Function as_some_pattern 

pub fn as_some_pattern<'a, 'hir>(
    cx: &LateContext<'_>,
    pat: &'a Pat<'hir>,
) -> Option<&'a [Pat<'hir>]>

If pat is:

• Some(inner), returns inner
  • it will usually contain just one element, but could have two, given patterns like Some(inner, ..) or Some(.., inner)
• Some, returns []
• otherwise, returns None