Question: Difference between CORINFO_FLG_CONTAINS_GC_PTR and varDsc->HasGCPtr()

[yowl]

A while back there was some discussion on a means to decide if a struct should be GC tracked for the LLVM/Wasm backend.
#1647 (comment)
and
#1647 (comment)

There's a different between these 2 for Span<char> as one method includes type.IsByReferenceOfT and one doesn't. Why is that and should type.IsByReferenceOfT be considered when passing Span<char> as an argument?

Currently the IL->LLVM backed passes Span<char> on the LLVM stack, so is that correct?

[jkotas]

Span<char> has to be GC tracked, so it means varDsc->HasGCPtr() is what you need.

There was a discussion about CORINFO_FLG_CONTAINS_GC_PTR back in the day when Span<T> was introduced, and we agreed that it should not be set for Span: dotnet/runtime#6909 (comment)