diff --git a/src/syntax.c b/src/syntax.c
index e37dacb..ac80ab4 100644
--- a/src/syntax.c
+++ b/src/syntax.c
@@ -8999,6 +8999,8 @@
 	    n = HL_TABLE()[id - 1].sg_cterm_fg - 1;
 	else
 	    n = HL_TABLE()[id - 1].sg_cterm_bg - 1;
+	if (n < 0)
+	    return NULL;
 	sprintf((char *)name, "%d", n);
 	return name;
     }
diff --git a/src/testdir/test_alot.vim b/src/testdir/test_alot.vim
index 6071756..a1d819d 100644
--- a/src/testdir/test_alot.vim
+++ b/src/testdir/test_alot.vim
@@ -16,5 +16,6 @@
 source test_searchpos.vim
 source test_set.vim
 source test_sort.vim
+source test_syn_attr.vim
 source test_undolevels.vim
 source test_unlet.vim
diff --git a/src/testdir/test_syn_attr.vim b/src/testdir/test_syn_attr.vim
new file mode 100644
index 0000000..20e9b17
--- /dev/null
+++ b/src/testdir/test_syn_attr.vim
@@ -0,0 +1,31 @@
+" Test syntax highlighting functions.
+
+func Test_missing_attr()
+  hi Mine term=bold cterm=italic
+  call assert_equal('Mine', synIDattr(hlID("Mine"), "name"))
+  call assert_equal('', synIDattr(hlID("Mine"), "bg", 'term'))
+  call assert_equal('1', synIDattr(hlID("Mine"), "bold", 'term'))
+  call assert_equal('1', synIDattr(hlID("Mine"), "italic", 'cterm'))
+  hi Mine term=reverse cterm=inverse
+  call assert_equal('1', synIDattr(hlID("Mine"), "reverse", 'term'))
+  call assert_equal('1', synIDattr(hlID("Mine"), "inverse", 'cterm'))
+  hi Mine term=underline cterm=standout gui=undercurl
+  call assert_equal('1', synIDattr(hlID("Mine"), "underline", 'term'))
+  call assert_equal('1', synIDattr(hlID("Mine"), "standout", 'cterm'))
+  call assert_equal('1', synIDattr(hlID("Mine"), "undercurl", 'gui'))
+  hi Mine term=NONE cterm=NONE gui=NONE
+  call assert_equal('', synIDattr(hlID("Mine"), "bold", 'term'))
+  call assert_equal('', synIDattr(hlID("Mine"), "italic", 'cterm'))
+  call assert_equal('', synIDattr(hlID("Mine"), "reverse", 'term'))
+  call assert_equal('', synIDattr(hlID("Mine"), "inverse", 'cterm'))
+  call assert_equal('', synIDattr(hlID("Mine"), "underline", 'term'))
+  call assert_equal('', synIDattr(hlID("Mine"), "standout", 'cterm'))
+  call assert_equal('', synIDattr(hlID("Mine"), "undercurl", 'gui'))
+
+  if has('gui')
+    hi Mine guifg=blue guibg=red font=something
+    call assert_equal('blue', synIDattr(hlID("Mine"), "fg", 'gui'))
+    call assert_equal('red', synIDattr(hlID("Mine"), "bg", 'gui'))
+    call assert_equal('something', synIDattr(hlID("Mine"), "font", 'gui'))
+  endif
+endfunc
diff --git a/src/version.c b/src/version.c
index fc9cebe..c2ba553 100644
--- a/src/version.c
+++ b/src/version.c
@@ -744,6 +744,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1547,
+/**/
     1546,
 /**/
     1545,