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rustc: decompose Adjustment into a vector of adjustment steps.

This commit is contained in:
Eduard-Mihai Burtescu 2017-05-27 10:29:24 +03:00
parent 91d603a2a7
commit 194fe695e3
19 changed files with 677 additions and 851 deletions
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14
src/librustc/ich/impls_ty.rs
View File

@ -99,16 +99,20 @@ impl<'a, 'tcx> HashStable<StableHashingContext<'a, 'tcx>> for ty::adjustment::Ad
ty::adjustment::Adjust::ReifyFnPointer |
ty::adjustment::Adjust::UnsafeFnPointer |
ty::adjustment::Adjust::ClosureFnPointer |
ty::adjustment::Adjust::MutToConstPointer => {}
ty::adjustment::Adjust::Deref(ref autoderefs) => {
autoderefs.hash_stable(hcx, hasher);
ty::adjustment::Adjust::MutToConstPointer |
ty::adjustment::Adjust::Unsize => {}
ty::adjustment::Adjust::Deref(ref overloaded) => {
overloaded.hash_stable(hcx, hasher);
}
ty::adjustment::Adjust::Borrow(ref autoref) => {
autoref.hash_stable(hcx, hasher);
}
}
}
}
impl_stable_hash_for!(struct ty::adjustment::Adjustment<'tcx> { kind, autoref, unsize, target });
impl_stable_hash_for!(struct ty::adjustment::OverloadedDeref<'tcx> { region, mutbl, target });
impl_stable_hash_for!(struct ty::adjustment::Adjustment<'tcx> { kind, target });
impl_stable_hash_for!(struct ty::adjustment::OverloadedDeref<'tcx> { region, mutbl });
impl_stable_hash_for!(struct ty::UpvarId { var_id, closure_expr_id });
impl_stable_hash_for!(struct ty::UpvarBorrow<'tcx> { kind, region });

98
src/librustc/middle/expr_use_visitor.rs
View File

@ -704,89 +704,55 @@ impl<'a, 'gcx, 'tcx> ExprUseVisitor<'a, 'gcx, 'tcx> {
// consumed or borrowed as part of the automatic adjustment
// process.
fn walk_adjustment(&mut self, expr: &hir::Expr) {
let infcx = self.mc.infcx;
//NOTE(@jroesch): mixed RefCell borrow causes crash
let adj = infcx.tables.borrow().adjustments.get(&expr.id).cloned();
let adjustments = self.mc.infcx.tables.borrow().expr_adjustments(expr).to_vec();
let mut cmt = return_if_err!(self.mc.cat_expr_unadjusted(expr));
if let Some(adjustment) = adj {
for adjustment in adjustments {
debug!("walk_adjustment expr={:?} adj={:?}", expr, adjustment);
match adjustment.kind {
adjustment::Adjust::NeverToAny |
adjustment::Adjust::ReifyFnPointer |
adjustment::Adjust::UnsafeFnPointer |
adjustment::Adjust::ClosureFnPointer |
adjustment::Adjust::MutToConstPointer => {
adjustment::Adjust::MutToConstPointer |
adjustment::Adjust::Unsize => {
// Creating a closure/fn-pointer or unsizing consumes
// the input and stores it into the resulting rvalue.
self.delegate_consume(expr.id, expr.span, cmt);
assert!(adjustment.autoref.is_none() && !adjustment.unsize);
return;
self.delegate_consume(expr.id, expr.span, cmt.clone());
}
adjustment::Adjust::Deref(ref autoderefs) => {
cmt = return_if_err!(self.walk_autoderefs(expr, cmt, autoderefs));
adjustment::Adjust::Deref(None) => {}
// Autoderefs for overloaded Deref calls in fact reference
// their receiver. That is, if we have `(*x)` where `x`
// is of type `Rc<T>`, then this in fact is equivalent to
// `x.deref()`. Since `deref()` is declared with `&self`,
// this is an autoref of `x`.
adjustment::Adjust::Deref(Some(ref deref)) => {
let bk = ty::BorrowKind::from_mutbl(deref.mutbl);
self.delegate.borrow(expr.id, expr.span, cmt.clone(),
deref.region, bk, AutoRef);
}
adjustment::Adjust::Borrow(ref autoref) => {
self.walk_autoref(expr, cmt.clone(), autoref);
}
}
cmt = self.walk_autoref(expr, cmt, adjustment.autoref);
if adjustment.unsize {
// Unsizing consumes the thin pointer and produces a fat one.
self.delegate_consume(expr.id, expr.span, cmt);
}
cmt = return_if_err!(self.mc.cat_expr_adjusted(expr, cmt, &adjustment));
}
}
/// Autoderefs for overloaded Deref calls in fact reference their receiver. That is, if we have
/// `(*x)` where `x` is of type `Rc<T>`, then this in fact is equivalent to `x.deref()`. Since
/// `deref()` is declared with `&self`, this is an autoref of `x`.
fn walk_autoderefs(&mut self,
expr: &hir::Expr,
mut cmt: mc::cmt<'tcx>,
autoderefs: &[Option<adjustment::OverloadedDeref<'tcx>>])
-> mc::McResult<mc::cmt<'tcx>> {
debug!("walk_autoderefs expr={:?} autoderefs={:?}", expr, autoderefs);
for &overloaded in autoderefs {
if let Some(deref) = overloaded {
let bk = ty::BorrowKind::from_mutbl(deref.mutbl);
self.delegate.borrow(expr.id, expr.span, cmt.clone(),
deref.region, bk, AutoRef);
cmt = self.mc.cat_overloaded_autoderef(expr, deref)?;
} else {
cmt = self.mc.cat_deref(expr, cmt, false)?;
}
}
Ok(cmt)
}
/// Walks the autoref `opt_autoref` applied to the autoderef'd
/// `expr`. `cmt_derefd` is the mem-categorized form of `expr`
/// after all relevant autoderefs have occurred. Because AutoRefs
/// can be recursive, this function is recursive: it first walks
/// deeply all the way down the autoref chain, and then processes
/// the autorefs on the way out. At each point, it returns the
/// `cmt` for the rvalue that will be produced by introduced an
/// autoref.
/// Walks the autoref `autoref` applied to the autoderef'd
/// `expr`. `cmt_base` is the mem-categorized form of `expr`
/// after all relevant autoderefs have occurred.
fn walk_autoref(&mut self,
expr: &hir::Expr,
cmt_base: mc::cmt<'tcx>,
opt_autoref: Option<adjustment::AutoBorrow<'tcx>>)
-> mc::cmt<'tcx>
{
debug!("walk_autoref(expr.id={} cmt_derefd={:?} opt_autoref={:?})",
autoref: &adjustment::AutoBorrow<'tcx>) {
debug!("walk_autoref(expr.id={} cmt_base={:?} autoref={:?})",
expr.id,
cmt_base,
opt_autoref);
let cmt_base_ty = cmt_base.ty;
let autoref = match opt_autoref {
Some(ref autoref) => autoref,
None => {
// No AutoRef.
return cmt_base;
}
};
autoref);
match *autoref {
adjustment::AutoBorrow::Ref(r, m) => {
@ -816,14 +782,6 @@ impl<'a, 'gcx, 'tcx> ExprUseVisitor<'a, 'gcx, 'tcx> {
AutoUnsafe);
}
}
// Construct the categorization for the result of the autoref.
// This is always an rvalue, since we are producing a new
// (temporary) indirection.
let adj_ty = cmt_base_ty.adjust_for_autoref(self.tcx(), opt_autoref);
self.mc.cat_rvalue_node(expr.id, expr.span, adj_ty)
}

103
src/librustc/middle/mem_categorization.rs
View File

@ -466,42 +466,62 @@ impl<'a, 'gcx, 'tcx> MemCategorizationContext<'a, 'gcx, 'tcx> {
}
pub fn cat_expr(&self, expr: &hir::Expr) -> McResult<cmt<'tcx>> {
match self.infcx.tables.borrow().adjustments.get(&expr.id) {
None => {
// No adjustments.
self.cat_expr_unadjusted(expr)
// This recursion helper avoids going through *too many*
// adjustments, since *only* non-overloaded deref recurses.
fn helper<'a, 'gcx, 'tcx>(mc: &MemCategorizationContext<'a, 'gcx, 'tcx>,
expr: &hir::Expr,
adjustments: &[adjustment::Adjustment<'tcx>])
-> McResult<cmt<'tcx>> {
match adjustments.split_last() {
None => mc.cat_expr_unadjusted(expr),
Some((adjustment, previous)) => {
mc.cat_expr_adjusted_with(expr, || helper(mc, expr, previous), adjustment)
}
}
}
helper(self, expr, self.infcx.tables.borrow().expr_adjustments(expr))
}
pub fn cat_expr_adjusted(&self, expr: &hir::Expr,
previous: cmt<'tcx>,
adjustment: &adjustment::Adjustment<'tcx>)
-> McResult<cmt<'tcx>> {
self.cat_expr_adjusted_with(expr, || Ok(previous), adjustment)
}
fn cat_expr_adjusted_with<F>(&self, expr: &hir::Expr,
previous: F,
adjustment: &adjustment::Adjustment<'tcx>)
-> McResult<cmt<'tcx>>
where F: FnOnce() -> McResult<cmt<'tcx>>
{
debug!("cat_expr_adjusted_with({:?}): {:?}", adjustment, expr);
let target = self.infcx.resolve_type_vars_if_possible(&adjustment.target);
match adjustment.kind {
adjustment::Adjust::Deref(overloaded) => {
// Equivalent to *expr or something similar.
let base = if let Some(deref) = overloaded {
let ref_ty = self.tcx().mk_ref(deref.region, ty::TypeAndMut {
ty: target,
mutbl: deref.mutbl,
});
self.cat_rvalue_node(expr.id, expr.span, ref_ty)
} else {
previous()?
};
self.cat_deref(expr, base, false)
}
Some(adjustment) => {
debug!("cat_expr({:?}): {:?}", adjustment, expr);
match adjustment.kind {
adjustment::Adjust::Deref(ref autoderefs)
if adjustment.autoref.is_none() && !adjustment.unsize => {
// Equivalent to *expr or something similar.
let mut cmt = self.cat_expr_unadjusted(expr)?;
debug!("cat_expr: autoderefs={:?}, cmt={:?}",
autoderefs, cmt);
for &overloaded in autoderefs {
if let Some(deref) = overloaded {
cmt = self.cat_overloaded_autoderef(expr, deref)?;
} else {
cmt = self.cat_deref(expr, cmt, false)?;
}
}
return Ok(cmt);
}
adjustment::Adjust::NeverToAny |
adjustment::Adjust::ReifyFnPointer |
adjustment::Adjust::UnsafeFnPointer |
adjustment::Adjust::ClosureFnPointer |
adjustment::Adjust::MutToConstPointer |
adjustment::Adjust::Deref(_) => {
// Result is an rvalue.
let expr_ty = self.expr_ty_adjusted(expr)?;
Ok(self.cat_rvalue_node(expr.id(), expr.span(), expr_ty))
}
}
adjustment::Adjust::NeverToAny |
adjustment::Adjust::ReifyFnPointer |
adjustment::Adjust::UnsafeFnPointer |
adjustment::Adjust::ClosureFnPointer |
adjustment::Adjust::MutToConstPointer |
adjustment::Adjust::Borrow(_) |
adjustment::Adjust::Unsize => {
// Result is an rvalue.
Ok(self.cat_rvalue_node(expr.id, expr.span, target))
}
}
}
@ -931,21 +951,6 @@ impl<'a, 'gcx, 'tcx> MemCategorizationContext<'a, 'gcx, 'tcx> {
self.cat_deref(expr, base_cmt, implicit)
}
pub fn cat_overloaded_autoderef(&self,
expr: &hir::Expr,
deref: adjustment::OverloadedDeref<'tcx>)
-> McResult<cmt<'tcx>> {
debug!("cat_overloaded_autoderef: deref={:?}", deref);
let target = self.infcx.resolve_type_vars_if_possible(&deref.target);
let ref_ty = self.tcx().mk_ref(deref.region, ty::TypeAndMut {
ty: target,
mutbl: deref.mutbl,
});
let base_cmt = self.cat_rvalue_node(expr.id, expr.span, ref_ty);
self.cat_deref(expr, base_cmt, false)
}
pub fn cat_deref<N:ast_node>(&self,
node: &N,
base_cmt: cmt<'tcx>,

