use mrb_str_cat_str() instead of mrb_str_append()

If the argument is always a string, then mrb_str_cat_str() can be
directly called instead of indirectly by mrb_str_append().

mrb_any_to_s(), mrb_obj_as_string(), mrb_inspect() always return a
string.

1 files changed, 2 insertions, 2 deletions

diff --git a/src/range.c b/src/range.c
index b427dc1b7..b58b6a1c8 100644
--- a/src/range.c
+++ b/src/range.c
@@ -290,7 +290,7 @@ range_to_s(mrb_state *mrb, mrb_value range)
   str2 = mrb_obj_as_string(mrb, r->edges->end);
   str  = mrb_str_dup(mrb, str);
   mrb_str_cat(mrb, str, "...", r->excl ? 3 : 2);
-  mrb_str_append(mrb, str, str2);
+  mrb_str_cat_str(mrb, str, str2);
 
   return str;
 }
@@ -315,7 +315,7 @@ range_inspect(mrb_state *mrb, mrb_value range)
   str2 = mrb_inspect(mrb, r->edges->end);
   str  = mrb_str_dup(mrb, str);
   mrb_str_cat(mrb, str, "...", r->excl ? 3 : 2);
-  mrb_str_append(mrb, str, str2);
+  mrb_str_cat_str(mrb, str, str2);
 
   return str;
 }