graphql allows types mismatch

[olegrok]

I have a type declaration:

kind_to_parse = {
    long = types.long.parseLiteral,
    float = types.float.parseLiteral,
    string = types.string.parseLiteral,
    boolean = types.boolean.parseLiteral,
}
types_any = types.scalar{
    name = 'Any',
    serialize = tostring, -- not used
    parseValue = tostring, -- not used
    parseLiteral = function(lit)
        if kind_to_parse[lit.kind] then
            return kind_to_parse[lit.kind](lit)
        end
        return nil
    end,
    isValueOfTheType = function(value)
        return type(value) ~= 'table'
    end
}

And I make a query - works OK:

query($login: Any, $is_active: Boolean) {
  Smth(first: 100, cid: [$login], is_active: $is_active) {
    myarg
  }
}

After changing "Any" to "String" query still works fine but GraphiQL shows an error: