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pub use self::ParamSpace::*;
pub use self::RegionSubsts::*;
use middle::ty::{self, Ty};
use middle::ty_fold::{self, TypeFoldable, TypeFolder};
use util::ppaux::Repr;
use std::fmt;
use std::iter::IntoIterator;
use std::slice::Iter;
use std::vec::{Vec, IntoIter};
use syntax::codemap::{Span, DUMMY_SP};
#[derive(Clone, PartialEq, Eq, Hash, Debug)]
pub struct Substs<'tcx> {
pub types: VecPerParamSpace<Ty<'tcx>>,
pub regions: RegionSubsts,
}
#[derive(Clone, PartialEq, Eq, Hash, Debug)]
pub enum RegionSubsts {
ErasedRegions,
NonerasedRegions(VecPerParamSpace<ty::Region>)
}
impl<'tcx> Substs<'tcx> {
pub fn new(t: VecPerParamSpace<Ty<'tcx>>,
r: VecPerParamSpace<ty::Region>)
-> Substs<'tcx>
{
Substs { types: t, regions: NonerasedRegions(r) }
}
pub fn new_type(t: Vec<Ty<'tcx>>,
r: Vec<ty::Region>)
-> Substs<'tcx>
{
Substs::new(VecPerParamSpace::new(t, Vec::new(), Vec::new()),
VecPerParamSpace::new(r, Vec::new(), Vec::new()))
}
pub fn new_trait(t: Vec<Ty<'tcx>>,
r: Vec<ty::Region>,
s: Ty<'tcx>)
-> Substs<'tcx>
{
Substs::new(VecPerParamSpace::new(t, vec!(s), Vec::new()),
VecPerParamSpace::new(r, Vec::new(), Vec::new()))
}
pub fn erased(t: VecPerParamSpace<Ty<'tcx>>) -> Substs<'tcx>
{
Substs { types: t, regions: ErasedRegions }
}
pub fn empty() -> Substs<'tcx> {
Substs {
types: VecPerParamSpace::empty(),
regions: NonerasedRegions(VecPerParamSpace::empty()),
}
}
pub fn trans_empty() -> Substs<'tcx> {
Substs {
types: VecPerParamSpace::empty(),
regions: ErasedRegions
}
}
pub fn is_noop(&self) -> bool {
let regions_is_noop = match self.regions {
ErasedRegions => false,
NonerasedRegions(ref regions) => regions.is_empty(),
};
regions_is_noop && self.types.is_empty()
}
pub fn type_for_def(&self, ty_param_def: &ty::TypeParameterDef) -> Ty<'tcx> {
*self.types.get(ty_param_def.space, ty_param_def.index as usize)
}
pub fn has_regions_escaping_depth(&self, depth: u32) -> bool {
self.types.iter().any(|&t| ty::type_escapes_depth(t, depth)) || {
match self.regions {
ErasedRegions =>
false,
NonerasedRegions(ref regions) =>
regions.iter().any(|r| r.escapes_depth(depth)),
}
}
}
pub fn self_ty(&self) -> Option<Ty<'tcx>> {
self.types.get_self().cloned()
}
pub fn with_self_ty(&self, self_ty: Ty<'tcx>) -> Substs<'tcx> {
assert!(self.self_ty().is_none());
let mut s = (*self).clone();
s.types.push(SelfSpace, self_ty);
s
}
pub fn erase_regions(self) -> Substs<'tcx> {
let Substs { types, regions: _ } = self;
Substs { types: types, regions: ErasedRegions }
}
pub fn regions<'a>(&'a self) -> &'a VecPerParamSpace<ty::Region> {
match self.regions {
ErasedRegions => panic!("Erased regions only expected in trans"),
NonerasedRegions(ref r) => r
}
}
pub fn mut_regions<'a>(&'a mut self) -> &'a mut VecPerParamSpace<ty::Region> {
match self.regions {
ErasedRegions => panic!("Erased regions only expected in trans"),
NonerasedRegions(ref mut r) => r
}
}
pub fn with_method(self,
m_types: Vec<Ty<'tcx>>,
m_regions: Vec<ty::Region>)
-> Substs<'tcx>
{
let Substs { types, regions } = self;
let types = types.with_vec(FnSpace, m_types);
let regions = regions.map(m_regions,
|r, m_regions| r.with_vec(FnSpace, m_regions));
Substs { types: types, regions: regions }
}
}
impl RegionSubsts {
fn map<A, F>(self, a: A, op: F) -> RegionSubsts where
F: FnOnce(VecPerParamSpace<ty::Region>, A) -> VecPerParamSpace<ty::Region>,
{
match self {
ErasedRegions => ErasedRegions,
NonerasedRegions(r) => NonerasedRegions(op(r, a))
}
}
pub fn is_erased(&self) -> bool {
match *self {
ErasedRegions => true,
NonerasedRegions(_) => false,
}
}
}
#[derive(PartialOrd, Ord, PartialEq, Eq, Copy,
Clone, Hash, RustcEncodable, RustcDecodable, Debug)]
pub enum ParamSpace {
TypeSpace,
SelfSpace,
FnSpace,
}
impl ParamSpace {
pub fn all() -> [ParamSpace; 3] {
[TypeSpace, SelfSpace, FnSpace]
}
pub fn to_uint(self) -> usize {
match self {
TypeSpace => 0,
SelfSpace => 1,
FnSpace => 2,
}
}
pub fn from_uint(u: usize) -> ParamSpace {
match u {
0 => TypeSpace,
1 => SelfSpace,
2 => FnSpace,
_ => panic!("Invalid ParamSpace: {}", u)
}
}
}
#[derive(PartialEq, Eq, Clone, Hash, RustcEncodable, RustcDecodable)]
pub struct VecPerParamSpace<T> {
type_limit: usize,
self_limit: usize,
content: Vec<T>,
}
pub struct SeparateVecsPerParamSpace<T> {
pub types: Vec<T>,
pub selfs: Vec<T>,
pub fns: Vec<T>,
}
impl<T: fmt::Debug> fmt::Debug for VecPerParamSpace<T> {
fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
try!(write!(fmt, "VecPerParamSpace {{"));
for space in &ParamSpace::all() {
try!(write!(fmt, "{:?}: {:?}, ", *space, self.get_slice(*space)));
}
try!(write!(fmt, "}}"));
Ok(())
}
}
impl<T> VecPerParamSpace<T> {
fn limits(&self, space: ParamSpace) -> (usize, usize) {
match space {
TypeSpace => (0, self.type_limit),
SelfSpace => (self.type_limit, self.self_limit),
FnSpace => (self.self_limit, self.content.len()),
}
}
pub fn empty() -> VecPerParamSpace<T> {
VecPerParamSpace {
type_limit: 0,
self_limit: 0,
content: Vec::new()
}
}
pub fn params_from_type(types: Vec<T>) -> VecPerParamSpace<T> {
VecPerParamSpace::empty().with_vec(TypeSpace, types)
}
pub fn new(t: Vec<T>, s: Vec<T>, f: Vec<T>) -> VecPerParamSpace<T> {
let type_limit = t.len();
let self_limit = type_limit + s.len();
let mut content = t;
content.extend(s.into_iter());
content.extend(f.into_iter());
VecPerParamSpace {
type_limit: type_limit,
self_limit: self_limit,
content: content,
}
}
fn new_internal(content: Vec<T>, type_limit: usize, self_limit: usize)
-> VecPerParamSpace<T>
{
VecPerParamSpace {
type_limit: type_limit,
self_limit: self_limit,
content: content,
}
}
pub fn push(&mut self, space: ParamSpace, value: T) {
let (_, limit) = self.limits(space);
match space {
TypeSpace => { self.type_limit += 1; self.self_limit += 1; }
SelfSpace => { self.self_limit += 1; }
FnSpace => { }
}
self.content.insert(limit, value);
}
pub fn extend<I:Iterator<Item=T>>(&mut self, space: ParamSpace, values: I) {
for item in values {
self.push(space, item);
}
}
pub fn pop(&mut self, space: ParamSpace) -> Option<T> {
let (start, limit) = self.limits(space);
if start == limit {
None
} else {
match space {
TypeSpace => { self.type_limit -= 1; self.self_limit -= 1; }
SelfSpace => { self.self_limit -= 1; }
FnSpace => {}
}
if self.content.is_empty() {
None
} else {
Some(self.content.remove(limit - 1))
}
}
}
pub fn truncate(&mut self, space: ParamSpace, len: usize) {
while self.len(space) > len {
self.pop(space);
}
}
pub fn replace(&mut self, space: ParamSpace, elems: Vec<T>) {
self.truncate(space, 0);
for t in elems {
self.push(space, t);
}
}
pub fn get_self<'a>(&'a self) -> Option<&'a T> {
let v = self.get_slice(SelfSpace);
assert!(v.len() <= 1);
if v.is_empty() { None } else { Some(&v[0]) }
}
pub fn len(&self, space: ParamSpace) -> usize {
self.get_slice(space).len()
}
pub fn is_empty_in(&self, space: ParamSpace) -> bool {
self.len(space) == 0
}
pub fn get_slice<'a>(&'a self, space: ParamSpace) -> &'a [T] {
let (start, limit) = self.limits(space);