101
src/librustc/ty/adjustment.rs
View File

@ -10,29 +10,18 @@
use hir;
use hir::def_id::DefId;
use ty::{self, Ty, TyCtxt, TypeAndMut};
use ty::{self, Ty, TyCtxt};
use ty::subst::Substs;
/// Represents coercing a value to a different type of value.
///
/// We transform values by following the following steps in order:
/// 1. Apply a step of `Adjust` (see its variants for details).
/// 2. If `autoref` is `Some(_)`, then take the address and produce either a
/// `&` or `*` pointer.
/// 3. If `unsize` is `true`, then apply the unsize transformation,
/// which will do things like convert thin pointers to fat
/// pointers, or convert structs containing thin pointers to
/// structs containing fat pointers, or convert between fat
/// pointers. We don't store the details of how the transform is
/// done (in fact, we don't know that, because it might depend on
/// the precise type parameters). We just store the target
/// type. Trans figures out what has to be done at monomorphization
/// time based on the precise source/target type at hand.
/// We transform values by following a number of `Adjust` steps in order.
/// See the documentation on variants of `Adjust` for more details.
///
/// To make that more concrete, here are some common scenarios:
/// Here are some common scenarios:
///
/// 1. The simplest cases are where the pointer is not adjusted fat vs thin.
/// 1. The simplest cases are where a pointer is not adjusted fat vs thin.
/// Here the pointer will be dereferenced N times (where a dereference can
/// happen to raw or borrowed pointers or any smart pointer which implements
/// Deref, including Box<_>). The types of dereferences is given by
@ -48,12 +37,9 @@ use ty::subst::Substs;
/// represented by:
///
/// ```
/// Adjustment {
/// kind: Adjust::Deref(vec![None]),// &[i32; 4] -> [i32; 4]
/// autoref: Some(AutoBorrow::Ref), // [i32; 4] -> &[i32; 4]
/// unsize: true, // &[i32; 4] -> &[i32]
/// target: `[i32]`,
/// }
/// Deref(None) -> [i32; 4],
/// Borrow(AutoBorrow::Ref) -> &[i32; 4],
/// Unsize -> &[i32],
/// ```
///
/// Note that for a struct, the 'deep' unsizing of the struct is not recorded.
@ -67,28 +53,10 @@ use ty::subst::Substs;
/// autoderefs, and no autoref. Instead we just do the `Unsize` transformation.
/// At some point, of course, `Box` should move out of the compiler, in which
/// case this is analogous to transformating a struct. E.g., Box<[i32; 4]> ->
/// Box<[i32]> is represented by:
///
/// ```
/// Adjustment {
/// kind: Adjust::Deref(vec![]),
/// autoref: None,
/// unsize: true,
/// target: `Box<[i32]>`,
/// }
/// ```
/// Box<[i32]> is an `Adjust::Unsize` with the target `Box<[i32]>`.
#[derive(Clone, RustcEncodable, RustcDecodable)]
pub struct Adjustment<'tcx> {
/// Step 1.
pub kind: Adjust<'tcx>,
/// Step 2. Optionally produce a pointer/reference from the value.
pub autoref: Option<AutoBorrow<'tcx>>,
/// Step 3. Unsize a pointer/reference value, e.g. `&[T; n]` to
/// `&[T]`. Note that the source could be a thin or fat pointer.
pub unsize: bool,
pub target: Ty<'tcx>,
}
@ -109,27 +77,23 @@ pub enum Adjust<'tcx> {
/// Go from a mut raw pointer to a const raw pointer.
MutToConstPointer,
/// Apply a number of dereferences, producing an lvalue,
/// if there are more than 0 dereferences.
Deref(Vec<Option<OverloadedDeref<'tcx>>>),
}
/// Dereference once, producing an lvalue.
Deref(Option<OverloadedDeref<'tcx>>),
impl<'tcx> Adjustment<'tcx> {
pub fn is_identity(&self) -> bool {
if self.autoref.is_some() || self.unsize {
return false;
}
match self.kind {
Adjust::NeverToAny => self.target.is_never(),
/// Take the address and produce either a `&` or `*` pointer.
Borrow(AutoBorrow<'tcx>),
Adjust::Deref(ref autoderefs) => autoderefs.is_empty(),
Adjust::ReifyFnPointer |
Adjust::UnsafeFnPointer |
Adjust::ClosureFnPointer |
Adjust::MutToConstPointer => false,
}
}
/// Unsize a pointer/reference value, e.g. `&[T; n]` to
/// `&[T]`. Note that the source could be a thin or fat pointer.
/// This will do things like convert thin pointers to fat
/// pointers, or convert structs containing thin pointers to
/// structs containing fat pointers, or convert between fat
/// pointers. We don't store the details of how the transform is
/// done (in fact, we don't know that, because it might depend on
/// the precise type parameters). We just store the target
/// type. Trans figures out what has to be done at monomorphization
/// time based on the precise source/target type at hand.
Unsize,
}
/// An overloaded autoderef step, representing a `Deref(Mut)::deref(_mut)`
@ -140,7 +104,6 @@ impl<'tcx> Adjustment<'tcx> {
pub struct OverloadedDeref<'tcx> {
pub region: ty::Region<'tcx>,
pub mutbl: hir::Mutability,
pub target: Ty<'tcx>,
}
impl<'a, 'gcx, 'tcx> OverloadedDeref<'tcx> {
@ -185,19 +148,3 @@ pub enum CustomCoerceUnsized {
/// Records the index of the field being coerced.
Struct(usize)
}
impl<'a, 'gcx, 'tcx> ty::TyS<'tcx> {
pub fn adjust_for_autoref(&'tcx self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
autoref: Option<AutoBorrow<'tcx>>)
-> Ty<'tcx> {
match autoref {
None => self,
Some(AutoBorrow::Ref(r, m)) => {
tcx.mk_ref(r, TypeAndMut { ty: self, mutbl: m })
}
Some(AutoBorrow::RawPtr(m)) => {
tcx.mk_ptr(TypeAndMut { ty: self, mutbl: m })
}
}
}
}

16
src/librustc/ty/context.rs
View File

@ -221,7 +221,7 @@ pub struct TypeckTables<'tcx> {
/// other items.
pub node_substs: NodeMap<&'tcx Substs<'tcx>>,
pub adjustments: NodeMap<ty::adjustment::Adjustment<'tcx>>,
pub adjustments: NodeMap<Vec<ty::adjustment::Adjustment<'tcx>>>,
/// Borrows
pub upvar_capture_map: ty::UpvarCaptureMap<'tcx>,
@ -343,16 +343,24 @@ impl<'tcx> TypeckTables<'tcx> {
self.node_id_to_type_opt(expr.id)
}
pub fn expr_adjustments(&self, expr: &hir::Expr)
-> &[ty::adjustment::Adjustment<'tcx>] {
self.adjustments.get(&expr.id).map_or(&[], |a| &a[..])
}
/// Returns the type of `expr`, considering any `Adjustment`
/// entry recorded for that expression.
pub fn expr_ty_adjusted(&self, expr: &hir::Expr) -> Ty<'tcx> {
self.adjustments.get(&expr.id)
self.expr_adjustments(expr)
.last()
.map_or_else(|| self.expr_ty(expr), |adj| adj.target)
}
pub fn expr_ty_adjusted_opt(&self, expr: &hir::Expr) -> Option<Ty<'tcx>> {
self.adjustments.get(&expr.id)
.map(|adj| adj.target).or_else(|| self.expr_ty_opt(expr))
self.expr_adjustments(expr)
.last()
.map(|adj| adj.target)
.or_else(|| self.expr_ty_opt(expr))
}
pub fn is_method_call(&self, expr: &hir::Expr) -> bool {

