feat: support ref and out parameter migration

Source/Mockolate.Migration.Analyzers.CodeFixers/MoqCodeFixProvider.cs

@@ -390,7 +390,8 @@ private static Dictionary<InvocationExpressionSyntax, InvocationExpressionSyntax
 			}
 
 			SimpleNameSyntax methodNameSyntax = lambdaMemberAccess.Name;
-			ArgumentListSyntax transformedArgs = TransformMoqItReferences(lambdaBody.ArgumentList);
+			ArgumentListSyntax transformedArgs = TransformMoqItReferences(
+				TransformRefAndOutArguments(lambdaBody.ArgumentList, semanticModel, cancellationToken));
 
 			InvocationExpressionSyntax replacement;
 			if (navigationChain.Count == 0)
@@ -594,7 +595,8 @@ private static Dictionary<InvocationExpressionSyntax, InvocationExpressionSyntax
 			}
 
 			SimpleNameSyntax methodNameSyntax = lambdaMemberAccess.Name;
-			ArgumentListSyntax transformedArgs = TransformMoqItReferences(lambdaBody.ArgumentList);
+			ArgumentListSyntax transformedArgs = TransformMoqItReferences(
+				TransformRefAndOutArguments(lambdaBody.ArgumentList, semanticModel, cancellationToken));
 
 			InvocationExpressionSyntax baseInvocation;
 			if (navigationChain.Count == 0)
@@ -927,6 +929,107 @@ private static bool IsMoqItCall(InvocationExpressionSyntax invocation, out strin
 		return true;
 	}
 
