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use middle::traits;
use middle::ty;
use middle::infer::{self, new_infer_ctxt};
use syntax::ast::DefId;
use syntax::ast::LOCAL_CRATE;
use syntax::ast;
use syntax::ast_util;
use syntax::visit;
use syntax::codemap::Span;
use util::nodemap::DefIdMap;
use util::ppaux::{Repr, UserString};
pub fn check(tcx: &ty::ctxt) {
let mut overlap = OverlapChecker { tcx: tcx, default_impls: DefIdMap() };
overlap.check_for_overlapping_impls();
visit::walk_crate(&mut overlap, tcx.map.krate());
}
struct OverlapChecker<'cx, 'tcx:'cx> {
tcx: &'cx ty::ctxt<'tcx>,
default_impls: DefIdMap<ast::NodeId>,
}
impl<'cx, 'tcx> OverlapChecker<'cx, 'tcx> {
fn check_for_overlapping_impls(&self) {
debug!("check_for_overlapping_impls");
let trait_def_ids: Vec<(ast::DefId, Vec<ast::DefId>)> =
self.tcx.trait_impls.borrow().iter().map(|(&k, v)| {
ty::populate_implementations_for_trait_if_necessary(self.tcx, k);
(k, v.borrow().clone())
}).collect();
for &(trait_def_id, ref impls) in &trait_def_ids {
self.check_for_overlapping_impls_of_trait(trait_def_id, impls);
}
}
fn check_for_overlapping_impls_of_trait(&self,
trait_def_id: ast::DefId,
trait_impls: &Vec<ast::DefId>)
{
debug!("check_for_overlapping_impls_of_trait(trait_def_id={})",
trait_def_id.repr(self.tcx));
for (i, &impl1_def_id) in trait_impls.iter().enumerate() {
if impl1_def_id.krate != ast::LOCAL_CRATE {
continue;
}
for &impl2_def_id in &trait_impls[(i+1)..] {
self.check_if_impls_overlap(trait_def_id,
impl1_def_id,
impl2_def_id);
}
}
}
fn check_if_impls_overlap(&self,
trait_def_id: ast::DefId,
impl1_def_id: ast::DefId,
impl2_def_id: ast::DefId)
{
assert_eq!(impl1_def_id.krate, ast::LOCAL_CRATE);
debug!("check_if_impls_overlap({}, {}, {})",
trait_def_id.repr(self.tcx),
impl1_def_id.repr(self.tcx),
impl2_def_id.repr(self.tcx));
let infcx = infer::new_infer_ctxt(self.tcx);
if !traits::overlapping_impls(&infcx, impl1_def_id, impl2_def_id) {
return;
}
self.report_overlap_error(trait_def_id, impl1_def_id, impl2_def_id);
}
fn report_overlap_error(&self, trait_def_id: ast::DefId,
impl1: ast::DefId, impl2: ast::DefId) {
span_err!(self.tcx.sess, self.span_of_impl(impl1), E0119,
"conflicting implementations for trait `{}`",
ty::item_path_str(self.tcx, trait_def_id));
self.report_overlap_note(impl1, impl2);
}
fn report_overlap_note(&self, impl1: ast::DefId, impl2: ast::DefId) {
if impl2.krate == ast::LOCAL_CRATE {
span_note!(self.tcx.sess, self.span_of_impl(impl2),
"note conflicting implementation here");
} else {
let crate_store = &self.tcx.sess.cstore;
let cdata = crate_store.get_crate_data(impl2.krate);
span_note!(self.tcx.sess, self.span_of_impl(impl1),
"conflicting implementation in crate `{}`",
cdata.name);
}
}
fn span_of_impl(&self, impl_did: ast::DefId) -> Span {
assert_eq!(impl_did.krate, ast::LOCAL_CRATE);
self.tcx.map.span(impl_did.node)
}
}
impl<'cx, 'tcx,'v> visit::Visitor<'v> for OverlapChecker<'cx, 'tcx> {
fn visit_item(&mut self, item: &'v ast::Item) {
match item.node {
ast::ItemDefaultImpl(_, _) => {
let impl_def_id = ast_util::local_def(item.id);
let trait_ref = ty::impl_trait_ref(self.tcx, impl_def_id).unwrap();
let prev_default_impl = self.default_impls.insert(trait_ref.def_id, item.id);
match prev_default_impl {
Some(prev_id) => {
self.report_overlap_error(trait_ref.def_id,
impl_def_id,
ast_util::local_def(prev_id));
}
None => { }
}
}
ast::ItemImpl(_, _, _, Some(_), ref self_ty, _) => {
let impl_def_id = ast_util::local_def(item.id);
let trait_ref = ty::impl_trait_ref(self.tcx, impl_def_id).unwrap();
let trait_def_id = trait_ref.def_id;
match trait_ref.self_ty().sty {
ty::ty_trait(ref data) => {
if !traits::is_object_safe(self.tcx, data.principal_def_id()) {
span_err!(self.tcx.sess, self_ty.span, E0372,
"the trait `{}` cannot be made into an object",
ty::item_path_str(self.tcx, data.principal_def_id()));
} else {
let mut supertrait_def_ids =
traits::supertrait_def_ids(self.tcx, data.principal_def_id());
if supertrait_def_ids.any(|d| d == trait_def_id) {
span_err!(self.tcx.sess, item.span, E0371,
"the object type `{}` automatically \
implements the trait `{}`",
trait_ref.self_ty().user_string(self.tcx),
ty::item_path_str(self.tcx, trait_def_id));
}
}
}
_ => { }
}
}
_ => {
}
}
visit::walk_item(self, item);
}
}