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liveness: substitute bound regions with free ones before normalizing the return type #32332

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Mar 19, 2016
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4 changes: 3 additions & 1 deletion src/librustc/middle/liveness.rs
Original file line number Diff line number Diff line change
Expand Up @@ -115,6 +115,7 @@ use middle::pat_util;
use middle::ty::{self, TyCtxt, ParameterEnvironment};
use middle::traits::{self, ProjectionMode};
use middle::infer;
use middle::subst::Subst;
use lint;
use util::nodemap::NodeMap;

Expand Down Expand Up @@ -1495,14 +1496,15 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
if self.live_on_entry(entry_ln, self.s.no_ret_var).is_some() => {

let param_env = ParameterEnvironment::for_item(&self.ir.tcx, id);
let t_ret_subst = t_ret.subst(&self.ir.tcx, &param_env.free_substs);
let infcx = infer::new_infer_ctxt(&self.ir.tcx,
&self.ir.tcx.tables,
Some(param_env),
ProjectionMode::Any);
let cause = traits::ObligationCause::dummy();
let norm = traits::fully_normalize(&infcx,
cause,
&t_ret);
&t_ret_subst);

if norm.unwrap().is_nil() {
// for nil return types, it is ok to not return a value expl.
Expand Down
18 changes: 18 additions & 0 deletions src/test/compile-fail/issue-32323.rs
Original file line number Diff line number Diff line change
@@ -0,0 +1,18 @@
// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

pub trait Tr<'a> {
type Out;
}

pub fn f<'a, T: Tr<'a>>() -> <T as Tr<'a>>::Out {}
//~^ ERROR not all control paths return a value

pub fn main() {}