diff --git a/src/testdir/test_ins_complete.vim b/src/testdir/test_ins_complete.vim
index 2a2df51..06ab6cf 100644
--- a/src/testdir/test_ins_complete.vim
+++ b/src/testdir/test_ins_complete.vim
@@ -225,7 +225,7 @@
   call assert_equal(0, s:args[1][0])
   set omnifunc=
 
-  set complete=fCompleteFunc
+  set complete=FCompleteFunc
   call feedkeys("i\<C-N>\<Esc>", 'x')
   call assert_equal([1, 1], s:args[0])
   call assert_equal(0, s:args[1][0])
@@ -299,7 +299,7 @@
   call assert_equal(oldline, newline)
   let s:called_completedone = 0
 
-  set complete=f<SID>CompleteDone_CompleteFuncNone
+  set complete=F<SID>CompleteDone_CompleteFuncNone
   execute "normal a\<C-N>\<C-Y>"
   set complete&
   let newline = join(map(range(&columns), 'nr2char(screenchar(&lines-1, v:val+1))'), '')
@@ -326,7 +326,7 @@
   endfunc
   set omnifunc=CompleteFunc
   set completefunc=CompleteFunc
-  set complete=.,fCompleteFunc
+  set complete=.,FCompleteFunc
   set completeopt+=menuone
 
   new
@@ -418,7 +418,7 @@
   au CompleteDonePre * :call <SID>CompleteDone_CheckCompletedItemDict(2)
   au CompleteDone * :call <SID>CompleteDone_CheckCompletedItemDict(0)
 
-  set complete=.,f<SID>CompleteDone_CompleteFuncDict
+  set complete=.,F<SID>CompleteDone_CompleteFuncDict
   execute "normal a\<C-N>\<C-Y>"
   set complete&
 
@@ -471,7 +471,7 @@
 
   let s:called_completedone = 0
 
-  set complete=.,f<SID>CompleteDone_CompleteFuncDictNoUserData
+  set complete=.,F<SID>CompleteDone_CompleteFuncDictNoUserData
   execute "normal a\<C-N>\<C-Y>"
   set complete&
 
@@ -513,7 +513,7 @@
 
   let s:called_completedone = 0
 
-  set complete=.,f<SID>CompleteDone_CompleteFuncList
+  set complete=.,F<SID>CompleteDone_CompleteFuncList
   execute "normal a\<C-N>\<C-Y>"
   set complete&
 
@@ -522,7 +522,7 @@
 
   let s:called_completedone = 0
 
-  set complete=.,f
+  set complete=.,F
   execute "normal a\<C-N>\<C-Y>"
   set complete&
 
@@ -573,11 +573,11 @@
   call feedkeys("i\<C-X>\<C-U>\<C-R>\<C-R>=string(complete_info())\<CR>\<ESC>", "tx")
   call assert_equal("matched{'pum_visible': 1, 'mode': 'function', 'selected': 0, 'items': [{'word': 'matched', 'menu': '', 'user_data': '', 'info': '', 'kind': '', 'abbr': ''}]}", getline(1))
   %d
-  set complete=.,fCompleteTest
+  set complete=.,FCompleteTest
   call feedkeys("i\<C-N>\<C-R>\<C-R>=string(complete_info())\<CR>\<ESC>", "tx")
   call assert_equal("matched{'pum_visible': 1, 'mode': 'keyword', 'selected': 0, 'items': [{'word': 'matched', 'menu': '', 'user_data': '', 'info': '', 'kind': '', 'abbr': ''}]}", getline(1))
   %d
-  set complete=.,f
+  set complete=.,F
   call feedkeys("i\<C-N>\<C-R>\<C-R>=string(complete_info())\<CR>\<ESC>", "tx")
   call assert_equal("matched{'pum_visible': 1, 'mode': 'keyword', 'selected': 0, 'items': [{'word': 'matched', 'menu': '', 'user_data': '', 'info': '', 'kind': '', 'abbr': ''}]}", getline(1))
   set completeopt&
@@ -597,7 +597,7 @@
     return v:none
   endfunc
 