+	private static ArgumentListSyntax TransformRefAndOutArguments(
+		ArgumentListSyntax args,
+		SemanticModel? semanticModel,
+		CancellationToken cancellationToken)
+	{
+		IdentifierNameSyntax itIdentifier = SyntaxFactory.IdentifierName("It");
+
+		return args.ReplaceNodes(
+			args.Arguments.Where(a =>
+				a.RefKindKeyword.IsKind(SyntaxKind.OutKeyword) ||
+				a.RefKindKeyword.IsKind(SyntaxKind.RefKeyword)),
+			(original, _) =>
+			{
+				ExpressionSyntax expr = original.Expression.WithoutTrivia();
+
+				if (original.RefKindKeyword.IsKind(SyntaxKind.OutKeyword))
+				{
+					// out varName → It.IsOut(() => varName)
+					ParenthesizedLambdaExpressionSyntax lambda = SyntaxFactory.ParenthesizedLambdaExpression(expr);
+					InvocationExpressionSyntax isOut = BuildItInvocation(
+						itIdentifier, "IsOut", null,
+						SyntaxFactory.ArgumentList(SyntaxFactory.SeparatedList([SyntaxFactory.Argument(lambda),])));
+					return SyntaxFactory.Argument(isOut).WithTriviaFrom(original);
+				}
+
+				// ref Moq.It.Ref<T>.IsAny → It.IsAnyRef<T>()
+				if (TryExtractItRefIsAnyTypeArgs(original.Expression, out TypeArgumentListSyntax? isAnyTypeArgs))
+				{
+					InvocationExpressionSyntax isAnyRef = BuildItInvocation(
+						itIdentifier, "IsAnyRef", isAnyTypeArgs,
+						SyntaxFactory.ArgumentList());
+					return SyntaxFactory.Argument(isAnyRef).WithTriviaFrom(original);
+				}
+
+				// ref expr → It.IsRef<T>(_ => expr)
+				TypeArgumentListSyntax? typeArgs = null;
+				if (semanticModel is not null)
+				{
+					ITypeSymbol? typeSymbol = semanticModel.GetTypeInfo(original.Expression, cancellationToken).Type;
+					if (typeSymbol is not null)
+					{
+						TypeSyntax typeSyntax = SyntaxFactory.ParseTypeName(
+							typeSymbol.ToDisplayString(SymbolDisplayFormat.MinimallyQualifiedFormat)).WithoutTrivia();
+						typeArgs = SyntaxFactory.TypeArgumentList(SyntaxFactory.SeparatedList([typeSyntax,]));
+					}
+				}
+
+				SimpleLambdaExpressionSyntax refLambda = SyntaxFactory.SimpleLambdaExpression(
+					SyntaxFactory.Parameter(SyntaxFactory.Identifier("_")),
+					expr);
+				InvocationExpressionSyntax isRef = BuildItInvocation(
+					itIdentifier, "IsRef", typeArgs,
+					SyntaxFactory.ArgumentList(SyntaxFactory.SeparatedList([SyntaxFactory.Argument(refLambda),])));
+				return SyntaxFactory.Argument(isRef).WithTriviaFrom(original);
+			});
+	}
+
+	/// <summary>
+	///     Matches <c>[Moq.]It.Ref&lt;T&gt;.IsAny</c> and returns the type argument list.
+	/// </summary>
+	private static bool TryExtractItRefIsAnyTypeArgs(ExpressionSyntax expression,
+		out TypeArgumentListSyntax? typeArgs)
+	{
+		typeArgs = null;
+		// expression must be: <receiver>.IsAny
+		if (expression is not MemberAccessExpressionSyntax { Name.Identifier.Text: "IsAny", } isAnyAccess)
+		{
+			return false;
+		}
+
+		// receiver must be: It.Ref<T> or Moq.It.Ref<T>
+		if (isAnyAccess.Expression is not MemberAccessExpressionSyntax refAccess)
+		{
+			return false;
+		}
+
+		if (refAccess.Name is not GenericNameSyntax { Identifier.Text: "Ref", TypeArgumentList: var tArgs, })
+		{
+			return false;
+		}
+
+		bool isIt = refAccess.Expression switch
+		{
+			IdentifierNameSyntax { Identifier.Text: "It", } => true,
+			MemberAccessExpressionSyntax
+			{
+				Expression: IdentifierNameSyntax { Identifier.Text: "Moq", },
+				Name.Identifier.Text: "It",
+			} => true,
+			_ => false,
+		};
+
+		if (!isIt)
+		{
+			return false;
+		}
+
+		typeArgs = tArgs;
+		return true;
+	}
+
 	private static InvocationExpressionSyntax BuildItInvocation(
 		IdentifierNameSyntax itIdentifier,
 		string methodName,

