Location Improvements

Motivation and Context

Related issue: #1503

This MR is the first step towards removing Location.dummy and Location.generated. It aims at ensuring locations are explicit (up until Mini_c) by removing many of the optional ?loc/?location parameters from our AST combinators.

Description

Added several virtual locations that are more descriptive than dummy / generated e.g. Location.interpreter for Ast fragments generated by the interpreter.

Require variables to have explicit locations.

Modified Ast_(imperative|core|typed|aggregated) combinators to require explicit locations.

A non-trivial amount of trivial updates to various functions for passing around locations.

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

Location tracking improvements within the compiler

Checklist:

• 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).