2 files changed, 6 insertions, 0 deletions
diff --git a/src/nvim/api/private/converter.c b/src/nvim/api/private/converter.c
index e370c0d4d4..3d4ff202fe 100644
--- a/src/nvim/api/private/converter.c
+++ b/src/nvim/api/private/converter.c
@@ -233,6 +233,7 @@ Object vim_to_object(typval_T *obj)
 {
   if (obj->v_type == VAR_FUNC) {
     ufunc_T *fp = find_func(obj->vval.v_string);
+    assert(fp != NULL);
     if (fp->uf_cb == nlua_CFunction_func_call) {
       LuaRef ref = api_new_luaref(((LuaCFunctionState *)fp->uf_cb_state)->lua_callable.func_ref);
       return LUAREF_OBJ(ref);
diff --git a/src/nvim/api/vim.c b/src/nvim/api/vim.c
index cc622a00dc..7c194935ce 100644
--- a/src/nvim/api/vim.c
+++ b/src/nvim/api/vim.c
@@ -2283,6 +2283,11 @@ Dictionary nvim_eval_statusline(String str, Dict(eval_statusline) *opts, Error *
     fillchar = ' ';
   } else {
     wp = find_window_by_handle(window, err);
+
+    if (wp == NULL) {
+      api_set_error(err, kErrorTypeException, "unknown winid %d", window);
+      return result;
+    }
     ewp = wp;
 
     if (fillchar == 0) {