47
src/librustc/ty/structural_impls.rs
View File

@ -224,13 +224,8 @@ impl<'a, 'tcx> Lift<'tcx> for ty::adjustment::Adjustment<'a> {
type Lifted = ty::adjustment::Adjustment<'tcx>;
fn lift_to_tcx<'b, 'gcx>(&self, tcx: TyCtxt<'b, 'gcx, 'tcx>) -> Option<Self::Lifted> {
tcx.lift(&self.kind).and_then(|kind| {
tcx.lift(&(self.autoref, self.target)).map(|(autoref, target)| {
ty::adjustment::Adjustment {
kind,
autoref,
unsize: self.unsize,
target,
}
tcx.lift(&self.target).map(|target| {
ty::adjustment::Adjustment { kind, target }
})
})
}
@ -250,8 +245,13 @@ impl<'a, 'tcx> Lift<'tcx> for ty::adjustment::Adjust<'a> {
Some(ty::adjustment::Adjust::ClosureFnPointer),
ty::adjustment::Adjust::MutToConstPointer =>
Some(ty::adjustment::Adjust::MutToConstPointer),
ty::adjustment::Adjust::Deref(ref autoderefs) => {
tcx.lift(autoderefs).map(ty::adjustment::Adjust::Deref)
ty::adjustment::Adjust::Unsize =>
Some(ty::adjustment::Adjust::Unsize),
ty::adjustment::Adjust::Deref(ref overloaded) => {
tcx.lift(overloaded).map(ty::adjustment::Adjust::Deref)
}
ty::adjustment::Adjust::Borrow(ref autoref) => {
tcx.lift(autoref).map(ty::adjustment::Adjust::Borrow)
}
}
}
@ -260,11 +260,10 @@ impl<'a, 'tcx> Lift<'tcx> for ty::adjustment::Adjust<'a> {
impl<'a, 'tcx> Lift<'tcx> for ty::adjustment::OverloadedDeref<'a> {
type Lifted = ty::adjustment::OverloadedDeref<'tcx>;
fn lift_to_tcx<'b, 'gcx>(&self, tcx: TyCtxt<'b, 'gcx, 'tcx>) -> Option<Self::Lifted> {
tcx.lift(&(self.region, self.target)).map(|(region, target)| {
tcx.lift(&self.region).map(|region| {
ty::adjustment::OverloadedDeref {
region,
mutbl: self.mutbl,
target,
}
})
}
@ -685,15 +684,12 @@ impl<'tcx> TypeFoldable<'tcx> for ty::adjustment::Adjustment<'tcx> {
fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
ty::adjustment::Adjustment {
kind: self.kind.fold_with(folder),
autoref: self.autoref.fold_with(folder),
unsize: self.unsize,
target: self.target.fold_with(folder),
}
}
fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
self.kind.visit_with(visitor) ||
self.autoref.visit_with(visitor) ||
self.target.visit_with(visitor)
}
}
@ -705,9 +701,13 @@ impl<'tcx> TypeFoldable<'tcx> for ty::adjustment::Adjust<'tcx> {
ty::adjustment::Adjust::ReifyFnPointer |
ty::adjustment::Adjust::UnsafeFnPointer |
ty::adjustment::Adjust::ClosureFnPointer |
ty::adjustment::Adjust::MutToConstPointer => self.clone(),
ty::adjustment::Adjust::Deref(ref autoderefs) => {
ty::adjustment::Adjust::Deref(autoderefs.fold_with(folder))
ty::adjustment::Adjust::MutToConstPointer |
ty::adjustment::Adjust::Unsize => self.clone(),
ty::adjustment::Adjust::Deref(ref overloaded) => {
ty::adjustment::Adjust::Deref(overloaded.fold_with(folder))
}
ty::adjustment::Adjust::Borrow(ref autoref) => {
ty::adjustment::Adjust::Borrow(autoref.fold_with(folder))
}
}
}
@ -718,9 +718,13 @@ impl<'tcx> TypeFoldable<'tcx> for ty::adjustment::Adjust<'tcx> {
ty::adjustment::Adjust::ReifyFnPointer |
ty::adjustment::Adjust::UnsafeFnPointer |
ty::adjustment::Adjust::ClosureFnPointer |
ty::adjustment::Adjust::MutToConstPointer => false,
ty::adjustment::Adjust::Deref(ref autoderefs) => {
autoderefs.visit_with(visitor)
ty::adjustment::Adjust::MutToConstPointer |
ty::adjustment::Adjust::Unsize => false,
ty::adjustment::Adjust::Deref(ref overloaded) => {
overloaded.visit_with(visitor)
}
ty::adjustment::Adjust::Borrow(ref autoref) => {
autoref.visit_with(visitor)
}
}
}
@ -731,12 +735,11 @@ impl<'tcx> TypeFoldable<'tcx> for ty::adjustment::OverloadedDeref<'tcx> {
ty::adjustment::OverloadedDeref {
region: self.region.fold_with(folder),
mutbl: self.mutbl,
target: self.target.fold_with(folder),
}
}
fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
self.region.visit_with(visitor) || self.target.visit_with(visitor)
self.region.visit_with(visitor)
}
}

21
src/librustc_lint/builtin.rs
View File

@ -889,22 +889,15 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UnconditionalRecursion {
};
// Check for overloaded autoderef method calls.
if let Some(&Adjustment {
kind: Adjust::Deref(ref autoderefs), ..
}) = cx.tables.adjustments.get(&id) {
let mut source = cx.tables.expr_ty(expr);
for &overloaded in autoderefs {
if let Some(deref) = overloaded {
let (def_id, substs) = deref.method_call(cx.tcx, source);
if method_call_refers_to_method(cx.tcx, method, def_id, substs, id) {
return true;
}
source = deref.target;
} else {
source = source.builtin_deref(true,
ty::LvaluePreference::NoPreference).unwrap().ty;
let mut source = cx.tables.expr_ty(expr);
for adjustment in cx.tables.expr_adjustments(expr) {
if let Adjust::Deref(Some(deref)) = adjustment.kind {
let (def_id, substs) = deref.method_call(cx.tcx, source);
if method_call_refers_to_method(cx.tcx, method, def_id, substs, id) {
return true;
}
}
source = adjustment.target;
}
// Check for method calls and overloaded operators.

20
src/librustc_lint/unused.rs
View File

@ -468,19 +468,13 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UnusedAllocation {
_ => return,
}
if let Some(adjustment) = cx.tables.adjustments.get(&e.id) {
match adjustment.autoref {
Some(adjustment::AutoBorrow::Ref(_, hir::MutImmutable)) => {
cx.span_lint(UNUSED_ALLOCATION,
e.span,
"unnecessary allocation, use & instead");
}
Some(adjustment::AutoBorrow::Ref(_, hir::MutMutable)) => {
cx.span_lint(UNUSED_ALLOCATION,
e.span,
"unnecessary allocation, use &mut instead");
}
_ => (),
for adj in cx.tables.expr_adjustments(e) {
if let adjustment::Adjust::Borrow(adjustment::AutoBorrow::Ref(_, m)) = adj.kind {
let msg = match m {
hir::MutImmutable => "unnecessary allocation, use & instead",
hir::MutMutable => "unnecessary allocation, use &mut instead"
};
cx.span_lint(UNUSED_ALLOCATION, e.span, msg);
}
}
}

271
src/librustc_mir/hair/cx/expr.rs
View File

@ -17,6 +17,7 @@ use hair::cx::to_ref::ToRef;
use rustc::hir::def::{Def, CtorKind};
use rustc::middle::const_val::ConstVal;
use rustc::ty::{self, AdtKind, VariantDef, Ty};
use rustc::ty::adjustment::{Adjustment, Adjust, AutoBorrow};
use rustc::ty::cast::CastKind as TyCastKind;
use rustc::ty::subst::Subst;
use rustc::hir;
@ -32,177 +33,13 @@ impl<'tcx> Mirror<'tcx> for &'tcx hir::Expr {
debug!("Expr::make_mirror(): id={}, span={:?}", self.id, self.span);
let mut expr = make_mirror_unadjusted(cx, self);
let adj = cx.tables().adjustments.get(&self.id);
debug!("make_mirror: unadjusted-expr={:?} applying adjustments={:?}",
expr,
adj);
// Now apply adjustments, if any.
match adj.map(|adj| (&adj.kind, adj.target)) {
None => {}
Some((&ty::adjustment::Adjust::ReifyFnPointer, adjusted_ty)) => {
expr = Expr {
temp_lifetime: temp_lifetime,
temp_lifetime_was_shrunk: was_shrunk,
ty: adjusted_ty,
span: self.span,
kind: ExprKind::ReifyFnPointer { source: expr.to_ref() },
};
}
Some((&ty::adjustment::Adjust::UnsafeFnPointer, adjusted_ty)) => {
expr = Expr {
temp_lifetime: temp_lifetime,
temp_lifetime_was_shrunk: was_shrunk,
ty: adjusted_ty,
span: self.span,
kind: ExprKind::UnsafeFnPointer { source: expr.to_ref() },
};
}
Some((&ty::adjustment::Adjust::ClosureFnPointer, adjusted_ty)) => {
expr = Expr {
temp_lifetime: temp_lifetime,
temp_lifetime_was_shrunk: was_shrunk,
ty: adjusted_ty,
span: self.span,
kind: ExprKind::ClosureFnPointer { source: expr.to_ref() },
};
}
Some((&ty::adjustment::Adjust::NeverToAny, adjusted_ty)) => {
expr = Expr {
temp_lifetime: temp_lifetime,
temp_lifetime_was_shrunk: was_shrunk,
ty: adjusted_ty,
span: self.span,
kind: ExprKind::NeverToAny { source: expr.to_ref() },
};
}
Some((&ty::adjustment::Adjust::MutToConstPointer, adjusted_ty)) => {
expr = Expr {
temp_lifetime: temp_lifetime,
temp_lifetime_was_shrunk: was_shrunk,
ty: adjusted_ty,
span: self.span,
kind: ExprKind::Cast { source: expr.to_ref() },
};
}
Some((&ty::adjustment::Adjust::Deref(ref autoderefs), _)) => {
for &overloaded in autoderefs {
let source = expr.ty;
let target;
let kind = if let Some(deref) = overloaded {
debug!("make_mirror: overloaded autoderef ({:?})", deref);
expr = Expr {
temp_lifetime: temp_lifetime,
temp_lifetime_was_shrunk: was_shrunk,
ty: cx.tcx.mk_ref(deref.region,
ty::TypeAndMut {
ty: source,
mutbl: deref.mutbl,
}),
span: expr.span,
kind: ExprKind::Borrow {
region: deref.region,
borrow_kind: to_borrow_kind(deref.mutbl),
arg: expr.to_ref(),
},
};
target = deref.target;
let call = deref.method_call(cx.tcx, source);
overloaded_lvalue(cx,
self,
deref.target,
Some(call),
PassArgs::ByRef,
expr.to_ref(),
vec![])
} else {
match source.builtin_deref(true,
ty::LvaluePreference::NoPreference) {
Some(mt) => {
target = mt.ty;
}
None => {
span_bug!(self.span, "autoderef for {} failed: {}",
self.id, source);
}
};
debug!("make_mirror: built-in autoderef");
ExprKind::Deref { arg: expr.to_ref() }
};
debug!("make_mirror: autoderef target={:?}", target);
expr = Expr {
temp_lifetime: temp_lifetime,
temp_lifetime_was_shrunk: was_shrunk,
ty: target,
span: self.span,
kind: kind,
};
}
}
}
if let Some(adj) = adj {
if let Some(autoref) = adj.autoref {
let adjusted_ty = expr.ty.adjust_for_autoref(cx.tcx, Some(autoref));
match autoref {
ty::adjustment::AutoBorrow::Ref(r, m) => {
expr = Expr {
temp_lifetime: temp_lifetime,
temp_lifetime_was_shrunk: was_shrunk,
ty: adjusted_ty,
span: self.span,
kind: ExprKind::Borrow {
region: r,
borrow_kind: to_borrow_kind(m),
arg: expr.to_ref(),
},
};
}
ty::adjustment::AutoBorrow::RawPtr(m) => {
// Convert this to a suitable `&foo` and
// then an unsafe coercion. Limit the region to be just this
// expression.
let region = ty::ReScope(expr_extent);
let region = cx.tcx.mk_region(region);
expr = Expr {
temp_lifetime: temp_lifetime,
temp_lifetime_was_shrunk: was_shrunk,
ty: cx.tcx.mk_ref(region,
ty::TypeAndMut {
ty: expr.ty,
mutbl: m,
}),
span: self.span,
kind: ExprKind::Borrow {
region: region,
borrow_kind: to_borrow_kind(m),
arg: expr.to_ref(),
},
};
expr = Expr {
temp_lifetime: temp_lifetime,
temp_lifetime_was_shrunk: was_shrunk,
ty: adjusted_ty,
span: self.span,
kind: ExprKind::Cast { source: expr.to_ref() },
};
}
}
}
if adj.unsize {
expr = Expr {
temp_lifetime: temp_lifetime,
temp_lifetime_was_shrunk: was_shrunk,
ty: adj.target,
span: self.span,
kind: ExprKind::Unsize { source: expr.to_ref() },
};
}
for adjustment in cx.tables().expr_adjustments(self) {
debug!("make_mirror: expr={:?} applying adjustment={:?}",
expr,
adjustment);
expr = apply_adjustment(cx, self, expr, adjustment);
}
// Next, wrap this up in the expr's scope.
@ -236,6 +73,102 @@ impl<'tcx> Mirror<'tcx> for &'tcx hir::Expr {
}
}
fn apply_adjustment<'a, 'gcx, 'tcx>(cx: &mut Cx<'a, 'gcx, 'tcx>,
hir_expr: &'tcx hir::Expr,
mut expr: Expr<'tcx>,
adjustment: &Adjustment<'tcx>)
-> Expr<'tcx> {
let Expr { temp_lifetime, temp_lifetime_was_shrunk, span, .. } = expr;
let kind = match adjustment.kind {
Adjust::ReifyFnPointer => {
ExprKind::ReifyFnPointer { source: expr.to_ref() }
}
Adjust::UnsafeFnPointer => {
ExprKind::UnsafeFnPointer { source: expr.to_ref() }
}
Adjust::ClosureFnPointer => {
ExprKind::ClosureFnPointer { source: expr.to_ref() }
}
Adjust::NeverToAny => {
ExprKind::NeverToAny { source: expr.to_ref() }
}
Adjust::MutToConstPointer => {
ExprKind::Cast { source: expr.to_ref() }
}
Adjust::Deref(None) => {
ExprKind::Deref { arg: expr.to_ref() }
}
Adjust::Deref(Some(deref)) => {
let call = deref.method_call(cx.tcx, expr.ty);
expr = Expr {
temp_lifetime,
temp_lifetime_was_shrunk,
ty: cx.tcx.mk_ref(deref.region,
ty::TypeAndMut {
ty: expr.ty,
mutbl: deref.mutbl,
}),
span,
kind: ExprKind::Borrow {
region: deref.region,
borrow_kind: to_borrow_kind(deref.mutbl),
arg: expr.to_ref(),
},
};
overloaded_lvalue(cx,
hir_expr,
adjustment.target,
Some(call),
PassArgs::ByValue,
expr.to_ref(),
vec![])
}
Adjust::Borrow(AutoBorrow::Ref(r, m)) => {
ExprKind::Borrow {
region: r,
borrow_kind: to_borrow_kind(m),
arg: expr.to_ref(),
}
}
Adjust::Borrow(AutoBorrow::RawPtr(m)) => {
// Convert this to a suitable `&foo` and
// then an unsafe coercion. Limit the region to be just this
// expression.
let region = ty::ReScope(CodeExtent::Misc(hir_expr.id));
let region = cx.tcx.mk_region(region);
expr = Expr {
temp_lifetime,
temp_lifetime_was_shrunk,
ty: cx.tcx.mk_ref(region,
ty::TypeAndMut {
ty: expr.ty,
mutbl: m,
}),
span,
kind: ExprKind::Borrow {
region: region,
borrow_kind: to_borrow_kind(m),
arg: expr.to_ref(),
},
};
ExprKind::Cast { source: expr.to_ref() }
}
Adjust::Unsize => {
ExprKind::Unsize { source: expr.to_ref() }
}
};
Expr {
temp_lifetime,
temp_lifetime_was_shrunk,
ty: adjustment.target,
span,
kind,
}
}
fn make_mirror_unadjusted<'a, 'gcx, 'tcx>(cx: &mut Cx<'a, 'gcx, 'tcx>,
expr: &'tcx hir::Expr)
-> Expr<'tcx> {

