105 lines
3.4 KiB
Rust
105 lines
3.4 KiB
Rust
// Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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use common::*;
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use rustc::hir::def_id::DefId;
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use rustc::infer::TransNormalize;
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use rustc::ty::fold::{TypeFolder, TypeFoldable};
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use rustc::ty::subst::{Subst, Substs};
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use rustc::ty::{self, Ty, TyCtxt};
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use rustc::util::ppaux;
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use rustc::util::common::MemoizationMap;
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use std::fmt;
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#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
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pub struct Instance<'tcx> {
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pub def: DefId,
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pub substs: &'tcx Substs<'tcx>,
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}
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impl<'tcx> fmt::Display for Instance<'tcx> {
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fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
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ppaux::parameterized(f, &self.substs, self.def, &[])
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}
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}
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impl<'tcx> Instance<'tcx> {
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pub fn new(def_id: DefId, substs: &'tcx Substs<'tcx>)
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-> Instance<'tcx> {
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assert!(substs.regions().all(|&r| r == ty::ReErased));
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Instance { def: def_id, substs: substs }
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}
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pub fn mono<'a>(scx: &SharedCrateContext<'a, 'tcx>, def_id: DefId) -> Instance<'tcx> {
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Instance::new(def_id, scx.empty_substs_for_def_id(def_id))
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}
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}
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/// Monomorphizes a type from the AST by first applying the in-scope
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/// substitutions and then normalizing any associated types.
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pub fn apply_param_substs<'a, 'tcx, T>(scx: &SharedCrateContext<'a, 'tcx>,
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param_substs: &Substs<'tcx>,
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value: &T)
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-> T
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where T: TransNormalize<'tcx>
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{
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let tcx = scx.tcx();
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debug!("apply_param_substs(param_substs={:?}, value={:?})", param_substs, value);
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let substituted = value.subst(tcx, param_substs);
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let substituted = scx.tcx().erase_regions(&substituted);
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AssociatedTypeNormalizer::new(scx).fold(&substituted)
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}
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/// Returns the normalized type of a struct field
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pub fn field_ty<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
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param_substs: &Substs<'tcx>,
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f: &'tcx ty::FieldDef)
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-> Ty<'tcx>
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{
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tcx.normalize_associated_type(&f.ty(tcx, param_substs))
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}
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struct AssociatedTypeNormalizer<'a, 'b: 'a, 'gcx: 'b> {
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shared: &'a SharedCrateContext<'b, 'gcx>,
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}
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impl<'a, 'b, 'gcx> AssociatedTypeNormalizer<'a, 'b, 'gcx> {
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fn new(shared: &'a SharedCrateContext<'b, 'gcx>) -> Self {
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AssociatedTypeNormalizer {
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shared: shared,
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}
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}
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fn fold<T:TypeFoldable<'gcx>>(&mut self, value: &T) -> T {
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if !value.has_projection_types() {
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value.clone()
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} else {
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value.fold_with(self)
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}
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}
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}
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impl<'a, 'b, 'gcx> TypeFolder<'gcx, 'gcx> for AssociatedTypeNormalizer<'a, 'b, 'gcx> {
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fn tcx<'c>(&'c self) -> TyCtxt<'c, 'gcx, 'gcx> {
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self.shared.tcx()
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}
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fn fold_ty(&mut self, ty: Ty<'gcx>) -> Ty<'gcx> {
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if !ty.has_projection_types() {
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ty
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} else {
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self.shared.project_cache().memoize(ty, || {
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debug!("AssociatedTypeNormalizer: ty={:?}", ty);
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self.shared.tcx().normalize_associated_type(&ty)
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})
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}
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}
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}
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