src/test/ui/derived-errors/issue-30580.rs

// Test that we do not see uninformative region-related errors
// when we get some basic type-checking failure. See #30580.

pub struct Foo { a: u32 }
pub struct Pass<'a, 'tcx: 'a>(&'a mut &'a (), &'a &'tcx ());

impl<'a, 'tcx> Pass<'a, 'tcx>
{
    pub fn tcx(&self) -> &'a &'tcx () { self.1 }
    fn lol(&mut self, b: &Foo)
    {
        b.c; //~ ERROR no field `c` on type `&Foo`
        self.tcx();
    }
}

fn main() {}