The fix is blocked by slow defeq checks for TC instances; see issues 1986 and 2055. Enabling it right now causes lots of timeouts in mathlib4. https://leanprover.zulipchat.com/#narrow/stream/287929-mathlib4/topic/bump.20to.202023-02-06/near/326223768 This reverts commit 15a045ee66.
15a045ee66
Fixes #2074.
See https://leanprover.zulipchat.com/#narrow/stream/270676-lean4/topic/.60constructor.60.20and.20.60Applicative.60/near/279984801