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use middle::traits;
use middle::ty;
use syntax::ast::{Item, ItemImpl};
use syntax::ast;
use syntax::ast_util;
use syntax::codemap::Span;
use syntax::visit;
use util::ppaux::Repr;
pub fn check(tcx: &ty::ctxt) {
let mut orphan = OrphanChecker { tcx: tcx };
visit::walk_crate(&mut orphan, tcx.map.krate());
}
struct OrphanChecker<'cx, 'tcx:'cx> {
tcx: &'cx ty::ctxt<'tcx>
}
impl<'cx, 'tcx> OrphanChecker<'cx, 'tcx> {
fn check_def_id(&self, span: Span, def_id: ast::DefId) {
if def_id.krate != ast::LOCAL_CRATE {
span_err!(self.tcx.sess, span, E0116,
"cannot associate methods with a type outside the \
crate the type is defined in; define and implement \
a trait or new type instead");
}
}
}
impl<'cx, 'tcx,'v> visit::Visitor<'v> for OrphanChecker<'cx, 'tcx> {
fn visit_item(&mut self, item: &'v ast::Item) {
let def_id = ast_util::local_def(item.id);
match item.node {
ast::ItemImpl(_, _, None, _, _) => {
debug!("coherence2::orphan check: inherent impl {}", item.repr(self.tcx));
let self_ty = ty::lookup_item_type(self.tcx, def_id).ty;
match self_ty.sty {
ty::ty_enum(def_id, _) |
ty::ty_struct(def_id, _) => {
self.check_def_id(item.span, def_id);
}
ty::ty_trait(ref data) => {
self.check_def_id(item.span, data.principal_def_id());
}
_ => {
span_err!(self.tcx.sess, item.span, E0118,
"no base type found for inherent implementation; \
implement a trait or new type instead");
}
}
}
ast::ItemImpl(_, _, Some(_), _, _) => {
debug!("coherence2::orphan check: trait impl {}", item.repr(self.tcx));
if traits::is_orphan_impl(self.tcx, def_id) {
span_err!(self.tcx.sess, item.span, E0117,
"cannot provide an extension implementation \
where both trait and type are not defined in this crate");
}
}
_ => {
}
}
visit::walk_item(self, item);
}
}