Add extensibility point for LINQ expression tree compilation

CHANGELOG.md

@@ -7,6 +7,10 @@ The format is loosely based on [Keep a Changelog](http://keepachangelog.com/en/1
 
 ## Unreleased
 
+#### Added
+
+* `ExpressionCompiler`: An extensibility point for setting up alternate LINQ expression tree compilation strategies (@stakx, #647)
+
 #### Fixed
 
 * More precise `out` parameter detection for mocking COM interfaces with `[in,out]` parameters (@koutinho, #645)

src/Moq/CaptureMatch.cs

@@ -79,7 +79,7 @@ private static Predicate<T> CreatePredicate(Action<T> captureCallback)
 
 		private static Predicate<T> CreatePredicate(Action<T> captureCallback, Expression<Func<T, bool>> predicate)
 		{
-			var predicateDelegate = predicate.Compile();
+			var predicateDelegate = predicate.CompileUsingExpressionCompiler();
 			return value =>
 			{
 				var matches = predicateDelegate.Invoke(value);

src/Moq/DefaultExpressionCompiler.cs

@@ -0,0 +1,64 @@
+//Copyright (c) 2007. Clarius Consulting, Manas Technology Solutions, InSTEDD
+//https://github.com/moq/moq4
+//All rights reserved.
+//
+//Redistribution and use in source and binary forms,
+//with or without modification, are permitted provided
+//that the following conditions are met:
+//
+//    * Redistributions of source code must retain the
+//    above copyright notice, this list of conditions and
+//    the following disclaimer.
+//
+//    * Redistributions in binary form must reproduce
+//    the above copyright notice, this list of conditions
+//    and the following disclaimer in the documentation
+//    and/or other materials provided with the distribution.
+//
+//    * Neither the name of Clarius Consulting, Manas Technology Solutions or InSTEDD nor the
+//    names of its contributors may be used to endorse
+//    or promote products derived from this software
+//    without specific prior written permission.
+//
+//THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+//CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+//INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+//MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+//DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+//CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+//SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+//BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+//SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+//INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+//WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+//NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+//OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+//SUCH DAMAGE.
+//
+//[This is the BSD license, see
+// http://www.opensource.org/licenses/bsd-license.php]
+
+using System;
+using System.Linq.Expressions;
+
+namespace Moq
+{
+	internal sealed class DefaultExpressionCompiler : ExpressionCompiler
+	{
+		new public static readonly DefaultExpressionCompiler Instance = new DefaultExpressionCompiler();
+
+		private DefaultExpressionCompiler()
+		{
+		}
+
+		public override Delegate Compile(LambdaExpression expression)
+		{
+			return expression.Compile();
+		}
+
+		public override TDelegate Compile<TDelegate>(Expression<TDelegate> expression)
+		{
+			return expression.Compile();
+		}
+	}
+}

src/Moq/Evaluator.cs

@@ -110,7 +110,7 @@ private static Expression Evaluate(Expression e)
 					return e;
 				}
 				LambdaExpression lambda = Expression.Lambda(e);
-				Delegate fn = lambda.Compile();
+				Delegate fn = lambda.CompileUsingExpressionCompiler();
 				return Expression.Constant(fn.DynamicInvoke(null), e.Type);
 			}
 		}

src/Moq/ExpressionCompiler.cs

@@ -0,0 +1,91 @@
+//Copyright (c) 2007. Clarius Consulting, Manas Technology Solutions, InSTEDD
+//https://github.com/moq/moq4
+//All rights reserved.
+//
+//Redistribution and use in source and binary forms,
+//with or without modification, are permitted provided
+//that the following conditions are met:
+//
+//    * Redistributions of source code must retain the
+//    above copyright notice, this list of conditions and
+//    the following disclaimer.
+//
+//    * Redistributions in binary form must reproduce
+//    the above copyright notice, this list of conditions
+//    and the following disclaimer in the documentation
+//    and/or other materials provided with the distribution.
+//
+//    * Neither the name of Clarius Consulting, Manas Technology Solutions or InSTEDD nor the
+//    names of its contributors may be used to endorse
+//    or promote products derived from this software
+//    without specific prior written permission.
+//
+//THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+//CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+//INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+//MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+//DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+//CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+//SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+//BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+//SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+//INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+//WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+//NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+//OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+//SUCH DAMAGE.
+//
+//[This is the BSD license, see
+// http://www.opensource.org/licenses/bsd-license.php]
+
+using System;
+using System.ComponentModel;
+using System.Linq.Expressions;
+
+namespace Moq
+{
+	/// <summary>
+	///   An <see cref="ExpressionCompiler"/> compiles LINQ expression trees (<see cref="Expression"/>) to delegates.
+	///   Whenever Moq needs to compile an expression tree, it uses the instance set up by <see cref="ExpressionCompiler.Instance"/>.
+	/// </summary>
+	[EditorBrowsable(EditorBrowsableState.Advanced)]
+	public abstract class ExpressionCompiler
+	{
+		private static ExpressionCompiler instance = DefaultExpressionCompiler.Instance;
+
+		/// <summary>
+		///   The default <see cref="ExpressionCompiler"/> instance, which simply delegates to the framework's <see cref="LambdaExpression.Compile"/>.
+		/// </summary>
+		public static ExpressionCompiler Default => DefaultExpressionCompiler.Instance;
+
+		/// <summary>
+		///   Gets or sets the <see cref="ExpressionCompiler"/> instance that Moq uses to compile <see cref="Expression"/> (LINQ expression trees).
+		///   Defaults to <see cref="Default"/>.
+		/// </summary>
+		public static ExpressionCompiler Instance
+		{
+			get => instance;
+			set => instance = value ?? throw new ArgumentNullException(nameof(value));
+		}
+
+		/// <summary>
+		///   Initializes a new instance of the <see cref="ExpressionCompiler"/> class.
+		/// </summary>
+		protected ExpressionCompiler()
+		{
+		}
+
+		/// <summary>
+		///   Compiles the specified LINQ expression tree.
+		/// </summary>
+		/// <param name="expression">The LINQ expression tree that should be compiled.</param>
+		public abstract Delegate Compile(LambdaExpression expression);
+
+		/// <summary>
+		///   Compiles the specified LINQ expression tree.
+		/// </summary>
+		/// <typeparam name="TDelegate">The type of delegate to which the expression will be compiled.</typeparam>
+		/// <param name="expression">The LINQ expression tree that should be compiled.</param>
+		public abstract TDelegate Compile<TDelegate>(Expression<TDelegate> expression) where TDelegate : Delegate;
+	}
+}

