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[PFA 1/n] Support PFA syntax #20717

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677e251
Support PFA syntax
arnaud-lb Dec 16, 2025
905b311
Disallow FCC with more than one arg, or non-variadic placeholder
arnaud-lb Dec 16, 2025
1ac09e0
Review
arnaud-lb Dec 18, 2025
a65e668
Use distinct constants for AST attrs, simplify placeholder types
arnaud-lb Dec 18, 2025
098862d
Review
arnaud-lb Dec 18, 2025
54b61c8
Throw
arnaud-lb Dec 18, 2025
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10 changes: 10 additions & 0 deletions Zend/tests/first_class_callable/first_class_callable_non_unary_error.phpt
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Original file line number Diff line number Diff line change
@@ -0,0 +1,10 @@
--TEST--
First class callable error: more than one argument
--FILE--
<?php

foo(1, ...);

?>
--EXPECTF--
Fatal error: Cannot create a Closure for call expression with more than one argument, or non-variadic placeholders in %s on line %d
10 changes: 10 additions & 0 deletions Zend/tests/first_class_callable/first_class_callable_non_variadic_error.phpt
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Original file line number Diff line number Diff line change
@@ -0,0 +1,10 @@
--TEST--
First class callable error: non-variadic placeholder
--FILE--
<?php

foo(?);

?>
--EXPECTF--
Fatal error: Cannot create a Closure for call expression with more than one argument, or non-variadic placeholders in %s on line %d
127 changes: 122 additions & 5 deletions Zend/zend_ast.c
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Original file line number Diff line number Diff line change
Expand Up @@ -54,13 +54,14 @@ ZEND_API zend_ast * ZEND_FASTCALL zend_ast_create_znode(const znode *node) {
return (zend_ast *) ast;
}

ZEND_API zend_ast * ZEND_FASTCALL zend_ast_create_fcc(void) {
ZEND_API zend_ast * ZEND_FASTCALL zend_ast_create_fcc(zend_ast *args) {
zend_ast_fcc *ast;

ast = zend_ast_alloc(sizeof(zend_ast_fcc));
ast->kind = ZEND_AST_CALLABLE_CONVERT;
ast->attr = 0;
ast->lineno = CG(zend_lineno);
ast->args = args;
ZEND_MAP_PTR_INIT(ast->fptr, NULL);

return (zend_ast *) ast;
Expand Down Expand Up @@ -157,6 +158,12 @@ ZEND_API zend_ast *zend_ast_create_decl(
return (zend_ast *) ast;
}

static bool zend_ast_is_placeholder_arg(zend_ast *arg) {
return arg->kind == ZEND_AST_PLACEHOLDER_ARG
|| (arg->kind == ZEND_AST_NAMED_ARG
&& arg->child[1]->kind == ZEND_AST_PLACEHOLDER_ARG);
}

#if ZEND_AST_SPEC
ZEND_API zend_ast * ZEND_FASTCALL zend_ast_create_0(zend_ast_kind kind) {
zend_ast *ast;
Expand Down Expand Up @@ -400,6 +407,30 @@ ZEND_API zend_ast * ZEND_FASTCALL zend_ast_create_list_2(zend_ast_kind kind, zen

return ast;
}

ZEND_API zend_ast * ZEND_FASTCALL zend_ast_create_arg_list_0(zend_ast_kind kind) {
return zend_ast_create_list(0, kind);
}

ZEND_API zend_ast * ZEND_FASTCALL zend_ast_create_arg_list_1(zend_ast_kind kind, zend_ast *arg) {
zend_ast *list = zend_ast_create_list(1, kind, arg);

if (zend_ast_is_placeholder_arg(arg)) {
return zend_ast_create_fcc(list);
}

return list;
}

ZEND_API zend_ast * ZEND_FASTCALL zend_ast_create_arg_list_2(zend_ast_kind kind, zend_ast *arg1, zend_ast *arg2) {
zend_ast *list = zend_ast_create_list(2, kind, arg1, arg2);

if (zend_ast_is_placeholder_arg(arg1) || zend_ast_is_placeholder_arg(arg2)) {
return zend_ast_create_fcc(list);
}

return list;
}
#else
static zend_ast *zend_ast_create_from_va_list(zend_ast_kind kind, zend_ast_attr attr, va_list va) {
uint32_t i, children = kind >> ZEND_AST_NUM_CHILDREN_SHIFT;
Expand Down Expand Up @@ -479,6 +510,41 @@ ZEND_API zend_ast *zend_ast_create_list(uint32_t init_children, zend_ast_kind ki

return ast;
}

ZEND_API zend_ast *zend_ast_create_arg_list(uint32_t init_children, zend_ast_kind kind, ...) {
zend_ast *ast;
zend_ast_list *list;
bool has_placeholders = false;

ast = zend_ast_alloc(zend_ast_list_size(4));
list = (zend_ast_list *) ast;
list->kind = kind;
list->attr = 0;
list->lineno = CG(zend_lineno);
list->children = 0;

