// Must not be called directly from outside the unifier.
func (u *unifier) nify(x, y Type, mode unifyMode, p *ifacePair) (result bool) {
	u.depth++
	if traceInference {
		u.tracef("%s ≡ %s\t// %s", x, y, mode)
	}
	defer func() {
		if traceInference && !result {
			u.tracef("%s ≢ %s", x, y)
		}
		u.depth--
	}()

	// nothing to do if x == y
	if x == y || Unalias(x) == Unalias(y) {
		return true

				// .(*TypeParam) type assertion above.
				untyped = append(untyped, i)
			}
		}
	}

	if traceInference {
		inferred := u.inferred(tparams)
		u.tracef("=> %s ➞ %s\n", tparams, inferred)
	}

	// --- 2 ---
	// use information from type parameter constraints

	if traceInference {
		u.tracef("== type parameters: %s", tparams)
	}

	// Unify type parameters with their constraints as long

// Must not be called directly from outside the unifier.
func (u *unifier) nify(x, y Type, mode unifyMode, p *ifacePair) (result bool) {
	u.depth++
	if traceInference {
		u.tracef("%s ≡ %s\t// %s", x, y, mode)
	}
	defer func() {
		if traceInference && !result {
			u.tracef("%s ≢ %s", x, y)
		}
		u.depth--
	}()

	// nothing to do if x == y
	if x == y || Unalias(x) == Unalias(y) {
		return true

				// .(*TypeParam) type assertion above.
				untyped = append(untyped, i)
			}
		}
	}

	if traceInference {
		inferred := u.inferred(tparams)
		u.tracef("=> %s ➞ %s\n", tparams, inferred)
	}

	// --- 2 ---
	// use information from type parameter constraints

	if traceInference {
		u.tracef("== type parameters: %s", tparams)
	}

	// Unify type parameters with their constraints as long