This looks right to me. And we could add {-# UNPACK #-} as well. IIRC strict fields should be unpacked when compiling with -O2 automatically, but IMO it doesn't hurt to add.

IIRC strict fields should be unpacked when compiling with -O2 automatically, but IMO it doesn't hurt to add.

Yes, they're even unpacked with -O1 (see -funbox-small-strict-fields). But all the other strict fields also have {-# UNPAPCK #-} pragmas, so ig it makes sense to add it here too.

Thank you for this change. I wanted to make Size strict for for a while, but I always thought it was maybe lazy on purpose, potentially due to occasional case where size calculation is discarded. After dedicating a bit of time investigating this theory due to this PR I couldn't really find any function that could benefit from such laziness. Of course, this investigation was by no means exhaustive. In any case, if there is such place where size calculation turns out to be redundant, majority of the time it is better to not pay the price for thunks.