Original bug ID: 5322
Reporter: poluxmoon
Status: closed (set by @garrigue on 2011-07-29T01:56:43Z)
Resolution: fixed
Priority: normal
Severity: minor
Version: 3.12.0
Fixed in version: 3.13.0+dev
Category: ~DO NOT USE (was: OCaml general)

Bug description

Type error on code similar to :

type 'par t = 'par

let ident v = v

class alias =
object
method alias : 'a . 'a t -> 'a = ident (* type error here *)
end

Which gives :

Error: This expression has type 'a. 'a t -> 'a
but an expression was expected of type 'b. 'b t -> 'b
Type 'a a = 'a is not compatible with type 'b t = 'b

Additional information

The problem is related to unification of foralls containing named type in a method.
The compiler accepts equivalent code when not using the named type "t" or when not using a method (see attached file).

File attachments

• forallclass.ml