if p.path.segments.len() != 1 { unimplemented!(); }
let mut args = p.path.segments[0].arguments.clone();
if let syn::PathArguments::AngleBracketed(ref mut generics) = &mut args {
if p.path.segments.len() != 1 { unimplemented!(); }
let mut args = p.path.segments[0].arguments.clone();
if let syn::PathArguments::AngleBracketed(ref mut generics) = &mut args {