-  set complete=fCptColTest
+  set complete=FCptColTest
   new
   call feedkeys("ifoo bar\<C-N>", "tx")
   bwipe!
@@ -689,12 +689,12 @@
   let completed = a:idx != -1 ? ['foo', 'bar', 'baz', 'qux']->get(a:idx) : ''
   call assert_equal(completed. "{'pum_visible': 1, 'mode': 'function', 'selected': " . a:idx . ", 'items': " . items . "}", getline(1))
   %d
-  set complete=.,fCompleteInfoUserDefinedFn
+  set complete=.,FCompleteInfoUserDefinedFn
   call feedkeys("i\<C-N>" . a:mvmt . "\<C-R>\<C-R>=string(complete_info())\<CR>\<ESC>", "tx")
   let completed = a:idx != -1 ? ['foo', 'bar', 'baz', 'qux']->get(a:idx) : ''
   call assert_equal(completed. "{'pum_visible': 1, 'mode': 'keyword', 'selected': " . a:idx . ", 'items': " . items . "}", getline(1))
   %d
-  set complete=.,f
+  set complete=.,F
   call feedkeys("i\<C-N>" . a:mvmt . "\<C-R>\<C-R>=string(complete_info())\<CR>\<ESC>", "tx")
   let completed = a:idx != -1 ? ['foo', 'bar', 'baz', 'qux']->get(a:idx) : ''
   call assert_equal(completed. "{'pum_visible': 1, 'mode': 'keyword', 'selected': " . a:idx . ", 'items': " . items . "}", getline(1))
@@ -969,9 +969,9 @@
   set completefunc=CompleteFunc
   call setline(1, ['', 'abcd', ''])
   call assert_fails('exe "normal 2G$a\<C-X>\<C-U>"', 'E565:')
-  set complete=fCompleteFunc
+  set complete=FCompleteFunc
   call assert_fails('exe "normal 2G$a\<C-N>"', 'E565:')
-  set complete=f
+  set complete=F
   call assert_fails('exe "normal 2G$a\<C-N>"', 'E565:')
 
   " delete text when called for the second time
@@ -985,9 +985,9 @@
   set completefunc=CompleteFunc2
   call setline(1, ['', 'abcd', ''])
   call assert_fails('exe "normal 2G$a\<C-X>\<C-U>"', 'E565:')
-  set complete=fCompleteFunc2
+  set complete=FCompleteFunc2
   call assert_fails('exe "normal 2G$a\<C-N>"', 'E565:')
-  set complete=f
+  set complete=F
   call assert_fails('exe "normal 2G$a\<C-N>"', 'E565:')
 
   " Jump to a different window from the complete function
@@ -1002,10 +1002,10 @@
   new
   call assert_fails('exe "normal a\<C-X>\<C-U>"', 'E565:')
   %d
-  set complete=fCompleteFunc3
+  set complete=FCompleteFunc3
   call assert_fails('exe "normal a\<C-N>"', 'E565:')
   %d
-  set complete=f
+  set complete=F
   call assert_fails('exe "normal a\<C-N>"', 'E565:')
   close!
 
