Catch without variable fails

[langsamu]

Description

A variable is optional for a catch block:

try
{
}
catch (Exception)
{
}

But the comparer assumes the variable is set when determining whether two catch blocks are equal and when calculating the hash code for a catch block.

To reproduce

// Same expression twice to evade reference equality check
var x = Expression.TryCatch(Expression.Empty(), Expression.Catch(typeof(Exception), Expression.Empty()));
var y = Expression.TryCatch(Expression.Empty(), Expression.Catch(typeof(Exception), Expression.Empty()));

AssertAreEqual(x, y);

Resolution

These are the offending assumptions:

ExpressionTreeToolkit/src/ExpressionTreeToolkit.Core/ExpressionEqualityComparer.Try.cs

Line 35 in da989e1

&& EqualsParameter(x.Variable, y.Variable);

ExpressionTreeToolkit/src/ExpressionTreeToolkit.Core/ExpressionEqualityComparer.Try.cs

Line 60 in da989e1

GetHashCodeParameter(catchBlock.Variable));

Replacing EqualsParameter and GetHashCodeParameter with Equals and GetHashCode respectively solves the problem.