Refactor parse tree for function arguments.

[cristianoc]

Put the label and type together, so in future it will be possible to represent a function of several arguments with a list.

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commit: ec0e8c2

[Copilot]

Pull Request Overview

This PR refactors the representation of function arguments by combining the label and type into a single arg record and updating all related pattern matches, constructors, and functions across the codebase.

• Introduce a new arg record to encapsulate an argument’s lbl and typ.
• Refactor Tarrow and Ptyp_arrow definitions and all pattern matches/constructors to use arg instead of separate label/type fields.
• Update parser, syntax, typedtree, typecore, and helper modules to align with the new arrow type structure.

Reviewed Changes

Copilot reviewed 48 out of 48 changed files in this pull request and generated no comments.

File	Description
tools/src/tools.ml	Update collectSignatureTypes to extract arg.typ and return type from new Tarrow
compiler/syntax/src/res_parsetree_viewer.ml	Refactor Ptyp_arrow patterns to match on arg.lbl and arg.typ
compiler/ml/types.mli	Add new arg type and update Tarrow signature
compiler/ml/typedtree.mli	Add arg record and update Ttyp_arrow to use arg

Comments suppressed due to low confidence (2)

compiler/ml/types.mli:60

• [nitpick] The type name arg is very generic and may conflict with other contexts; consider renaming it to something more descriptive like arrow_arg or func_arg to improve clarity.

and arg = {lbl: Noloc.arg_label; typ: type_expr}

compiler/syntax/src/res_parsetree_viewer.ml:14

• This new Ptyp_arrow pattern should be covered by unit tests for arrow_type to ensure unlabelled arrows are handled correctly after the refactor.

     ptyp_desc = Ptyp_arrow {arg = {lbl = Nolabel} as arg; ret};

[cknitt]

Put the label and type together, so in future it will be possible to represent a function of several arguments with a list.

That would be great, now that curried mode is gone! 👍