 100644
--- a/Xamarin.Forms.Build.Tasks/SetPropertiesVisitor.cs
+++ b/Xamarin.Forms.Build.Tasks/SetPropertiesVisitor.cs
@@ -498,6 +498,10 @@ namespace Xamarin.Forms.Build.Tasks
 			// Worst case scenario ? InvalidCastException at runtime
 			if (attached && varValue.VariableType.FullName == "System.Object") 
 				return true;
+			var implicitOperator = varValue.VariableType.GetImplicitOperatorTo(bpTypeRef, module);
+			if (implicitOperator != null)
+				return true;
+
 			return varValue.VariableType.InheritsFromOrImplements(bpTypeRef);
 		}
 
@@ -520,9 +524,17 @@ namespace Xamarin.Forms.Build.Tasks
 				foreach (var instruction in valueNode.PushConvertedValue(context, bpRef, valueNode.PushServiceProvider(context, bpRef:bpRef), true, false))
 					yield return instruction;
 			} else if (elementNode != null) {
-				yield return Instruction.Create(OpCodes.Ldloc, context.Variables [elementNode]);
-				if (context.Variables [elementNode].VariableType.IsValueType)
-					yield return Instruction.Create(OpCodes.Box, context.Variables [elementNode].VariableType);
+				var bpTypeRef = bpRef.GetBindablePropertyType(iXmlLineInfo, module);
+				var varDef = context.Variables[elementNode];
+				var varType = varDef.VariableType;
+				var implicitOperator = varDef.VariableType.GetImplicitOperatorTo(bpTypeRef, module);
+				yield return Instruction.Create(OpCodes.Ldloc, varDef);
+				if (implicitOperator != null) {
+					yield return Instruction.Create(OpCodes.Call, module.Import(implicitOperator));
+					varType = module.Import(bpTypeRef);
+				}
+				if (varType.IsValueType)
+					yield return Instruction.Create(OpCodes.Box, varType);
 			}
 
 			yield return Instruction.Create(OpCodes.Callvirt, module.Import(setValue));
diff --git a/Xamarin.Forms.Build.Tasks/TypeReferenceExtensions.cs b/Xamarin.Forms.Build.Tasks/TypeReferenceExtensions.cs
index f0a6cef7..d0ccbc59 100644
--- a/Xamarin.Forms.Build.Tasks/TypeReferenceExtensions.cs
+++ b/Xamarin.Forms.Build.Tasks/TypeReferenceExtensions.cs
@@ -204,9 +204,10 @@ namespace Xamarin.Forms.Build.Tasks
 		}
 
 		public static MethodReference GetImplicitOperatorTo(this TypeReference fromType, TypeReference toType, ModuleDefinition module)
-		{ 
-			var implicitOperators = fromType.GetMethods(md => md.IsPublic && md.IsStatic && md.IsSpecialName && md.Name == "op_Implicit",
-												module).ToList();
+		{
+			var implicitOperatorsOnFromType = fromType.GetMethods(md => md.IsPublic && md.IsStatic && md.IsSpecialName && md.Name == "op_Implicit", module);
+			var implicitOperatorsOnToType = toType.GetMethods(md => md.IsPublic && md.IsStatic && md.IsSpecialName && md.Name == "op_Implicit", module);
+			var implicitOperators = implicitOperatorsOnFromType.Concat(implicitOperatorsOnToType).ToList();
 			if (implicitOperators.Any()) {
 				foreach (var op in implicitOperators) {
 					var cast = op.Item1;
diff --git a/Xamarin.Forms.Core/ConstraintTypeConverter.cs b/Xamarin.Forms.Core/ConstraintTypeConverter.cs
index 8cc45229..fb0be513 100644
--- a/Xamarin.Forms.Core/ConstraintTypeConverter.cs
+++ b/Xamarin.Forms.Core/ConstraintTypeConverter.cs
@@ -11,7 +11,7 @@ namespace Xamarin.Forms
