type parameter inference

Currently if you have a function f[T](T t) you have to call it with explicit type parameters, such as f[int](10) or f[char]('a'). This is not generally necessary given the restricted set of contexts in which we permit type parameters; the type inference system should be able to infer parameters.

Implement this.

1. Add automatic parameter instantiation. Closed by a7eeeb596a9aa0660e6e3f8cff92876ac1686007.

   Patrick Walton at 2010-08-26 21:48:30