&self.content[start.. limit]
}
pub fn get_mut_slice<'a>(&'a mut self, space: ParamSpace) -> &'a mut [T] {
let (start, limit) = self.limits(space);
&mut self.content[start.. limit]
}
pub fn opt_get<'a>(&'a self,
space: ParamSpace,
index: usize)
-> Option<&'a T> {
let v = self.get_slice(space);
if index < v.len() { Some(&v[index]) } else { None }
}
pub fn get<'a>(&'a self, space: ParamSpace, index: usize) -> &'a T {
&self.get_slice(space)[index]
}
pub fn iter<'a>(&'a self) -> Iter<'a,T> {
self.content.iter()
}
pub fn into_iter(self) -> IntoIter<T> {
self.content.into_iter()
}
pub fn iter_enumerated<'a>(&'a self) -> EnumeratedItems<'a,T> {
EnumeratedItems::new(self)
}
pub fn as_slice(&self) -> &[T] {
&self.content
}
pub fn into_vec(self) -> Vec<T> {
self.content
}
pub fn all_vecs<P>(&self, mut pred: P) -> bool where
P: FnMut(&[T]) -> bool,
{
let spaces = [TypeSpace, SelfSpace, FnSpace];
spaces.iter().all(|&space| { pred(self.get_slice(space)) })
}
pub fn all<P>(&self, pred: P) -> bool where P: FnMut(&T) -> bool {
self.iter().all(pred)
}
pub fn any<P>(&self, pred: P) -> bool where P: FnMut(&T) -> bool {
self.iter().any(pred)
}
pub fn is_empty(&self) -> bool {
self.all_vecs(|v| v.is_empty())
}
pub fn map<U, P>(&self, pred: P) -> VecPerParamSpace<U> where P: FnMut(&T) -> U {
let result = self.iter().map(pred).collect();
VecPerParamSpace::new_internal(result,
self.type_limit,
self.self_limit)
}
pub fn map_enumerated<U, P>(&self, pred: P) -> VecPerParamSpace<U> where
P: FnMut((ParamSpace, usize, &T)) -> U,
{
let result = self.iter_enumerated().map(pred).collect();
VecPerParamSpace::new_internal(result,
self.type_limit,
self.self_limit)
}
pub fn map_move<U, F>(self, mut pred: F) -> VecPerParamSpace<U> where
F: FnMut(T) -> U,
{
let SeparateVecsPerParamSpace {
types: t,
selfs: s,
fns: f
} = self.split();
VecPerParamSpace::new(t.into_iter().map(|p| pred(p)).collect(),
s.into_iter().map(|p| pred(p)).collect(),
f.into_iter().map(|p| pred(p)).collect())
}
pub fn split(self) -> SeparateVecsPerParamSpace<T> {
let VecPerParamSpace { type_limit, self_limit, content } = self;
let mut content_iter = content.into_iter();
SeparateVecsPerParamSpace {
types: content_iter.by_ref().take(type_limit).collect(),
selfs: content_iter.by_ref().take(self_limit - type_limit).collect(),
fns: content_iter.collect()
}
}
pub fn with_vec(mut self, space: ParamSpace, vec: Vec<T>)
-> VecPerParamSpace<T>
{
assert!(self.is_empty_in(space));
self.replace(space, vec);
self
}
}
#[derive(Clone)]
pub struct EnumeratedItems<'a,T:'a> {
vec: &'a VecPerParamSpace<T>,
space_index: usize,
elem_index: usize
}
impl<'a,T> EnumeratedItems<'a,T> {
fn new(v: &'a VecPerParamSpace<T>) -> EnumeratedItems<'a,T> {
let mut result = EnumeratedItems { vec: v, space_index: 0, elem_index: 0 };
result.adjust_space();
result
}
fn adjust_space(&mut self) {
let spaces = ParamSpace::all();
while
self.space_index < spaces.len() &&
self.elem_index >= self.vec.len(spaces[self.space_index])
{
self.space_index += 1;
self.elem_index = 0;
}
}
}
impl<'a,T> Iterator for EnumeratedItems<'a,T> {
type Item = (ParamSpace, usize, &'a T);
fn next(&mut self) -> Option<(ParamSpace, usize, &'a T)> {
let spaces = ParamSpace::all();
if self.space_index < spaces.len() {
let space = spaces[self.space_index];
let index = self.elem_index;
let item = self.vec.get(space, index);
self.elem_index += 1;
self.adjust_space();
Some((space, index, item))
} else {
None
}
}
}
impl<T> IntoIterator for VecPerParamSpace<T> {
type Item = T;
