Invalid use of Unsafe.As in System.Diagnostics.DiagnosticSource

[jkotas]

runtime/src/libraries/System.Diagnostics.DiagnosticSource/src/System/Diagnostics/Activity.cs

Line 258 in a4f15bf

get => _tags?.Enumerate() ?? Unsafe.As<IEnumerable<KeyValuePair<string, object?>>>(s_emptyBaggageTags);

is invalid use of Unsafe.As.

Unsafe.As cannot be used to cast object to a type that it is not assignable to and then hand the reference of invalid type out.

Please do not use Unsafe.As unless it is really required. Having an extra static field of the right type is both more correct and also likely cheaper than Unsafe.As.

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[tarekgh]

Thanks @jkotas. it is me who introduced this code. I was trying to avoid introducing extra static field. but I understand your point. wil fix that.

[tarekgh]

This is will be addressed as part of #40362

[tarekgh]

This is fixed by the linked PR