> %name parse
> %tokentype { Token }
> %token Int { TokenInt }
> %%

> Expr :: { Int }
> Expr : Term { $1 }

The constant in the next rule would be defaulted to Integer, but it is
forced to Int by the type signature of Expr above.  This test exposed
a bug in the unsafeCoerce method.

> Term : Int { 42 }

> {
> main = print (parse [TokenInt])
> 
> data Token = TokenInt
> 
> happyError = error ""
> }