[WIP][RFC]Spread Operator in Array

Zend/tests/array_unpack/already_occupied.phpt

@@ -0,0 +1,41 @@
+--TEST--
+Appending to an array via unpack may fail
+--SKIPIF--
+<?php if (PHP_INT_SIZE != 8) die("skip 64bit only"); ?>
+--FILE--
+<?php
+
+$arr = [1, 2, 3];
+var_dump([PHP_INT_MAX-1 => 0, ...$arr]);
+
+var_dump([PHP_INT_MAX-1 => 0, ...[1, 2, 3]]);
+
+const ARR = [1, 2, 3];
+const ARR2 = [PHP_INT_MAX-1 => 0, ...ARR];
+var_dump(ARR2);
+
+?>
+--EXPECTF--
+Warning: Cannot add element to the array as the next element is already occupied in %s on line %d
+array(2) {
+  [9223372036854775806]=>
+  int(0)
+  [9223372036854775807]=>
+  int(1)
+}
+
+Warning: Cannot add element to the array as the next element is already occupied in %s on line %d
+array(2) {
+  [9223372036854775806]=>
+  int(0)
+  [9223372036854775807]=>
+  int(1)
+}
+
+Warning: Cannot add element to the array as the next element is already occupied in %s on line %d
+array(2) {
+  [9223372036854775806]=>
+  int(0)
+  [9223372036854775807]=>
+  int(1)
+}

Zend/tests/array_unpack/basic.phpt

@@ -0,0 +1,119 @@
+--TEST--
+Basic array unpacking
+--FILE--
+<?php
+$array = [1, 2, 3];
+
+function getArr() {
+	return [4, 5];
+}
+
+function arrGen() {
+	for($i = 11; $i < 15; $i++) {
+		yield $i;
+	}
+}
+
+var_dump([...[]]);
+var_dump([...[1, 2, 3]]);
+var_dump([...$array]);
+var_dump([...getArr()]);
+var_dump([...arrGen()]);
+var_dump([...new ArrayIterator(['a', 'b', 'c'])]);
+
+var_dump([0, ...$array, ...getArr(), 6, 7, 8, 9, 10, ...arrGen()]);
+var_dump([0, ...$array, ...$array, 'end']);
+
+--EXPECT--
+array(0) {
+}
+array(3) {
+  [0]=>
+  int(1)
+  [1]=>
+  int(2)
+  [2]=>
+  int(3)
+}
+array(3) {
+  [0]=>
+  int(1)
+  [1]=>
+  int(2)
+  [2]=>
+  int(3)
+}
+array(2) {
+  [0]=>
+  int(4)
+  [1]=>
+  int(5)
+}
+array(4) {
+  [0]=>
+  int(11)
+  [1]=>
+  int(12)
+  [2]=>
+  int(13)
+  [3]=>
+  int(14)
+}
+array(3) {
+  [0]=>
+  string(1) "a"
+  [1]=>
+  string(1) "b"
+  [2]=>
+  string(1) "c"
+}
+array(15) {
+  [0]=>
+  int(0)
+  [1]=>
+  int(1)
+  [2]=>
+  int(2)
+  [3]=>
+  int(3)
+  [4]=>
+  int(4)
+  [5]=>
+  int(5)
+  [6]=>
+  int(6)
+  [7]=>
+  int(7)
+  [8]=>
+  int(8)
+  [9]=>
+  int(9)
+  [10]=>
+  int(10)
+  [11]=>
+  int(11)
+  [12]=>
+  int(12)
+  [13]=>
+  int(13)
+  [14]=>
+  int(14)
+}
+array(8) {
+  [0]=>
+  int(0)
+  [1]=>
+  int(1)
+  [2]=>
+  int(2)
+  [3]=>
+  int(3)
+  [4]=>
+  int(1)
+  [5]=>
+  int(2)
+  [6]=>
+  int(3)
+  [7]=>
+  string(3) "end"
+}

Zend/tests/array_unpack/classes.phpt

@@ -0,0 +1,46 @@
+--TEST--
+Array unpacking with classes
+--FILE--
+<?php
+
+class C {
+	public const FOO = [0, ...self::ARR, 4];
+	public const ARR = [1, 2, 3];
+	public static $bar = [...self::ARR];
+}
+
+class D {
+	public const A = [...self::B];
+	public const B = [...self::A];
+}
+
+var_dump(C::FOO);
+var_dump(C::$bar);
+
+try {
+	var_dump(D::A);
+} catch (Error $ex) {
+	echo "Exception: " . $ex->getMessage() . "\n";
+}
+--EXPECT--
+array(5) {
+  [0]=>
+  int(0)
+  [1]=>
+  int(1)
+  [2]=>
+  int(2)
+  [3]=>
+  int(3)
+  [4]=>
+  int(4)
+}
+array(3) {
+  [0]=>
+  int(1)
+  [1]=>
+  int(2)
+  [2]=>
+  int(3)
+}
+Exception: Cannot declare self-referencing constant 'self::B'

Zend/tests/array_unpack/in_destructuring.phpt

@@ -0,0 +1,10 @@
+--TEST--
+Spread operator is not supported in destructuring assignments
+--FILE--
+<?php
+
+[$head, ...$tail] = [1, 2, 3];
+
+?>
+--EXPECTF--
+Fatal error: Spread operator is not supported in assignments in %s on line %d

