Albate I think this issue is pertaining to the standard or slang English, Still I want to ensure if it's related to that or not.
Since I came across many times in movies and some everyday english talks they use the main clause of the 3rd conditional as the next part of a wish clause. The following example could illustrate much easier though.
i. I wish I could've gone there.
ii. I wish I had gone there.
Regarding the example, I need to know:
1.What's the difference between two in terms of meaning?
2.Is this variation regarded to the issue of standard/slang English or they totally differ from each other in terms of grammar?