Forbid unpacking in arrays with explicit keys

Zend/tests/array_unpack/with_keys_1.phpt

@@ -0,0 +1,11 @@
+--TEST--
+Cannot unpack in array with keys
+--FILE--
+<?php
+
+$ary = [1, 2, 3];
+$ary2 = [42 => 0, ...$ary];
+
+?>
+--EXPECTF--
+Fatal error: Cannot use unpacking in arrays with explicit keys in %s on line %d

Zend/tests/array_unpack/with_keys_2.phpt

@@ -0,0 +1,11 @@
+--TEST--
+Cannot unpack in array with keys (2)
+--FILE--
+<?php
+
+$ary = [1, 2, 3];
+$ary2 = [...$ary, 'a' => 4];
+
+?>
+--EXPECTF--
+Fatal error: Cannot use unpacking in arrays with explicit keys in %s on line %d

Zend/zend_compile.c

@@ -6946,6 +6946,8 @@ static zend_bool zend_try_ct_eval_array(zval *result, zend_ast *ast) /* {{{ */
 	zend_ast *last_elem_ast = NULL;
 	uint32_t i;
 	zend_bool is_constant = 1;
+	zend_bool has_explicit_keys = 0;
+	uint32_t unpack_lineno = (uint32_t)-1;
 
 	if (ast->attr == ZEND_ARRAY_SYNTAX_LIST) {
 		zend_error(E_COMPILE_ERROR, "Cannot use list() as standalone expression");
@@ -6972,7 +6974,11 @@ static zend_bool zend_try_ct_eval_array(zval *result, zend_ast *ast) /* {{{ */
 			) {
 				is_constant = 0;
 			}
+			if (elem_ast->child[1]) {
+				has_explicit_keys = 1;
+			}
 		} else {
+			unpack_lineno = zend_ast_get_lineno(elem_ast);
 			zend_eval_const_expr(&elem_ast->child[0]);
 
 			if (elem_ast->child[0]->kind != ZEND_AST_ZVAL) {
@@ -6983,6 +6989,11 @@ static zend_bool zend_try_ct_eval_array(zval *result, zend_ast *ast) /* {{{ */
 		last_elem_ast = elem_ast;
 	}
 
+	if (has_explicit_keys && unpack_lineno != (uint32_t) -1) {
+		CG(zend_lineno) = unpack_lineno;
+		zend_error_noreturn(E_COMPILE_ERROR, "Cannot use unpacking in arrays with explicit keys");
+	}
+
 	if (!is_constant) {
 		return 0;
 	}