unison/unison-src/transcripts/fix3196.md

scratch/main> builtins.merge

Tests ability checking in scenarios where one side is concrete and the other is a variable. This was supposed to be covered, but the method wasn't actually symmetric, so doing equate l r might work, but not equate r l.

Below were cases that caused the failing order.

structural type W es = W

unique ability Zoot where
  zoot : ()

woot : W {g} -> '{g, Zoot} a ->{Zoot} a
woot w a = todo ()

ex = do
  w = (W : W {Zoot})
  woot w do bug "why don't you typecheck?"

w1 : W {Zoot}
w1 = W

w2 : W {g} -> W {g}
w2 = cases W -> W

> w2 w1