Document private keyword in module type  #508

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1. quinn-dougherty

   changed the title [-]`private` keyword in `module type` [/-] [+]Document `private` keyword in `module type` [/+] on Apr 8, 2022
2. fhammerschmidt commented on May 9, 2025

   

   fhammerschmidt

   on May 9, 2025

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   There is also this idiom:

   type element = private {}

   Which can be used instead of an abstract type in order for the compiler to not unnecessarily add Primitive_option.some calls for optional props.

   Explanation: https://github.com/rescript-lang/rescript/pull/7450/files#r2081532393
3. fhammerschmidt

   added this to the v12.0 milestone on May 9, 2025
4. fhammerschmidt

   modified the milestones: v12.0, v12.1 on Sep 18, 2025
5. jderochervlk

   self-assigned this

   on Apr 10, 2026
6. jderochervlk

   added

   documentationChanges required for markdown documentationChanges required for markdown documentation

   on Apr 10, 2026
7. fhammerschmidt commented on Nov 3, 2026

   

   fhammerschmidt

   on Nov 3, 2026 – with ChatGPT Codex Connector

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   Closing as covered by Refining Module Types with Constraints.

   The Storage with type t = private string example explains how a private type exposes its representation for coercion while preventing callers from constructing values directly. Additional guidance about the private {} optimization mentioned later in this thread can be tracked as a separate documentation improvement.
8. fhammerschmidt

   closed this as completedon Nov 3, 2026