{
va_list va;
uint32_t i;
va_start(va, kind);
for (i = 0; i < init_children; ++i) {
zend_ast *child = va_arg(va, zend_ast *);
ast = zend_ast_list_add(ast, child);
uint32_t lineno = zend_ast_get_lineno(child);
if (lineno < ast->lineno) {
ast->lineno = lineno;
}
has_placeholders = has_placeholders || zend_ast_is_placeholder_arg(child);
}
va_end(va);
}

if (has_placeholders) {
return zend_ast_create_fcc(list);
}

return ast;
}
#endif

zend_ast *zend_ast_create_concat_op(zend_ast *op0, zend_ast *op1) {
Expand Down Expand Up @@ -508,6 +574,23 @@ ZEND_ATTRIBUTE_NODISCARD ZEND_API zend_ast * ZEND_FASTCALL zend_ast_list_add(zen
return (zend_ast *) list;
}

ZEND_API zend_ast * ZEND_FASTCALL zend_ast_arg_list_add(zend_ast *list, zend_ast *arg)
{
if (list->kind == ZEND_AST_CALLABLE_CONVERT) {
zend_ast_fcc *fcc_ast = (zend_ast_fcc*)list;
fcc_ast->args = zend_ast_list_add(fcc_ast->args, arg);
return (zend_ast*)fcc_ast;
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@TimWolla TimWolla Dec 16, 2025

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Not sure if this is clearer (the fcc_ast doesn't actually change):

Suggested change
return (zend_ast*)fcc_ast;
return list;

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@arnaud-lb arnaud-lb Dec 18, 2025

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I prefer return (zend_ast*)fcc_ast, but no strong opinion

}

ZEND_ASSERT(list->kind == ZEND_AST_ARG_LIST);

if (zend_ast_is_placeholder_arg(arg)) {
return zend_ast_create_fcc(zend_ast_list_add(list, arg));
}

return zend_ast_list_add(list, arg);
}

static zend_result zend_ast_add_array_element(const zval *result, zval *offset, zval *expr)
{
if (Z_TYPE_P(offset) == IS_UNDEF) {
Expand Down Expand Up @@ -1060,6 +1143,15 @@ static zend_result ZEND_FASTCALL zend_ast_evaluate_inner(
case ZEND_AST_CALL: {
ZEND_ASSERT(ast->child[1]->kind == ZEND_AST_CALLABLE_CONVERT);
zend_ast_fcc *fcc_ast = (zend_ast_fcc*)ast->child[1];

zend_ast_list *args = zend_ast_get_list(fcc_ast->args);
ZEND_ASSERT(args->children > 0);
if (args->children != 1 || args->child[0]->attr != ZEND_PLACEHOLDER_VARIADIC) {
/* TODO: PFAs */
zend_error_noreturn(E_COMPILE_ERROR, "Constant expression contains invalid operations");
return FAILURE;
}

fptr = ZEND_MAP_PTR_GET(fcc_ast->fptr);

if (!fptr) {
Expand Down Expand Up @@ -1087,6 +1179,14 @@ static zend_result ZEND_FASTCALL zend_ast_evaluate_inner(
ZEND_ASSERT(ast->child[2]->kind == ZEND_AST_CALLABLE_CONVERT);
zend_ast_fcc *fcc_ast = (zend_ast_fcc*)ast->child[2];

zend_ast_list *args = zend_ast_get_list(fcc_ast->args);
ZEND_ASSERT(args->children > 0);
if (args->children != 1 || args->child[0]->attr != ZEND_PLACEHOLDER_VARIADIC) {
/* TODO: PFAs */
zend_error_noreturn(E_COMPILE_ERROR, "Constant expression contains invalid operations");
return FAILURE;
}