24
src/librustc_passes/consts.rs
View File

@ -441,17 +441,21 @@ fn check_expr<'a, 'tcx>(v: &mut CheckCrateVisitor<'a, 'tcx>, e: &hir::Expr, node
fn check_adjustments<'a, 'tcx>(v: &mut CheckCrateVisitor<'a, 'tcx>, e: &hir::Expr) {
use rustc::ty::adjustment::*;
match v.tables.adjustments.get(&e.id).map(|adj| &adj.kind) {
None |
Some(&Adjust::NeverToAny) |
Some(&Adjust::ReifyFnPointer) |
Some(&Adjust::UnsafeFnPointer) |
Some(&Adjust::ClosureFnPointer) |
Some(&Adjust::MutToConstPointer) => {}
for adjustment in v.tables.expr_adjustments(e) {
match adjustment.kind {
Adjust::NeverToAny |
Adjust::ReifyFnPointer |
Adjust::UnsafeFnPointer |
Adjust::ClosureFnPointer |
Adjust::MutToConstPointer |
Adjust::Borrow(_) |
Adjust::Unsize => {}
Some(&Adjust::Deref(ref autoderefs)) => {
if autoderefs.iter().any(|overloaded| overloaded.is_some()) {
v.promotable = false;
Adjust::Deref(ref overloaded) => {
if overloaded.is_some() {
v.promotable = false;
break;
}
}
}
}

24
src/librustc_typeck/check/autoderef.rs
View File

@ -18,11 +18,13 @@ use rustc::traits;
use rustc::ty::{self, Ty, TraitRef};
use rustc::ty::{ToPredicate, TypeFoldable};
use rustc::ty::{LvaluePreference, NoPreference};
use rustc::ty::adjustment::{AutoBorrow, OverloadedDeref};
use rustc::ty::adjustment::{Adjustment, Adjust, OverloadedDeref};
use syntax_pos::Span;
use syntax::symbol::Symbol;
use std::iter;
#[derive(Copy, Clone, Debug)]
enum AutoderefKind {
Builtin,
@ -152,25 +154,26 @@ impl<'a, 'gcx, 'tcx> Autoderef<'a, 'gcx, 'tcx> {
self.steps.len()
}
/// Returns the steps required in adjustments (overloaded deref calls).
/// Returns the adjustment steps.
pub fn adjust_steps(&self, pref: LvaluePreference)
-> Vec<Option<OverloadedDeref<'tcx>>> {
-> Vec<Adjustment<'tcx>> {
self.fcx.register_infer_ok_obligations(self.adjust_steps_as_infer_ok(pref))
}
pub fn adjust_steps_as_infer_ok(&self, pref: LvaluePreference)
-> InferOk<'tcx, Vec<Option<OverloadedDeref<'tcx>>>> {
-> InferOk<'tcx, Vec<Adjustment<'tcx>>> {
let mut obligations = vec![];
let targets = self.steps.iter().skip(1).map(|&(ty, _)| ty)
.chain(iter::once(self.cur_ty));
let steps: Vec<_> = self.steps.iter().map(|&(source, kind)| {
if let AutoderefKind::Overloaded = kind {
self.fcx.try_overloaded_deref(self.span, source, pref)
.and_then(|InferOk { value: (_, method), obligations: o }| {
.and_then(|InferOk { value: method, obligations: o }| {
obligations.extend(o);
if let ty::TyRef(region, mt) = method.sig.output().sty {
Some(OverloadedDeref {
region,
mutbl: mt.mutbl,
target: mt.ty
})
} else {
None
@ -179,6 +182,11 @@ impl<'a, 'gcx, 'tcx> Autoderef<'a, 'gcx, 'tcx> {
} else {
None
}
}).zip(targets).map(|(autoderef, target)| {
Adjustment {
kind: Adjust::Deref(autoderef),
target
}
}).collect();
InferOk {
@ -213,9 +221,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
span: Span,
base_ty: Ty<'tcx>,
pref: LvaluePreference)
-> Option<InferOk<'tcx,
(Option<AutoBorrow<'tcx>>,
MethodCallee<'tcx>)>> {
-> Option<InferOk<'tcx, MethodCallee<'tcx>>> {
self.try_overloaded_lvalue_op(span, base_ty, &[], pref, LvalueOp::Deref)
}
}