@@ -1029,11 +1029,11 @@
   exe "normal i\<C-X>\<C-U>"
   call assert_equal('moon', getline(1))
   %d
-  set complete=fCompleteFunc
+  set complete=FCompleteFunc
   exe "normal i\<C-N>"
   call assert_equal('moon', getline(1))
   %d
-  set complete=f
+  set complete=F
   exe "normal i\<C-N>"
   call assert_equal('moon', getline(1))
   set completefunc& complete&
@@ -1717,13 +1717,13 @@
   call assert_equal(6, g:CallCount)
   %d
   let g:CallCount = 0
-  set complete=fTcomplete
+  set complete=FTcomplete
   exe "normal! iup\<C-N>\<BS>\<BS>\<BS>\<BS>\<BS>"
   call assert_equal('up', getline(1))
   call assert_equal(6, g:CallCount)
   %d
   let g:CallCount = 0
-  set complete=f
+  set complete=F
   exe "normal! iup\<C-N>\<BS>\<BS>\<BS>\<BS>\<BS>"
   call assert_equal('up', getline(1))
   call assert_equal(6, g:CallCount)
@@ -1750,10 +1750,10 @@
     call assert_equal(-999, a:findstart) " Should not reach here
   endfunc
   new
-  set complete=ffunction('CompleteFail'\\,\ [-2])
+  set complete=Ffunction('CompleteFail'\\,\ [-2])
   exe "normal! ia\<C-N>"
   %d
-  set complete=ffunction('CompleteFail'\\,\ [-3])
+  set complete=Ffunction('CompleteFail'\\,\ [-3])
   exe "normal! ia\<C-N>"
   bw!
 
@@ -1771,7 +1771,7 @@
   endfunc
   new
   set completeopt=menuone,noselect
-  set complete=ffunction('CompleteFailIntermittent'\\,\ [-2])
+  set complete=Ffunction('CompleteFailIntermittent'\\,\ [-2])
   let g:CallCount = 0
   exe "normal! if\<C-N>\<c-r>=complete_info([\"items\"])\<cr>"
   call assert_match('''word'': ''foo''.*''word'': ''fbar''', getline(1))
@@ -1782,13 +1782,13 @@
   call assert_match('''selected'': -1.*''word'': ''foo1''.*''word'': ''foo2''', getline(1))
   call assert_equal(2, g:CallCount)
   %d
-  set complete=ffunction('CompleteFailIntermittent'\\,\ [-3])
+  set complete=Ffunction('CompleteFailIntermittent'\\,\ [-3])
   let g:CallCount = 0
   exe "normal! if\<C-N>o\<c-r>=complete_info([\"items\", \"selected\"])\<cr>"
   call assert_match('''selected'': -1.*''word'': ''foo1''.*''word'': ''foo2''', getline(1))
   call assert_equal(2, g:CallCount)
   %d
-  set complete=ffunction('CompleteFailIntermittent'\\,\ [-2])
+  set complete=Ffunction('CompleteFailIntermittent'\\,\ [-2])
   " completion mode is dismissed when there are no matches in list
   let g:CallCount = 0
   exe "normal! if\<C-N>oo\<c-r>=complete_info([\"items\"])\<cr>"
@@ -1801,7 +1801,7 @@
   call assert_equal(3, g:CallCount)
   %d
   " completion mode continues when matches from other sources present
-  set complete=.,ffunction('CompleteFailIntermittent'\\,\ [-2])
+  set complete=.,Ffunction('CompleteFailIntermittent'\\,\ [-2])
   call setline(1, 'fooo1')
   let g:CallCount = 0
   exe "normal! Gof\<C-N>oo\<c-r>=complete_info([\"items\", \"selected\"])\<cr>"
@@ -1817,7 +1817,7 @@
   call assert_equal(4, g:CallCount)
   %d
   " refresh will stop when -3 is returned
-  set complete=.,,\ ffunction('CompleteFailIntermittent'\\,\ [-3])
+  set complete=.,,\ Ffunction('CompleteFailIntermittent'\\,\ [-3])
   call setline(1, 'fooo1')
   let g:CallCount = 0
   exe "normal! Gof\<C-N>o\<bs>\<c-r>=complete_info([\"items\", \"selected\"])\<cr>"
@@ -1862,7 +1862,7 @@
   endfunc
 
   new
-  set complete=.,ffunction('CompleteItemsSelect'\\,\ [[]])
+  set complete=.,Ffunction('CompleteItemsSelect'\\,\ [[]])
   call setline(1, "foobarbar")
   let g:CallCount = 0
   exe "normal! Gof\<c-n>\<c-n>\<c-r>=CompleteMenuWords()\<cr>"
@@ -1894,7 +1894,7 @@
   call assert_equal(2, g:CallCount)
 