zend_class_entry *ce = zend_ast_fetch_class(ast->child[0], scope);
if (!ce) {
return FAILURE;
Expand Down Expand Up @@ -1243,7 +1343,8 @@ static size_t ZEND_FASTCALL zend_ast_tree_size(zend_ast *ast)
} else if (ast->kind == ZEND_AST_OP_ARRAY) {
size = sizeof(zend_ast_op_array);
} else if (ast->kind == ZEND_AST_CALLABLE_CONVERT) {
size = sizeof(zend_ast_fcc);
zend_ast *args_ast = ((zend_ast_fcc*)ast)->args;
size = sizeof(zend_ast_fcc) + zend_ast_tree_size(args_ast);
} else if (zend_ast_is_list(ast)) {
uint32_t i;
const zend_ast_list *list = zend_ast_get_list(ast);
Expand Down Expand Up @@ -1320,6 +1421,8 @@ static void* ZEND_FASTCALL zend_ast_tree_copy(zend_ast *ast, void *buf)
new->lineno = old->lineno;
ZEND_MAP_PTR_INIT(new->fptr, ZEND_MAP_PTR(old->fptr));
buf = (void*)((char*)buf + sizeof(zend_ast_fcc));
new->args = buf;
buf = zend_ast_tree_copy(old->args, buf);
} else if (zend_ast_is_decl(ast)) {
/* Not implemented. */
ZEND_UNREACHABLE();
Expand Down Expand Up @@ -1403,6 +1506,11 @@ ZEND_API void ZEND_FASTCALL zend_ast_destroy(zend_ast *ast)
zend_ast_destroy(decl->child[3]);
ast = decl->child[4];
goto tail_call;
} else if (EXPECTED(ast->kind == ZEND_AST_CALLABLE_CONVERT)) {
zend_ast_fcc *fcc_ast = (zend_ast_fcc*) ast;

ast = fcc_ast->args;
goto tail_call;
}
}

Expand Down Expand Up @@ -2299,6 +2407,13 @@ static ZEND_COLD void zend_ast_export_ex(smart_str *str, zend_ast *ast, int prio
EMPTY_SWITCH_DEFAULT_CASE();
}
break;
case ZEND_AST_PLACEHOLDER_ARG:
if (ast->attr == ZEND_PLACEHOLDER_VARIADIC) {
APPEND_STR("...");
} else {
APPEND_STR("?");
}
break;

/* 1 child node */
case ZEND_AST_VAR:
Expand Down Expand Up @@ -2445,9 +2560,11 @@ static ZEND_COLD void zend_ast_export_ex(smart_str *str, zend_ast *ast, int prio
zend_ast_export_ex(str, ast->child[1], 0, indent);
smart_str_appendc(str, ')');
break;
case ZEND_AST_CALLABLE_CONVERT:
smart_str_appends(str, "...");
break;
case ZEND_AST_CALLABLE_CONVERT: {
zend_ast_fcc *fcc_ast = (zend_ast_fcc*)ast;
ast = fcc_ast->args;
goto simple_list;
}
case ZEND_AST_CLASS_CONST:
zend_ast_export_ns_name(str, ast->child[0], 0, indent);
smart_str_appends(str, "::");
Expand Down
17 changes: 16 additions & 1 deletion Zend/zend_ast.h
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Original file line number Diff line number Diff line change
Expand Up @@ -76,6 +76,7 @@ enum _zend_ast_kind {
ZEND_AST_TYPE,
ZEND_AST_CONSTANT_CLASS,
ZEND_AST_CALLABLE_CONVERT,
ZEND_AST_PLACEHOLDER_ARG,

/* 1 child node */
ZEND_AST_VAR = 1 << ZEND_AST_NUM_CHILDREN_SHIFT,
Expand Down Expand Up @@ -229,10 +230,12 @@ typedef struct _zend_ast_decl {
zend_ast *child[5];
} zend_ast_decl;

// TODO: rename
typedef struct _zend_ast_fcc {
zend_ast_kind kind; /* Type of the node (ZEND_AST_* enum constant) */
zend_ast_attr attr; /* Additional attribute, use depending on node type */
uint32_t lineno; /* Line number */
zend_ast *args;
ZEND_MAP_PTR_DEF(zend_function *, fptr);
} zend_ast_fcc;

Expand Down Expand Up @@ -307,27 +310,39 @@ ZEND_API zend_ast * ZEND_FASTCALL zend_ast_create_list_0(zend_ast_kind kind);
ZEND_API zend_ast * ZEND_FASTCALL zend_ast_create_list_1(zend_ast_kind kind, zend_ast *child);
ZEND_API zend_ast * ZEND_FASTCALL zend_ast_create_list_2(zend_ast_kind kind, zend_ast *child1, zend_ast *child2);

