internal compiler error: type_of with ty_param

[killerswan]

So I was trying to add an insert_with_key method to map like so, and I don't yet know how to avoid this error.

On one of the branches where I'm playing with this, this is a commit before which things compile, and after which I see error like so. All that change does is change the argument type from fn(uint) to fn(V).

What's more, I haven't been able to reduce this to a problem outside of the standard library. For example, this compiles just fine. :P

Any ideas?

[killerswan]

Note that at the moment, both @nikomatsakis and I think the no_non_implicitly_copyable_typarams warnings are not directly related to this issue.

[nikomatsakis]

I think this is most likely a bug in monomorphization. That's precisely what I added the assert to detect. However, it might be a benign bug. It sounds to me like the fn(V) in the argument type of the interface is not being substituted.

[catamorphism]

@killerswan - is there any way you can try to reproduce this again? I'm not able to, as apparently the commits you linked to aren't in your repo anymore.

[killerswan]

Hmm, shouldn't have been so tidy and cleaned out those old branches...

I was trying (and would still like) to add an insert_with_key ([as in Haskell](http://hackage.haskell.org/packages/archive/containers/0.4.0.0/doc/html/Data-Map.html#g:5 as in Haskell)) to the Map trait. It would be something like the following:

fn insert_with_key(ff: fn(K, V, V) -> V: , key: K, value: V) -> bool;

But then I was getting all those errors and could never compile it. Maybe this is possible now, and I should try again...