73
src/librustc_typeck/check/callee.rs
View File

@ -17,7 +17,7 @@ use hir::def_id::{DefId, LOCAL_CRATE};
use rustc::{infer, traits};
use rustc::ty::{self, TyCtxt, LvaluePreference, Ty};
use rustc::ty::subst::Subst;
use rustc::ty::adjustment::{Adjustment, Adjust, AutoBorrow, OverloadedDeref};
use rustc::ty::adjustment::{Adjustment, Adjust, AutoBorrow};
use syntax::abi;
use syntax::symbol::Symbol;
use syntax_pos::Span;
@ -96,8 +96,8 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
// If the callee is a bare function or a closure, then we're all set.
match adjusted_ty.sty {
ty::TyFnDef(..) | ty::TyFnPtr(_) => {
let autoderefs = autoderef.adjust_steps(LvaluePreference::NoPreference);
self.apply_autoderef_adjustment(callee_expr.id, autoderefs, adjusted_ty);
let adjustments = autoderef.adjust_steps(LvaluePreference::NoPreference);
self.apply_adjustments(callee_expr, adjustments);
return Some(CallStep::Builtin(adjusted_ty));
}
@ -113,13 +113,13 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
infer::FnCall,
&closure_ty)
.0;
let autoderefs = autoderef.adjust_steps(LvaluePreference::NoPreference);
let adjustments = autoderef.adjust_steps(LvaluePreference::NoPreference);
self.record_deferred_call_resolution(def_id, DeferredCallResolution {
call_expr: call_expr,
callee_expr: callee_expr,
adjusted_ty: adjusted_ty,
autoderefs: autoderefs,
fn_sig: fn_sig.clone(),
call_expr,
callee_expr,
adjusted_ty,
adjustments,
fn_sig,
closure_def_id: def_id,
});
return Some(CallStep::DeferredClosure(fn_sig));
@ -142,13 +142,9 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
}
self.try_overloaded_call_traits(call_expr, adjusted_ty).map(|(autoref, method)| {
let autoderefs = autoderef.adjust_steps(LvaluePreference::NoPreference);
self.apply_adjustment(callee_expr.id, Adjustment {
kind: Adjust::Deref(autoderefs),
autoref,
unsize: false,
target: method.sig.inputs()[0]
});
let mut adjustments = autoderef.adjust_steps(LvaluePreference::NoPreference);
adjustments.extend(autoref);
self.apply_adjustments(callee_expr, adjustments);
CallStep::Overloaded(method)
})
}
@ -156,25 +152,37 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
fn try_overloaded_call_traits(&self,
call_expr: &hir::Expr,
adjusted_ty: Ty<'tcx>)
-> Option<(Option<AutoBorrow<'tcx>>,
-> Option<(Option<Adjustment<'tcx>>,
MethodCallee<'tcx>)> {
// Try the options that are least restrictive on the caller first.
for &(opt_trait_def_id, method_name) in
&[(self.tcx.lang_items.fn_trait(), Symbol::intern("call")),
(self.tcx.lang_items.fn_mut_trait(), Symbol::intern("call_mut")),
(self.tcx.lang_items.fn_once_trait(), Symbol::intern("call_once"))] {
for &(opt_trait_def_id, method_name, borrow) in
&[(self.tcx.lang_items.fn_trait(), Symbol::intern("call"), true),
(self.tcx.lang_items.fn_mut_trait(), Symbol::intern("call_mut"), true),
(self.tcx.lang_items.fn_once_trait(), Symbol::intern("call_once"), false)] {
let trait_def_id = match opt_trait_def_id {
Some(def_id) => def_id,
None => continue,
};
match self.lookup_method_in_trait_adjusted(call_expr.span,
method_name,
trait_def_id,
adjusted_ty,
None) {
match self.lookup_method_in_trait(call_expr.span,
method_name,
trait_def_id,
adjusted_ty,
None) {
None => continue,
Some(ok) => return Some(self.register_infer_ok_obligations(ok))
Some(ok) => {
let method = self.register_infer_ok_obligations(ok);
let mut autoref = None;
if borrow {
if let ty::TyRef(region, mt) = method.sig.inputs()[0].sty {
autoref = Some(Adjustment {
kind: Adjust::Borrow(AutoBorrow::Ref(region, mt.mutbl)),
target: method.sig.inputs()[0]
});
}
}
return Some((autoref, method));
}
}
}
@ -317,7 +325,7 @@ pub struct DeferredCallResolution<'gcx: 'tcx, 'tcx> {
call_expr: &'gcx hir::Expr,
callee_expr: &'gcx hir::Expr,
adjusted_ty: Ty<'tcx>,
autoderefs: Vec<Option<OverloadedDeref<'tcx>>>,
adjustments: Vec<Adjustment<'tcx>>,
fn_sig: ty::FnSig<'tcx>,
closure_def_id: DefId,
}
@ -353,12 +361,9 @@ impl<'a, 'gcx, 'tcx> DeferredCallResolution<'gcx, 'tcx> {
fcx.demand_eqtype(self.call_expr.span, method_sig.output(), self.fn_sig.output());
fcx.apply_adjustment(self.callee_expr.id, Adjustment {
kind: Adjust::Deref(self.autoderefs),
autoref,
unsize: false,
target: method_sig.inputs()[0]
});
let mut adjustments = self.adjustments;
adjustments.extend(autoref);
fcx.apply_adjustments(self.callee_expr, adjustments);
fcx.write_method_call(self.call_expr.id, method_callee);
}

171
src/librustc_typeck/check/coercion.rs
View File

@ -95,7 +95,7 @@ impl<'a, 'gcx, 'tcx> Deref for Coerce<'a, 'gcx, 'tcx> {
}
}
type CoerceResult<'tcx> = InferResult<'tcx, Adjustment<'tcx>>;
type CoerceResult<'tcx> = InferResult<'tcx, (Vec<Adjustment<'tcx>>, Ty<'tcx>)>;
fn coerce_mutbls<'tcx>(from_mutbl: hir::Mutability,
to_mutbl: hir::Mutability)
@ -108,24 +108,18 @@ fn coerce_mutbls<'tcx>(from_mutbl: hir::Mutability,
}
}
fn identity<'tcx>(target: Ty<'tcx>) -> Adjustment<'tcx> {
simple(Adjust::Deref(vec![]))(target)
fn identity(_: Ty) -> Vec<Adjustment> { vec![] }
fn simple<'tcx>(kind: Adjust<'tcx>) -> impl FnOnce(Ty<'tcx>) -> Vec<Adjustment<'tcx>> {
move |target| vec![Adjustment { kind, target }]
}
fn simple<'tcx>(kind: Adjust<'tcx>) -> impl FnOnce(Ty<'tcx>) -> Adjustment<'tcx> {
move |target| Adjustment {
kind,
autoref: None,
unsize: false,
target
}
}
fn success<'tcx>(adj: Adjustment<'tcx>,
fn success<'tcx>(adj: Vec<Adjustment<'tcx>>,
target: Ty<'tcx>,
obligations: traits::PredicateObligations<'tcx>)
-> CoerceResult<'tcx> {
Ok(InferOk {
value: adj,
value: (adj, target),
obligations
})
}
@ -153,10 +147,10 @@ impl<'f, 'gcx, 'tcx> Coerce<'f, 'gcx, 'tcx> {
/// Unify two types (using sub or lub) and produce a specific coercion.
fn unify_and<F>(&self, a: Ty<'tcx>, b: Ty<'tcx>, f: F)
-> CoerceResult<'tcx>
where F: FnOnce(Ty<'tcx>) -> Adjustment<'tcx>
where F: FnOnce(Ty<'tcx>) -> Vec<Adjustment<'tcx>>
{
self.unify(&a, &b).and_then(|InferOk { value: ty, obligations }| {
success(f(ty), obligations)
success(f(ty), ty, obligations)
})
}
@ -166,7 +160,7 @@ impl<'f, 'gcx, 'tcx> Coerce<'f, 'gcx, 'tcx> {
// Just ignore error types.
if a.references_error() || b.references_error() {
return success(identity(b), vec![]);
return success(vec![], b, vec![]);
}
if a.is_never() {
@ -185,7 +179,7 @@ impl<'f, 'gcx, 'tcx> Coerce<'f, 'gcx, 'tcx> {
TypeVariableOrigin::AdjustmentType(self.cause.span));
self.unify_and(&b, &diverging_ty, simple(Adjust::NeverToAny))
} else {
success(simple(Adjust::NeverToAny)(b), vec![])
success(simple(Adjust::NeverToAny)(b), b, vec![])
};
}
@ -407,34 +401,31 @@ impl<'f, 'gcx, 'tcx> Coerce<'f, 'gcx, 'tcx> {
// `self.x`, but we auto-coerce it to `foo(&mut *self.x)`,
// which is a borrow.
assert_eq!(mt_b.mutbl, hir::MutImmutable); // can only coerce &T -> &U
return success(identity(ty), obligations);
return success(vec![], ty, obligations);
}
let pref = LvaluePreference::from_mutbl(mt_b.mutbl);
let InferOk { value: mut adjustments, obligations: o }
= autoderef.adjust_steps_as_infer_ok(pref);
obligations.extend(o);
obligations.extend(autoderef.into_obligations());
// Now apply the autoref. We have to extract the region out of
// the final ref type we got.
let r_borrow = match ty.sty {
ty::TyRef(r_borrow, _) => r_borrow,
_ => span_bug!(span, "expected a ref type, got {:?}", ty),
};
let autoref = Some(AutoBorrow::Ref(r_borrow, mt_b.mutbl));
let pref = LvaluePreference::from_mutbl(mt_b.mutbl);
let InferOk { value: autoderefs, obligations: o }
= autoderef.adjust_steps_as_infer_ok(pref);
obligations.extend(o);
obligations.extend(autoderef.into_obligations());
debug!("coerce_borrowed_pointer: succeeded ty={:?} autoderefs={:?} autoref={:?}",
ty,
autoderefs,
autoref);
success(Adjustment {
kind: Adjust::Deref(autoderefs),
autoref,
unsize: false,
adjustments.push(Adjustment {
kind: Adjust::Borrow(AutoBorrow::Ref(r_borrow, mt_b.mutbl)),
target: ty
}, obligations)
});
debug!("coerce_borrowed_pointer: succeeded ty={:?} adjustments={:?}",
ty,
adjustments);
success(adjustments, ty, obligations)
}
@ -459,21 +450,40 @@ impl<'f, 'gcx, 'tcx> Coerce<'f, 'gcx, 'tcx> {
// that, at which point we will need extra checks on the target here.
// Handle reborrows before selecting `Source: CoerceUnsized<Target>`.
let (source, reborrow) = match (&source.sty, &target.sty) {
let reborrow = match (&source.sty, &target.sty) {
(&ty::TyRef(_, mt_a), &ty::TyRef(_, mt_b)) => {
coerce_mutbls(mt_a.mutbl, mt_b.mutbl)?;
let coercion = Coercion(self.cause.span);
let r_borrow = self.next_region_var(coercion);
(mt_a.ty, Some(AutoBorrow::Ref(r_borrow, mt_b.mutbl)))
Some((Adjustment {
kind: Adjust::Deref(None),
target: mt_a.ty
}, Adjustment {
kind: Adjust::Borrow(AutoBorrow::Ref(r_borrow, mt_b.mutbl)),
target: self.tcx.mk_ref(r_borrow, ty::TypeAndMut {
mutbl: mt_b.mutbl,
ty: mt_a.ty
})
}))
}
(&ty::TyRef(_, mt_a), &ty::TyRawPtr(mt_b)) => {
coerce_mutbls(mt_a.mutbl, mt_b.mutbl)?;
(mt_a.ty, Some(AutoBorrow::RawPtr(mt_b.mutbl)))
Some((Adjustment {
kind: Adjust::Deref(None),
target: mt_a.ty
}, Adjustment {
kind: Adjust::Borrow(AutoBorrow::RawPtr(mt_b.mutbl)),
target: self.tcx.mk_ptr(ty::TypeAndMut {
mutbl: mt_b.mutbl,
ty: mt_a.ty
})
}))
}
_ => (source, None),
_ => None,
};
let coerce_source = source.adjust_for_autoref(self.tcx, reborrow);
let coerce_source = reborrow.as_ref().map_or(source, |&(_, ref r)| r.target);
// Setup either a subtyping or a LUB relationship between
// the `CoerceUnsized` target type and the expected type.
@ -481,11 +491,17 @@ impl<'f, 'gcx, 'tcx> Coerce<'f, 'gcx, 'tcx> {
// for the former and let type inference do the rest.
let origin = TypeVariableOrigin::MiscVariable(self.cause.span);
let coerce_target = self.next_ty_var(origin);
let mut coercion = self.unify_and(coerce_target, target, |target| Adjustment {
kind: Adjust::Deref(if reborrow.is_some() { vec![None] } else { vec![] }),
autoref: reborrow,
unsize: true,
target
let mut coercion = self.unify_and(coerce_target, target, |target| {
let unsize = Adjustment {
kind: Adjust::Unsize,
target
};
match reborrow {
None => vec![unsize],
Some((ref deref, ref autoref)) => {
vec![deref.clone(), autoref.clone(), unsize]
}
}
})?;
let mut selcx = traits::SelectionContext::new(self);
@ -546,8 +562,8 @@ impl<'f, 'gcx, 'tcx> Coerce<'f, 'gcx, 'tcx> {
to_unsafe: F,
normal: G)
-> CoerceResult<'tcx>
where F: FnOnce(Ty<'tcx>) -> Adjustment<'tcx>,
G: FnOnce(Ty<'tcx>) -> Adjustment<'tcx>
where F: FnOnce(Ty<'tcx>) -> Vec<Adjustment<'tcx>>,
G: FnOnce(Ty<'tcx>) -> Vec<Adjustment<'tcx>>
{
if let ty::TyFnPtr(fn_ty_b) = b.sty {
match (fn_ty_a.unsafety(), fn_ty_b.unsafety()) {
@ -668,11 +684,14 @@ impl<'f, 'gcx, 'tcx> Coerce<'f, 'gcx, 'tcx> {
// representation, we still register an Adjust::DerefRef so that
// regionck knows that the region for `a` must be valid here.
if is_ref {
self.unify_and(a_unsafe, b, |target| Adjustment {
kind: Adjust::Deref(vec![None]),
autoref: Some(AutoBorrow::RawPtr(mutbl_b)),
unsize: false,
target
self.unify_and(a_unsafe, b, |target| {
vec![Adjustment {
kind: Adjust::Deref(None),
target: mt_a.ty
}, Adjustment {
kind: Adjust::Borrow(AutoBorrow::RawPtr(mutbl_b)),
target
}]
})
} else if mt_a.mutbl != mutbl_b {
self.unify_and(a_unsafe, b, simple(Adjust::MutToConstPointer))
@ -707,12 +726,8 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
let coerce = Coerce::new(self, cause);
let ok = self.commit_if_ok(|_| coerce.coerce(source, target))?;
let adjustment = self.register_infer_ok_obligations(ok);
self.apply_adjustment(expr.id, adjustment);
// We should now have added sufficient adjustments etc to
// ensure that the type of expression, post-adjustment, is
// a subtype of target.
let (adjustments, _) = self.register_infer_ok_obligations(ok);
self.apply_adjustments(expr, adjustments);
Ok(target)
}
@ -781,12 +796,10 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
for expr in exprs.iter().map(|e| e.as_coercion_site()).chain(Some(new)) {
// The only adjustment that can produce an fn item is
// `NeverToAny`, so this should always be valid.
self.apply_adjustment(expr.id, Adjustment {
self.apply_adjustments(expr, vec![Adjustment {
kind: Adjust::ReifyFnPointer,
autoref: None,
unsize: false,
target: fn_ptr
});
}]);
}
return Ok(fn_ptr);
}
@ -803,9 +816,8 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
let result = self.commit_if_ok(|_| coerce.coerce(new_ty, prev_ty));
match result {
Ok(ok) => {
let adjustment = self.register_infer_ok_obligations(ok);
let target = adjustment.target;
self.apply_adjustment(new.id, adjustment);
let (adjustments, target) = self.register_infer_ok_obligations(ok);
self.apply_adjustments(new, adjustments);
return Ok(target);
}
Err(e) => first_error = Some(e),
@ -817,26 +829,23 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
// previous expressions, other than noop reborrows (ignoring lifetimes).
for expr in exprs {
let expr = expr.as_coercion_site();
let noop = match self.tables.borrow().adjustments.get(&expr.id) {
Some(&Adjustment {
kind: Adjust::Deref(ref autoderefs),
autoref: Some(AutoBorrow::Ref(_, mutbl_adj)),
unsize: false,
target: _
}) if autoderefs.len() == 1 => {
let noop = match self.tables.borrow().expr_adjustments(expr) {
&[
Adjustment { kind: Adjust::Deref(_), .. },
Adjustment { kind: Adjust::Borrow(AutoBorrow::Ref(_, mutbl_adj)), .. }
] => {
match self.node_ty(expr.id).sty {
ty::TyRef(_, mt_orig) => {
// Reborrow that we can safely ignore, because
// the next adjustment can only be a DerefRef
// the next adjustment can only be a Deref
// which will be merged into it.
mutbl_adj == mt_orig.mutbl
}
_ => false,
}
}
Some(&Adjustment { kind: Adjust::NeverToAny, .. }) => true,
Some(_) => false,
None => true,
&[Adjustment { kind: Adjust::NeverToAny, .. }] | &[] => true,
_ => false,
};
if !noop {
@ -860,12 +869,12 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
}
}
Ok(ok) => {
let adjustment = self.register_infer_ok_obligations(ok);
let (adjustments, target) = self.register_infer_ok_obligations(ok);
for expr in exprs {
let expr = expr.as_coercion_site();
self.apply_adjustment(expr.id, adjustment.clone());
self.apply_adjustments(expr, adjustments.clone());
}
Ok(adjustment.target)
Ok(target)
}
}
}

