feat: single expression functions

Zend/tests/short_function/global_declaration.phpt

@@ -0,0 +1,26 @@
+--TEST--
+Short global function declaration
+--FILE--
+<?php
+function buz(): int => 123;
+echo buz() . PHP_EOL;
+
+function compare(int $what, int $with): string => match(true) {
+     $what > $with => "greater",
+     $what < $with => "less",
+     $what == $with => "equals",
+    default => throw new Exception("Unreachable statement"),
+};
+
+var_dump(compare(1, 2));
+var_dump(compare(20, 10));
+var_dump(compare(5, 5));
+
+echo "done";
+?>
+--EXPECT--
+123
+string(4) "less"
+string(7) "greater"
+string(6) "equals"
+done

Zend/tests/short_function/inline_function.phpt

@@ -0,0 +1,17 @@
+--TEST--
+Inline short declaration function
+--FILE--
+<?php
+$f = function() => 123;
+
+var_dump($f());
+var_dump((function() => null)());
+var_dump(get_debug_type(function() => null()));
+var_dump(get_debug_type((function() => null)()));
+
+?>
+--EXPECT--
+int(123)
+NULL
+string(7) "Closure"
+string(4) "null"

Zend/tests/short_function/inline_function_deref.phpt

@@ -0,0 +1,28 @@
+--TEST--
+Inline short declaration function dereference
+--FILE--
+<?php
+
+function a () {
+    $a = function() => 123;
+    $b = function() => $a;
+
+    return $b;
+}
+
+var_dump(get_debug_type( a()() ));
+
+function b () {
+    $a = fn() => 123;
+    $b = fn() => $a;
+
+    return $b;
+}
+
+var_dump(get_debug_type( b()() ));
+
+?>
+--EXPECTF--
+Warning: Undefined variable $a in %s on line %d
+string(4) "null"
+string(7) "Closure"

Zend/tests/short_function/method_declaration.phpt

@@ -0,0 +1,40 @@
+--TEST--
+Short function method declaration
+--FILE--
+<?php
+class Decorator {
+  public $proxy;
+  function getId() => $this->proxy->id;
+  function getName() => $this->proxy->name;
+
+  function setId($value) => $this->proxy->id = $value;
+  function setName($value) => $this->proxy->name = $value;
+}
+
+$decorated = new stdClass;
+$decorated->id = null;
+$decorated->name = null;
+
+$decorator = new Decorator;
+$decorator->proxy = $decorated;
+
+var_dump($decorated);
+
+$decorator->setId(1);
+$decorator->setName('Dmitrii');
+
+var_dump($decorated);
+?>
+--EXPECT--
+object(stdClass)#1 (2) {
+  ["id"]=>
+  NULL
+  ["name"]=>
+  NULL
+}
+object(stdClass)#1 (2) {
+  ["id"]=>
+  int(1)
+  ["name"]=>
+  string(7) "Dmitrii"
+}

Zend/tests/short_function/method_declaration2.phpt

@@ -0,0 +1,14 @@
+--TEST--
+Short function method declaration
+--FILE--
+<?php
+class Describer {
+  function getType(): string => $this->type;
+  function getTypeName(): string => match($type) {
+    "variable" => "Variable",
+    "function_return" => "Function Return Type",
+    default => "unknown"
+  };
+}
+?>
+--EXPECT--

Zend/tests/short_function/possible_declaration.phpt

@@ -0,0 +1,11 @@
+--TEST--
+Test possible declarations for expr&stmt options
+--FILE--
+<?php
+function expr() => 123; // returns 123
+
+var_dump(expr());
+
+?>
+--EXPECT--
+int(123)

Zend/tests/type_declarations/intersection_types/invalid_types/invalid_nullable_type.phpt

@@ -7,4 +7,4 @@ function foo(): ?Countable&Iterator {}
 
 ?>
 --EXPECTF--
-Parse error: syntax error, unexpected token "&", expecting "{" in %s on line %d
+Parse error: syntax error, unexpected token "&", expecting "=>" or "{" in %s on line %d

Zend/zend_compile.c

@@ -8365,7 +8365,7 @@ static zend_op_array *zend_compile_func_decl_ex(
 		zend_compile_closure_uses(uses_ast);
 	}
 
-	if (ast->kind == ZEND_AST_ARROW_FUNC && decl->child[2]->kind != ZEND_AST_RETURN) {
+	if (decl->flags & ZEND_ACC_SHORT_DECLARATION && stmt_ast->kind != ZEND_AST_RETURN) {
 		bool needs_return = true;
 		if (op_array->fn_flags & ZEND_ACC_HAS_RETURN_TYPE) {
 			zend_arg_info *return_info = CG(active_op_array)->arg_info - 1;