ZEND_API zend_ast * ZEND_FASTCALL zend_ast_create_arg_list_0(zend_ast_kind kind);
ZEND_API zend_ast * ZEND_FASTCALL zend_ast_create_arg_list_1(zend_ast_kind kind, zend_ast *child);
ZEND_API zend_ast * ZEND_FASTCALL zend_ast_create_arg_list_2(zend_ast_kind kind, zend_ast *child1, zend_ast *child2);

# define zend_ast_create(...) \
ZEND_AST_SPEC_CALL(zend_ast_create, __VA_ARGS__)
# define zend_ast_create_ex(...) \
ZEND_AST_SPEC_CALL_EX(zend_ast_create_ex, __VA_ARGS__)
# define zend_ast_create_list(init_children, ...) \
ZEND_AST_SPEC_CALL(zend_ast_create_list, __VA_ARGS__)
# define zend_ast_create_arg_list(init_children, ...) \
ZEND_AST_SPEC_CALL(zend_ast_create_arg_list, __VA_ARGS__)

#else
ZEND_API zend_ast *zend_ast_create(zend_ast_kind kind, ...);
ZEND_API zend_ast *zend_ast_create_ex(zend_ast_kind kind, zend_ast_attr attr, ...);
ZEND_API zend_ast *zend_ast_create_list(uint32_t init_children, zend_ast_kind kind, ...);
ZEND_API zend_ast *zend_ast_create_arg_list(uint32_t init_children, zend_ast_kind kind, ...);
#endif

ZEND_ATTRIBUTE_NODISCARD ZEND_API zend_ast * ZEND_FASTCALL zend_ast_list_add(zend_ast *list, zend_ast *op);

/* Like zend_ast_list_add(), but wraps the list into a ZEND_AST_CALLABLE_CONVERT
* if any arg is a ZEND_AST_PLACEHOLDER_ARG. list can be a zend_ast_list, or a
* zend_ast_fcc. */
ZEND_API zend_ast * ZEND_FASTCALL zend_ast_arg_list_add(zend_ast *list, zend_ast *arg);

ZEND_API zend_ast *zend_ast_create_decl(
zend_ast_kind kind, uint32_t flags, uint32_t start_lineno, zend_string *doc_comment,
zend_string *name, zend_ast *child0, zend_ast *child1, zend_ast *child2, zend_ast *child3, zend_ast *child4
);

ZEND_API zend_ast * ZEND_FASTCALL zend_ast_create_fcc(void);
ZEND_API zend_ast * ZEND_FASTCALL zend_ast_create_fcc(zend_ast *args);

typedef struct {
bool had_side_effects;
Expand Down
5 changes: 5 additions & 0 deletions Zend/zend_compile.c
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Expand Up @@ -3950,6 +3950,11 @@ static bool zend_compile_call_common(znode *result, zend_ast *args_ast, const ze
zend_error_noreturn(E_COMPILE_ERROR, "Cannot create Closure for new expression");
}

zend_ast_list *args = zend_ast_get_list(((zend_ast_fcc*)args_ast)->args);
if (args->children != 1 || args->child[0]->attr != ZEND_PLACEHOLDER_VARIADIC) {
zend_error_noreturn(E_COMPILE_ERROR, "Cannot create a Closure for call expression with more than one argument, or non-variadic placeholders");
}

if (opcode == ZEND_INIT_FCALL) {
opline->op1.num = zend_vm_calc_used_stack(0, fbc);
}
Expand Down
3 changes: 3 additions & 0 deletions Zend/zend_compile.h
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Expand Up @@ -1236,6 +1236,9 @@ static zend_always_inline bool zend_check_arg_send_type(const zend_function *zf,
#define ZEND_IS_BINARY_ASSIGN_OP_OPCODE(opcode) \
(((opcode) >= ZEND_ADD) && ((opcode) <= ZEND_POW))

/* PFAs/FCCs */
#define ZEND_PLACEHOLDER_VARIADIC (1<<0)

/* Pseudo-opcodes that are used only temporarily during compilation */
#define ZEND_GOTO 253
#define ZEND_BRK 254
Expand Down
27 changes: 16 additions & 11 deletions Zend/zend_language_parser.y
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Expand Up @@ -901,16 +901,15 @@ return_type:
;

argument_list:
'(' ')' { $$ = zend_ast_create_list(0, ZEND_AST_ARG_LIST); }
'(' ')' { $$ = zend_ast_create_arg_list(0, ZEND_AST_ARG_LIST); }
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@ndossche ndossche Jan 2, 2026

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zend_ast_create_arg_list is always used with ZEND_AST_ARG_LIST. Looks a bit redundant but perhaps this is for the future proofing.

