Add support for short methods.

Author: Crell

Zend/tests/short_functions/short-method.phpt

@@ -0,0 +1,19 @@
+--TEST--
+Basic short functions return values.
+--FILE--
+<?php
+
+class Test {
+
+    public function __construct(private int $b) {}
+
+    public function addUp(int $a) => $a + $this->b;
+}
+
+$t = new Test(1);
+
+print $t->addUp(5);
+
+?>
+--EXPECT--
+6

Zend/zend_language_parser.y

@@ -927,6 +927,7 @@ absolute_trait_method_reference:
 method_body:
 		';' /* abstract method */		{ $$ = NULL; }
 	|	'{' inner_statement_list '}'	{ $$ = $2; }
+	|   T_DOUBLE_ARROW inner_statement  { $$ = zend_ast_create(ZEND_AST_RETURN, $2); }
 ;
 
 variable_modifiers: