diff --git a/src/testdir/test53.in b/src/testdir/test53.in
index cc333c7a1f..be76b05c1c 100644
--- a/src/testdir/test53.in
+++ b/src/testdir/test53.in
@@ -34,7 +34,13 @@ gncsearchmatch/one\_s*two\_s
 gnd
 /[a]bcdx
 :1
-2gnd
+2gnd/join
+/$
+0gnd
+/\>\zs
+0gnd/^
+gnd$h/\zs
+gnd
 :/^start:/,/^end:/wq! test.out
 ENDTEST
 
@@ -57,4 +63,8 @@ foobar
 one
 two
 abcdx | abcdx | abcdx
+join 
+lines
+zero width pattern
+delete first and last chars
 end:
diff --git a/src/testdir/test53.ok b/src/testdir/test53.ok
index 4f1e5a671e..928caff7c0 100644
--- a/src/testdir/test53.ok
+++ b/src/testdir/test53.ok
@@ -21,4 +21,7 @@ a
 SEARCH:
 searchmatch
 abcdx |  | abcdx
+join lines
+zerowidth pattern
+elete first and last char
 end:
diff --git a/src/testdir/test55.in b/src/testdir/test55.in
index cf85f57a6c..f255e33e4e 100644
--- a/src/testdir/test55.in
+++ b/src/testdir/test55.in
@@ -378,6 +378,16 @@ let l = [0, 1, 2, 3]
 :unlet dict
 :call garbagecollect(1)
 :"
+:" test for patch 7.3.637
+:let a = 'No error caught'
+:try|foldopen|catch|let a = matchstr(v:exception,'^[^ ]*')|endtry
+o=a
:"
+:lang C
+:redir => a
+:try|foobar|catch|let a = matchstr(v:exception,'^[^ ]*')|endtry
+:redir END
+o=a
:"
+:"
 :/^start:/,$wq! test.out
 ENDTEST
 
diff --git a/src/testdir/test55.ok b/src/testdir/test55.ok
index fde085ce76..7375007a70 100644
--- a/src/testdir/test55.ok
+++ b/src/testdir/test55.ok
@@ -115,3 +115,9 @@ caught a:000[3]
 {'a': {'b': 'B'}}
 Vim(call):E737: a
 {'a': {'b': 'B'}}
+Vim(foldopen):E490:
+
+
+Error detected while processing :
+E492: Not an editor command: foobar|catch|let a = matchstr(v:exception,'^[^ ]*')|endtry
+
diff --git a/src/version.c b/src/version.c
index 70bcc99263..f30551b867 100644
--- a/src/version.c
+++ b/src/version.c
@@ -719,6 +719,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    645,
 /**/
     644,
 /**/