`copilot-core`: record fields of `UExpr` are unnecessary

[ivanperez-keera]

Description

The record fields uExprType and uExprExpr, part of Copilot.Core.Expr.UExpr, are never really used within the module and only rarely used elsewhere in Copilot or, as far as we know, by any user of Copilot. As a matter of fact, we cannot use them to obtain the value inside the UExpr due to the existential it encloses.

This fields are not necessary parts of the interface to use Copilot, and not required by Copilot's requirements. Therefore, it would be suitable to remove that definitions from the module.

As per our internal policy of waiting 3 versions from deprecation until a public interface declaration can be removed, those definitions should be deprecated.

Type

• Bug: unused code included in the implementation.

Additional context

None.

Requester

• Ivan Perez

Method to check presence of bug

The field is mentioned in the record definition, but making it a non-record datatype, or not exporting that field in the module exports, does not change the behavior and does not otherwise affect Copilot.

The code compiles without errors and behaves in the same way.

Expected result

The following elements are deprecated:

• Copilot.Core.Expr.UExpr.uExprExpr
• Copilot.Core.Expr.UExpr.uExprType

Desired result

The following elements are deprecated:

• Copilot.Core.Expr.UExpr.uExprExpr
• Copilot.Core.Expr.UExpr.uExprType

Proposed solution

Deprecate the following functions:

• Copilot.Core.Expr.UExpr.uExprExpr
• Copilot.Core.Expr.UExpr.uExprType

Modify any uses of those fields anywhere in Copilot to use pattern matching instead.

Further notes

None.

[ivanperez-keera]

Change Manager: Confirmed that the issue exists.

[ivanperez-keera]

Technical Lead: Confirmed that the issue should be addressed.

[ivanperez-keera]

Technical Lead: Issue scheduled for fixing in Copilot 4.2.

Fix assigned to: @kaBeech.