131
src/librustc_typeck/check/method/confirm.rs
View File

@ -15,7 +15,7 @@ use hir::def_id::DefId;
use rustc::ty::subst::Substs;
use rustc::traits;
use rustc::ty::{self, LvaluePreference, NoPreference, PreferMutLvalue, Ty};
use rustc::ty::adjustment::{Adjustment, Adjust, AutoBorrow};
use rustc::ty::adjustment::{Adjustment, Adjust, AutoBorrow, OverloadedDeref};
use rustc::ty::fold::TypeFoldable;
use rustc::infer::{self, InferOk};
use syntax_pos::Span;
@ -118,40 +118,49 @@ impl<'a, 'gcx, 'tcx> ConfirmContext<'a, 'gcx, 'tcx> {
unadjusted_self_ty: Ty<'tcx>,
pick: &probe::Pick<'tcx>)
-> Ty<'tcx> {
let autoref = if let Some(mutbl) = pick.autoref {
// Commit the autoderefs by calling `autoderef` again, but this
// time writing the results into the various tables.
let mut autoderef = self.autoderef(self.span, unadjusted_self_ty);
let (_, n) = autoderef.nth(pick.autoderefs).unwrap();
assert_eq!(n, pick.autoderefs);
let mut adjustments = autoderef.adjust_steps(LvaluePreference::NoPreference);
let mut target = autoderef.unambiguous_final_ty();
if let Some(mutbl) = pick.autoref {
let region = self.next_region_var(infer::Autoref(self.span));
Some(AutoBorrow::Ref(region, mutbl))
target = self.tcx.mk_ref(region, ty::TypeAndMut {
mutbl,
ty: target
});
adjustments.push(Adjustment {
kind: Adjust::Borrow(AutoBorrow::Ref(region, mutbl)),
target
});
if let Some(unsize_target) = pick.unsize {
target = self.tcx.mk_ref(region, ty::TypeAndMut {
mutbl,
ty: unsize_target
});
adjustments.push(Adjustment {
kind: Adjust::Unsize,
target
});
}
} else {
// No unsizing should be performed without autoref (at
// least during method dispach). This is because we
// currently only unsize `[T;N]` to `[T]`, and naturally
// that must occur being a reference.
assert!(pick.unsize.is_none());
None
};
}
// Commit the autoderefs by calling `autoderef` again, but this
// time writing the results into the various tables.
let mut autoderef = self.autoderef(self.span, unadjusted_self_ty);
let (autoderefd_ty, n) = autoderef.nth(pick.autoderefs).unwrap();
assert_eq!(n, pick.autoderefs);
let autoderefs = autoderef.adjust_steps(LvaluePreference::NoPreference);
autoderef.unambiguous_final_ty();
autoderef.finalize();
let target = pick.unsize.unwrap_or(autoderefd_ty);
let target = target.adjust_for_autoref(self.tcx, autoref);
// Write out the final adjustment.
self.apply_adjustment(self.self_expr.id, Adjustment {
kind: Adjust::Deref(autoderefs),
autoref,
unsize: pick.unsize.is_some(),
target,
});
// Write out the final adjustments.
self.apply_adjustments(self.self_expr, adjustments);
target
}
@ -436,17 +445,22 @@ impl<'a, 'gcx, 'tcx> ConfirmContext<'a, 'gcx, 'tcx> {
// Fix up the autoderefs. Autorefs can only occur immediately preceding
// overloaded lvalue ops, and will be fixed by them in order to get
// the correct region.
let expr_ty = self.node_ty(expr.id);
if let Some(adj) = self.tables.borrow_mut().adjustments.get_mut(&expr.id) {
if let Adjust::Deref(ref mut autoderefs) = adj.kind {
let mut autoderef = self.autoderef(expr.span, expr_ty);
autoderef.nth(autoderefs.len()).unwrap_or_else(|| {
span_bug!(expr.span,
"expr was deref-able as {:?} but now isn't?",
autoderefs);
});
*autoderefs = autoderef.adjust_steps(LvaluePreference::PreferMutLvalue);
autoderef.finalize();
let mut source = self.node_ty(expr.id);
if let Some(adjustments) = self.tables.borrow_mut().adjustments.get_mut(&expr.id) {
let pref = LvaluePreference::PreferMutLvalue;
for adjustment in adjustments {
if let Adjust::Deref(Some(ref mut deref)) = adjustment.kind {
if let Some(ok) = self.try_overloaded_deref(expr.span, source, pref) {
let method = self.register_infer_ok_obligations(ok);
if let ty::TyRef(region, mt) = method.sig.output().sty {
*deref = OverloadedDeref {
region,
mutbl: mt.mutbl
};
}
}
}
source = adjustment.target;
}
}
@ -478,7 +492,7 @@ impl<'a, 'gcx, 'tcx> ConfirmContext<'a, 'gcx, 'tcx> {
return
}
let base_ty = self.tables.borrow().adjustments.get(&base_expr.id)
let base_ty = self.tables.borrow().expr_adjustments(base_expr).last()
.map_or_else(|| self.node_ty(expr.id), |adj| adj.target);
let base_ty = self.resolve_type_vars_if_possible(&base_ty);
@ -489,28 +503,43 @@ impl<'a, 'gcx, 'tcx> ConfirmContext<'a, 'gcx, 'tcx> {
let method = self.try_overloaded_lvalue_op(
expr.span, base_ty, arg_tys, PreferMutLvalue, op);
let ok = match method {
Some(method) => method,
let method = match method {
Some(ok) => self.register_infer_ok_obligations(ok),
None => return self.tcx.sess.delay_span_bug(expr.span, "re-trying op failed")
};
let (_, method) = self.register_infer_ok_obligations(ok);
debug!("convert_lvalue_op_to_mutable: method={:?}", method);
self.write_method_call(expr.id, method);
let (region, mutbl) = if let ty::TyRef(r, mt) = method.sig.inputs()[0].sty {
(r, mt.mutbl)
} else {
span_bug!(expr.span, "input to lvalue op is not a ref?");
};
// Convert the autoref in the base expr to mutable with the correct
// region and mutability.
if let Some(&mut Adjustment {
ref mut target,
autoref: Some(AutoBorrow::Ref(ref mut r, ref mut mutbl)), ..
}) = self.tables.borrow_mut().adjustments.get_mut(&base_expr.id) {
debug!("convert_lvalue_op_to_mutable: converting autoref of {:?}", target);
let base_expr_ty = self.node_ty(base_expr.id);
if let Some(adjustments) = self.tables.borrow_mut().adjustments.get_mut(&base_expr.id) {
let mut source = base_expr_ty;
for adjustment in &mut adjustments[..] {
if let Adjust::Borrow(AutoBorrow::Ref(..)) = adjustment.kind {
debug!("convert_lvalue_op_to_mutable: converting autoref {:?}", adjustment);
adjustment.kind = Adjust::Borrow(AutoBorrow::Ref(region, mutbl));
adjustment.target = self.tcx.mk_ref(region, ty::TypeAndMut {
ty: source,
mutbl
});
}
source = adjustment.target;
}
*target = method.sig.inputs()[0];
if let ty::TyRef(r_, mt) = target.sty {
*r = r_;
*mutbl = mt.mutbl;
} else {
span_bug!(expr.span, "input to lvalue op is not a ref?");
// If we have an autoref followed by unsizing at the end, fix the unsize target.
match adjustments[..] {
[.., Adjustment { kind: Adjust::Borrow(AutoBorrow::Ref(..)), .. },
Adjustment { kind: Adjust::Unsize, ref mut target }] => {
*target = method.sig.inputs()[0];
}
_ => {}
}
}
}

