equateContexts ((x, t):rest) ctxt =
  case varTypeJudgment x ctxt of
    Just (_, t') -> S.insert (t,t') (equateContexts rest ctxt)
    Nothing -> equateContexts rest ctxt

-- Infer the type of a term in a given context.
equateContexts ((x, t):rest) ctxt =
  case varTypeJudgment x ctxt of
    Just (_, t') -> S.insert (t,t') (equateContexts rest ctxt)
    Nothing -> equateContexts rest ctxt

-- Infer the type of a term in a given context.
equateContexts ((x, t):rest) ctxt =
  case varTypeJudgment x ctxt of
    Just (_, t') -> S.insert (t,t') (equateContexts rest ctxt)
    Nothing -> equateContexts rest ctxt

-- Infer the type of a term in a given context.