From 0c03a886d3d9cb6e43207fa66d798ac5871dcbf1 Mon Sep 17 00:00:00 2001
From: Niko Matsakis <niko@alum.mit.edu>
Date: Thu, 13 Oct 2016 12:31:55 -0400
Subject: [PATCH] run compare method in old-broken-way and new-good-way
---
src/librustc_typeck/check/compare_method.rs | 25 ++++++++++++++++-----
src/librustc_typeck/check/mod.rs | 15 ++++++++++++-
2 files changed, 34 insertions(+), 6 deletions(-)
diff --git a/src/librustc_typeck/check/compare_method.rs b/src/librustc_typeck/check/compare_method.rs
index d9af317eab0..19966d3ee86 100644
--- a/src/librustc_typeck/check/compare_method.rs
+++ b/src/librustc_typeck/check/compare_method.rs
@@ -9,6 +9,7 @@
// except according to those terms.
use rustc::infer::{self, InferOk, TypeOrigin};
+use rustc::middle::free_region::FreeRegionMap;
use rustc::ty;
use rustc::traits::{self, Reveal};
use rustc::ty::error::{ExpectedFound, TypeError};
@@ -39,8 +40,10 @@ pub fn compare_impl_method<'a, 'tcx>(ccx: &CrateCtxt<'a, 'tcx>,
impl_m_body_id: ast::NodeId,
trait_m: &ty::Method<'tcx>,
impl_trait_ref: &ty::TraitRef<'tcx>,
- trait_item_span: Option<Span>) {
- debug!("compare_impl_method(impl_trait_ref={:?})", impl_trait_ref);
+ trait_item_span: Option<Span>,
+ old_broken_mode: bool) {
+ debug!("compare_impl_method(impl_trait_ref={:?})",
+ impl_trait_ref);
debug!("compare_impl_method: impl_trait_ref (liberated) = {:?}",
impl_trait_ref);
@@ -367,7 +370,7 @@ pub fn compare_impl_method<'a, 'tcx>(ccx: &CrateCtxt<'a, 'tcx>,
item_name: impl_m.name,
impl_item_def_id: impl_m.def_id,
trait_item_def_id: trait_m.def_id,
- lint_id: Some(impl_m_body_id),
+ lint_id: if !old_broken_mode { Some(impl_m_body_id) } else { None },
},
};
@@ -473,8 +476,20 @@ pub fn compare_impl_method<'a, 'tcx>(ccx: &CrateCtxt<'a, 'tcx>,
// Finally, resolve all regions. This catches wily misuses of
// lifetime parameters.
- let fcx = FnCtxt::new(&inh, tcx.types.err, impl_m_body_id);
- fcx.regionck_item(impl_m_body_id, impl_m_span, &[]);
+ if old_broken_mode {
+ // FIXME(#18937) -- this is how the code used to
+ // work. This is buggy because the fulfillment cx creates
+ // region obligations that get overlooked. The right
+ // thing to do is the code below. But we keep this old
+ // pass around temporarily.
+ let mut free_regions = FreeRegionMap::new();
+ free_regions.relate_free_regions_from_predicates(
+ &infcx.parameter_environment.caller_bounds);
+ infcx.resolve_regions_and_report_errors(&free_regions, impl_m_body_id);
+ } else {
+ let fcx = FnCtxt::new(&inh, tcx.types.err, impl_m_body_id);
+ fcx.regionck_item(impl_m_body_id, impl_m_span, &[]);
+ }
});
fn check_region_bounds_on_impl_method<'a, 'tcx>(ccx: &CrateCtxt<'a, 'tcx>,
diff --git a/src/librustc_typeck/check/mod.rs b/src/librustc_typeck/check/mod.rs
index ef127feb042..4e0f455e362 100644
--- a/src/librustc_typeck/check/mod.rs
+++ b/src/librustc_typeck/check/mod.rs
@@ -1028,13 +1028,26 @@ fn check_impl_items_against_trait<'a, 'tcx>(ccx: &CrateCtxt<'a, 'tcx>,
let trait_span = tcx.map.span_if_local(ty_trait_item.def_id());
if let &ty::MethodTraitItem(ref trait_method) = ty_trait_item {
+ let err_count = tcx.sess.err_count();
compare_impl_method(ccx,
&impl_method,
impl_item.span,
body.id,
&trait_method,
&impl_trait_ref,
- trait_span);
+ trait_span,
+ true); // start with old-broken-mode
+ if err_count == tcx.sess.err_count() {
+ // old broken mode did not report an error. Try with the new mode.
+ compare_impl_method(ccx,
+ &impl_method,
+ impl_item.span,
+ body.id,
+ &trait_method,
+ &impl_trait_ref,
+ trait_span,
+ false); // use the new mode
+ }
} else {
let mut err = struct_span_err!(tcx.sess, impl_item.span, E0324,
"item `{}` is an associated method, \