feat(zend, reflection): enforce generic-arg arity at call sites and inheritance

Signed-off-by: azjezz <azjezz@protonmail.com>

Author: azjezz

Zend/tests/generics/erasure/turbofish_no_runtime_effect.phpt

@@ -1,11 +1,11 @@
 --TEST--
-Erasure: turbofish has zero runtime effect
+Erasure: turbofish (with matching arity) has zero runtime effect
 --FILE--
 <?php
-function f($x) { return $x * 2; }
+function f<T>($x) { return $x * 2; }
 var_dump(f(5));
 var_dump(f::<int>(5));
-var_dump(f::<int, string, float>(5));
+var_dump(f::<string>(5));
 ?>
 --EXPECT--
 int(10)

Zend/tests/generics/inheritance/arity/extends_non_generic.phpt

@@ -0,0 +1,9 @@
+--TEST--
+Inheritance arity: extends a non-generic class with type arguments is a compile error
+--FILE--
+<?php
+class Plain {}
+class Bad extends Plain<int> {}
+?>
+--EXPECTF--
+Fatal error: Too many generic type arguments to extends Plain in Bad, 1 passed and exactly 0 expected in %s on line %d

Zend/tests/generics/inheritance/arity/extends_over_default_max.phpt

@@ -0,0 +1,9 @@
+--TEST--
+Inheritance arity: extends Pair<K, V=mixed> with 3 args is a compile error
+--FILE--
+<?php
+class Pair<K, V = mixed> {}
+class Bad extends Pair<int, string, float> {}
+?>
+--EXPECTF--
+Fatal error: Too many generic type arguments to extends Pair in Bad, 3 passed and at most 2 expected in %s on line %d

Zend/tests/generics/inheritance/arity/extends_too_few.phpt

@@ -0,0 +1,9 @@
+--TEST--
+Inheritance arity: extends with too few type arguments is a compile error
+--FILE--
+<?php
+class Pair<K, V> {}
+class Bad extends Pair<int> {}
+?>
+--EXPECTF--
+Fatal error: Too few generic type arguments to extends Pair in Bad, 1 passed and exactly 2 expected in %s on line %d

Zend/tests/generics/inheritance/arity/extends_too_many.phpt

@@ -0,0 +1,9 @@
+--TEST--
+Inheritance arity: extends with too many type arguments is a compile error
+--FILE--
+<?php
+class Box<T> {}
+class Bad extends Box<int, string> {}
+?>
+--EXPECTF--
+Fatal error: Too many generic type arguments to extends Box in Bad, 2 passed and exactly 1 expected in %s on line %d

Zend/tests/generics/inheritance/arity/implements_too_few.phpt

@@ -0,0 +1,9 @@
+--TEST--
+Inheritance arity: implements with too few type arguments is a compile error
+--FILE--
+<?php
+interface Map<K, V> {}
+class Bad implements Map<int> {}
+?>
+--EXPECTF--
+Fatal error: Too few generic type arguments to implements Map in Bad, 1 passed and exactly 2 expected in %s on line %d

Zend/tests/generics/inheritance/arity/interface_extends_arity.phpt

@@ -0,0 +1,9 @@
+--TEST--
+Inheritance arity: interface extends another interface with wrong arity is a compile error
+--FILE--
+<?php
+interface J<T> {}
+interface IExt extends J<int, string> {}
+?>
+--EXPECTF--
+Fatal error: Too many generic type arguments to extends J in IExt, 2 passed and exactly 1 expected in %s on line %d

Zend/tests/generics/inheritance/arity/use_trait_too_many.phpt

@@ -0,0 +1,9 @@
+--TEST--
+Inheritance arity: use trait with too many type arguments is a compile error
+--FILE--
+<?php
+trait Holder<T> { public T $v; }
+class Bad { use Holder<int, string>; }
+?>
+--EXPECTF--
+Fatal error: Too many generic type arguments to use Holder in Bad, 2 passed and exactly 1 expected in %s on line %d

Zend/tests/generics/inheritance/arity/with_defaults.phpt

@@ -0,0 +1,19 @@
+--TEST--
+Inheritance arity: defaults extend the accepted range
+--FILE--
+<?php
+class Pair<K, V = mixed> {}
+interface Maybe<T = mixed> {}
+trait Slot<T = int> {}
+
+// Required-only arity
+class P1 extends Pair<int> {}
+// Including the optional
+class P2 extends Pair<int, string> {}
+// Trait with default — works without args
+class T1 { use Slot; }
+
+echo "OK\n";
+?>
+--EXPECT--
+OK

Zend/tests/generics/syntax/turbofish_complex_args.phpt

@@ -2,7 +2,7 @@
 Generic syntax: turbofish with composite type arguments
 --FILE--
 <?php
-function f($x) { return $x; }
+function f<A, B = mixed>($x) { return $x; }
 echo f::<int|string>(42), "\n";
 echo f::<int|string, (Throwable&Stringable)|null>('hi'), "\n";
 ?>