116 lines
4.1 KiB
Rust
116 lines
4.1 KiB
Rust
// Copyright 2012 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.
|
|
|
|
use super::{InferCtxt, fixup_err, fres, unresolved_ty, unresolved_int_ty, unresolved_float_ty};
|
|
use middle::ty::{mod, Ty};
|
|
use middle::ty_fold::{mod, TypeFoldable};
|
|
use util::ppaux::Repr;
|
|
|
|
///////////////////////////////////////////////////////////////////////////
|
|
// OPPORTUNISTIC TYPE RESOLVER
|
|
|
|
/// The opportunistic type resolver can be used at any time. It simply replaces
|
|
/// type variables that have been unified with the things they have
|
|
/// been unified with (similar to `shallow_resolve`, but deep). This is
|
|
/// useful for printing messages etc but also required at various
|
|
/// points for correctness.
|
|
pub struct OpportunisticTypeResolver<'a, 'tcx:'a> {
|
|
infcx: &'a InferCtxt<'a, 'tcx>,
|
|
}
|
|
|
|
impl<'a, 'tcx> OpportunisticTypeResolver<'a, 'tcx> {
|
|
pub fn new(infcx: &'a InferCtxt<'a, 'tcx>) -> OpportunisticTypeResolver<'a, 'tcx> {
|
|
OpportunisticTypeResolver { infcx: infcx }
|
|
}
|
|
}
|
|
|
|
impl<'a, 'tcx> ty_fold::TypeFolder<'tcx> for OpportunisticTypeResolver<'a, 'tcx> {
|
|
fn tcx(&self) -> &ty::ctxt<'tcx> {
|
|
self.infcx.tcx
|
|
}
|
|
|
|
fn fold_ty(&mut self, t: Ty<'tcx>) -> Ty<'tcx> {
|
|
if !ty::type_has_ty_infer(t) {
|
|
t // micro-optimize -- if there is nothing in this type that this fold affects...
|
|
} else {
|
|
let t0 = self.infcx.shallow_resolve(t);
|
|
ty_fold::super_fold_ty(self, t0)
|
|
}
|
|
}
|
|
}
|
|
|
|
///////////////////////////////////////////////////////////////////////////
|
|
// FULL TYPE RESOLUTION
|
|
|
|
/// Full type resolution replaces all type and region variables with
|
|
/// their concrete results. If any variable cannot be replaced (never unified, etc)
|
|
/// then an `Err` result is returned.
|
|
pub fn fully_resolve<'a, 'tcx, T>(infcx: &InferCtxt<'a,'tcx>, value: &T) -> fres<T>
|
|
where T : TypeFoldable<'tcx>
|
|
{
|
|
let mut full_resolver = FullTypeResolver { infcx: infcx, err: None };
|
|
let result = value.fold_with(&mut full_resolver);
|
|
match full_resolver.err {
|
|
None => Ok(result),
|
|
Some(e) => Err(e),
|
|
}
|
|
}
|
|
|
|
// N.B. This type is not public because the protocol around checking the
|
|
// `err` field is not enforcable otherwise.
|
|
struct FullTypeResolver<'a, 'tcx:'a> {
|
|
infcx: &'a InferCtxt<'a, 'tcx>,
|
|
err: Option<fixup_err>,
|
|
}
|
|
|
|
impl<'a, 'tcx> ty_fold::TypeFolder<'tcx> for FullTypeResolver<'a, 'tcx> {
|
|
fn tcx(&self) -> &ty::ctxt<'tcx> {
|
|
self.infcx.tcx
|
|
}
|
|
|
|
fn fold_ty(&mut self, t: Ty<'tcx>) -> Ty<'tcx> {
|
|
if !ty::type_needs_infer(t) {
|
|
t // micro-optimize -- if there is nothing in this type that this fold affects...
|
|
} else {
|
|
let t = self.infcx.shallow_resolve(t);
|
|
match t.sty {
|
|
ty::ty_infer(ty::TyVar(vid)) => {
|
|
self.err = Some(unresolved_ty(vid));
|
|
ty::mk_err()
|
|
}
|
|
ty::ty_infer(ty::IntVar(vid)) => {
|
|
self.err = Some(unresolved_int_ty(vid));
|
|
ty::mk_err()
|
|
}
|
|
ty::ty_infer(ty::FloatVar(vid)) => {
|
|
self.err = Some(unresolved_float_ty(vid));
|
|
ty::mk_err()
|
|
}
|
|
ty::ty_infer(_) => {
|
|
self.infcx.tcx.sess.bug(
|
|
format!("Unexpected type in full type resolver: {}",
|
|
t.repr(self.infcx.tcx))[]);
|
|
}
|
|
_ => {
|
|
ty_fold::super_fold_ty(self, t)
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
fn fold_region(&mut self, r: ty::Region) -> ty::Region {
|
|
match r {
|
|
ty::ReInfer(ty::ReVar(rid)) => self.infcx.region_vars.resolve_var(rid),
|
|
_ => r,
|
|
}
|
|
}
|
|
}
|
|
|