   %d
-  set complete=.,ffunction('CompleteItemsSelect'\\,\ [['foonext']])
+  set complete=.,Ffunction('CompleteItemsSelect'\\,\ [['foonext']])
   call setline(1, "foobarbar")
   let g:CallCount = 0
   exe "normal! Gof\<c-n>\<c-n>\<bs>\<c-r>=CompleteMenuWords()\<cr>"
@@ -1934,7 +1934,7 @@
   call assert_equal(3, g:CallCount)
 
   %d
-  set complete=.,ffunction('CompleteItemsSelect'\\,\ [['fo'\\,\ 'foonext']])
+  set complete=.,Ffunction('CompleteItemsSelect'\\,\ [['fo'\\,\ 'foonext']])
   call setline(1, "foobarbar")
   let g:CallCount = 0
   exe "normal! Gof\<c-n>\<c-n>\<bs>\<c-r>=CompleteMenuWords()\<cr>"
@@ -1986,7 +1986,7 @@
   call assert_equal("f\x0e" . '{''matches'': [], ''selected'': -1}', getline(1))
 
   set completeopt=menuone,noselect
-  set complete=fCompleteItems1,fCompleteItems2
+  set complete=FCompleteItems1,FCompleteItems2
 
   new
   let g:CallCount1 = 0
@@ -2118,7 +2118,7 @@
 
   let lines =<< trim END
     #" Test for using a global function name
-    set complete=fg:CompleteFunc2
+    set complete=Fg:CompleteFunc2
     new
     call setline(1, 'global')
     LET g:CompleteFunc2Args = []
@@ -2128,7 +2128,7 @@
     bw!
 
     #" Test for using a function()
-    set complete=ffunction('g:CompleteFunc1'\\,\ [10])
+    set complete=Ffunction('g:CompleteFunc1'\\,\ [10])
     new
     call setline(1, 'one')
     LET g:CompleteFunc1Args = []
@@ -2138,7 +2138,7 @@
     bw!
 
     #" Using a funcref variable
-    set complete=ffuncref('g:CompleteFunc1'\\,\ [11])
+    set complete=Ffuncref('g:CompleteFunc1'\\,\ [11])
     new
     call setline(1, 'two')
     LET g:CompleteFunc1Args = []
@@ -2155,7 +2155,7 @@
     call add(g:CompleteFunc3Args, [a:findstart, a:base])
     return a:findstart ? 0 : []
   endfunc
-  set complete=fs:CompleteFunc3
+  set complete=Fs:CompleteFunc3
   new
   call setline(1, 'script1')
   let g:CompleteFunc3Args = []
@@ -2164,7 +2164,7 @@
   set complete&
   bw!
 
-  let &complete = 'fs:CompleteFunc3'
+  let &complete = 'Fs:CompleteFunc3'
   new
   call setline(1, 'script2')
   let g:CompleteFunc3Args = []
@@ -2182,7 +2182,7 @@
         add(CompleteFunc4Args, [findstart, base])
         return findstart ? 0 : []
       enddef
-      set complete=fCompleteFunc4
+      set complete=FCompleteFunc4
       new
       setline(1, 'script1')
       feedkeys("A\<C-N>\<Esc>", 'x')
@@ -2202,7 +2202,7 @@
     enddef
 
     # Test for using a def function with completefunc
-    set complete=ffunction('Vim9CompleteFunc'\\,\ [60])
+    set complete=Ffunction('Vim9CompleteFunc'\\,\ [60])
     new | only
     setline(1, 'one')
     g:Vim9completeFuncArgs = []
@@ -2211,7 +2211,7 @@
     bw!
 
     # Test for using a global function name
-    &complete = 'fg:CompleteFunc2'
+    &complete = 'Fg:CompleteFunc2'
     new | only
     setline(1, 'two')
     g:CompleteFunc2Args = []
@@ -2224,7 +2224,7 @@
       add(g:LocalCompleteFuncArgs, [findstart, base])
       return findstart ? 0 : []
     enddef
-    &complete = 'fLocalCompleteFunc'
+    &complete = 'FLocalCompleteFunc'
     new | only
     setline(1, 'three')
     g:LocalCompleteFuncArgs = []
@@ -3122,12 +3122,12 @@
   let result = getline(1,'$')
   call assert_equal(['', '{','}',''], result)
   %d
-  setlocal complete=fFooBarComplete
+  setlocal complete=FFooBarComplete
   exe "norm! o{\<cr>\<c-n>\<c-p>}\<cr>\<esc>"
   let result = getline(1,'$')
   call assert_equal(['', '{','}',''], result)
   %d
-  setlocal complete=f
+  setlocal complete=F
   exe "norm! o{\<cr>\<c-n>\<c-p>}\<cr>\<esc>"
   let result = getline(1,'$')
   call assert_equal(['', '{','}',''], result)
@@ -4121,7 +4121,7 @@
 
   %d
   set completefunc=ComplFunc
-  set cpt=.^1,f^2
+  set cpt=.^1,F^2
   call setline(1, ["fo", "foo", "foobar", "fobarbaz"])
   exe "normal! Gof\<c-n>\<c-r>=PrintMenuWords()\<cr>"
   call assert_equal('fo{''matches'': [''fo'', ''foo1'', ''foo2''], ''selected'': 0}', getline(5))
@@ -4156,7 +4156,7 @@
 
   %d
   call setline(1, ["foo"])
-  set cpt=fComplFunc^2,.
+  set cpt=FComplFunc^2,.
   exe "normal! Gof\<c-n>\<c-r>=PrintMenuWords()\<cr>"
   call assert_equal('foo1{''matches'': [''foo1'', ''foo2'', ''foo''], ''selected'': 0}', getline(2))
   bw!
@@ -4173,7 +4173,7 @@
   endfunc
 
   new
-  set complete=.,ffunction('CompleteItemsSelect')^2
+  set complete=.,Ffunction('CompleteItemsSelect')^2
   call setline(1, "foobarbar")
   let g:CallCount = 0
   exe "normal! Gof\<c-n>\<c-n>\<c-r>=PrintMenuWords()\<cr>"
diff --git a/src/testdir/test_options.vim b/src/testdir/test_options.vim
index 1f71e1f..8679198 100644
--- a/src/testdir/test_options.vim
+++ b/src/testdir/test_options.vim
@@ -274,7 +274,7 @@
   call assert_fails('set complete=ix', 'E535:')
   call assert_fails('set complete=x', 'E539:')
   call assert_fails('set complete=..', 'E535:')
-  set complete=.,w,b,u,k,\ s,i,d,],t,U,f,o
+  set complete=.,w,b,u,k,\ s,i,d,],t,U,F,o
   call assert_fails('set complete=i^-10', 'E535:')
   call assert_fails('set complete=i^x', 'E535:')
   call assert_fails('set complete=k^2,t^-1,s^', 'E535:')
@@ -282,13 +282,13 @@
   call assert_fails('set complete=kfoo^foo2', 'E535:')
   call assert_fails('set complete=kfoo^', 'E535:')
   call assert_fails('set complete=.^', 'E535:')
-  set complete=.,w,b,u,k,s,i,d,],t,U,f,o
+  set complete=.,w,b,u,k,s,i,d,],t,U,F,o
   set complete=.
   set complete=.^10,t^0
-  set complete+=ffuncref('foo'\\,\ [10])
-  set complete=ffuncref('foo'\\,\ [10])^10
+  set complete+=Ffuncref('foo'\\,\ [10])
+  set complete=Ffuncref('foo'\\,\ [10])^10
   set complete&
-  set complete+=ffunction('g:foo'\\,\ [10\\,\ 20])
+  set complete+=Ffunction('g:foo'\\,\ [10\\,\ 20])
   set complete&
 endfun