Test plan for "ref and unsafe in iterators and async" feature

[jjonescz]

Speclet: https://github.com/dotnet/csharplang/blob/main/proposals/ref-unsafe-in-iterators-async.md Feature branch: https://github.com/dotnet/roslyn/tree/features/RefInAsync Label: https://github.com/dotnet/roslyn/labels/New%20Feature%20-%20Ref%2FUnsafe%20in%20Iterators%2FAsync

• [ ] Review feature specification at LDM
• [x] Breaking change around unsafe context within iterators is documented
• [ ] language version
  • [ ] ref / ref struct local in
    • [x] async method
    • [ ] iterator method
  • [ ] unsafe block is allowed in C# 13 in
    • [ ] async method (this is a preserved legacy behavior)
    • [x] iterator method
  • [x] unsafe modifier is allowed on an iterator in C# 13, still an error (a language version error) in previous versions
    • [x] regular method
    • [x] property get
    • [x] local function
    • [x] operator
  • [ ] effect on unsafe context within iterator's body (the breaking change)
    • [x] regular method
    • [ ] property get
    • [x] local function
    • [ ] operator
• [ ] use ref / ref struct local
  • [ ] within / across await
  • [ ] within / across yield return; in
    • [ ] regular iterators
    • [ ] async iterators
  • [ ] across yield break; in
    • [ ] regular iterators
    • [ ] async iterators
  • [ ] within / across async foreach block
  • [ ] yield in nested block
  • [ ] within async lambda / local function
  • [ ] within iterator local function
  • [ ] within property / indexer get iterator
  • [ ] error in async / iterator even in unsafe context
  • [ ] await in elements of stackalloc, the result span should be usable afterwards
  • [ ] async Task<int[]> M() => ... ReadOnlySpan<int> x = await M(); is expected to work
  • [ ] Buffer2<int> b = [await a, await b]; // inline array type (ref struct)
  • [ ] using (refStruct = ...) { await ...; }
  • [ ] foreach (var _ in refStruct) { await ...; }
  • [ ] Interpolation handlers with awaits in the middle handler is a ref struct
    • [ ] no awaits in async method should work
    • [ ] Has await should be blocked
• [x] unsafe context
  • [x] unannotated / unsafe containing type
  • [x] unannotated / unsafe iterator method declaration
  • [x] unannotated / unsafe iterator block
  • [x] unannotated / unsafe local function
  • [x] unannotated lambda
  • [x] unannotated / unsafe property
  • [x] unannotated / unsafe property / indexer get iterator
• [ ] within unsafe context
  • [ ] error for await (confirm we have a legacy test)
  • [x] error for yield return;
  • [x] no diagnostic for yield break;
• [x] within lock
  • [x] next warning waive warning for yield return; for legacy lock
  • [x] error for yield return; for Lock type
  • [x] no diagnostic for yield break;
• [x] taking address of local / parameter
  • [x] error in iterator method
  • [x] error in iterator method for an indirect case
  • [x] warning in async method (C#12 warning wave)
• [x] taking address of a field is allowed in async/iterator

Related:

• https://github.com/dotnet/csharplang/issues/1331