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Original file line number Diff line number Diff line change
@@ -0,0 +1,31 @@
--TEST--
Abstract generic types basic
--FILE--
<?php

interface I<T> {
public function foo(T $param): T;
}

class CS implements I<string> {
public function foo(string $param): string {
return $param . '!';
}
}

class CI implements I<int> {
public function foo(int $param): int {
return $param + 42;
}
}

$cs = new CS();
var_dump($cs->foo("Hello"));

$ci = new CI();
var_dump($ci->foo(5));

?>
--EXPECT--
string(6) "Hello!"
int(47)
Original file line number Diff line number Diff line change
@@ -0,0 +1,31 @@
--TEST--
Abstract generic type with a constraint
--FILE--
<?php

interface I<T : int|string> {
public function foo(T $param): T;
}

class CS implements I<string> {
public function foo(string $param): string {
return $param . '!';
}
}

class CI implements I<int> {
public function foo(int $param): int {
return $param + 42;
}
}

$cs = new CS();
var_dump($cs->foo("Hello"));

$ci = new CI();
var_dump($ci->foo(5));

?>
--EXPECT--
string(6) "Hello!"
int(47)
Original file line number Diff line number Diff line change
@@ -0,0 +1,16 @@
--TEST--
Abstract generic type with a constraint that is not satisfied
--FILE--
<?php

interface I<T : int|string> {
public function foo(T $param): T;
}

class C implements I<float> {
public function foo(float $param): float {}
}

?>
--EXPECTF--
Fatal error: Bound type float is not a subtype of the constraint type string|int of generic type T of interface I in %s on line %d
100 changes: 100 additions & 0 deletions Zend/tests/type_declarations/abstract_generics/big_example.phpt
Original file line number Diff line number Diff line change
@@ -0,0 +1,100 @@
--TEST--
Concrete example of using AT
--CREDITS--
Levi Morrison
--FILE--
<?php declare(strict_types=1);

namespace Sequence;

// No null. This is probably going to be painful, but let's try it.
interface Sequence<Item : object|array|string|float|int|bool>
{
function next(): ?Item;

/**
* @param callable(Item, Item): Item $f
* @return ?Item
*/
function reduce(callable $f): ?Item;
}

final class StringTablePair
{
public function __construct(
public readonly string $string,
public readonly int $id,
) {}
}

final class StringTableSequence implements Sequence<StringTablePair>
{
private array $strings;

public function __construct(StringTable $string_table) {
$this->strings = $string_table->to_assoc_array();
}

function next(): ?StringTablePair
{
$key = \array_key_first($this->strings);
if (!isset($key)) {
return null;
}
$value = \array_shift($this->strings);
return new StringTablePair($key, $value);
}

/**
* @param callable(Item, Item): Item $f
* @return ?Item
*/
function reduce(callable $f): ?StringTablePair
{
$reduction = $this->next();
if (!isset($reduction)) {
return null;
}

while (($next = $this->next()) !== null) {
$reduction = $f($reduction, $next);
}
return $reduction;
}
}

final class StringTable
{
private array $strings = ["" => 0];

public function __construct() {}

public function offsetGet(string $offset): int
{
return $this->strings[$offset] ?? throw new \Exception();
}

public function offsetExists(string $offset): bool
{
return \isset($this->strings[$offset]);
}

public function intern(string $str): int
{
return $this->strings[$str]
?? ($this->strings[$str] = \count($this->strings));
}

public function to_sequence(): StringTableSequence
{
return new StringTableSequence($this);
}

public function to_assoc_array(): array {
return $this->strings;
}
}

?>
--EXPECTF--
Fatal error: Generic type cannot be part of a union type in %s on line %d
Comment on lines +99 to +100
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When I saw my example in here, I got excited that you added basic union support. Nope! 😆

One day 🙏🏻

Original file line number Diff line number Diff line change
@@ -0,0 +1,12 @@
--TEST--
Abstract generic type cannot be in intersection (simple intersection with class type)
--FILE--
<?php

interface I<T> {
public function foo(T&Traversable $param): T&Traversable;
}

?>
--EXPECTF--
Fatal error: Generic type cannot be part of an intersection type in %s on line %d
Original file line number Diff line number Diff line change
@@ -0,0 +1,12 @@
--TEST--
Abstract generic type cannot be in intersection (DNF type)
--FILE--
<?php

interface I<T> {
public function foo(stdClass|(T&Traversable) $param): stdClass|(T&Traversable);
}

