Issue #15809: IDLE shell now uses locale encoding instead of Latin1 for
decoding unicode literals.
diff --git a/Lib/idlelib/run.py b/Lib/idlelib/run.py
index 6ffc1b9..d023e28 100644
--- a/Lib/idlelib/run.py
+++ b/Lib/idlelib/run.py
@@ -210,6 +210,8 @@
         fn, ln, nm, line = tb[i]
         if nm == '?':
             nm = "-toplevel-"
+        if fn.startswith("<pyshell#") and IOBinding.encoding != 'utf-8':
+            ln -= 1  # correction for coding cookie
         if not line and fn.startswith("<pyshell#"):
             line = rpchandler.remotecall('linecache', 'getline',
                                               (fn, ln), {})