Reworking parametric types in CameLIGO and JsLIGO (concrete syntax, CST, pretty-printing)

Motivation and Context

In JsLIO, until now interface types could not be parametric and interface constants could not bear parametric types. This was an oversight. Also, the pretty-printing of parametric types wrongly discarded the parameters. Same with CameLIGO (val id : 'a.'a -> 'a).

Description

Component

• compiler
• website
• webide
• vscode-plugin
• debugger

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Performance improvement (non-breaking change that improves performance)
• None (change with no changelog)

Changelog

Checklist:

• If a new syntax has been introduced, put a message on slack ligo-lsp
• Changes follow the existing coding style (use dune @fmt to check).
• Tests for the changes have been added (for bug fixes / feature).
• Documentation has been updated.
• Changelog description has been added (if appropriate).
• Start titles under ## Changelog section with #### (if appropriate).
• There is no image or uploaded file in changelog
• Examples in changed behaviour have been added to the changelog (for breaking change / feature).

src/passes/03-unification/cameligo/decompile.ml

@@ -440,6 +440,12 @@ and ty_expr : CST.type_expr AST.ty_expr_ -> CST.type_expr =
   so we'll just drop the quantifiers here *)
   | T_abstraction Ligo_prim.Abstraction.{ ty_binder = _; kind = _; type_ }
   | T_for_all Ligo_prim.Abstraction.{ ty_binder = _; kind = _; type_ } -> type_
-  | T_for_alls Ligo_prim.Abstractions.{ ty_binders = _; kind = _; type_ } -> type_
+  | T_for_alls Ligo_prim.Abstractions.{ ty_binders = []; kind = _; type_ } -> type_
+  | T_for_alls Ligo_prim.Abstractions.{ ty_binders; kind = _; type_ } ->
+    let ty_binders =
+      List.map ~f:(fun v -> w @@ (None, decompile_tvar_into_var v)) ty_binders
+    in
+    let ty_binders : CST.type_var Utils.nseq = List.Ne.of_list ty_binders in
+    T_ForAll (w @@ (ty_binders, ghost_dot, type_))
   | T_module_app _ | T_constant _ ->
     Helpers.failwith_not_initial_node_decompiler @@ `Ty_expr te