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I haven't >> figured out where that is written down. > > My understanding is that while the feature enabling this syntax > (`raw_ref_op`) is stable since 1.82, it has been introduced as an > unstable feature before 1.78. So it is here, just not enabled by > default before 1.82. aha, that's the key point that I was missing. > > R4L enables some of these unstable features when needed, especially > since they have been stabilized meanwhile. For instance, we did it with > the `pointer_is_aligned` feature for the `FromBytes` patch [1]. > OK, I see. Thanks for explaining! thanks, -- John Hubbard