4 files changed, 12 insertions, 6 deletions
diff --git a/src/class.c b/src/class.c
index b1c7513de..2656806d2 100644
--- a/src/class.c
+++ b/src/class.c
@@ -145,7 +145,7 @@ class_name_str(mrb_state *mrb, struct RClass* c)
   if (mrb_nil_p(path)) {
     path = c->tt == MRB_TT_MODULE ? mrb_str_new_lit(mrb, "#<Module:") :
                                     mrb_str_new_lit(mrb, "#<Class:");
-    mrb_str_concat(mrb, path, mrb_ptr_to_str(mrb, c));
+    mrb_str_cat_str(mrb, path, mrb_ptr_to_str(mrb, c));
     mrb_str_cat_lit(mrb, path, ">");
   }
   return path;
@@ -1885,7 +1885,8 @@ mrb_mod_to_s(mrb_state *mrb, mrb_value klass)
     return mrb_str_cat_lit(mrb, str, ">");
   }
   else {
-    return class_name_str(mrb, mrb_class_ptr(klass));
+    mrb_value str = class_name_str(mrb, mrb_class_ptr(klass));
+    return mrb_frozen_p(mrb_basic_ptr(str)) ? mrb_str_dup(mrb, str) : str;
   }
 }
 
diff --git a/src/object.c b/src/object.c
index 4e2ba7154..33d570331 100644
--- a/src/object.c
+++ b/src/object.c
@@ -423,7 +423,7 @@ mrb_any_to_s(mrb_state *mrb, mrb_value obj)
   mrb_str_cat_cstr(mrb, str, cname);
   if (!mrb_immediate_p(obj)) {
     mrb_str_cat_lit(mrb, str, ":");
-    mrb_str_concat(mrb, str, mrb_ptr_to_str(mrb, mrb_ptr(obj)));
+    mrb_str_cat_str(mrb, str, mrb_ptr_to_str(mrb, mrb_ptr(obj)));
   }
   mrb_str_cat_lit(mrb, str, ">");
 
diff --git a/src/string.c b/src/string.c
index d3774f8c4..6ab9a1ff7 100644
--- a/src/string.c
+++ b/src/string.c
@@ -1388,8 +1388,13 @@ str_escape(mrb_state *mrb, mrb_value str, mrb_bool inspect)
   }
   mrb_str_cat_lit(mrb, result, "\"");
 #ifdef MRB_UTF8_STRING
-  mrb_str_ptr(str)->flags |= ascii_flag;
-  mrb_str_ptr(result)->flags |= ascii_flag;
+  if (inspect) {
+    mrb_str_ptr(str)->flags |= ascii_flag;
+    mrb_str_ptr(result)->flags |= ascii_flag;
+  }
+  else {
+    RSTR_SET_ASCII_FLAG(mrb_str_ptr(result));
+  }
 #endif
 
   return result;
diff --git a/src/variable.c b/src/variable.c
index dce598835..8fc01fe2d 100644
--- a/src/variable.c
+++ b/src/variable.c
@@ -509,7 +509,7 @@ mrb_obj_iv_inspect(mrb_state *mrb, struct RObject *obj)
     mrb_str_cat_lit(mrb, str, "-<");
     mrb_str_cat_cstr(mrb, str, cn);
     mrb_str_cat_lit(mrb, str, ":");
-    mrb_str_concat(mrb, str, mrb_ptr_to_str(mrb, obj));
+    mrb_str_cat_str(mrb, str, mrb_ptr_to_str(mrb, obj));
 
     iv_foreach(mrb, t, inspect_i, &str);
     mrb_str_cat_lit(mrb, str, ">");