1 files changed, 2 insertions, 1 deletions
diff --git a/symbol.c b/symbol.c
index 8e3e0c3c55..b37be2f65b 100644
--- a/symbol.c
+++ b/symbol.c
@@ -430,7 +430,8 @@ sym_check_asciionly(VALUE str)
     if (!rb_enc_asciicompat(rb_enc_get(str))) return FALSE;
     switch (rb_enc_str_coderange(str)) {
       case ENC_CODERANGE_BROKEN:
-	rb_raise(rb_eEncodingError, "invalid encoding symbol");
+	rb_raise(rb_eEncodingError, "invalid symbol in encoding %s :%+"PRIsVALUE,
+		 rb_enc_name(rb_enc_get(str)), str);
       case ENC_CODERANGE_7BIT:
 	return TRUE;
     }