Replace several Substrings with AsSpans by stephentoub · Pull Request #29539 · dotnet/corefx (original) (raw)

at least where the string is not necessarily needed?

That's the big caveat. In many cases it is needed, or at least it is in the local context... it could be that refactoring and changing signatures up the call stack could alleviate the need, but that requires investigation of each case to determine whether it's actually possible (many cases bottom out at a public API that returns a string).