Template covariance

src/Result.php

@@ -18,10 +18,10 @@
 /**
  * Describes a Result
  *
- * @template T
+ * @template-covariant T
  * The Ok value
  *
- * @template E
+ * @template-covariant E
  * The Err value
  */
 abstract class Result
@@ -45,14 +45,14 @@
     /**
      * Converts from Result<T, E> to Option<T>, and discarding the error, if any
      *
      * @return Option<T>
      */
     abstract public function ok(): Option;
 
     /**
      * Converts from Result<T, E> to Option<E>, and discarding the value, if any
      *
      * @return Option<E>
      */
     abstract public function err(): Option;
 
@@ -61,7 +61,7 @@
      *
      * @template U
      *
      * @param callable(T):U $mapper
      * @return Result<U,E>
      */
     abstract public function map(callable $mapper): self;
@@ -72,7 +72,7 @@
      * @template U
      *
      * @param U $default
      * @param callable(T):U $f
      *
      * @return U
      */
@@ -83,8 +83,8 @@
      *
      * @template U
      *
      * @param callable(E):U $default
      * @param callable(T):U $f
      *
      * @return U
      */
@@ -95,7 +95,7 @@
      *
      * @template F
      *
      * @param callable(E):F $op
      * @return Result<T,F>
      */
     abstract public function mapErr(callable $op): self;
@@ -103,7 +103,7 @@
     /**
      * Calls a function with a reference to the contained value if Ok.
      *
      * @param callable(T):void $f
      *
      * @return Result<T,E>
      */
@@ -112,7 +112,7 @@
     /**
      * Calls a function with a reference to the contained value if Err.
      *
      * @param callable(E):void $f
      *
      * @return Result<T,E>
      */
@@ -174,7 +174,7 @@
      * @template U
      * @template F
      *
      * @param callable(T):Result<U,F> $op
      * @return Result<U,E|F>
      */
     abstract public function andThen(callable $op): self;

src/Result/Err.php

@@ -20,7 +20,7 @@
 /**
  * Err
  *
- * @template E
+ * @template-covariant E
  * The Err value
  *
  * @extends Result<mixed, E>

src/Result/Ok.php

@@ -22,7 +22,7 @@
 /**
  * Ok
  *
- * @template T
+ * @template-covariant T
  * The Ok value
  *
  * @extends Result<T, mixed>