Tests/Mockolate.Migration.Example.Tests/MoqMigrationExamples.cs

@@ -0,0 +1,135 @@
+using System.Text.RegularExpressions;
+using Moq;
+using Range = Moq.Range;
+
+namespace Mockolate.Migration.Example.Tests;
+
+public class MoqMigrationExamples
+{
+	[Fact]
+	public async Task ExpectedMigrationResult()
+	{
+		IFoo mock = IFoo.CreateMock();
+
+		mock.Mock.Setup.DoSomething("ping").Returns(true);
+
+		// out arguments
+		string outString = "ack";
+		// TryParse will return true, and the out argument will return "ack", lazy evaluated
+		mock.Mock.Setup.TryParse("ping", It.IsOut(() => outString)).Returns(true);
+
+		// ref arguments
+		Bar instance = new();
+		// Only matches if the ref argument to the invocation is the same instance
+		mock.Mock.Setup.Submit(It.IsRef<Bar>(_ => instance)).Returns(true);
+
+		// access invocation arguments when returning a value
+		mock.Mock.Setup.DoSomethingStringy(It.IsAny<string>())
+			.Returns(s => s.ToLower());
+		// Multiple parameters overloads available
+
+		// throwing when invoked with specific parameters
+		mock.Mock.Setup.DoSomething("reset").Throws<InvalidOperationException>();
+		mock.Mock.Setup.DoSomething("").Throws(new ArgumentException("command"));
+
+		// lazy evaluating return value
+		int count = 1;
+		mock.Mock.Setup.GetCount().Returns(() => count);
+
+
+		/* ------ Matching Argument ------ */
+		// any value
+		mock.Mock.Setup.DoSomething(It.IsAny<string>()).Returns(true);
+
+		// any value passed in a `ref` parameter (requires Moq 4.8 or later):
+		mock.Mock.Setup.Submit(It.IsAnyRef<Bar>()).Returns(true);
+
+		// matching Func<int>, lazy evaluated
+		mock.Mock.Setup.Add(It.Satisfies<int>(i => i % 2 == 0)).Returns(true);
+
+		// matching ranges
+		mock.Mock.Setup.Add(It.IsInRange(0, 10)).Returns(true);
+
+		// matching regex
+		mock.Mock.Setup.DoSomethingStringy(It.Matches("[a-d]+").AsRegex(RegexOptions.IgnoreCase)).Returns("foo");
+	}
+
+	/// <summary>
+	///     <see href="https://github.com/devlooped/moq/wiki/Quickstart" />
+	/// </summary>
+	[Fact]
+	public async Task MoqCreation()
+	{
+#pragma warning disable MockolateM001
+		Mock<IFoo> mock = new();
+#pragma warning restore MockolateM001
+
+		mock.Setup(foo => foo.DoSomething("ping")).Returns(true);
+
+		// out arguments
+		string outString = "ack";
+		// TryParse will return true, and the out argument will return "ack", lazy evaluated
+		mock.Setup(foo => foo.TryParse("ping", out outString)).Returns(true);
+
+		// ref arguments
+		Bar instance = new();
+		// Only matches if the ref argument to the invocation is the same instance
+		mock.Setup(foo => foo.Submit(ref instance)).Returns(true);
+
+		// access invocation arguments when returning a value
+		mock.Setup(x => x.DoSomethingStringy(Moq.It.IsAny<string>()))
+			.Returns((string s) => s.ToLower());
+		// Multiple parameters overloads available
+
+		// throwing when invoked with specific parameters
+		mock.Setup(foo => foo.DoSomething("reset")).Throws<InvalidOperationException>();
+		mock.Setup(foo => foo.DoSomething("")).Throws(new ArgumentException("command"));
+
+		// lazy evaluating return value
+		int count = 1;
+		mock.Setup(foo => foo.GetCount()).Returns(() => count);
+
+
+		/* ------ Matching Argument ------ */
+		// any value
+		mock.Setup(foo => foo.DoSomething(Moq.It.IsAny<string>())).Returns(true);
+
+		// any value passed in a `ref` parameter (requires Moq 4.8 or later):
+		mock.Setup(foo => foo.Submit(ref Moq.It.Ref<Bar>.IsAny)).Returns(true);
+
+		// matching Func<int>, lazy evaluated
+		mock.Setup(foo => foo.Add(Moq.It.Is<int>(i => i % 2 == 0))).Returns(true);
+
+		// matching ranges
+		mock.Setup(foo => foo.Add(Moq.It.IsInRange(0, 10, Range.Inclusive))).Returns(true);
+
+		// matching regex
+		mock.Setup(x => x.DoSomethingStringy(Moq.It.IsRegex("[a-d]+", RegexOptions.IgnoreCase))).Returns("foo");
+	}
+
+	public interface IFoo
+	{
+		Bar Bar { get; set; }
+		string Name { get; set; }
+		int Value { get; set; }
+		bool DoSomething(string value);
+		bool DoSomething(int number, string value);
+		Task<bool> DoSomethingAsync();
+		string DoSomethingStringy(string value);
+		bool TryParse(string value, out string outputValue);
+		bool Submit(ref Bar bar);
+		int GetCount();
+		bool Add(int value);
+	}
+
+	public class Bar
+	{
+		public virtual Baz Baz { get; set; }
+		public virtual bool Submit() => false;
+	}
+
+	public class Baz
+	{
+		public virtual string Name { get; set; }
+	}
+}