Martin Foster (aka. EvilTerran) suggested an interesting idea, and I decided it was too nice to ignore/be forgotten inside Martin's head... So I'd like to try and suggest it.
Type wildcards that allow partially specifying types, e.g: f :: _ -> String f x = show x This will instruct the type-inferrer to "fill out" the wild-card part only (e.g: Show a => a). This feature can be used for a couple of benefits: A. It allows hard-coding part of a type, rather than the all-or-nothing situation we have now (I want to force a single parameter to be more specific, but I'd still prefer to infer the whole type). B. Without scoped type variables, there are currently situations you cannot provide a type signature at all. This may mean that you cannot resolve type ambiguities in some cases, or make types more specific for some purpose. A type wild-card, in addition to scoped type variables, will allow to only specify the part we want. C. Its a nice way to kill the -Wall warnings about missing type declarations, if you want to: f :: _ f = "I am explicitly asking to infer this type, rather than specifying it" Eyal
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