Add @psalm-return -1|0|1 on compareTo methods.

src/Duration.php

@@ -466,6 +466,8 @@ public function abs(): Duration
      * @param Duration $that The other duration to compare to.
      *
      * @return int [-1,0,1] If this duration is less than, equal to, or greater than the given duration.
+     *
+     * @psalm-return -1|0|1
      */
     public function compareTo(Duration $that): int
     {

src/Instant.php

@@ -238,6 +238,8 @@ public function getNano(): int
      * Compares this instant with another.
      *
      * @return int [-1,0,1] If this instant is before, on, or after the given instant.
+     *
+     * @psalm-return -1|0|1
      */
     public function compareTo(Instant $that): int
     {

src/LocalDate.php

@@ -591,6 +591,8 @@ public function minusDays(int $days): LocalDate
      * Returns -1 if this date is before the given date, 1 if after, 0 if the dates are equal.
      *
      * @return int [-1,0,1] If this date is before, on, or after the given date.
+     *
+     * @psalm-return -1|0|1
      */
     public function compareTo(LocalDate $that): int
     {

src/LocalDateTime.php

@@ -659,6 +659,8 @@ public function minusNanos(int $nanos): LocalDateTime
      * @param LocalDateTime $that The date-time to compare to.
      *
      * @return int [-1,0,1] If this date-time is before, on, or after the given date-time.
+     *
+     * @psalm-return -1|0|1
      */
     public function compareTo(LocalDateTime $that): int
     {

src/LocalTime.php

@@ -527,6 +527,8 @@ public function minusNanos(int $nanos): LocalTime
      * @param LocalTime $that The time to compare to.
      *
      * @return int [-1,0,1] If this time is before, on, or after the given time.
+     *
+     * @psalm-return -1|0|1
      */
     public function compareTo(LocalTime $that): int
     {

src/MonthDay.php

@@ -133,6 +133,8 @@ public function getDayOfMonth(): int
      * Returns -1 if this date is before the given date, 1 if after, 0 if the dates are equal.
      *
      * @return int [-1,0,1] If this date is before, on, or after the given date.
+     *
+     * @psalm-return -1|0|1
      */
     public function compareTo(MonthDay $that): int
     {

src/Year.php

@@ -178,6 +178,8 @@ public function minus(int $years): Year
      * @param Year $that The year to compare to.
      *
      * @return int [-1, 0, 1] If this year is before, equal to, or after the given year.
+     *
+     * @psalm-return -1|0|1
      */
     public function compareTo(Year $that): int
     {

src/YearMonth.php

@@ -147,6 +147,8 @@ public function getLengthOfYear(): int
 
     /**
      * @return int [-1,0,1] If this year-month is before, on, or after the given year-month.
+     *
+     * @psalm-return -1|0|1
      */
     public function compareTo(YearMonth $that): int
     {

src/YearWeek.php

@@ -106,6 +106,8 @@ public function getWeek(): int
 
     /**
      * @return int [-1,0,1] If this year-week is before, on, or after the given year-week.
+     *
+     * @psalm-return -1|0|1
      */
     public function compareTo(YearWeek $that): int
     {

src/ZonedDateTime.php

@@ -611,6 +611,8 @@ public function minusSeconds(int $seconds): ZonedDateTime
      * The comparison is performed on the instant.
      *
      * @return int [-1,0,1] If this zoned date-time is before, on, or after the given one.
+     *
+     * @psalm-return -1|0|1
      */
     public function compareTo(ZonedDateTime $that): int
     {