[PDG] Arguments and returns not correctly connected with external functions in certain cases.

[JustusAdam]

Here is the code I tried

fn main() -> u32 {
    id(create())
}

// external 
fn create() -> u32;
fn id<T>(t: T) -> T;

I would have expected this to create a PDG return@create -> arg[0]@id -> return@id -> return@main but instead it creates this

The input of id is for some reason not connected to anything, but its parent is connected to its return? This is very strange.