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ICE with Self in function bodies, associated types, and lifetimes #27281
Description
STR
pub trait Trait<'a> {
type T;
fn foo(&self, s: &'a ()) -> &'a ();
}
impl<'a> Trait<'a> for () {
type T = &'a ();
fn foo(&self, s: &'a ()) -> &'a () {
let t: Self::T = s; s
}
}
fn main() {}Result
<anon>:10:16: 10:23 error: internal compiler error: cannot relate bound region: '_#0r <= ReEarlyBound(48, TypeSpace, 0, 'a)
<anon>:10 let t: Self::T = s; s
^~~~~~~
note: the compiler unexpectedly panicked. this is a bug.
note: we would appreciate a bug report: https://github.com/rust-lang/rust/blob/master/CONTRIBUTING.md#bug-reports
note: run with `RUST_BACKTRACE=1` for a backtrace
thread 'rustc' panicked at 'Box<Any>', /home/rustbuild/src/rust-buildbot/slave/stable-dist-rustc-linux/build/src/libsyntax/diagnostic.rs:170
Orig
use std::marker::PhantomData;
pub struct GILGuard;
trait PythonObject<'a> {
fn dummy() -> &'a i32;
}
#[derive(Copy, Clone)]
pub struct Python<'p>(PhantomData<&'p GILGuard>);
pub struct PyErr<'p> {
pub ptype : PyObject<'p>,
}
type PyResult<'p, T> = Result<T, PyErr<'p>>;
pub struct PyObject<'a> {
dummy : &'a i32
}
impl <'p> PyObject<'p> {
pub fn cast_into<T>(self) -> Result<T, PythonObjectDowncastError<'p>> where T: PythonObjectWithCheckedDowncast<'p> {
PythonObjectWithCheckedDowncast::downcast_from(self)
}
}
pub struct PythonObjectDowncastError<'p>(pub Python<'p>);
pub trait PythonObjectWithCheckedDowncast<'p> : PythonObject<'p> {
fn downcast_from(PyObject<'p>) -> Result<Self, PythonObjectDowncastError<'p>>;
}
impl <'p> PythonObjectWithCheckedDowncast<'p> for PyObject<'p> {
#[inline]
fn downcast_from(obj: PyObject<'p>) -> Result<PyObject<'p>, PythonObjectDowncastError<'p>> {
Ok(obj)
}
}
impl <'p> PythonObject<'p> for PyObject<'p> {
fn dummy() -> &'p i32 { &7 }
}
pub trait PyExtractor<'python, 'source, 'prepared> {
type Prepared;
fn extract<T>(prepared: &'prepared Self::Prepared) -> PyResult<'python, T>
where T: PythonObjectWithCheckedDowncast<'python> ;
}
pub struct PyObjectExtractor;
impl <'python, 'source, 'prepared> PyExtractor<'python, 'source, 'prepared>
for PyObjectExtractor {
type Prepared = &'source PyObject<'python>;
#[inline]
fn extract<T>(&&ref obj: &'prepared Self::Prepared) -> PyResult<'python, T>
where T: PythonObjectWithCheckedDowncast<'python> {
Ok(try!(obj.clone().cast_into()))
}
}
pub trait ExtractPyObject<'python, 'source, 'prepared> {
type Prepared;
fn prepare_extract(obj: &'source PyObject<'python>) -> PyResult<'python, Self::Prepared>;
fn extract<E: PyExtractor<'python, 'source, 'prepared>>(prepared: &'prepared Self::Prepared) -> PyResult<'python, Self>;
}
impl <'python, 'source, 'prepared, T> ExtractPyObject<'python, 'source, 'prepared>
for T where T: PythonObjectWithCheckedDowncast<'python> {
type Prepared = &'source PyObject<'python>;
#[inline]
fn prepare_extract(obj: &'source PyObject<'python>) -> PyResult<'python, Self::Prepared> {
Ok(obj)
}
#[inline]
fn extract<E: PyExtractor<'python, 'source, 'prepared>>(&&ref obj: &'prepared Self::Prepared) -> PyResult<'python, T> {
E::extract::<Self::Prepared>(&obj)
}
}
Activity
Substitute free lifetimes in `Self::T`