關於英文for dinner與to dinner的語意差異。?

I think you need to throw away that yahoo dictionary.

1. Having XX  for dinner...

means you cook XX and eat XX at the dinner.  I don't think you should eat your friends at any time.

for example:
(A) I had some fried chicken for dinner last night. = I ate fried chicken at the dinner last night.

2. Having someone over for dinner....
The "to have...over" here means "to invite" - good uses indeed.

3. to have someone to...
Usually this implies certain degree of "demand" and "force" against someone's will.

4. So, please don't use those strange English..
Use "invite" a few friends to my dinner ...

5. Also, avoid using "some" friends - "some" also implies important and significant.
Please use "a few" instead.

很爛的例句，英語人應該不會理解的。因為用for dinner和to dinner的說/寫法不會是這樣的。

for dinner意思有點像中文的"飯局"
因此通常會說明"飯局"的地點或處境：
We had some friends over to our home for dinner last night.
才會是英語人的說法。當然沒有了地點令句子的意義減半，但這例句還未算寫錯。

to dinner意思必須是"外出用饍"或"去別人的地方晚餐"
因此這例句去了那裏也沒有看來英語人會感覺"極怪"。可能是翻譯機器把proposition加入基本句式，便產生出這兩句。
若嘗試把句定按正常的英語寫/說應該是：
We and some friends went to dinner last night.
留意當中必定有一個"行動"(go)動詞，原例句的動詞had(have)並不能連上to dinner，沒有了"動作"動詞接to dinner是錯句。

另外由於to dinner的重點應該是"去晚餐"的地方或去吃的東西，因此通常要附上地點或外饍的原因才算是完整理解的句子。