showError (TypeMismatch expected found) = "Invalid type: expected " ++ expected
                                       ++ ", found " ++ show found
showError (TypeMismatch expected found) = "Invalid type: expected " ++ expected
                                       ++ ", found " ++ show found
showError (TypeMismatch expected found) = "Invalid type: expected " ++ expected
                                       ++ ", found " ++ show found