 			if (value != null && double.TryParse(value, NumberStyles.Number, CultureInfo.InvariantCulture, out size))
 				return Constraint.Constant(size);
 
-			throw new InvalidOperationException(string.Format("Cannot convert \"{0}\" into {1}", value, typeof(Color)));
+			throw new InvalidOperationException(string.Format("Cannot convert \"{0}\" into {1}", value, typeof(Constraint)));
 		}
 	}
 }
\ No newline at end of file
diff --git a/Xamarin.Forms.Xaml.UnitTests/Issues/Unreported007.xaml b/Xamarin.Forms.Xaml.UnitTests/Issues/Unreported007.xaml
new file mode 100644
index 00000000..4132f908
--- /dev/null
+++ b/Xamarin.Forms.Xaml.UnitTests/Issues/Unreported007.xaml
@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
+		xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
+		x:Class="Xamarin.Forms.Xaml.UnitTests.Unreported007">
+
+	<Label Text="Foo" x:Name="label">
+		<RelativeLayout.XConstraint>
+			<OnPlatform x:TypeArguments="Constraint" Android="{ConstraintExpression Type=Constant,Constant=6}" iOS="{ConstraintExpression Type=Constant,Constant=3}" />
+		</RelativeLayout.XConstraint>
+	</Label>
+</ContentPage>
diff --git a/Xamarin.Forms.Xaml.UnitTests/Issues/Unreported007.xaml.cs b/Xamarin.Forms.Xaml.UnitTests/Issues/Unreported007.xaml.cs
new file mode 100644
index 00000000..279deed4
--- /dev/null
+++ b/Xamarin.Forms.Xaml.UnitTests/Issues/Unreported007.xaml.cs
@@ -0,0 +1,47 @@
+using System;
+using System.Collections.Generic;
+using NUnit.Framework;
+using Xamarin.Forms;
+using Xamarin.Forms.Core.UnitTests;
+
+namespace Xamarin.Forms.Xaml.UnitTests
+{
+	public partial class Unreported007 : ContentPage
+	{
+		public Unreported007()
+		{
+			InitializeComponent();
+		}
+		public Unreported007(bool useCompiledXaml)
+		{
+			//this stub will be replaced at compile time
+		}
+
+		[TestFixture]
+		class Tests
+		{
+			[SetUp]
+			public void Setup()
+			{
+				Device.PlatformServices = new MockPlatformServices();
+			}
+
+			[TearDown]
+			public void TearDown()
+			{
+				Device.PlatformServices = null;
+			}
+
+			[TestCase(true), TestCase(false)]
+			public void ConstraintsAreEvaluatedWithOnPlatform(bool useCompiledXaml)
+			{
+				if (useCompiledXaml)
+					MockCompiler.Compile(typeof(Unreported007));
+				Device.OS = TargetPlatform.iOS;
+				var page = new Unreported007(useCompiledXaml);
+				Assert.That(RelativeLayout.GetXConstraint(page.label), Is.TypeOf<Constraint>());
+				Assert.AreEqual(3, RelativeLayout.GetXConstraint(page.label).Compute(null));
+			}
+		}
+	}
+}
diff --git a/Xamarin.Forms.Xaml.UnitTests/SetValue.xaml b/Xamarin.Forms.Xaml.UnitTests/SetValue.xaml
index 40cf6210..61451223 100644
--- a/Xamarin.Forms.Xaml.UnitTests/SetValue.xaml
+++ b/Xamarin.Forms.Xaml.UnitTests/SetValue.xaml
@@ -84,5 +84,17 @@
 			</ContentView.Content>
 		</ContentView>
 		<local:ViewWithEnums x:Name="enums" IntEnum="Foo" ByteEnum="Bar" />
+		<local:MockViewWithValues x:Name="implicit0">
+			<local:MockViewWithValues.BPBar>
+				<local:SV_Foo Value="Bar"/>
+			</local:MockViewWithValues.BPBar>
+		</local:MockViewWithValues>
+		<!--<local:MockViewWithValues x:Name="implicit1" BPFoo="Foo" />-->
+		<local:MockViewWithValues x:Name="implicit2">
