diff --git a/embed.fnc b/embed.fnc
index 862f5f1578b6..3ffb19bb1ce0 100644
--- a/embed.fnc
+++ b/embed.fnc
@@ -3068,23 +3068,23 @@ Adfpv	|void	|sv_catpvf_mg	|NN SV * const sv			\
 				|...
 Adp	|void	|sv_catpv_mg	|NN SV * const dsv			\
 				|NULLOK const char * const sstr
-AMbdp	|void	|sv_catpvn	|NN SV *dsv				\
+AMbdp	|void	|sv_catpvn	|NN SV * const dsv			\
 				|NN const char *sstr			\
 				|STRLEN len
 Adp	|void	|sv_catpvn_flags|NN SV * const dsv			\
 				|NN const char *sstr			\
 				|const STRLEN len			\
 				|const I32 flags
-AMbdp	|void	|sv_catpvn_mg	|NN SV *dsv				\
+AMbdp	|void	|sv_catpvn_mg	|NN SV * const dsv			\
 				|NN const char *sstr			\
 				|STRLEN len
-AMbdp	|void	|sv_catsv	|NN SV *dsv				\
-				|NULLOK SV *sstr
+AMbdp	|void	|sv_catsv	|NN SV * const dsv			\
+				|NULLOK SV * const sstr
 Adp	|void	|sv_catsv_flags |NN SV * const dsv			\
 				|NULLOK SV * const sstr 		\
 				|const I32 flags
-AMbdp	|void	|sv_catsv_mg	|NN SV *dsv				\
-				|NULLOK SV *sstr
+AMbdp	|void	|sv_catsv_mg	|NN SV * const dsv			\
+				|NULLOK SV * const sstr
 Adp	|void	|sv_chop	|NN SV * const sv			\
 				|NULLOK const char * const ptr
 : Used only in perl.c
diff --git a/mathoms.c b/mathoms.c
index 1abd36ad295f..27fa2969d1b1 100644
--- a/mathoms.c
+++ b/mathoms.c
@@ -256,7 +256,7 @@ Perl_sv_catpvn_mg(pTHX_ SV *dsv, const char *sstr, STRLEN len)
  */
 
 void
-Perl_sv_catsv(pTHX_ SV *dsv, SV *sstr)
+Perl_sv_catsv(pTHX_ SV *dsv, SV * const sstr)
 {
     PERL_ARGS_ASSERT_SV_CATSV;
 
@@ -264,7 +264,7 @@ Perl_sv_catsv(pTHX_ SV *dsv, SV *sstr)
 }
 
 void
-Perl_sv_catsv_mg(pTHX_ SV *dsv, SV *sstr)
+Perl_sv_catsv_mg(pTHX_ SV *dsv, SV * const sstr)
 {
     PERL_ARGS_ASSERT_SV_CATSV_MG;
 
diff --git a/proto.h b/proto.h
index c399427c6378..ad33674ff597 100644
--- a/proto.h
+++ b/proto.h
@@ -5891,22 +5891,22 @@ Perl_sv_2uv(pTHX_ SV *sv);
         assert(sv)
 
 PERL_CALLCONV void
-Perl_sv_catpvn(pTHX_ SV *dsv, const char *sstr, STRLEN len);
+Perl_sv_catpvn(pTHX_ SV * const dsv, const char *sstr, STRLEN len);
 # define PERL_ARGS_ASSERT_SV_CATPVN             \
         assert(dsv); assert(sstr)
 
 PERL_CALLCONV void
-Perl_sv_catpvn_mg(pTHX_ SV *dsv, const char *sstr, STRLEN len);
+Perl_sv_catpvn_mg(pTHX_ SV * const dsv, const char *sstr, STRLEN len);
 # define PERL_ARGS_ASSERT_SV_CATPVN_MG          \
         assert(dsv); assert(sstr)
 
 PERL_CALLCONV void
-Perl_sv_catsv(pTHX_ SV *dsv, SV *sstr);
+Perl_sv_catsv(pTHX_ SV * const dsv, SV * const sstr);
 # define PERL_ARGS_ASSERT_SV_CATSV              \
         assert(dsv)
 
 PERL_CALLCONV void
-Perl_sv_catsv_mg(pTHX_ SV *dsv, SV *sstr);
+Perl_sv_catsv_mg(pTHX_ SV * const dsv, SV * const sstr);
 # define PERL_ARGS_ASSERT_SV_CATSV_MG           \
         assert(dsv)
 
diff --git a/sv.h b/sv.h
index 6cca512dabe9..47434ad6c0fd 100644
--- a/sv.h
+++ b/sv.h
@@ -2242,7 +2242,7 @@ immediately written again.
         sv_setsv_flags(dsv, ssv, SV_GMAGIC|SV_DO_COW_SVSETSV)
 /*
 =for apidoc_defn Am|void|sv_setsv_nomg|SV *dsv|SV *ssv
-=for apidoc_defn Am|void|sv_catsv_nomg|SV *dsv|SV *ssv
+=for apidoc_defn Am|void|sv_catsv_nomg|SV * const dsv|SV * const sstr
 =cut
 */
 #define sv_setsv_nomg(dsv, ssv) sv_setsv_flags(dsv, ssv, SV_DO_COW_SVSETSV)