diff --git a/embed.fnc b/embed.fnc
index f669d1822af5..9bf834d8e927 100644
--- a/embed.fnc
+++ b/embed.fnc
@@ -5497,7 +5497,7 @@ CRip	|bool	|check_regnode_after					\
 				|const STRLEN extra
 CRip	|regnode *|regnext	|NULLOK const regnode *p
 CRip	|regnode *|regnode_after|NULLOK const regnode *p		\
-				|bool varies
+				|const bool varies
 # if defined(DEBUGGING)
 Ep	|void	|debug_peep	|NN const char *str			\
 				|NN const RExC_state_t *pRExC_state	\
diff --git a/proto.h b/proto.h
index 15bb8df97e7b..027948aba2cc 100644
--- a/proto.h
+++ b/proto.h
@@ -8853,7 +8853,7 @@ Perl_regnext(pTHX_ const regnode *p)
 #   define PERL_ARGS_ASSERT_REGNEXT
 
 PERL_STATIC_INLINE regnode *
-Perl_regnode_after(pTHX_ const regnode *p, bool varies)
+Perl_regnode_after(pTHX_ const regnode *p, const bool varies)
         __attribute__warn_unused_result__;
 #   define PERL_ARGS_ASSERT_REGNODE_AFTER