52
src/librustc_typeck/check/method/mod.rs
View File

@ -16,7 +16,6 @@ use hir::def_id::DefId;
use rustc::ty::subst::Substs;
use rustc::traits;
use rustc::ty::{self, ToPredicate, ToPolyTraitRef, TraitRef, TypeFoldable};
use rustc::ty::adjustment::AutoBorrow;
use rustc::ty::subst::Subst;
use rustc::infer::{self, InferOk};
@ -165,26 +164,22 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
supplied_method_types))
}
/// `lookup_in_trait_adjusted` is used for overloaded operators.
/// `lookup_method_in_trait` is used for overloaded operators.
/// It does a very narrow slice of what the normal probe/confirm path does.
/// In particular, it doesn't really do any probing: it simply constructs
/// an obligation for aparticular trait with the given self-type and checks
/// whether that trait is implemented.
///
/// FIXME(#18741) -- It seems likely that we can consolidate some of this
/// code with the other method-lookup code. In particular, autoderef on
/// index is basically identical to autoderef with normal probes, except
/// that the test also looks for built-in indexing. Also, the second half of
/// this method is basically the same as confirmation.
pub fn lookup_method_in_trait_adjusted(&self,
span: Span,
m_name: ast::Name,
trait_def_id: DefId,
self_ty: ty::Ty<'tcx>,
opt_input_types: Option<&[ty::Ty<'tcx>]>)
-> Option<InferOk<'tcx,
(Option<AutoBorrow<'tcx>>,
MethodCallee<'tcx>)>> {
/// code with the other method-lookup code. In particular, the second half
/// of this method is basically the same as confirmation.
pub fn lookup_method_in_trait(&self,
span: Span,
m_name: ast::Name,
trait_def_id: DefId,
self_ty: ty::Ty<'tcx>,
opt_input_types: Option<&[ty::Ty<'tcx>]>)
-> Option<InferOk<'tcx, MethodCallee<'tcx>>> {
debug!("lookup_in_trait_adjusted(self_ty={:?}, \
m_name={}, trait_def_id={:?})",
self_ty,
@ -237,8 +232,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
// NB: Instantiate late-bound regions first so that
// `instantiate_type_scheme` can normalize associated types that
// may reference those regions.
let original_method_ty = tcx.type_of(def_id);
let fn_sig = original_method_ty.fn_sig();
let fn_sig = tcx.type_of(def_id).fn_sig();
let fn_sig = self.replace_late_bound_regions_with_fresh_var(span,
infer::FnCall,
&fn_sig).0;
@ -249,11 +243,6 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
value
}
};
let method_ty = tcx.mk_fn_def(def_id, substs, ty::Binder(fn_sig));
debug!("lookup_in_trait_adjusted: matched method method_ty={:?} obligation={:?}",
method_ty,
obligation);
// Register obligations for the parameters. This will include the
// `Self` parameter, which in turn has a bound of the main trait,
@ -276,21 +265,12 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
obligations.extend(traits::predicates_for_generics(cause.clone(), &bounds));
// Also add an obligation for the method type being well-formed.
let method_ty = tcx.mk_fn_ptr(ty::Binder(fn_sig));
debug!("lookup_in_trait_adjusted: matched method method_ty={:?} obligation={:?}",
method_ty,
obligation);
obligations.push(traits::Obligation::new(cause, ty::Predicate::WellFormed(method_ty)));
let autoref = match (&original_method_ty.fn_sig().input(0).skip_binder().sty,
&fn_sig.inputs()[0].sty) {
(&ty::TyRef(..), &ty::TyRef(region, ty::TypeAndMut { mutbl, ty: _ })) => {
// Trait method is fn(&self) or fn(&mut self), need an
// autoref. Pull the region etc out of the type of first argument.
Some(AutoBorrow::Ref(region, mutbl))
}
_ => {
// Trait method is fn(self), no transformation needed.
None
}
};
let callee = MethodCallee {
def_id: def_id,
substs: trait_ref.substs,
@ -301,7 +281,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
Some(InferOk {
obligations,
value: (autoref, callee)
value: callee
})
}

