Test plan for "collection expression arguments" feature

[jcouv]

Championed proposal: dotnet/csharplang#8887
Speclet: https://github.com/dotnet/csharplang/blob/main/proposals/collection-expression-arguments.md

Compiler:

• LangVer behavior
• order of evaluation
• ref analysis
• API review
• nullability analysis
• __arglist
• semantic model
• IOperation
• update compiler test plan
• update BindCollectionExpressionForErrorRecovery?

[MihuBot]

I'm a bot. Here is a possible related and/or duplicate issue (I may be wrong):

• Test plan for Dictionary Expressions #76310