Fix nullable annotation on IEnumerator.Current #37969
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src/libraries/System.Net.Mail/src/System/Net/Mail/MailWriter.cs
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For the non-generic IEnumerator, we don't have any idea whether the type contains nulls or not. If we're forced to annotate it, `?` is correct, because it says "it's possible this is null" and we can't prove it's not. But that ends up leading to lots of spurious warnings, in particular when enumerating over supplied collections that won't ever contain null, e.g. enumerating a CookieCollection. Since the non-generic IEnumerator is effectively legacy, our best path forward while maintaining correctness and avoiding causing unnecessary warnings is to simply not annotate `IEnumerator.Current` at all, leaving it "oblivious"; in that way, we don't make any claims about its state, and leave it up to tooling how to best convey that.
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Reworking of dotnet#37969. Block LSRA from using R2 around the profiler leave callback, but don't kill GC refs in R2, since late codegen will use R2 to temporarily hold return values around the callback. Fixes dotnet#37223.
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) Reworking of #37969. Block LSRA from using R2 around the profiler leave callback, but don't kill GC refs in R2, since late codegen will use R2 to temporarily hold return values around the callback. Fixes #37223. Co-authored-by: Carol Eidt <[email protected]>
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…net#40123) Reworking of dotnet#37969. Block LSRA from using R2 around the profiler leave callback, but don't kill GC refs in R2, since late codegen will use R2 to temporarily hold return values around the callback. Fixes dotnet#37223. Co-authored-by: Carol Eidt <[email protected]>
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For the non-generic IEnumerator, we don't have any idea whether the type contains nulls or not. If we're forced to annotate it,
?is correct, because it says "it's possible this is null" and we can't prove it's not. But that ends up leading to lots of spurious warnings, in particular when enumerating over supplied collections that won't ever contain null, e.g. enumerating a CookieCollection. Since the non-generic IEnumerator is effectively legacy, our best path forward while maintaining correctness and avoiding causing unnecessary warnings is to simply not annotateIEnumerator.Currentat all, leaving it "oblivious"; in that way, we don't make any claims about its state, and leave it up to tooling how to best convey that.Fixes https://github.com/dotnet/csharplang/issues/3214
cc: @buyaa-n