--- a/runtime/doc/quickfix.txt
+++ b/runtime/doc/quickfix.txt
@@ -1422,6 +1422,7 @@ rest is ignored.  Items can only be 1023
 Basic items
 
 	%f		file name (finds a string)
+	%b		buffer number (finds a number)
 	%o		module name (finds a string)
 	%l		line number (finds a number)
 	%e		end line number (finds a number)
@@ -1461,6 +1462,11 @@ On MS-Windows a leading "C:" will be inc
 This means that a file name which is a single alphabetical letter will not be
 detected.
 
+The "%b" conversion is used to parse a buffer number.  This is useful for
+referring to lines in a scratch buffer or a buffer with no name.  If a buffer
+with the matching number doesn't exist, then that line is used as a non-error
+line.
+
 The "%p" conversion is normally followed by a "^".  It's used for compilers
 that output a line like: >
 	    ^

--- a/runtime/doc/todo.txt
+++ b/runtime/doc/todo.txt
@@ -5945,8 +5945,6 @@ 8   Add ":rename" command: rename the fi
 7   Instead of filtering errors with a shell script it should be possible to
     do this with Vim script.  A function that filters the raw text that comes
     from the 'makeprg'?
--   Add %b to 'errorformat': buffer number. (Yegappan Lakshmanan / Suresh
-    Govindachar)
 7   Allow a window not to have a statusline.  Makes it possible to use a
     window as a buffer-tab selection.
 8   Allow non-active windows to have a different statusline. (Yakov Lerner)

--- a/src/quickfix.c
+++ b/src/quickfix.c
@@ -120,7 +120,7 @@ struct qf_info_S
 static qf_info_T ql_info;	// global quickfix list
 static int_u last_qf_id = 0;	// Last used quickfix list id
 
-#define FMT_PATTERNS 13		// maximum number of % recognized
+#define FMT_PATTERNS 14		// maximum number of % recognized
 
 /*
  * Structure used to hold the info of one part of 'errorformat'
@@ -275,20 +275,21 @@ static struct fmtpattern
 } fmt_pat[FMT_PATTERNS] =
     {
 	{'f', ".\\+"},	    // only used when at end
-	{'n', "\\d\\+"},	// 1
-	{'l', "\\d\\+"},	// 2
-	{'e', "\\d\\+"},	// 3
-	{'c', "\\d\\+"},	// 4
-	{'k', "\\d\\+"},	// 5
-	{'t', "."},		// 6
-#define FMT_PATTERN_M 7
-	{'m', ".\\+"},		// 7
-#define FMT_PATTERN_R 8
-	{'r', ".*"},		// 8
-	{'p', "[-	 .]*"},	// 9
-	{'v', "\\d\\+"},	// 10
-	{'s', ".\\+"},		// 11
-	{'o', ".\\+"}		// 12
+	{'b', "\\d\\+"},	// 1
+	{'n', "\\d\\+"},	// 2
+	{'l', "\\d\\+"},	// 3
+	{'e', "\\d\\+"},	// 4
+	{'c', "\\d\\+"},	// 5
+	{'k', "\\d\\+"},	// 6
+	{'t', "."},		// 7
+#define FMT_PATTERN_M 8
+	{'m', ".\\+"},		// 8
+#define FMT_PATTERN_R 9
+	{'r', ".*"},		// 9
+	{'p', "[-	 .]*"},	// 10
+	{'v', "\\d\\+"},	// 11
+	{'s', ".\\+"},		// 12
+	{'o', ".\\+"}		// 13
     };
 
 /*
@@ -942,6 +943,7 @@ qf_get_nextline(qfstate_T *state)
 
