diff --git a/reference/constraints/Charset.rst b/reference/constraints/Charset.rst
index 278ea570831..4f1a260356f 100644
--- a/reference/constraints/Charset.rst
+++ b/reference/constraints/Charset.rst
@@ -89,7 +89,7 @@ Options
 An encoding or a set of encodings to check against. If you pass an array of
 encodings, the validator will check if the value is encoded in *any* of the
 encodings. This option accepts any value that can be passed to
-:phpfunction:`mb_detect_encoding()`.
+:phpfunction:`mb_detect_encoding`.
 
 .. include:: /reference/constraints/_groups-option.rst.inc