rust/src/rustc/middle/check_self.rs

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/*
This module checks that within a class, "self" doesn't escape.
That is, it rejects any class in which "self" occurs other than
as the left-hand side of a field reference.
*/
import syntax::ast::*;
import syntax::visit::*;
import driver::session::session;
import std::map::hashmap;
import resolve::def_map;
fn check_crate(cx: ty::ctxt, crate: @crate) {
visit_crate(*crate, cx, mk_vt(@{
visit_item: bind check_item(_, _, _)
with *default_visitor()
}));
cx.sess.abort_if_errors();
}
fn check_item(it: @item, &&cx: ty::ctxt, &&_v: vt<ty::ctxt>) {
alt it.node {
item_class(*) {
visit_item(it, cx, check_self_visitor());
}
_ {}
}
}
fn check_self_visitor() -> vt<ty::ctxt> {
mk_vt(@{
visit_expr: bind check_self_expr(_, _, _)
with *default_visitor()
})
}
fn check_self_expr(e: @expr, &&cx: ty::ctxt, &&v: vt<ty::ctxt>) {
alt e.node {
expr_field(@{node: expr_path(p),_},_,_) {
// self is ok here; don't descend
}
expr_path(_) {
alt cx.def_map.find(e.id) {
some(def_self(_)) {
cx.sess.span_err(e.span, "can't return self or store \
it in a data structure");
}
_ {}
}
}
_ { visit_expr(e, cx, v); }
}
}
// Local Variables:
// mode: rust
// fill-column: 78;
// indent-tabs-mode: nil
// c-basic-offset: 4
// buffer-file-coding-system: utf-8-unix
// End: