Champion "pattern-based `with` expressions"

[gafter]

• Proposal added
• Discussed in LDM
• Decision in LDM
• Finalized (done, rejected, inactive)
• Spec'ed

In C# 9.0, we did with on records only, not some generalized pattern-based with expression.

See also

• the proposal in proposals/records.md for one possible approach.
• Discussion of nested use cases in Discussion: complex nested `with` expressions #77

Design meetings

https://github.com/dotnet/csharplang/blob/main/meetings/2022/LDM-2022-09-26.md#construction-improvements

[orthoxerox]

Why is it tentatively planned for 7.2 if records themselves are in 8.0?

[gafter]

Records build on this, not vice versa.

@MadsTorgersen are you working on a proposal for this?