fix: derive generic method call shapes from declarations

[ivov]

Generic method calls now compile when the result is bound and when function or spread arguments need shape adaptation, using the method's declared shape instead of the instantiated type. This extends #461 from free functions to methods.

pub interface Face {}

pub fn resultant(arg: int) -> Result<int, Face> {
  Ok(arg)
}

pub struct Holder { pub n: int }

impl Holder {
  pub fn resolve<R, E>(self, f: fn(int) -> Result<R, E>) -> Result<R, E> {
    f(self.n)
  }
}

fn main() {
  let rez = Holder { n: 4 }.resolve(resultant)
  let _ = rez
}

[github-actions]

Released in lisette-v0.2.9