I'm a bit skeptical of this idea. Afterall, adding cases to the lexer for every tool that wants a pragma seems quite unsustainable.
I don't find this argument that convincing. Given the list already includes CATCH and DERIVE, the bar can't have been _that_ high to entry. And yet, the list remains pretty short. My guess is the demand is pretty low - we're just whitelisting a handful of additional words that aren't misspellings.
I agree. GHC presumably gives warnings for most names because most possible pragma names really are misspellings of what the user intended to say. Some select few pragma names are likely *not* misspellings (like CATCH, DERIVE, HLINT, etc), so there the policy is reversed. Common usage is what tells us is likely a misspelling vs not. Simply tracking the common usage is the pragmatic choice.