diff --git a/Zend/tests/gh9500.phpt b/Zend/tests/gh9500.phpt
new file mode 100644
index 0000000000000..4afc8c579677f
--- /dev/null
+++ b/Zend/tests/gh9500.phpt
@@ -0,0 +1,25 @@
+--TEST--
+Bug GH-9500: Disjunctive Normal Form Types - readonly property followed by (
+--FILE--
+<?php
+class Dnf
+{
+    var A|(B&C) $a;
+    var (B&C)|A $b;
+    private A|(B&C) $c;
+    private (B&C)|A $d;
+    static A|(B&C) $e;
+    static (B&C)|A $f;
+    private static A|(B&C) $g;
+    private static (B&C)|A $h;
+    readonly private A|(B&C) $i;
+    readonly private (B&C)|A $j;
+    readonly A|(B&C) $k;
+    readonly (B&C)|A $l;
+    private readonly A|(B&C) $m;
+    private readonly (B&C)|A $n;
+}
+?>
+DONE
+--EXPECT--
+DONE
diff --git a/Zend/tests/readonly_function.phpt b/Zend/tests/readonly_function.phpt
index 0262b3b7348ce..35102d36b9dcd 100644
--- a/Zend/tests/readonly_function.phpt
+++ b/Zend/tests/readonly_function.phpt
@@ -7,10 +7,34 @@ function readonly() {
     echo "Hi!\n";
 }
 
+class A {
+    const readonly = 'Const hi!';
+
+    static function readonly() {
+        echo "Static hi!\n";
+    }
+}
+
+class B {
+    public $readonly = 'Prop hi!';
+
+    function readonly() {
+        echo "Instance hi!\n";
+    }
+}
+
+$b = new B();
+
 readonly();
-readonly ();
+echo A::readonly, "\n";
+A::readonly();
+$b->readonly();
+echo $b->readonly, "\n";
 
 ?>
 --EXPECT--
 Hi!
-Hi!
+Const hi!
+Static hi!
+Instance hi!
+Prop hi!
diff --git a/Zend/zend_language_parser.y b/Zend/zend_language_parser.y
index 7194f70b9d471..f0c6622171ae0 100644
--- a/Zend/zend_language_parser.y
+++ b/Zend/zend_language_parser.y
@@ -278,6 +278,7 @@ static YYSIZE_T zend_yytnamerr(char*, const char*);
 %type <ast> attribute_decl attribute attributes attribute_group namespace_declaration_name
 %type <ast> match match_arm_list non_empty_match_arm_list match_arm match_arm_cond_list
 %type <ast> enum_declaration_statement enum_backing_type enum_case enum_case_expr
+%type <ast> function_name
 
 %type <num> returns_ref function fn is_reference is_variadic variable_modifiers
 %type <num> method_modifiers non_empty_member_modifiers member_modifier
@@ -560,8 +561,17 @@ unset_variable:
 		variable { $$ = zend_ast_create(ZEND_AST_UNSET, $1); }
 ;
 
+function_name:
+		T_STRING { $$ = $1; }
+	|	T_READONLY {
+			zval zv;
+			if (zend_lex_tstring(&zv, $1) == FAILURE) { YYABORT; }
+			$$ = zend_ast_create_zval(&zv);
+		}
+;
+
 function_declaration_statement:
-	function returns_ref T_STRING backup_doc_comment '(' parameter_list ')' return_type
+	function returns_ref function_name backup_doc_comment '(' parameter_list ')' return_type
 	backup_fn_flags '{' inner_statement_list '}' backup_fn_flags
 		{ $$ = zend_ast_create_decl(ZEND_AST_FUNC_DECL, $2 | $13, $1, $4,
 		      zend_ast_get_str($3), $6, NULL, $11, $8, NULL); CG(extra_fn_flags) = $9; }
@@ -1270,6 +1280,11 @@ lexical_var:
 function_call:
 		name argument_list
 			{ $$ = zend_ast_create(ZEND_AST_CALL, $1, $2); }
+	|	T_READONLY argument_list {
+			zval zv;
+			if (zend_lex_tstring(&zv, $1) == FAILURE) { YYABORT; }
+			$$ = zend_ast_create(ZEND_AST_CALL, zend_ast_create_zval(&zv), $2);
+		}
 	|	class_name T_PAAMAYIM_NEKUDOTAYIM member_name argument_list
 			{ $$ = zend_ast_create(ZEND_AST_STATIC_CALL, $1, $3, $4); }
 	|	variable_class_name T_PAAMAYIM_NEKUDOTAYIM member_name argument_list
diff --git a/Zend/zend_language_scanner.l b/Zend/zend_language_scanner.l
index a367c2acb82da..c73a50948d6bc 100644
--- a/Zend/zend_language_scanner.l
+++ b/Zend/zend_language_scanner.l
@@ -1729,12 +1729,6 @@ NEWLINE ("\r"|"\n"|"\r\n")
 	RETURN_TOKEN_WITH_IDENT(T_READONLY);
 }
 
-/* Don't treat "readonly(" as a keyword, to allow using it as a function name. */
-<ST_IN_SCRIPTING>"readonly"[ \n\r\t]*"(" {
-	yyless(strlen("readonly"));
-	RETURN_TOKEN_WITH_STR(T_STRING, 0);
-}
-
 <ST_IN_SCRIPTING>"unset" {
 	RETURN_TOKEN_WITH_IDENT(T_UNSET);
 }