Add two readonlys to IcuLocaleData.cs

[stephentoub]

Follow-up to #45296
cc: @marek-safar

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Issue Details

---

Follow-up to #45296
cc: @marek-safar

Author:	stephentoub
Assignees:	-
Labels:	area-System.Globalization
Milestone:	-

[marek-safar]

Is there analyzer we could enable to catch this?

[stephentoub]

Is there analyzer we could enable to catch this?

https://docs.microsoft.com/en-us/dotnet/fundamentals/code-analysis/style-rules/ide0044

runtime/eng/CodeAnalysis.ruleset

Line 446 in 296f4de

<Rule Id="IDE0044" Action="Hidden" /> <!-- MakeFieldReadonly -->

It's not ideal for Corelib, though, given how many fields end up being used from native.

[marek-safar]

It's not ideal for Corelib, though, given how many fields end up being used from native.

What do you mean, it should kick in only for the inline assigned fields. Do we do that for such fields?

[stephentoub]

it should kick in only for the inline assigned fields

It warns about any fields for which there aren't any assignments outside of ctors / declarations. That means any fields which are set by the EE end up getting flagged. Just change that one line from Hidden to Warning, build corelib, and you'll see what I mean.