2 files changed, 7 insertions, 0 deletions
diff --git a/string.c b/string.c
index 82fa603ada..9079387fac 100644
--- a/string.c
+++ b/string.c
@@ -2560,6 +2560,7 @@ str_substr(VALUE str, long beg, long len, int empty)
 	str2 = str_new_shared(rb_obj_class(str2), str2);
 	RSTRING(str2)->as.heap.ptr += ofs;
 	RSTRING(str2)->as.heap.len = len;
+	ENC_CODERANGE_CLEAR(str2);
     }
     else {
 	if (!len && !empty) return Qnil;
diff --git a/test/ruby/test_string.rb b/test/ruby/test_string.rb
index b0c6e447eb..dd3a0349b5 100644
--- a/test/ruby/test_string.rb
+++ b/test/ruby/test_string.rb
@@ -3087,6 +3087,12 @@ CODE
     assert_equal("\u3042", "\u3042\u3043".chr)
     assert_equal('', ''.chr)
   end
+
+  def test_substr_code_range
+    data = "\xff" + "a"*200
+    assert_not_predicate(data, :valid_encoding?)
+    assert_predicate(data[100..-1], :valid_encoding?)
+  end
 end
 
 class TestString2 < TestString