Zend/tests/array_unpack/non_integer_keys.phpt

@@ -0,0 +1,17 @@
+--TEST--
+Array unpacking does not work with non-integer keys
+--FILE--
+<?php
+function gen() {
+	yield [] => 1;
+	yield 1.23 => 123;
+}
+
+try {
+	[...gen()];
+} catch (Error $ex) {
+	echo "Exception: " . $ex->getMessage() . "\n";
+}
+
+--EXPECT--
+Exception: Cannot unpack Traversable with non-integer keys

Zend/tests/array_unpack/ref1.phpt

@@ -0,0 +1,17 @@
+--TEST--
+Array unpacking with element rc=1
+--FILE--
+<?php
+
+$a = 1;
+$b = [&$a]; //array (0 => (refcount=2, is_ref=1)=1)
+
+unset($a); //array (0 => (refcount=1, is_ref=1)=1)
+
+var_dump([...$b]); //array (0 => (refcount=0, is_ref=0)=1)
+
+--EXPECT--
+array(1) {
+  [0]=>
+  int(1)
+}

Zend/tests/array_unpack/string_keys.phpt

@@ -0,0 +1,21 @@
+--TEST--
+array unpacking with string keys (not supported)
+--FILE--
+<?php
+
+try {
+	$array = [1, 2, "foo" => 3, 4];
+	var_dump([...$array]);
+} catch (Error $ex) {
+	var_dump($ex->getMessage());
+}
+try {
+	$iterator = new ArrayIterator([1, 2, "foo" => 3, 4]);
+	var_dump([...$iterator]);
+} catch (Error $ex) {
+	var_dump($ex->getMessage());
+}
+
+--EXPECT--
+string(36) "Cannot unpack array with string keys"
+string(42) "Cannot unpack Traversable with string keys"

Zend/tests/array_unpack/undef_var.phpt

@@ -0,0 +1,14 @@
+--TEST--
+array unpacking with undefinded variable
+--FILE--
+<?php
+
+var_dump([...$arr]);
+
+--EXPECTF--
+Notice: Undefined variable: arr in %s on line %d
+
+Fatal error: Uncaught Error: Only arrays and Traversables can be unpacked in %s:%d
+Stack trace:
+#0 {main}
+  thrown in %s on line %d

Zend/tests/array_unpack/unpack_invalid_type_compile_time.phpt

@@ -0,0 +1,10 @@
+--TEST--
+Unpacking non-array/Traversable detected at compile-time
+--FILE--
+<?php
+
+var_dump([...42]);
+
+?>
+--EXPECTF--
+Fatal error: Only arrays and Traversables can be unpacked in %s on line %d

Zend/tests/array_unpack/unpack_string_keys_compile_time.phpt

@@ -0,0 +1,10 @@
+--TEST--
+Unpacking of string keys detected at compile-time
+--FILE--
+<?php
+
+var_dump([...['a' => 'b']]);
+
+?>
+--EXPECTF--
+Fatal error: Cannot unpack array with string keys in %s on line %d

Zend/zend_ast.c

@@ -446,6 +446,32 @@ static int zend_ast_add_array_element(zval *result, zval *offset, zval *expr)
 	return SUCCESS;
 }
 
+static int zend_ast_add_unpacked_element(zval *result, zval *expr) {
+	if (EXPECTED(Z_TYPE_P(expr) == IS_ARRAY)) {
+		HashTable *ht = Z_ARRVAL_P(expr);
+		zval *val;
+		zend_string *key;
+
+		ZEND_HASH_FOREACH_STR_KEY_VAL(ht, key, val) {
+			if (key) {
+				zend_throw_error(NULL, "Cannot unpack array with string keys");
+				return FAILURE;
+			} else {
+				if (!zend_hash_next_index_insert(Z_ARRVAL_P(result), val)) {
+					zend_error(E_WARNING, "Cannot add element to the array as the next element is already occupied");
+					break;
+				}
+				Z_TRY_ADDREF_P(val);
+			}
+		} ZEND_HASH_FOREACH_END();
+		return SUCCESS;
+	}
+
+	/* Objects or references cannot occur in a constant expression. */
+	zend_throw_error(NULL, "Only arrays and Traversables can be unpacked");
+	return FAILURE;
+}
+
 ZEND_API int ZEND_FASTCALL zend_ast_evaluate(zval *result, zend_ast *ast, zend_class_entry *scope)
 {
 	zval op1, op2;
@@ -642,6 +668,19 @@ ZEND_API int ZEND_FASTCALL zend_ast_evaluate(zval *result, zend_ast *ast, zend_c
 				array_init(result);
 				for (i = 0; i < list->children; i++) {
 					zend_ast *elem = list->child[i];
+					if (elem->kind == ZEND_AST_UNPACK) {
+						if (UNEXPECTED(zend_ast_evaluate(&op1, elem->child[0], scope) != SUCCESS)) {
+							zval_ptr_dtor_nogc(result);
+							return FAILURE;
+						}
+						if (UNEXPECTED(zend_ast_add_unpacked_element(result, &op1) != SUCCESS)) {
+							zval_ptr_dtor_nogc(&op1);
+							zval_ptr_dtor_nogc(result);
+							return FAILURE;
+						}
+						zval_ptr_dtor_nogc(&op1);
+						continue;
+					}
 					if (elem->child[1]) {
 						if (UNEXPECTED(zend_ast_evaluate(&op1, elem->child[1], scope) != SUCCESS)) {
 							zval_ptr_dtor_nogc(result);