diff --git a/ChangeLog b/ChangeLog
index c0d3607e..d1e0bc10 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,23 @@
+2009-08-19  Joel E. Denny  <jdenny@clemson.edu>
+
+	Fix complaints about escape sequences.
+	Discussed starting at
+	<http://lists.gnu.org/archive/html/bison-patches/2009-08/msg00036.html>.
+	* src/scan-gram.l (SC_ESCAPED_STRING, SC_ESCAPED_CHARACTER):
+	For a \0 and similar escape sequences meaning the null
+	character, report an invalid escape sequence instead of an
+	invalid null character because the latter does not actually
+	appear in the user's input.
+	In all escape sequence complaints, don't escape the initial
+	backslash, and don't quote when the sequence appears at the end
+	of the complaint line unless there's whitespace that quotearg
+	won't escape.
+	Consistently say "invalid" not "unrecognized".
+	Consistently prefer "empty character literal" over "extra
+	characters in character literal" warning for invalid escape
+	sequences; that is, consistently discard those sequences.
+	* tests/input.at (Bad escapes in literals): New.
+
 2009-08-19  Akim Demaille  <demaille@gostai.com>
 
 	doc: fixes.
diff --git a/src/scan-gram.l b/src/scan-gram.l
index 7a6d7bfe..4ed30c6f 100644
--- a/src/scan-gram.l
+++ b/src/scan-gram.l
@@ -37,6 +37,7 @@
 #include <src/reader.h>
 #include <src/uniqstr.h>
 
+#include <ctype.h>
 #include <mbswidth.h>
 #include <quote.h>
 
@@ -578,10 +579,9 @@ splice	 (\\[ \f\t\v]*\n)*
 {
   \\[0-7]{1,3} {
     unsigned long int c = strtoul (yytext + 1, NULL, 8);
-    if (UCHAR_MAX < c)
-      complain_at (*loc, _("invalid escape sequence: %s"), quote (yytext));
-    else if (! c)
-      complain_at (*loc, _("invalid null character: %s"), quote (yytext));
+    if (!c || UCHAR_MAX < c)
+      complain_at (*loc, _("invalid number after \\-escape: %s"),
+                   yytext+1);
     else
       obstack_1grow (&obstack_for_string, c);
   }
@@ -589,10 +589,9 @@ splice	 (\\[ \f\t\v]*\n)*
   \\x[0-9abcdefABCDEF]+ {
     verify (UCHAR_MAX < ULONG_MAX);
     unsigned long int c = strtoul (yytext + 2, NULL, 16);
-    if (UCHAR_MAX < c)
-      complain_at (*loc, _("invalid escape sequence: %s"), quote (yytext));
-    else if (! c)
-      complain_at (*loc, _("invalid null character: %s"), quote (yytext));
+    if (!c || UCHAR_MAX < c)
+      complain_at (*loc, _("invalid number after \\-escape: %s"),
+                   yytext+1);
     else
       obstack_1grow (&obstack_for_string, c);
   }
@@ -610,16 +609,23 @@ splice	 (\\[ \f\t\v]*\n)*
 
   \\(u|U[0-9abcdefABCDEF]{4})[0-9abcdefABCDEF]{4} {
     int c = convert_ucn_to_byte (yytext);
-    if (c < 0)
-      complain_at (*loc, _("invalid escape sequence: %s"), quote (yytext));
-    else if (! c)
-      complain_at (*loc, _("invalid null character: %s"), quote (yytext));
+    if (c <= 0)
+      complain_at (*loc, _("invalid number after \\-escape: %s"),
+                   yytext+1);
     else
       obstack_1grow (&obstack_for_string, c);
   }
   \\(.|\n)	{
-    complain_at (*loc, _("unrecognized escape sequence: %s"), quote (yytext));
-    STRING_GROW;
+    char const *p = yytext + 1;
+    char quoted_ws[] = "` '";
+    if (isspace (*p) && isprint (*p))
+      {
+        quoted_ws[1] = *p;
+        p = quoted_ws;
+      }
+    else
+      p = quotearg_style_mem (escape_quoting_style, p, 1);
+    complain_at (*loc, _("invalid character after \\-escape: %s"), p);
   }
 }
 
diff --git a/tests/input.at b/tests/input.at
index 810e7601..f91c0fb8 100644
--- a/tests/input.at
+++ b/tests/input.at
@@ -1220,3 +1220,46 @@ three.y:4.8-11: missing `'' at end of file
 ]])
 
 AT_CLEANUP
+
+## ------------------------- ##
+## Bad escapes in literals.  ##
+## ------------------------- ##
+
+AT_SETUP([[Bad escapes in literals]])
+
+AT_DATA([input.y],
+[[%%
+start: '\777' '\0' '\xfff' '\x0'
+       '\uffff' '\u0000' '\Uffffffff' '\U00000000'
+       '\ ' '\A';
+]])
+echo 'start: "\T\F\0\1" ;' | tr 'TF01' '\011\014\0\1' >> input.y
+
+AT_BISON_CHECK([input.y], [1], [],
+[[input.y:2.9-12: invalid number after \-escape: 777
+input.y:2.8-13: warning: empty character literal
+input.y:2.16-17: invalid number after \-escape: 0
+input.y:2.15-18: warning: empty character literal
+input.y:2.21-25: invalid number after \-escape: xfff
+input.y:2.20-26: warning: empty character literal
+input.y:2.29-31: invalid number after \-escape: x0
+input.y:2.28-32: warning: empty character literal
+input.y:3.9-14: invalid number after \-escape: uffff
+input.y:3.8-15: warning: empty character literal
+input.y:3.18-23: invalid number after \-escape: u0000
+input.y:3.17-24: warning: empty character literal
+input.y:3.27-36: invalid number after \-escape: Uffffffff
+input.y:3.26-37: warning: empty character literal
+input.y:3.40-49: invalid number after \-escape: U00000000
+input.y:3.39-50: warning: empty character literal
+input.y:4.9-10: invalid character after \-escape: ` '
+input.y:4.8-11: warning: empty character literal
+input.y:4.14-15: invalid character after \-escape: A
+input.y:4.13-16: warning: empty character literal
+input.y:5.9-16: invalid character after \-escape: \t
+input.y:5.17: invalid character after \-escape: \f
+input.y:5.18: invalid character after \-escape: \0
+input.y:5.19: invalid character after \-escape: \001
+]])
+
+AT_CLEANUP