+			<local:MockViewWithValues.Bar>
+				<local:SV_Foo Value="Bar"/>
+			</local:MockViewWithValues.Bar>
+		</local:MockViewWithValues>
+		<!--<local:MockViewWithValues x:Name="implicit3" Foo="Foo" />-->
 	</StackLayout>
 </ContentPage>
diff --git a/Xamarin.Forms.Xaml.UnitTests/SetValue.xaml.cs b/Xamarin.Forms.Xaml.UnitTests/SetValue.xaml.cs
index 963fca06..b6395a7f 100644
--- a/Xamarin.Forms.Xaml.UnitTests/SetValue.xaml.cs
+++ b/Xamarin.Forms.Xaml.UnitTests/SetValue.xaml.cs
@@ -17,6 +17,38 @@ namespace Xamarin.Forms.Xaml.UnitTests
 	{ 
 		public UInt16 UShort { get; set; }
 		public decimal ADecimal { get; set; }
+		public SV_Foo Foo { get; set; }
+		public string Bar { get; set; }
+
+		public static readonly BindableProperty BPFooProperty =
+			BindableProperty.Create("BPFoo", typeof(SV_Foo), typeof(MockViewWithValues), default(SV_Foo));
+
+		public SV_Foo BPFoo {
+			get { throw new NotImplementedException(); }
+			set { throw new NotImplementedException(); }
+		}
+
+		public static readonly BindableProperty BPBarProperty =
+			BindableProperty.Create("BPBar", typeof(string), typeof(MockViewWithValues), default(string));
+
+		public string BPBar {
+			get { throw new NotImplementedException(); }
+			set { throw new NotImplementedException(); }
+		}
+	}
+
+	public class SV_Foo
+	{
+		public string Value { get; set; }
+		public static implicit operator SV_Foo(string value)
+		{
+			return new SV_Foo { Value = value };
+		}
+
+		public static implicit operator string(SV_Foo foo)
+		{
+			return foo.Value;
+		}
 	}
 
 	public enum IntEnum
@@ -254,6 +286,36 @@ namespace Xamarin.Forms.Xaml.UnitTests
 				Assert.AreEqual(IntEnum.Foo, page.enums.IntEnum);
 				Assert.AreEqual(ByteEnum.Bar, page.enums.ByteEnum);
 			}
+
+			public void SetValueWithImplicitOperatorOnSource(bool useCompiledXaml)
+			{
+				var page = new SetValue(useCompiledXaml);
+				Assert.AreEqual("Bar", page.implicit0.GetValue(MockViewWithValues.BPBarProperty));
+			}
+
+			//[TestCase(false)]
+			//[TestCase(true)]
+			//public void SetValueWithImplicitOperatorOnTarget(bool useCompiledXaml)
+			//{
+			//	var page = new SetValue(useCompiledXaml);
+			//	Assert.AreEqual("Foo", ((SV_Foo)page.implicit1.GetValue(MockViewWithValues.BPFooProperty)).Value);
+			//}
+
+			[TestCase(false)]
+			[TestCase(true)]
+			public void SetWithImplicitOperatorOnSource(bool useCompiledXaml)
+			{
+				var page = new SetValue(useCompiledXaml);
+				Assert.AreEqual("Bar", page.implicit2.Bar);
+			}
+
+			//[TestCase(false)]
+			//[TestCase(true)]
+			//public void SetWithImplicitOperatorOnTarget(bool useCompiledXaml)
+			//{
+			//	var page = new SetValue(useCompiledXaml);
+			//	Assert.AreEqual("Foo", page.implicit3.Foo.Value);
+			//}
 		}
 	}
 }
diff --git a/Xamarin.Forms.Xaml.UnitTests/XStatic.xaml b/Xamarin.Forms.Xaml.UnitTests/XStatic.xaml
index 32d2945e..cf68525b 100644
--- a/Xamarin.Forms.Xaml.UnitTests/XStatic.xaml
+++ b/Xamarin.Forms.Xaml.UnitTests/XStatic.xaml
@@ -3,6 +3,9 @@
 			 xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
 			 xmlns:local="clr-namespace:Xamarin.Forms.Xaml.UnitTests"
 			 x:Class="Xamarin.Forms.Xaml.UnitTests.XStatic">
+	<ContentPage.ToolbarItems>
