Merge pull request #17143 from jamessan/coverity-fixes

Various Coverity fixes

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);

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) {