Added support for passing default using named arguments to closures.

Author: Bilge

Zend/tests/default_expression/named_arguments_closure.phpt

@@ -0,0 +1,10 @@
+--TEST--
+Tests passing default as a named argument to a closure
+--FILE--
+<?php
+
+$F = fn ($V = 1, $default = 2) => $V + $default;
+var_dump($F(default: default + 1));
+?>
+--EXPECT--
+int(4)

Zend/tests/default_expression/named_arguments_nonexistent.phpt

@@ -0,0 +1,12 @@
+--TEST--
+Tests passing default as a named argument to a closure that doesn't declare any argument by that name
+--FILE--
+<?php
+
+$F = fn ($V = 1) => $V;
+var_dump($F(default: default + 1));
+?>
+--EXPECTF--
+Fatal error: Uncaught ValueError: Cannot pass default to undeclared named parameter $default of {closure:%s:%d}() in %s:%d
+Stack trace:
+%a

Zend/tests/default_expression/nested_mixed_arguments.phpt

@@ -0,0 +1,10 @@
+--TEST--
+Tests passing default to a named parent argument whilst calling child arguments positionally
+--FILE--
+<?php
+
+$F = fn ($X = 1, $Y = 2) => $X + $Y;
+var_dump($F(X: $F(0, 1) + default));
+?>
+--EXPECTF--
+int(4)

Zend/tests/default_expression/nested_named_arguments.phpt

@@ -0,0 +1,10 @@
+--TEST--
+Tests passing default to a named parent argument that is different from the child call's last named argument
+--FILE--
+<?php
+
+$F = fn ($X = 1, $Y = 2) => $X + $Y;
+var_dump($F(X: $F(X: 0, Y: 1) + default));
+?>
+--EXPECTF--
+int(4)

Zend/zend_compile.c

@@ -3703,6 +3703,7 @@ static uint32_t zend_compile_args(
 	bool uses_arg_unpack = 0;
 	uint32_t arg_count = 0; /* number of arguments not including unpacks */
 	uint32_t prev_arg_num = CG(context).arg_num;
+	zend_string *prev_arg_name = CG(context).arg_name;
 
 	/* Whether named arguments are used syntactically, to enforce language level limitations.
 	 * May not actually use named argument passing. */
@@ -3781,6 +3782,7 @@ static uint32_t zend_compile_args(
 		}
 
 		CG(context).arg_num = arg_num;
+		CG(context).arg_name = arg_name;
 
 		/* Treat passing of $GLOBALS the same as passing a call.
 		 * This will error at runtime if the argument is by-ref. */
@@ -3897,6 +3899,7 @@ static uint32_t zend_compile_args(
 	}
 
 	CG(context).arg_num = prev_arg_num;
+	CG(context).arg_name = prev_arg_name;
 
 	return arg_count;
 }
@@ -3905,13 +3908,20 @@ static uint32_t zend_compile_args(
 static void zend_compile_default(znode *result, zend_ast *ast)
 {
 	uint32_t arg_num = CG(context).arg_num;
+	zend_string *arg_name = CG(context).arg_name;
 
 	if (arg_num == 0) {
 		zend_error_noreturn(E_COMPILE_ERROR, "Cannot use default in non-argument context.");
 	}
 
 	zend_op *opline = zend_emit_op_tmp(result, ZEND_FETCH_DEFAULT_ARG, NULL, NULL);
 	opline->op1.num = arg_num;
+
+	if (arg_num == (uint32_t) -1) {
+		opline->op1_type = IS_CONST;
+		zend_string_addref(arg_name);
+		opline->op1.constant = zend_add_literal_string(&arg_name);
+	}
 }
 
 ZEND_API uint8_t zend_get_call_op(const zend_op *init_op, zend_function *fbc) /* {{{ */

Zend/zend_compile.h

@@ -208,6 +208,7 @@ typedef struct _zend_oparray_context {
 	zend_property_hook_kind active_property_hook_kind;
 	bool       in_jmp_frameless_branch;
 	uint32_t arg_num; // Current 1-based argument index if compiling arguments, otherwise zero.
+	zend_string *arg_name;
 } zend_oparray_context;
 
 /* Class, property and method flags                  class|meth.|prop.|const*/

Zend/zend_vm_def.h

@@ -9808,7 +9808,7 @@ ZEND_VM_HANDLER(209, ZEND_INIT_PARENT_PROPERTY_HOOK_CALL, CONST, UNUSED|NUM, NUM
 	ZEND_VM_NEXT_OPCODE();
 }
 
-ZEND_VM_HANDLER(210, ZEND_FETCH_DEFAULT_ARG, UNUSED|NUM, UNUSED)
+ZEND_VM_HANDLER(210, ZEND_FETCH_DEFAULT_ARG, UNUSED|NUM|CONST, UNUSED)
 {
 	USE_OPLINE
 	SAVE_OPLINE();
@@ -9817,16 +9817,33 @@ ZEND_VM_HANDLER(210, ZEND_FETCH_DEFAULT_ARG, UNUSED|NUM, UNUSED)
 	ZVAL_UNDEF(EX_VAR(opline->result.var));
 
 	zend_function *called_func = EX(call)->func;
-
 	reflection_parameter_reference param;
-	param.offset = opline->op1.num - 1;
+	param.offset = (uint32_t) -1;
+
+	zend_string *arg_name;
+	if (OP1_TYPE == IS_CONST) {
+		arg_name = Z_STR_P(RT_CONSTANT(opline, opline->op1));
+
+		for (uint32_t i = 0; i < called_func->common.num_args; ++i) {
+			if (zend_string_equals(arg_name, called_func->common.arg_info[i].name)) {
+				param.offset = i;
+				break;
+			}
+		}
+	} else {
+		param.offset = opline->op1.num - 1;
+	}
+
 	param.required = param.offset < called_func->common.required_num_args;
 	param.fptr = called_func;
 
 	if (UNEXPECTED(param.required || param.offset >= called_func->common.num_args)) {
-		zend_value_error("Cannot pass default to %s parameter %u of %s%s%s()",
+		zend_value_error(
+			OP1_TYPE == IS_CONST
+				? "Cannot pass default to %s named parameter $%s of %s%s%s()"
+				: "Cannot pass default to %s parameter %u of %s%s%s()",
 			param.required ? "required" : "undeclared",
-			opline->op1.num,
+			OP1_TYPE == IS_CONST ? ZSTR_VAL(arg_name) : opline->op1.num,
 			called_func->common.scope ? ZSTR_VAL(called_func->common.scope->name) : "",
 			called_func->common.scope ? "::" : "",
 			ZSTR_VAL(called_func->common.function_name)