Record failure on .NET (ok until 3.0.28)

I updated LanguageExt in a project and now get errors.

Version 3.0.28 works, Version 3.0.31 and 3.1.13 raise errors in my project. I have a unit test showing the problem in my code but I could not reproduce it outside of my project. After copying the test and types into LanguageExt source code (test project) the test is green there (current master == 3.1.13). I’m confused why same test shows different behaviour.

My guess: it is something around 2f1e06.

System.TypeInitializationException: The type initializer for 'LanguageExt.RecordType`1' threw an exception.
   at LanguageExt.Record`1.Equals(RECORDTYPE other)
   at MyProject.Actors.MyStaticClass.MyRecordClass.Equals(MyRecordClass rhs) in MyStaticClass.cs:line 488
   at Xunit.Sdk.AssertEqualityComparer`1.Equals(T x, T y)
   at Xunit.Assert.Equal[T](T expected, T actual, IEqualityComparer`1 comparer)
   at Xunit.Assert.Equal[T](T expected, T actual)
   at MyProject.Actors.MyTests.TestMyRecordClass() in MyTests.cs:line 22
System.InvalidOperationException: CompileToMethod cannot compile constant 'MyProject.Actors.MyStaticClass+MyRecordClass' because it is a non-trivial value, such as a live object. Instead, create an expression tree that can construct this value.
   at System.Linq.Expressions.Compiler.BoundConstants.EmitConstant(LambdaCompiler lc, Object value, Type type)
   at System.Linq.Expressions.Compiler.LambdaCompiler.EmitConstant(Object value, Type type)
   at System.Linq.Expressions.Compiler.LambdaCompiler.EmitConstantExpression(Expression expr)
   at System.Linq.Expressions.Compiler.LambdaCompiler.EmitExpression(Expression node, CompilationFlags flags)
   at System.Linq.Expressions.Compiler.LambdaCompiler.EmitBinaryExpression(Expression expr, CompilationFlags flags)
   at System.Linq.Expressions.Compiler.LambdaCompiler.EmitExpression(Expression node, CompilationFlags flags)
   at System.Linq.Expressions.Compiler.LambdaCompiler.EmitUnliftedAndAlso(BinaryExpression b)
   at System.Linq.Expressions.Compiler.LambdaCompiler.EmitAndAlsoBinaryExpression(Expression expr, CompilationFlags flags)
   at System.Linq.Expressions.Compiler.LambdaCompiler.EmitExpression(Expression node, CompilationFlags flags)
   at System.Linq.Expressions.Compiler.LambdaCompiler.EmitTypeBinaryExpression(Expression expr)
   at System.Linq.Expressions.Compiler.LambdaCompiler.EmitExpression(Expression node, CompilationFlags flags)
   at System.Linq.Expressions.Compiler.LambdaCompiler.EmitBranchComparison(Boolean branch, BinaryExpression node, Label label)
   at System.Linq.Expressions.Compiler.LambdaCompiler.EmitExpressionAndBranch(Boolean branchValue, Expression node, Label label)
   at System.Linq.Expressions.Compiler.LambdaCompiler.EmitUnliftedAndAlso(BinaryExpression b)
   at System.Linq.Expressions.Compiler.LambdaCompiler.EmitAndAlsoBinaryExpression(Expression expr, CompilationFlags flags)
   at System.Linq.Expressions.Compiler.LambdaCompiler.EmitExpression(Expression node, CompilationFlags flags)
   at System.Linq.Expressions.Compiler.LambdaCompiler.EmitUnliftedAndAlso(BinaryExpression b)
   at System.Linq.Expressions.Compiler.LambdaCompiler.EmitAndAlsoBinaryExpression(Expression expr, CompilationFlags flags)
   at System.Linq.Expressions.Compiler.LambdaCompiler.EmitExpression(Expression node, CompilationFlags flags)
   at System.Linq.Expressions.Compiler.LambdaCompiler.EmitUnliftedAndAlso(BinaryExpression b)
   at System.Linq.Expressions.Compiler.LambdaCompiler.EmitAndAlsoBinaryExpression(Expression expr, CompilationFlags flags)
   at System.Linq.Expressions.Compiler.LambdaCompiler.EmitExpression(Expression node, CompilationFlags flags)
   at System.Linq.Expressions.Compiler.LambdaCompiler.EmitUnliftedOrElse(BinaryExpression b)
   at System.Linq.Expressions.Compiler.LambdaCompiler.EmitOrElseBinaryExpression(Expression expr, CompilationFlags flags)
   at System.Linq.Expressions.Compiler.LambdaCompiler.EmitExpression(Expression node, CompilationFlags flags)
   at System.Linq.Expressions.Compiler.LambdaCompiler.EmitLambdaBody(CompilerScope parent, Boolean inlined, CompilationFlags flags)
   at System.Linq.Expressions.Compiler.LambdaCompiler.EmitLambdaBody()
   at System.Linq.Expressions.Compiler.LambdaCompiler.Compile(LambdaExpression lambda, MethodBuilder method, DebugInfoGenerator debugInfoGenerator)
   at System.Linq.Expressions.LambdaExpression.CompileToMethodInternal(MethodBuilder method, DebugInfoGenerator debugInfoGenerator)
   at LanguageExt.IL.Compile[F](LambdaExpression lambda, String typeName, String methodName)
   at LanguageExt.IL.Equals[A](Boolean includeBase)
   at LanguageExt.RecordType`1..cctor()

public static class MyStaticClass
{
	internal class MyRecordClass : Record<MyRecordClass>
	{
		public MyRecordClass(MyEvent @event)
		{
			Name = @event.Name;
			BirthDay = @event.BirthDay;
		}

		public MyRecordClass(string name, DateTime birthDay)
		{
			Name = name;
			BirthDay = birthDay;
		}

		public DateTime BirthDay { get; }

		[OptOutOfEq, OptOutOfHashCode, OptOutOfOrd]
		//[Eq(typeof(EqStringOrdinalIgnoreCase))]
		public string Name { get; }

		public override bool Equals(MyRecordClass rhs) =>
			base.Equals(rhs) && EqStringOrdinalIgnoreCase.Inst.Equals(rhs.Name, Name);
	}
}

[Fact]
public static void BirthdayTest()
{
	var key1 = new MyStaticClass.MyRecordClass("john", DateTime.Parse("2018-09-19"));
	var key2 = new MyStaticClass.MyRecordClass("John", DateTime.Parse("2018-09-19"));
	var key3 = new MyStaticClass.MyRecordClass("Jane", DateTime.Parse("2018-09-19"));
	Assert.Equal(key1, key2);
	Assert.NotEqual(key3, key2);
	Assert.Equal(0, key1.CompareTo(key2));
	Assert.Equal(key1.GetHashCode(), key2.GetHashCode());
}

I tested the new attributes / NonStructural – same problem.

Any idea how to reproduce this in LanguageExt / what the difference might be?

[StefanBertels]

@louthy: Happy new year!

I looked into this but I could not find out why exactly this fails / how to fix the optimized code. After reverting the change 2f1e06 (see PR #531) tests are green again.

[louthy]

This has the original lambda.Compile() restored (thanks @StefanBertels ) - and is now deploy in https://github.com/louthy/language-ext/releases/tag/v3.1.15