3 files changed, 9 insertions, 16 deletions
diff --git a/mrbgems/mruby-io/mrblib/kernel.rb b/mrbgems/mruby-io/mrblib/kernel.rb
index 42d5bb1d1..9cb3b5650 100644
--- a/mrbgems/mruby-io/mrblib/kernel.rb
+++ b/mrbgems/mruby-io/mrblib/kernel.rb
@@ -28,8 +28,4 @@ module Kernel
   def gets(*args)
     $stdin.gets(*args)
   end
-
-  def getc(*args)
-    $stdin.getc(*args)
-  end
 end
diff --git a/mrbgems/mruby-io/src/io.c b/mrbgems/mruby-io/src/io.c
index 624c27f47..3a6932b3a 100644
--- a/mrbgems/mruby-io/src/io.c
+++ b/mrbgems/mruby-io/src/io.c
@@ -284,12 +284,13 @@ mrb_io_alloc(mrb_state *mrb)
 #endif
 
 static int
-option_to_fd(mrb_state *mrb, mrb_value obj, const char *key)
+option_to_fd(mrb_state *mrb, mrb_value hash, const char *key)
 {
-  mrb_value opt = mrb_funcall(mrb, obj, "[]", 1, mrb_symbol_value(mrb_intern_static(mrb, key, strlen(key))));
-  if (mrb_nil_p(opt)) {
-    return -1;
-  }
+  mrb_value opt;
+
+  if (!mrb_hash_p(hash)) return -1;
+  opt = mrb_hash_fetch(mrb, hash, mrb_symbol_value(mrb_intern_static(mrb, key, strlen(key))), mrb_nil_value());
+  if (mrb_nil_p(opt)) return -1;
 
   switch (mrb_type(opt)) {
     case MRB_TT_DATA: /* IO */
@@ -907,11 +908,7 @@ mrb_io_syswrite(mrb_state *mrb, mrb_value io)
   }
 
   mrb_get_args(mrb, "S", &str);
-  if (!mrb_string_p(str)) {
-    buf = mrb_funcall(mrb, str, "to_s", 0);
-  } else {
-    buf = str;
-  }
+  buf = str;
 
   if (fptr->fd2 == -1) {
     fd = fptr->fd;
diff --git a/mrbgems/mruby-string-ext/src/string.c b/mrbgems/mruby-string-ext/src/string.c
index acf780005..ffad0f527 100644
--- a/mrbgems/mruby-string-ext/src/string.c
+++ b/mrbgems/mruby-string-ext/src/string.c
@@ -174,8 +174,8 @@ mrb_str_concat_m(mrb_state *mrb, mrb_value self)
     str = int_chr_binary(mrb, str);
 #endif
   else
-    str = mrb_ensure_string_type(mrb, str);
-  mrb_str_concat(mrb, self, str);
+    mrb_ensure_string_type(mrb, str);
+  mrb_str_cat_str(mrb, self, str);
   return self;
 }