Hello, What is wrong with the following code? type 'a t = A type 'a s = int t = A I get Error: This variant or record definition does not match that of type int t Their constraints differ. According to the OCaml manual Re-exported variant type or record type: an equation, a representation. …

Shouldn’t the second line of code be type 'a s = int s rather than type 'a s=int t ?

No, I’d like to re-export int t as 'a s. (This is a simplified example from my use case, in which the type 'a s is defined in a separate module.)

[image] Keiko: type 'a s = int t = A The problem is that you cannot add a new constraints on the type of A when you re-export the constructor. Otherwise, you would have two contradictory views on A : the original definition for which A has type 'a. 'a t and the re-exported one where A necessa…

Re-exported variant type with instantiated type parameters

Learning

Keiko March 14, 2019, 11:16am 5

ah, yes, that makes perfect sense!

Best regards,
Keiko

Topic		Replies	Views
Re-exporting recursive types Learning	4	921	June 16, 2017
Variant tags as parameters Learning	1	535	July 12, 2019
Constrain a type to be a polymorphic variant Learning	6	809	June 22, 2021
How exactly do type constraints work? Learning	4	702	April 9, 2021
A question on type/module equality Learning type-system , module , type-equality	12	2942	November 8, 2017

Re-exported variant type with instantiated type parameters

Related topics