diff --git a/src/testdir/test_vim9_disassemble.vim b/src/testdir/test_vim9_disassemble.vim
index 53bc4ba..fe1ce66 100644
--- a/src/testdir/test_vim9_disassemble.vim
+++ b/src/testdir/test_vim9_disassemble.vim
@@ -273,6 +273,34 @@
         res)
 enddef
 
+def s:ListAdd()
+  var l: list<number> = []
+  add(l, 123)
+  add(l, g:aNumber)
+enddef
+
+def Test_disassemble_list_add()
+  var res = execute('disass s:ListAdd')
+  assert_match('<SNR>\d*_ListAdd\_s*' ..
+        'var l: list<number> = []\_s*' ..
+        '\d NEWLIST size 0\_s*' ..
+        '\d STORE $0\_s*' ..
+        'add(l, 123)\_s*' ..
+        '\d LOAD $0\_s*' ..
+        '\d PUSHNR 123\_s*' ..
+        '\d LISTAPPEND\_s*' ..
+        '\d DROP\_s*' ..
+        'add(l, g:aNumber)\_s*' ..
+        '\d LOAD $0\_s*' ..
+        '\d\+ LOADG g:aNumber\_s*' ..
+        '\d\+ CHECKTYPE number stack\[-1\]\_s*' ..
+        '\d\+ LISTAPPEND\_s*' ..
+        '\d\+ DROP\_s*' ..
+        '\d\+ PUSHNR 0\_s*' ..
+        '\d\+ RETURN',
+        res)
+enddef
+
 def s:ScriptFuncUnlet()
   g:somevar = "value"
   unlet g:somevar
@@ -803,7 +831,7 @@
         'res->add(i)\_s*' ..
         '\d LOAD $0\_s*' ..
         '\d LOAD $2\_s*' ..
-        '\d\+ BCALL add(argc 2)\_s*' ..
+        '\d\+ LISTAPPEND\_s*' ..
         '\d\+ DROP\_s*' ..
         'endfor\_s*' ..
         '\d\+ JUMP -> \d\+\_s*' ..
diff --git a/src/testdir/test_vim9_func.vim b/src/testdir/test_vim9_func.vim
index cc6af6a..bded91f 100644
--- a/src/testdir/test_vim9_func.vim
+++ b/src/testdir/test_vim9_func.vim
@@ -1772,6 +1772,24 @@
   list2str(l, true)->assert_equal(s)
 enddef
 
+def Test_list_add()
+  var l: list<number>  # defaults to empty list
+  add(l, 9)
+  assert_equal([9], l)
+
+  var lines =<< trim END
+      var l: list<number>
+      add(l, "x")
+  END
+  CheckDefFailure(lines, 'E1012:', 2)
+
+  lines =<< trim END
+      var l: list<number> = test_null_list()
+      add(l, 123)
+  END
+  CheckDefExecFailure(lines, 'E1130:', 2)
+enddef
+
 def SID(): number
   return expand('<SID>')
           ->matchstr('<SNR>\zs\d\+\ze_$')