On 15 March 2011 19:21, Amitava Shee <amitava.shee@gmail.com> wrote:
*Kind> yesno 10

<interactive>:1:6:
    Ambiguous type variable `t' in the constraints:
      `Num t' arising from the literal `10' at <interactive>:1:6-7
      `Yesno t' arising from a use of `yesno' at <interactive>:1:0-7
    Probable fix: add a type signature that fixes these type variable(s)

The literal 10 has type (Num n => n), however, due to ghci's defaulting rules, it defaults to Integer, hence the error you've experienced.

Try yesno (10 :: Int), and check section 2.4.5 of [1].

[1] http://www.haskell.org/ghc/docs/7.0.2/html/users_guide/interactive-evaluation.html

Hope this helps,

--
Ozgur Akgun