diff --git a/resources/RegexGrammar.pp b/resources/RegexGrammar.pp
index b2cc45d89f..dd5b988d52 100644
--- a/resources/RegexGrammar.pp
+++ b/resources/RegexGrammar.pp
@@ -135,7 +135,7 @@
     alternation()
 
 alternation:
-    concatenation()? ( ::alternation:: concatenation()? #alternation )*
+    concatenation()? ( <alternation> concatenation()? #alternation )*
 
 concatenation:
     (   internal_options() | assertion() | quantification() | condition() )
@@ -155,7 +155,7 @@
       | ::assertion_reference_:: alternation() #assertioncondition
     )
     ::_capturing:: concatenation()?
-    ( ::alternation:: concatenation()? )?
+    ( <alternation> concatenation()? )?
     ::_capturing::
 
 assertion: