diff --git a/autoload/gyoza/applier.vim b/autoload/gyoza/applier.vim
index 9006f36..fa9f73f 100644
--- a/autoload/gyoza/applier.vim
+++ b/autoload/gyoza/applier.vim
@@ -19,7 +19,7 @@ function gyoza#applier#trigger_applicant(all_rules) abort
     return
   endif
 
-  let s:rule_stack = a:all_rules->copy()->filter('prevline =~# v:val.pattern')
+  let s:rule_stack = a:all_rules->deepcopy()->filter('prevline =~# v:val.pattern')
   let s:cursor_text = getline('.')[col('.') - 1 :]
 
   inoremap <buffer> <silent> <expr> <Plug>(_gyoza_apply) <SID>do_apply()
diff --git a/test/applier.vimspec b/test/applier.vimspec
index 562d309..807b9ed 100644
--- a/test/applier.vimspec
+++ b/test/applier.vimspec
@@ -435,6 +435,21 @@ Describe Applier class
       \.run()
   End
 
+  It forgets kept text on next application when rule is defined with a function.
+    let rules = NewConfig().add_rule('^\s*if', {lines ->
+      \ {'pair': 'endif', 'cursor_text': lines.current}})._rules
+    call setline(1, 'iffoo')
+    call NewScripter()
+      \.feedkeys('^la<CR>')
+      \.call({-> gyoza#applier#trigger_applicant(rules)})
+      \.call({-> s:assert.equals(GetAllLines(), ['if', "\tfoo", 'endif'])})
+      \.feedkeys('<ESC>Goif<CR>')
+      \.call({-> gyoza#applier#trigger_applicant(rules)})
+      \.call({-> s:assert.equals(GetAllLines(), ['if', "\tfoo", 'endif', 'if', "\t", 'endif'])})
+      \.call({-> s:assert.equals(GetCurpos(), [5, 2])})
+      \.run()
+  End
+
   It completes pair when block is nested.
     let rules = NewConfig()
       \.add_rule('^\s*if\>', 'endif')