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use common::*;
use rustc::hir::def_id::DefId;
use rustc::infer::TransNormalize;
use rustc::traits;
use rustc::ty::fold::{TypeFolder, TypeFoldable};
use rustc::ty::subst::{Subst, Substs};
use rustc::ty::{self, Ty, TyCtxt};
use rustc::util::ppaux;
use rustc::util::common::MemoizationMap;
use syntax::codemap::DUMMY_SP;
use std::fmt;
#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
pub struct Instance<'tcx> {
pub def: DefId,
pub substs: &'tcx Substs<'tcx>,
}
impl<'tcx> fmt::Display for Instance<'tcx> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
ppaux::parameterized(f, &self.substs, self.def, &[])
}
}
impl<'a, 'tcx> Instance<'tcx> {
pub fn new(def_id: DefId, substs: &'tcx Substs<'tcx>)
-> Instance<'tcx> {
assert!(substs.regions().all(|&r| r == ty::ReErased));
Instance { def: def_id, substs: substs }
}
pub fn mono(scx: &SharedCrateContext<'a, 'tcx>, def_id: DefId) -> Instance<'tcx> {
Instance::new(def_id, scx.empty_substs_for_def_id(def_id))
}
pub fn resolve_const(&self, scx: &SharedCrateContext<'a, 'tcx>) -> Self {
if let Some(trait_id) = scx.tcx().trait_of_item(self.def) {
let trait_ref = ty::TraitRef::new(trait_id, self.substs);
let trait_ref = ty::Binder(trait_ref);
let vtable = fulfill_obligation(scx, DUMMY_SP, trait_ref);
if let traits::VtableImpl(vtable_impl) = vtable {
let name = scx.tcx().item_name(self.def);
let ac = scx.tcx().associated_items(vtable_impl.impl_def_id)
.find(|item| item.kind == ty::AssociatedKind::Const && item.name == name);
if let Some(ac) = ac {
return Instance::new(ac.def_id, vtable_impl.substs);
}
}
}
*self
}
}
pub fn apply_param_substs<'a, 'tcx, T>(scx: &SharedCrateContext<'a, 'tcx>,
param_substs: &Substs<'tcx>,
value: &T)
-> T
where T: TransNormalize<'tcx>
{
let tcx = scx.tcx();
debug!("apply_param_substs(param_substs={:?}, value={:?})", param_substs, value);
let substituted = value.subst(tcx, param_substs);
let substituted = scx.tcx().erase_regions(&substituted);
AssociatedTypeNormalizer::new(scx).fold(&substituted)
}
pub fn field_ty<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
param_substs: &Substs<'tcx>,
f: &'tcx ty::FieldDef)
-> Ty<'tcx>
{
tcx.normalize_associated_type(&f.ty(tcx, param_substs))
}
struct AssociatedTypeNormalizer<'a, 'b: 'a, 'gcx: 'b> {
shared: &'a SharedCrateContext<'b, 'gcx>,
}
impl<'a, 'b, 'gcx> AssociatedTypeNormalizer<'a, 'b, 'gcx> {
fn new(shared: &'a SharedCrateContext<'b, 'gcx>) -> Self {
AssociatedTypeNormalizer {
shared: shared,
}
}
fn fold<T:TypeFoldable<'gcx>>(&mut self, value: &T) -> T {
if !value.has_projection_types() {
value.clone()
} else {
value.fold_with(self)
}
}
}
impl<'a, 'b, 'gcx> TypeFolder<'gcx, 'gcx> for AssociatedTypeNormalizer<'a, 'b, 'gcx> {
fn tcx<'c>(&'c self) -> TyCtxt<'c, 'gcx, 'gcx> {
self.shared.tcx()
}
fn fold_ty(&mut self, ty: Ty<'gcx>) -> Ty<'gcx> {
if !ty.has_projection_types() {
ty
} else {
self.shared.project_cache().memoize(ty, || {
debug!("AssociatedTypeNormalizer: ty={:?}", ty);
self.shared.tcx().normalize_associated_type(&ty)
})
}
}
}