Method EquivalentOrNull

postgres/parser/types/types.go:1778–1812

EquivalentOrNull is the same as Equivalent, except it returns true if: * `t` is Unknown (i.e., NULL) and `other` is not a tuple, * `t` is a tuple with all non-Unknown elements matching the types in `other`.

(other *T)

// * `t` is Unknown (i.e., NULL) and `other` is not a tuple,
// * `t` is a tuple with all non-Unknown elements matching the types in `other`.
func (t *T) EquivalentOrNull(other *T) bool {
	// Check normal equivalency first, then check for Null
	normalEquivalency := t.Equivalent(other)
	if normalEquivalency {
		return true
	}

	switch t.Family() {
	case UnknownFamily:
		return other.Family() != TupleFamily

	case TupleFamily:
		if other.Family() != TupleFamily {
			return false
		}
		// If either tuple is the wildcard tuple, it's equivalent to any other
		// tuple type. This allows overloads to specify that they take an arbitrary
		// tuple type.
		if IsWildcardTupleType(t) || IsWildcardTupleType(other) {
			return true
		}
		if len(t.TupleContents()) != len(other.TupleContents()) {
			return false
		}
		for i := range t.TupleContents() {
			if !t.TupleContents()[i].EquivalentOrNull(other.TupleContents()[i]) {
				return false
			}
		}
		return true

	default:
		return normalEquivalency
	}
}

// Identical returns true if every field in this ColumnType is exactly the same
// as every corresponding field in the given ColumnType. Identical performs a