I wish John could have come yesterday.

[diamondcutter]

1. I wish John could have come yesterday.

2. I wish John had come yesterday.
(By me)

I think the first sentence means John didn’t come yesterday and the reason could be that he was busy or he was not allowed to although he was willing to come.

For the second sentence, it also means John didn’t come but the reason could be that he wasn’t willing to or something else.

I’d like to know if my understanding is correct.

 

[Yankee]

I agree..

 

[Phaedrus]

1. I wish John could have come yesterday.

[. . .]

I think the first sentence means John didn’t come yesterday and the reason could be that he was busy or he was not allowed to although he was willing to come.

Another possibility is that he didn't come because he didn't think about coming at all:

I wish John could have come yesterday, but he didn't learn about the event in time.