 typedef struct {
     char_u	*namebuf;
+    int		bnr;
     char_u	*module;
     char_u	*errmsg;
     int		errmsglen;
@@ -989,6 +991,22 @@ qf_parse_fmt_f(regmatch_T *rmp, int midx
  * Return the matched value in "fields->enr".
  */
     static int
+qf_parse_fmt_b(regmatch_T *rmp, int midx, qffields_T *fields)
+{
+    if (rmp->startp[midx] == NULL)
+	return QF_FAIL;
+    int bnr = (int)atol((char *)rmp->startp[midx]);
+    if (buflist_findnr(bnr) == NULL)
+	return QF_FAIL;
+    fields->bnr = bnr;
+    return QF_OK;
+}
+
+/*
+ * Parse the match for error number ('%n') pattern in regmatch.
+ * Return the matched value in "fields->enr".
+ */
+    static int
 qf_parse_fmt_n(regmatch_T *rmp, int midx, qffields_T *fields)
 {
     if (rmp->startp[midx] == NULL)
@@ -1213,6 +1231,7 @@ qf_parse_fmt_o(regmatch_T *rmp, int midx
 static int (*qf_parse_fmt[FMT_PATTERNS])(regmatch_T *, int, qffields_T *) =
 {
     NULL, // %f
+    qf_parse_fmt_b,
     qf_parse_fmt_n,
     qf_parse_fmt_l,
     qf_parse_fmt_e,
@@ -1309,6 +1328,7 @@ qf_parse_get_fields(
 	return QF_FAIL;
 
     fields->namebuf[0] = NUL;
+    fields->bnr = 0;
     fields->module[0] = NUL;
     fields->pattern[0] = NUL;
     if (!qf_multiscan)
@@ -1713,7 +1733,7 @@ qf_init_process_nextline(
 		: ((qfl->qf_currfile != NULL && fields->valid)
 		    ? qfl->qf_currfile : (char_u *)NULL),
 		fields->module,
-		0,
+		fields->bnr,
 		fields->errmsg,
 		fields->lnum,
 		fields->end_lnum,

--- a/src/testdir/test_quickfix.vim
+++ b/src/testdir/test_quickfix.vim
@@ -6447,4 +6447,53 @@ func Test_quickfix_buffer_contents()
   call setqflist([], 'f')
 endfunc
 
+" Test for "%b" in "errorformat"
+func Test_efm_format_b()
+  call setqflist([], 'f')
+  new
+  call setline(1, ['1: abc', '1: def', '1: ghi'])
+  let b1 = bufnr()
+  new
+  call setline(1, ['2: abc', '2: def', '2: ghi'])
+  let b2 = bufnr()
+  new
+  call setline(1, ['3: abc', '3: def', '3: ghi'])
+  let b3 = bufnr()
+  new
+  let lines =<< trim eval END
+    {b1}:1:1
+    {b2}:2:2
+    {b3}:3:3
+  END
+  call setqflist([], ' ', #{lines: lines, efm: '%b:%l:%c'})
+  cfirst
+  call assert_equal([b1, 1, 1], [bufnr(), line('.'), col('.')])
+  cnext
+  call assert_equal([b2, 2, 2], [bufnr(), line('.'), col('.')])
+  cnext
+  call assert_equal([b3, 3, 3], [bufnr(), line('.'), col('.')])
+  enew!
+
+  " Use a non-existing buffer
+  let lines =<< trim eval END
+    9991:1:1:m1
+    9992:2:2:m2
+    {b3}:3:3:m3
+  END
+  call setqflist([], ' ', #{lines: lines, efm: '%b:%l:%c:%m'})
+  cfirst | cnext
+  call assert_equal([b3, 3, 3], [bufnr(), line('.'), col('.')])
+  " Lines with non-existing buffer numbers should be used as non-error lines
+  call assert_equal([
+    \ #{lnum: 0, bufnr: 0, end_lnum: 0, pattern: '', valid: 0, vcol: 0, nr: -1,
+    \   module: '', type: '', end_col: 0, col: 0, text: '9991:1:1:m1'},
+    \ #{lnum: 0, bufnr: 0, end_lnum: 0, pattern: '', valid: 0, vcol: 0, nr: -1,
+    \   module: '', type: '', end_col: 0, col: 0, text: '9992:2:2:m2'},
+    \ #{lnum: 3, bufnr: b3, end_lnum: 0, pattern: '', valid: 1, vcol: 0,
+    \   nr: -1, module: '', type: '', end_col: 0, col: 3, text: 'm3'}],
+    \ getqflist())
+  %bw!
+  call setqflist([], 'f')
+endfunc
+
 " vim: shiftwidth=2 sts=2 expandtab

--- a/src/version.c
+++ b/src/version.c
@@ -705,6 +705,8 @@ static char *(features[]) =
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2064,
+/**/
     2063,
 /**/
     2062,