type IntoIter = IntoIter<T>;
fn into_iter(self) -> IntoIter<T> {
self.into_vec().into_iter()
}
}
impl<'a,T> IntoIterator for &'a VecPerParamSpace<T> {
type Item = &'a T;
type IntoIter = Iter<'a, T>;
fn into_iter(self) -> Iter<'a, T> {
self.as_slice().into_iter()
}
}
pub trait Subst<'tcx> : Sized {
fn subst(&self, tcx: &ty::ctxt<'tcx>, substs: &Substs<'tcx>) -> Self {
self.subst_spanned(tcx, substs, None)
}
fn subst_spanned(&self, tcx: &ty::ctxt<'tcx>,
substs: &Substs<'tcx>,
span: Option<Span>)
-> Self;
}
impl<'tcx, T:TypeFoldable<'tcx>> Subst<'tcx> for T {
fn subst_spanned(&self,
tcx: &ty::ctxt<'tcx>,
substs: &Substs<'tcx>,
span: Option<Span>)
-> T
{
let mut folder = SubstFolder { tcx: tcx,
substs: substs,
span: span,
root_ty: None,
ty_stack_depth: 0,
region_binders_passed: 0 };
(*self).fold_with(&mut folder)
}
}
struct SubstFolder<'a, 'tcx: 'a> {
tcx: &'a ty::ctxt<'tcx>,
substs: &'a Substs<'tcx>,
span: Option<Span>,
root_ty: Option<Ty<'tcx>>,
ty_stack_depth: usize,
region_binders_passed: u32,
}
impl<'a, 'tcx> TypeFolder<'tcx> for SubstFolder<'a, 'tcx> {
fn tcx(&self) -> &ty::ctxt<'tcx> { self.tcx }
fn enter_region_binder(&mut self) {
self.region_binders_passed += 1;
}
fn exit_region_binder(&mut self) {
self.region_binders_passed -= 1;
}
fn fold_region(&mut self, r: ty::Region) -> ty::Region {
match r {
ty::ReEarlyBound(data) => {
match self.substs.regions {
ErasedRegions => ty::ReStatic,
NonerasedRegions(ref regions) =>
match regions.opt_get(data.space, data.index as usize) {
Some(&r) => {
self.shift_region_through_binders(r)
}
None => {
let span = self.span.unwrap_or(DUMMY_SP);
self.tcx().sess.span_bug(
span,
&format!("Type parameter out of range \
when substituting in region {} (root type={}) \
(space={:?}, index={})",
data.name.as_str(),
self.root_ty.repr(self.tcx()),
data.space,
data.index));
}
}
}
}
_ => r
}
}
fn fold_ty(&mut self, t: Ty<'tcx>) -> Ty<'tcx> {
if !ty::type_needs_subst(t) {
return t;
}
let depth = self.ty_stack_depth;
if depth == 0 {
self.root_ty = Some(t);
}
self.ty_stack_depth += 1;
let t1 = match t.sty {
ty::ty_param(p) => {
self.ty_for_param(p, t)
}
_ => {
ty_fold::super_fold_ty(self, t)
}
};
assert_eq!(depth + 1, self.ty_stack_depth);
self.ty_stack_depth -= 1;
if depth == 0 {
self.root_ty = None;
}
return t1;
}
}
impl<'a,'tcx> SubstFolder<'a,'tcx> {
fn ty_for_param(&self, p: ty::ParamTy, source_ty: Ty<'tcx>) -> Ty<'tcx> {
let opt_ty = self.substs.types.opt_get(p.space, p.idx as usize);
let ty = match opt_ty {
Some(t) => *t,
None => {
let span = self.span.unwrap_or(DUMMY_SP);
self.tcx().sess.span_bug(
span,
&format!("Type parameter `{}` ({}/{:?}/{}) out of range \
when substituting (root type={}) substs={}",
p.repr(self.tcx()),
source_ty.repr(self.tcx()),
p.space,
p.idx,
self.root_ty.repr(self.tcx()),
self.substs.repr(self.tcx())));
}
};
self.shift_regions_through_binders(ty)
}
fn shift_regions_through_binders(&self, ty: Ty<'tcx>) -> Ty<'tcx> {
debug!("shift_regions(ty={:?}, region_binders_passed={:?}, type_has_escaping_regions={:?})",
ty.repr(self.tcx()), self.region_binders_passed, ty::type_has_escaping_regions(ty));
if self.region_binders_passed == 0 || !ty::type_has_escaping_regions(ty) {
return ty;
}
let result = ty_fold::shift_regions(self.tcx(), self.region_binders_passed, &ty);
debug!("shift_regions: shifted result = {:?}", result.repr(self.tcx()));
result
}
fn shift_region_through_binders(&self, region: ty::Region) -> ty::Region {
ty_fold::shift_region(region, self.region_binders_passed)
}
}