This macro applies always_inline in addition to inline. It also applies artificial, which lets debugger know that this is an artificial function. The used attribute is added in debug builds to ensure that the symbol is emitted in the binary so that LLDB can invoke it.
Fix the common error of using underscores instead of dashes.
In the rebranch this is an error (lit got more picky), but it also makes sense to fix the tests in the main branch