patch 7.4.2274
Problem:    Command line completion on "find **/filename" drops sub-directory.
Solution:   Handle this case separately. (Harm te Hennepe, closes #932, closes
            #939)
diff --git a/src/testdir/test_cmdline.vim b/src/testdir/test_cmdline.vim
index 3a35637..f6721d5 100644
--- a/src/testdir/test_cmdline.vim
+++ b/src/testdir/test_cmdline.vim
@@ -180,3 +180,11 @@
 
   call assert_fails('call getcompletion("", "burp")', 'E475:')
 endfunc
+
+func Test_expand_star_star()
+  call mkdir('a/b', 'p')
+  call writefile(['asdfasdf'], 'a/b/fileXname')
+  call feedkeys(":find **/fileXname\<Tab>\<CR>", 'xt')
+  call assert_equal('find a/b/fileXname', getreg(':'))
+  call delete('a', 'rf')
+endfunc