src/Moq/ExpressionExtensions.cs

@@ -51,6 +51,20 @@ namespace Moq
 {
 	internal static class ExpressionExtensions
 	{
+		internal static Delegate CompileUsingExpressionCompiler(this LambdaExpression expression)
+		{
+			// Expression trees are not compiled directly.
+			// The indirection via an ExpressionCompiler allows users to plug a different expression compiler.
+			return ExpressionCompiler.Instance.Compile(expression);
+		}
+
+		internal static TDelegate CompileUsingExpressionCompiler<TDelegate>(this Expression<TDelegate> expression) where TDelegate : Delegate
+		{
+			// Expression trees are not compiled directly.
+			// The indirection via an ExpressionCompiler allows users to plug a different expression compiler.
+			return ExpressionCompiler.Instance.Compile(expression);
+		}
+
 		/// <summary>
 		/// Converts the body of the lambda expression into the <see cref="PropertyInfo"/> referenced by it.
 		/// </summary>
@@ -141,7 +155,7 @@ private static bool PartialMatcherAwareEval_ShouldEvaluate(Expression expression
 					// Evaluate everything but matchers:
 					using (var context = new FluentMockContext())
 					{
-						Expression.Lambda<Action>(expression).Compile().Invoke();
+						Expression.Lambda<Action>(expression).CompileUsingExpressionCompiler().Invoke();
 						return context.LastMatch == null;
 					}
 

src/Moq/It.cs

@@ -98,7 +98,7 @@ public static TValue IsNotNull<TValue>()
 		public static TValue Is<TValue>(Expression<Func<TValue, bool>> match)
 		{
 			return Match<TValue>.Create(
-				value => match.Compile().Invoke(value),
+				value => match.CompileUsingExpressionCompiler().Invoke(value),
 				() => It.Is<TValue>(match));
 		}
 

src/Moq/Linq/MockQuery.cs

@@ -109,7 +109,7 @@ public TResult Execute<TResult>(Expression expression)
 			var replaced = new MockSetupsBuilder(this.underlyingCreateMocks).Visit(expression);
 
 			var lambda = Expression.Lambda<Func<TResult>>(replaced);
-			return lambda.Compile().Invoke();
+			return lambda.CompileUsingExpressionCompiler().Invoke();
 		}
 
 		public IEnumerator<T> GetEnumerator()

src/Moq/MatcherFactory.cs

@@ -86,7 +86,7 @@ public static IMatcher CreateMatcher(Expression expression, bool isParams)
 				// Try to determine if invocation is to a matcher.
 				using (var context = new FluentMockContext())
 				{
-					Expression.Lambda<Action>(call).Compile().Invoke();
+					Expression.Lambda<Action>(call).CompileUsingExpressionCompiler().Invoke();
 
 					if (context.LastMatch != null)
 					{
@@ -110,7 +110,7 @@ public static IMatcher CreateMatcher(Expression expression, bool isParams)
 				// Try to determine if invocation is to a matcher.
 				using (var context = new FluentMockContext())
 				{
-					Expression.Lambda<Action>((MemberExpression)expression).Compile().Invoke();
+					Expression.Lambda<Action>((MemberExpression)expression).CompileUsingExpressionCompiler().Invoke();
 					if (context.LastMatch != null)
 					{
 						return context.LastMatch;

src/Moq/Mock.cs

@@ -852,7 +852,7 @@ private static Mock GetTargetMock(Expression fluentExpression, Mock mock)
 			var targetExpression = FluentMockVisitor.Accept(fluentExpression, mock);
 			var targetLambda = Expression.Lambda<Func<Mock>>(Expression.Convert(targetExpression, typeof(Mock)));
 
-			var targetObject = targetLambda.Compile()();
+			var targetObject = targetLambda.CompileUsingExpressionCompiler()();
 			return targetObject;
 		}
 

src/Moq/Moq.csproj

@@ -17,6 +17,7 @@
 		<SignAssembly>true</SignAssembly>
 		<TreatWarningsAsErrors>true</TreatWarningsAsErrors>
 		<WarningLevel>4</WarningLevel>
+		<LangVersion>7.3</LangVersion>
 	</PropertyGroup>
 
 	<PropertyGroup Condition=" '$(TargetFramework)' == 'net45' ">

src/Moq/Protected/ProtectedMock.cs

@@ -282,7 +282,7 @@ private static Action<T> GetSetterExpression(PropertyInfo property, Expression v
 
 			return Expression.Lambda<Action<T>>(
 				Expression.Call(param, property.GetSetMethod(true), value),
-				param).Compile();
+				param).CompileUsingExpressionCompiler();
 		}
 
 		private static void ThrowIfMemberMissing(string memberName, MemberInfo member)