LGTM.com - false positive - cs/useless-assignment-to-local doesn't always work for ref struct like Span<T> #2754
Description
Description of the false positive
In general, the cs/useless-assignment-to-local rule makes sense: https://lgtm.com/rules/1506093386171/
However, assigning a ref struct like Span<T> within an instance method of a containing ref struct to stackalloc is not redundant and necessary to give the compiler a hint that the local will not escape the stack/method. Otherwise, the compiler would complain since that ref struct local could be stashed as a field of the containing type.
URL to the alert on the project page on LGTM.com