+		<ToolbarItem Icon="{x:Static local:MockxStatic.MockFieldRef}" />
+	</ContentPage.ToolbarItems>
 	<StackLayout>
 		<Label x:Name="staticproperty"
 			   Text="{x:Static Member=local:MockxStatic.MockStaticProperty}" />
@@ -16,5 +19,7 @@
 				Text="{x:Static local:MockxStatic.MockField}"/>
 		<ScrollView x:Name="enuM"
 				Orientation="{x:Static ScrollOrientation.Both}"/>
+		<Label x:Name="field2"
+				Text="{x:Static local:MockxStatic.MockFieldRef}" />
 	</StackLayout>
 </ContentPage>
\ No newline at end of file
diff --git a/Xamarin.Forms.Xaml.UnitTests/XStatic.xaml.cs b/Xamarin.Forms.Xaml.UnitTests/XStatic.xaml.cs
index d8a466e9..19c62630 100644
--- a/Xamarin.Forms.Xaml.UnitTests/XStatic.xaml.cs
+++ b/Xamarin.Forms.Xaml.UnitTests/XStatic.xaml.cs
@@ -3,11 +3,18 @@ using Xamarin.Forms.Core.UnitTests;
 
 namespace Xamarin.Forms.Xaml.UnitTests
 {
+
+	public class Icons
+	{
+		public const string CLOSE = "ic_close.png";
+	}
+
 	public class MockxStatic
 	{
 		public static string MockStaticProperty { get { return "Property"; } }
 		public const string MockConstant = "Constant";
 		public static string MockField = "Field";
+		public static string MockFieldRef = Icons.CLOSE;
 		public string InstanceProperty { get { return "InstanceProperty"; } }
 		public static readonly Color BackgroundColor = Color.Fuchsia;
 	}
@@ -102,6 +109,23 @@ namespace Xamarin.Forms.Xaml.UnitTests
 				var layout = new XStatic(useCompiledXaml);
 				Assert.AreEqual(ScrollOrientation.Both, layout.enuM.Orientation);
 			}
+
+			[TestCase(false)]
+			[TestCase(true)]
+			public void FieldRef(bool useCompiledXaml)
+			{
+				var layout = new XStatic(useCompiledXaml);
+				Assert.AreEqual("ic_close.png", layout.field2.Text);
+			}
+
+			[TestCase(false)]
+			[TestCase(true)]
+			// https://bugzilla.xamarin.com/show_bug.cgi?id=48242
+			public void xStaticAndImplicitOperators(bool useCompiledXaml)
+			{
+				var layout = new XStatic(useCompiledXaml);
+				Assert.AreEqual("ic_close.png", layout.ToolbarItems[0].Icon.File);
+			}
 		}
 	}
 }
\ No newline at end of file
diff --git a/Xamarin.Forms.Xaml.UnitTests/Xamarin.Forms.Xaml.UnitTests.csproj b/Xamarin.Forms.Xaml.UnitTests/Xamarin.Forms.Xaml.UnitTests.csproj
index 582103bf..7096e520 100644
--- a/Xamarin.Forms.Xaml.UnitTests/Xamarin.Forms.Xaml.UnitTests.csproj
+++ b/Xamarin.Forms.Xaml.UnitTests/Xamarin.Forms.Xaml.UnitTests.csproj
@@ -383,6 +383,9 @@
     <Compile Include="Issues\Bz48554.xaml.cs">
       <DependentUpon>Bz48554.xaml</DependentUpon>
     </Compile>
+    <Compile Include="Issues\Unreported007.xaml.cs">
+      <DependentUpon>Unreported007.xaml</DependentUpon>
+    </Compile>
   </ItemGroup>
   <Import Project="$(MSBuildBinPath)\Microsoft.CSharp.targets" />
   <Import Project="..\.nuspec\Xamarin.Forms.Debug.targets" />
@@ -683,6 +686,9 @@
     <EmbeddedResource Include="Issues\Bz48554.xaml">
       <Generator>MSBuild:UpdateDesignTimeXaml</Generator>
     </EmbeddedResource>
+    <EmbeddedResource Include="Issues\Unreported007.xaml">
+      <Generator>MSBuild:UpdateDesignTimeXaml</Generator>
+    </EmbeddedResource>
   </ItemGroup>
   <ItemGroup>
     <Service Include="{82A7F48D-3B50-4B1E-B82E-3ADA8210C358}" />