remove almost unreachable NULL sv arg code from sv_2*n_flags

The NULL sv code being removed dates to commit e334a159a5 Perl 1.0 as
the pre-SV str_2ptr and str_2num calls. When SVs were intoduced in
commit 79072805bf Perl 5.0 alpha 2, the NULL sv code was copied to the new
SV functions. The functions were bulk marked non-NULL in commit f54cb97a39
during 5.9.3 development. The docs were corrected to say NULLOK support
in commit 53e8571218 during 5.11.0.

See the perldelta part of this patch for the rest of commit body.

1 files changed, 6 insertions, 0 deletions

diff --git a/mathoms.c b/mathoms.c
index b5ae5197bb..0543e88c7e 100644
--- a/mathoms.c
+++ b/mathoms.c
@@ -148,6 +148,8 @@ Perl_sv_taint(pTHX_ SV *sv)
 IV
 Perl_sv_2iv(pTHX_ SV *sv)
 {
+    PERL_ARGS_ASSERT_SV_2IV;
+
     return sv_2iv_flags(sv, SV_GMAGIC);
 }
 
@@ -158,6 +160,8 @@ Perl_sv_2iv(pTHX_ SV *sv)
 UV
 Perl_sv_2uv(pTHX_ SV *sv)
 {
+    PERL_ARGS_ASSERT_SV_2UV;
+
     return sv_2uv_flags(sv, SV_GMAGIC);
 }
 
@@ -179,6 +183,8 @@ Perl_sv_2nv(pTHX_ SV *sv)
 char *
 Perl_sv_2pv(pTHX_ SV *sv, STRLEN *lp)
 {
+    PERL_ARGS_ASSERT_SV_2PV;
+
     return sv_2pv_flags(sv, lp, SV_GMAGIC);
 }