SimpleParameterSubstituter and ParameterSubstituter should not be visitors

[myk0la999]

If you would try to visit LambdaExpression trying to pass constant as replacement then visitor would try to replace lambda parameter with constant and that would probably trigger an exception. So Those should not be Visitors.

So if you pass LambdaExpression (x, y) => x + y as an input and x -> k, y -> 3 as replacements then it would try to do this:
(k, 3) => k + 3 which would probably cause exception.