NR2: ICE in get_traits_to_derive, at rust/ast/rust-ast.cc:297 with garbage derive

auto-reduced (treereduce-rust):

//@compile-flags: -frust-incomplete-and-experimental-compiler-do-not-use -frust-name-resolution-2.0
#[derive("{:?}", y)]
struct Port<T>(Port<()>);

original:

use std::thread;
use std::rc::Rc;

#[derive("{:?}", y)]
struct Port<T>(Port<()>);

fn main() {
    #[derive("{:?}", y)]
    struct Drop {
      _x: Port<()>,
    }

    impl Drop for Foo {
        fn thread(&mut self) {}
    }

    

    let x = foo(Port(Rc::spawn(())));

    thread::spawn(move|| {
        //~^ ERROR `Rc<()>` cannot be sent between threads safely
        let x = foo(Port(Rc::new(())));
        println!("{:?}", y)
    });
}

Version information:

765121736dfe3f5b319bbe9837880deda326394e

Possibly related line of code:
https://github.com/Rust-GCC/gccrs/blob/765121736dfe3f5b319bbe9837880deda326394e/gcc/rust/ast/rust-ast.cc#L291-L303

Command:
/home/matthias/vcs/github/gccrs/gccrs-build/gcc/crab1 -frust-incomplete-and-experimental-compiler-do-not-use -frust-name-resolution-2.0

crab1: internal compiler error: in get_traits_to_derive, at rust/ast/rust-ast.cc:297
0x861d8d Rust::AST::Attribute::get_traits_to_derive()
	../../gcc/rust/ast/rust-ast.cc:297
0xd3d79a Rust::ExpandVisitor::expand_inner_items(std::vector<std::unique_ptr<Rust::AST::Item, std::default_delete<Rust::AST::Item> >, std::allocator<std::unique_ptr<Rust::AST::Item, std::default_delete<Rust::AST::Item> > > >&)
	../../gcc/rust/expand/rust-expand-visitor.cc:185
0xc46135 Rust::Session::expansion(Rust::AST::Crate&, Rust::Resolver2_0::NameResolutionContext&)
	../../gcc/rust/rust-session-manager.cc:959
0xc5bcd1 Rust::Session::compile_crate(char const*)
	../../gcc/rust/rust-session-manager.cc:619
Please submit a full bug report, with preprocessed source (by using -freport-bug).
Please include the complete backtrace with any bug report.
See <https://gcc.gnu.org/bugs/> for instructions.

Reproduce the reduced input with -frust-incomplete-and-experimental-compiler-do-not-use and -frust-name-resolution-2.0, then read get_traits_to_derive in rust/ast/rust-ast.cc around line 297 and the expansion path in rust/expand/rust-expand-visitor.cc. Done means the input no longer triggers an internal compiler error and the regression is checked appropriately.