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@arnaud-lb arnaud-lb Jan 3, 2026 •
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I considered this, but the variadic specialization trick implicitly expects the kind argument before the variadic ones, and I didn't want to create another variant of the specialization macro.

zend_ast_create_arg_list(init_children, ...) is defined as ZEND_AST_SPEC_CALL(zend_ast_create_arg_list, __VA_ARGS__), so that a call to zend_ast_create_arg_list() expands to zend_ast_create_arg_list_N(__VA_ARGS__) with N the number of va_args minus 1. As a result, zend_ast_create_arg_list(0, child1) expands to zend_ast_create_arg_list_0(child1), which is incorrect (should be zend_ast_create_arg_list_1(child1)).

| '(' non_empty_argument_list possible_comma ')' { $$ = $2; }
| '(' T_ELLIPSIS ')' { $$ = zend_ast_create_fcc(); }
;

non_empty_argument_list:
argument
{ $$ = zend_ast_create_list(1, ZEND_AST_ARG_LIST, $1); }
{ $$ = zend_ast_create_arg_list(1, ZEND_AST_ARG_LIST, $1); }
| non_empty_argument_list ',' argument
{ $$ = zend_ast_list_add($1, $3); }
{ $$ = zend_ast_arg_list_add($1, $3); }
;

/* `clone_argument_list` is necessary to resolve a parser ambiguity (shift-reduce conflict)
Expand All @@ -923,25 +922,31 @@ non_empty_argument_list:
* syntax.
*/
clone_argument_list:
'(' ')' { $$ = zend_ast_create_list(0, ZEND_AST_ARG_LIST); }
'(' ')' { $$ = zend_ast_create_arg_list(0, ZEND_AST_ARG_LIST); }
| '(' non_empty_clone_argument_list possible_comma ')' { $$ = $2; }
| '(' expr ',' ')' { $$ = zend_ast_create_list(1, ZEND_AST_ARG_LIST, $2); }
| '(' T_ELLIPSIS ')' { $$ = zend_ast_create_fcc(); }
| '(' expr ',' ')' { $$ = zend_ast_create_arg_list(1, ZEND_AST_ARG_LIST, $2); }
;

non_empty_clone_argument_list:
expr ',' argument
{ $$ = zend_ast_create_list(2, ZEND_AST_ARG_LIST, $1, $3); }
{ $$ = zend_ast_create_arg_list(2, ZEND_AST_ARG_LIST, $1, $3); }
| argument_no_expr
{ $$ = zend_ast_create_list(1, ZEND_AST_ARG_LIST, $1); }
{ $$ = zend_ast_create_arg_list(1, ZEND_AST_ARG_LIST, $1); }
| non_empty_clone_argument_list ',' argument
{ $$ = zend_ast_list_add($1, $3); }
{ $$ = zend_ast_arg_list_add($1, $3); }
;

argument_no_expr:
identifier ':' expr
{ $$ = zend_ast_create(ZEND_AST_NAMED_ARG, $1, $3); }
| T_ELLIPSIS expr { $$ = zend_ast_create(ZEND_AST_UNPACK, $2); }
| T_ELLIPSIS
{ $$ = zend_ast_create_ex(ZEND_AST_PLACEHOLDER_ARG, ZEND_PLACEHOLDER_VARIADIC); }
| '?'
{ $$ = zend_ast_create(ZEND_AST_PLACEHOLDER_ARG); }
| identifier ':' '?'
{ $$ = zend_ast_create(ZEND_AST_NAMED_ARG, $1, zend_ast_create(ZEND_AST_PLACEHOLDER_ARG)); }
| T_ELLIPSIS expr
{ $$ = zend_ast_create(ZEND_AST_UNPACK, $2); }
;

argument:
Expand Down
3 changes: 3 additions & 0 deletions Zend/zend_types.h
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Original file line number Diff line number Diff line change
Expand Up @@ -638,6 +638,9 @@ struct _zend_ast_ref {
#define _IS_BOOL 18
#define _IS_NUMBER 19

/* used for PFAs/FCCs */
#define _IS_PLACEHOLDER 20

/* guard flags */
#define ZEND_GUARD_PROPERTY_GET (1<<0)
#define ZEND_GUARD_PROPERTY_SET (1<<1)
Expand Down
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