?>
--EXPECTF--
Fatal error: Generic type cannot be part of an intersection type in %s on line %d
Original file line number Diff line number Diff line change
@@ -0,0 +1,12 @@
--TEST--
Abstract generic type cannot be in union (simple union with built-in type)
--FILE--
<?php

interface I<T> {
public function foo(T|int $param): T|int;
}

?>
--EXPECTF--
Fatal error: Generic type cannot be part of a union type in %s on line %d
Original file line number Diff line number Diff line change
@@ -0,0 +1,12 @@
--TEST--
Abstract generic type cannot be in union (simple union with class type)
--FILE--
<?php

interface I<T> {
public function foo(T|stdClass $param): T|stdClass;
}

?>
--EXPECTF--
Fatal error: Generic type cannot be part of a union type in %s on line %d
Original file line number Diff line number Diff line change
@@ -0,0 +1,12 @@
--TEST--
Abstract generic type cannot be in union (DNF type)
--FILE--
<?php

interface I<T> {
public function foo(T|(Traversable&Countable) $param): T|(Traversable&Countable);
}

?>
--EXPECTF--
Fatal error: Generic type cannot be part of a union type in %s on line %d
Original file line number Diff line number Diff line change
@@ -0,0 +1,12 @@
--TEST--
Abstract generic type cannot be in union (nullable type union with ?)
--FILE--
<?php

interface I<T> {
public function foo(?T $param): ?T;
}

?>
--EXPECTF--
Fatal error: Generic type cannot be part of a union type in %s on line %d
Original file line number Diff line number Diff line change
@@ -0,0 +1,12 @@
--TEST--
Abstract generic type cannot be in union (forced allowed null)
--FILE--
<?php

interface I<T> {
public function foo(T $param = null): T;
}

?>
--EXPECTF--
Fatal error: Generic type cannot be part of a union type (implicitly nullable due to default null value) in %s on line %d
Original file line number Diff line number Diff line change
@@ -0,0 +1,12 @@
--TEST--
Abstract generic type in class is invalid
--FILE--
<?php

class C<T> {
public function foo(T $param): T;
}

?>
--EXPECTF--
Parse error: syntax error, unexpected token "<", expecting "{" in %s on line %d
Original file line number Diff line number Diff line change
@@ -0,0 +1,12 @@
--TEST--
Abstract generic type in trait is invalid
--FILE--
<?php

trait C<T> {
public function foo(T $param): T;
}

?>
--EXPECTF--
Parse error: syntax error, unexpected token "<", expecting "{" in %s on line %d
Original file line number Diff line number Diff line change
@@ -0,0 +1,12 @@
--TEST--
Abstract generic type that is redeclared
--FILE--
<?php

interface I<T, S, T> {
public function foo(T&Traversable $param): T&Traversable;
}

?>
--EXPECTF--
Fatal error: Duplicate generic parameter T in %s on line %d
Original file line number Diff line number Diff line change
@@ -0,0 +1,16 @@
--TEST--
Implementing class does not bind any abstract generic type
--FILE--
<?php

interface I<T> {
public function foo(T $param): T;
}

class C implements I {
public function foo(float $param): float {}
}

?>
--EXPECTF--
Fatal error: Cannot implement I as it has generic parameters which are not specified in %s on line %d
Original file line number Diff line number Diff line change
@@ -0,0 +1,16 @@
--TEST--
Implementing class does not bind any abstract generic type
--FILE--
<?php

interface I<T : int|string> {
public function foo(T $param): T;
}

class C implements I {
public function foo(float $param): float {}
}

?>
--EXPECTF--
Fatal error: Cannot implement I as it has generic parameters which are not specified in %s on line %d
Original file line number Diff line number Diff line change
@@ -0,0 +1,20 @@
--TEST--
Implementing class does not bind any abstract generic type
--FILE--
<?php

interface I1<T> {
public function foo(T $param): T;
}
interface I2<T> {
public function bar(T $param): T;
}

class C implements I1<float>, I2 {
public function foo(float $param): float {}
public function bar(string $param): string {}
}

?>
--EXPECTF--
Fatal error: Cannot implement I2 as it has generic parameters which are not specified in %s on line %d
Original file line number Diff line number Diff line change
@@ -0,0 +1,21 @@
--TEST--
Abstract generic type behaviour in extended interface
--FILE--
<?php

interface I<T : int|string|(Traversable&Countable)> {
public function foo(T $param): T;
}

interface I2<T> extends I<T> {
public function bar(int $o, T $param): T;
}

class C implements I2<string> {
public function foo(string $param): string {}
public function bar(int $o, float $param): float {}
}

?>
--EXPECTF--
Fatal error: Constraint type mixed of generic type T of interface I2 is not a subtype of the constraint type (Traversable&Countable)|string|int of generic type T of interface I in %s on line %d
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