Parens of pattern matched arguments in anonymous functions

Sample code:
```hs
myAdd = \(x, y) => x + y
```

With this declaration in syntax table,
```lisp
(modify-syntax-entry ?\\ "/" st)
```

The open paren (right after backslash `\`) lost its syntactic meaning and does not match with the close paren.

My question is: is it an intended behavior? By using symbol constituent char "_" for the lambda backslash, seems those parens can be matched then. (like in `haskell-mode`)