From: "Chris King" <colanderman@gmail.com>
> I just took the leap to 3.10 and encountered some strangeness
> compiling my project with it:
> 
> The implementation input_test.ml
> does not match the interface (inferred signature):
> Type declarations do not match:
>   type button = FrGui.button
> is not included in
>   type button = FrGui.button#row
> 
> First, I don't understand how a module doesn't match its inferred
> signature.  Strangely, creating a blank input_test.mli file gets
> around this error.

This looks like a bug report, but I clearly miss information to solve it.

> Compiling this:
> 
> module A: sig
>   type t = [ `A | `B ]
> end = struct
>   type t = private [> `A ]
> end
> 
> results in the error:

It certainly should: here the signature is written first!
If you write it the other way round, it is accepted without problem.

Concerning your first problem, could you submit a bu report, attaching
relevant information?

Jacques Garrigue