Give a better error message when reading invalid "\unicode" escapes.

* src/lread.c (read_escape): Give a clearer error message on
Unicode escape sequences (bug#36988).

1 files changed, 2 insertions, 1 deletions

diff --git a/src/lread.c b/src/lread.c
index e444830c99a..6ae7a0d8ba0 100644
--- a/src/lread.c
+++ b/src/lread.c
@@ -2585,7 +2585,8 @@ read_escape (Lisp_Object readcharfun, bool stringp)
                want.  */
             int digit = char_hexdigit (c);
             if (digit < 0)
-              error ("Non-hex digit used for Unicode escape");
+              error ("Non-hex character used for Unicode escape: %c (%d)",
+                     c, c);
             i = (i << 4) + digit;
           }
         if (i > 0x10FFFF)