Zend/zend_compile.h

@@ -333,7 +333,7 @@ typedef struct _zend_oparray_context {
 /* Class cannot be serialized or unserialized             |     |     |     */
 #define ZEND_ACC_NOT_SERIALIZABLE        (1 << 29) /*  X  |     |     |     */
 /*                                                        |     |     |     */
-/* Function Flags (unused: 29-30)                         |     |     |     */
+/* Function Flags (unused: 30)                            |     |     |     */
 /* ==============                                         |     |     |     */
 /*                                                        |     |     |     */
 /* deprecation flag                                       |     |     |     */
@@ -395,6 +395,9 @@ typedef struct _zend_oparray_context {
 /* has #[\Override] attribute                             |     |     |     */
 #define ZEND_ACC_OVERRIDE                (1 << 28) /*     |  X  |     |     */
 /*                                                        |     |     |     */
+/* Function returning by reference						  |     |     |     */
+#define ZEND_ACC_SHORT_DECLARATION       (1 << 29) /*     |  X  |     |     */
+/*                                                        |     |     |     */
 /* op_array uses strict mode types                        |     |     |     */
 #define ZEND_ACC_STRICT_TYPES            (1U << 31) /*    |  X  |     |     */
 

Zend/zend_language_parser.y

@@ -248,7 +248,7 @@ static YYSIZE_T zend_yytnamerr(char*, const char*);
 /* Token used to force a parse error from the lexer */
 %token T_ERROR
 
-%type <ast> top_statement namespace_name name statement function_declaration_statement
+%type <ast> top_statement namespace_name name statement function_declaration_statement function_body inline_function_body
 %type <ast> class_declaration_statement trait_declaration_statement legacy_namespace_name
 %type <ast> interface_declaration_statement interface_extends_list
 %type <ast> group_use_declaration inline_use_declarations inline_use_declaration
@@ -578,9 +578,15 @@ function_name:
 
 function_declaration_statement:
 	function returns_ref function_name backup_doc_comment '(' parameter_list ')' return_type
-	backup_fn_flags '{' inner_statement_list '}' backup_fn_flags
-		{ $$ = zend_ast_create_decl(ZEND_AST_FUNC_DECL, $2 | $13, $1, $4,
-		      zend_ast_get_str($3), $6, NULL, $11, $8, NULL); CG(extra_fn_flags) = $9; }
+	backup_fn_flags function_body backup_fn_flags
+		{ $$ = zend_ast_create_decl(ZEND_AST_FUNC_DECL, $2 | $11, $1, $4,
+		      zend_ast_get_str($3), $6, NULL, $10, $8, NULL); CG(extra_fn_flags) = $9; }
+;
+
+function_body:
+        '{' inner_statement_list '}'    { $$ = $2; }
+    |   T_DOUBLE_ARROW expr ';'
+			{ $$ = $2; CG(extra_fn_flags) |= ZEND_ACC_SHORT_DECLARATION; }
 ;
 
 is_reference:
@@ -1030,6 +1036,8 @@ absolute_trait_method_reference:
 method_body:
 		';' /* abstract method */		{ $$ = NULL; }
 	|	'{' inner_statement_list '}'	{ $$ = $2; }
+	|	T_DOUBLE_ARROW expr ';'
+	        { $$ = $2; CG(extra_fn_flags) |= ZEND_ACC_SHORT_DECLARATION; }
 ;
 
 property_modifiers:
@@ -1335,17 +1343,23 @@ expr:
 
 inline_function:
 		function returns_ref backup_doc_comment '(' parameter_list ')' lexical_vars return_type
-		backup_fn_flags '{' inner_statement_list '}' backup_fn_flags
-			{ $$ = zend_ast_create_decl(ZEND_AST_CLOSURE, $2 | $13, $1, $3,
+		backup_fn_flags inline_function_body backup_fn_flags
+			{ $$ = zend_ast_create_decl(ZEND_AST_CLOSURE, $2 | $11, $1, $3,
 				  NULL,
-				  $5, $7, $11, $8, NULL); CG(extra_fn_flags) = $9; }
+				  $5, $7, $10, $8, NULL); CG(extra_fn_flags) = $9; }
 	|	fn returns_ref backup_doc_comment '(' parameter_list ')' return_type
 		T_DOUBLE_ARROW backup_fn_flags backup_lex_pos expr backup_fn_flags
-			{ $$ = zend_ast_create_decl(ZEND_AST_ARROW_FUNC, $2 | $12, $1, $3,
+			{ $$ = zend_ast_create_decl(ZEND_AST_ARROW_FUNC, $2 | $12 | ZEND_ACC_SHORT_DECLARATION, $1, $3,
 				  NULL, $5, NULL, $11, $7, NULL);
 				  CG(extra_fn_flags) = $9; }
 ;
 
+inline_function_body:
+        '{' inner_statement_list '}'    { $$ = $2; }
+    |   T_DOUBLE_ARROW expr
+			{ $$ = $2; CG(extra_fn_flags) |= ZEND_ACC_SHORT_DECLARATION; }
+;
+
 fn:
 	T_FN { $$ = CG(zend_lineno); }
 ;