134
src/librustc_typeck/check/mod.rs
View File

@ -96,7 +96,7 @@ use rustc::ty::subst::{Kind, Subst, Substs};
use rustc::traits::{self, FulfillmentContext, ObligationCause, ObligationCauseCode, Reveal};
use rustc::ty::{ParamTy, LvaluePreference, NoPreference, PreferMutLvalue};
use rustc::ty::{self, Ty, TyCtxt, Visibility};
use rustc::ty::adjustment::{Adjust, Adjustment, AutoBorrow, OverloadedDeref};
use rustc::ty::adjustment::{Adjust, Adjustment, AutoBorrow};
use rustc::ty::fold::{BottomUpFolder, TypeFoldable};
use rustc::ty::maps::Providers;
use rustc::ty::util::{Representability, IntTypeExt};
@ -1774,48 +1774,36 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
}
}
pub fn apply_autoderef_adjustment(&self,
node_id: ast::NodeId,
autoderefs: Vec<Option<OverloadedDeref<'tcx>>>,
adjusted_ty: Ty<'tcx>) {
self.apply_adjustment(node_id, Adjustment {
kind: Adjust::Deref(autoderefs),
autoref: None,
unsize: false,
target: adjusted_ty
});
}
pub fn apply_adjustments(&self, expr: &hir::Expr, adj: Vec<Adjustment<'tcx>>) {
debug!("apply_adjustments(expr={:?}, adj={:?})", expr, adj);
pub fn apply_adjustment(&self, node_id: ast::NodeId, adj: Adjustment<'tcx>) {
debug!("apply_adjustment(node_id={}, adj={:?})", node_id, adj);
if adj.is_identity() {
if adj.is_empty() {
return;
}
match self.tables.borrow_mut().adjustments.entry(node_id) {
match self.tables.borrow_mut().adjustments.entry(expr.id) {
Entry::Vacant(entry) => { entry.insert(adj); },
Entry::Occupied(mut entry) => {
debug!(" - composing on top of {:?}", entry.get());
match (entry.get(), &adj) {
match (&entry.get()[..], &adj[..]) {
// Applying any adjustment on top of a NeverToAny
// is a valid NeverToAny adjustment, because it can't
// be reached.
(&Adjustment { kind: Adjust::NeverToAny, .. }, _) => return,
(&Adjustment {
kind: Adjust::Deref(ref old),
autoref: Some(AutoBorrow::Ref(..)),
unsize: false, ..
}, &Adjustment {
kind: Adjust::Deref(ref new), ..
}) if old.len() == 1 && new.len() >= 1 => {
(&[Adjustment { kind: Adjust::NeverToAny, .. }], _) => return,
(&[
Adjustment { kind: Adjust::Deref(_), .. },
Adjustment { kind: Adjust::Borrow(AutoBorrow::Ref(..)), .. },
], &[
Adjustment { kind: Adjust::Deref(_), .. },
.. // Any following adjustments are allowed.
]) => {
// A reborrow has no effect before a dereference.
}
// FIXME: currently we never try to compose autoderefs
// and ReifyFnPointer/UnsafeFnPointer, but we could.
_ =>
bug!("while adjusting {}, can't compose {:?} and {:?}",
node_id, entry.get(), adj)
bug!("while adjusting {:?}, can't compose {:?} and {:?}",
expr, entry.get(), adj)
};
*entry.get_mut() = adj;
}
@ -2189,7 +2177,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
index_ty: Ty<'tcx>)
-> Option<(/*index type*/ Ty<'tcx>, /*element type*/ Ty<'tcx>)>
{
let mut adjusted_ty = autoderef.unambiguous_final_ty();
let adjusted_ty = autoderef.unambiguous_final_ty();
debug!("try_index_step(expr={:?}, base_expr={:?}, adjusted_ty={:?}, \
index_ty={:?})",
expr,
@ -2202,19 +2190,19 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
match (adjusted_ty.builtin_index(), &index_ty.sty) {
(Some(ty), &ty::TyUint(ast::UintTy::Us)) | (Some(ty), &ty::TyInfer(ty::IntVar(_))) => {
debug!("try_index_step: success, using built-in indexing");
let autoderefs = autoderef.adjust_steps(lvalue_pref);
self.apply_autoderef_adjustment(
base_expr.id, autoderefs, adjusted_ty);
let adjustments = autoderef.adjust_steps(lvalue_pref);
self.apply_adjustments(base_expr, adjustments);
return Some((self.tcx.types.usize, ty));
}
_ => {}
}
for &unsize in &[false, true] {
let mut self_ty = adjusted_ty;
if unsize {
// We only unsize arrays here.
if let ty::TyArray(element_ty, _) = adjusted_ty.sty {
adjusted_ty = self.tcx.mk_slice(element_ty);
self_ty = self.tcx.mk_slice(element_ty);
} else {
continue;
}
@ -2225,19 +2213,29 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
// If some lookup succeeded, install method in table
let input_ty = self.next_ty_var(TypeVariableOrigin::AutoDeref(base_expr.span));
let method = self.try_overloaded_lvalue_op(
expr.span, adjusted_ty, &[input_ty], lvalue_pref, LvalueOp::Index);
expr.span, self_ty, &[input_ty], lvalue_pref, LvalueOp::Index);
let result = method.map(|ok| {
debug!("try_index_step: success, using overloaded indexing");
let (autoref, method) = self.register_infer_ok_obligations(ok);
let method = self.register_infer_ok_obligations(ok);
let autoderefs = autoderef.adjust_steps(lvalue_pref);
self.apply_adjustment(base_expr.id, Adjustment {
kind: Adjust::Deref(autoderefs),
autoref,
unsize,
target: method.sig.inputs()[0]
});
let mut adjustments = autoderef.adjust_steps(lvalue_pref);
if let ty::TyRef(region, mt) = method.sig.inputs()[0].sty {
adjustments.push(Adjustment {
kind: Adjust::Borrow(AutoBorrow::Ref(region, mt.mutbl)),
target: self.tcx.mk_ref(region, ty::TypeAndMut {
mutbl: mt.mutbl,
ty: adjusted_ty
})
});
}
if unsize {
adjustments.push(Adjustment {
kind: Adjust::Unsize,
target: method.sig.inputs()[0]
});
}
self.apply_adjustments(base_expr, adjustments);
self.write_method_call(expr.id, method);
(input_ty, self.make_overloaded_lvalue_return_type(method).ty)
@ -2270,9 +2268,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
arg_tys: &[Ty<'tcx>],
lvalue_pref: LvaluePreference,
op: LvalueOp)
-> Option<InferOk<'tcx,
(Option<AutoBorrow<'tcx>>,
MethodCallee<'tcx>)>>
-> Option<InferOk<'tcx, MethodCallee<'tcx>>>
{
debug!("try_overloaded_lvalue_op({:?},{:?},{:?},{:?})",
span,
@ -2284,11 +2280,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
let (mut_tr, mut_op) = self.resolve_lvalue_op(op, true);
let method = match (lvalue_pref, mut_tr) {
(PreferMutLvalue, Some(trait_did)) => {
self.lookup_method_in_trait_adjusted(span,
mut_op,
trait_did,
base_ty,
Some(arg_tys))
self.lookup_method_in_trait(span, mut_op, trait_did, base_ty, Some(arg_tys))
}
_ => None,
};
@ -2297,11 +2289,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
let (imm_tr, imm_op) = self.resolve_lvalue_op(op, false);
let method = match (method, imm_tr) {
(None, Some(trait_did)) => {
self.lookup_method_in_trait_adjusted(span,
imm_op,
trait_did,
base_ty,
Some(arg_tys))
self.lookup_method_in_trait(span, imm_op, trait_did, base_ty, Some(arg_tys))
}
(method, _) => method,
};
@ -2645,12 +2633,10 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
"expression with never type wound up being adjusted");
let adj_ty = self.next_diverging_ty_var(
TypeVariableOrigin::AdjustmentType(expr.span));
self.apply_adjustment(expr.id, Adjustment {
self.apply_adjustments(expr, vec![Adjustment {
kind: Adjust::NeverToAny,
autoref: None,
unsize: false,
target: adj_ty
});
}]);
ty = adj_ty;
}
@ -2895,8 +2881,8 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
if let Some(field) = fields.iter().find(|f| f.name.to_ident() == ident) {
let field_ty = self.field_ty(expr.span, field, substs);
if field.vis.is_accessible_from(def_scope, self.tcx) {
let autoderefs = autoderef.adjust_steps(lvalue_pref);
self.apply_autoderef_adjustment(base.id, autoderefs, base_t);
let adjustments = autoderef.adjust_steps(lvalue_pref);
self.apply_adjustments(base, adjustments);
autoderef.finalize();
self.tcx.check_stability(field.did, expr.id, expr.span);
@ -3029,8 +3015,8 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
};
if let Some(field_ty) = field {
let autoderefs = autoderef.adjust_steps(lvalue_pref);
self.apply_autoderef_adjustment(base.id, autoderefs, base_t);
let adjustments = autoderef.adjust_steps(lvalue_pref);
self.apply_adjustments(base, adjustments);
autoderef.finalize();
return field_ty;
}
@ -3446,13 +3432,13 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
oprnd_t = mt.ty;
} else if let Some(ok) = self.try_overloaded_deref(
expr.span, oprnd_t, lvalue_pref) {
let (autoref, method) = self.register_infer_ok_obligations(ok);
self.apply_adjustment(oprnd.id, Adjustment {
kind: Adjust::Deref(vec![]),
autoref,
unsize: false,
target: method.sig.inputs()[0]
});
let method = self.register_infer_ok_obligations(ok);
if let ty::TyRef(region, mt) = method.sig.inputs()[0].sty {
self.apply_adjustments(oprnd, vec![Adjustment {
kind: Adjust::Borrow(AutoBorrow::Ref(region, mt.mutbl)),
target: method.sig.inputs()[0]
}]);
}
oprnd_t = self.make_overloaded_lvalue_return_type(method).ty;
self.write_method_call(expr.id, method);
} else {
@ -3466,9 +3452,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
hir::UnNot => {
oprnd_t = self.structurally_resolved_type(oprnd.span,
oprnd_t);
let result = self.check_user_unop("!", "not",
tcx.lang_items.not_trait(),
expr, &oprnd, oprnd_t, unop);
let result = self.check_user_unop(expr, &oprnd, oprnd_t, unop);
// If it's builtin, we can reuse the type, this helps inference.
if !(oprnd_t.is_integral() || oprnd_t.sty == ty::TyBool) {
oprnd_t = result;
@ -3477,9 +3461,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
hir::UnNeg => {
oprnd_t = self.structurally_resolved_type(oprnd.span,
oprnd_t);
let result = self.check_user_unop("-", "neg",
tcx.lang_items.neg_trait(),
expr, &oprnd, oprnd_t, unop);
let result = self.check_user_unop(expr, &oprnd, oprnd_t, unop);
// If it's builtin, we can reuse the type, this helps inference.
if !(oprnd_t.is_integral() || oprnd_t.is_fp()) {
oprnd_t = result;

98
src/librustc_typeck/check/op.rs
View File

@ -11,13 +11,11 @@
//! Code related to processing overloaded binary and unary operators.
use super::FnCtxt;
use hir::def_id::DefId;
use rustc::ty::{Ty, TypeFoldable, PreferMutLvalue, TypeVariants};
use rustc::ty::{self, Ty, TypeFoldable, PreferMutLvalue, TypeVariants};
use rustc::ty::TypeVariants::{TyStr, TyRef};
use rustc::ty::adjustment::{Adjustment, Adjust};
use rustc::ty::adjustment::{Adjustment, Adjust, AutoBorrow};
use rustc::infer::type_variable::TypeVariableOrigin;
use errors;
use syntax::ast;
use syntax::symbol::Symbol;
use rustc::hir;
@ -175,8 +173,6 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
lhs_ty,
is_assign);
let (name, trait_def_id) = self.name_and_trait_def_id(op, is_assign);
// NB: As we have not yet type-checked the RHS, we don't have the
// type at hand. Make a variable to represent it. The whole reason
// for this indirection is so that, below, we can check the expr
@ -186,8 +182,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
let rhs_ty_var = self.next_ty_var(TypeVariableOrigin::MiscVariable(rhs_expr.span));
let return_ty = self.lookup_op_method(expr, lhs_ty, &[rhs_ty_var],
Symbol::intern(name), trait_def_id,
lhs_expr);
Op::Binary(op, is_assign), lhs_expr);
// see `NB` above
let rhs_ty = self.check_expr_coercable_to_type(rhs_expr, rhs_ty_var);
@ -216,8 +211,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
if let TypeVariants::TyRef(_, ref ty_mut) = lhs_ty.sty {
if !self.infcx.type_moves_by_default(ty_mut.ty, lhs_expr.span) &&
self.lookup_op_method(expr, ty_mut.ty, &[rhs_ty],
Symbol::intern(name), trait_def_id,
lhs_expr).is_ok() {
Op::Binary(op, is_assign), lhs_expr).is_ok() {
err.note(
&format!(
"this is a reference to a type that `{}` can be applied \
@ -303,9 +297,6 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
}
pub fn check_user_unop(&self,
op_str: &str,
mname: &str,
trait_did: Option<DefId>,
ex: &'gcx hir::Expr,
operand_expr: &'gcx hir::Expr,
operand_ty: Ty<'tcx>,
@ -313,28 +304,31 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
-> Ty<'tcx>
{
assert!(op.is_by_value());
let mname = Symbol::intern(mname);
match self.lookup_op_method(ex, operand_ty, &[], mname, trait_did, operand_expr) {
match self.lookup_op_method(ex, operand_ty, &[], Op::Unary(op), operand_expr) {
Ok(t) => t,
Err(()) => {
let actual = self.resolve_type_vars_if_possible(&operand_ty);
if !actual.references_error() {
struct_span_err!(self.tcx.sess, ex.span, E0600,
"cannot apply unary operator `{}` to type `{}`",
op_str, actual).emit();
op.as_str(), actual).emit();
}
self.tcx.types.err
}
}
}
fn name_and_trait_def_id(&self,
op: hir::BinOp,
is_assign: IsAssign)
-> (&'static str, Option<DefId>) {
fn lookup_op_method(&self,
expr: &'gcx hir::Expr,
lhs_ty: Ty<'tcx>,
other_tys: &[Ty<'tcx>],
op: Op,
lhs_expr: &'a hir::Expr)
-> Result<Ty<'tcx>,()>
{
let lang = &self.tcx.lang_items;
if let IsAssign::Yes = is_assign {
let (opname, trait_did) = if let Op::Binary(op, IsAssign::Yes) = op {
match op.node {
hir::BiAdd => ("add_assign", lang.add_assign_trait()),
hir::BiSub => ("sub_assign", lang.sub_assign_trait()),
@ -355,7 +349,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
op.node.as_str())
}
}
} else {
} else if let Op::Binary(op, IsAssign::No) = op {
match op.node {
hir::BiAdd => ("add", lang.add_trait()),
hir::BiSub => ("sub", lang.sub_trait()),
@ -377,18 +371,14 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
span_bug!(op.span, "&& and || are not overloadable")
}
}
}
}
} else if let Op::Unary(hir::UnNot) = op {
("not", lang.not_trait())
} else if let Op::Unary(hir::UnNeg) = op {
("neg", lang.neg_trait())
} else {
bug!("lookup_op_method: op not supported: {:?}", op)
};
fn lookup_op_method(&self,
expr: &'gcx hir::Expr,
lhs_ty: Ty<'tcx>,
other_tys: &[Ty<'tcx>],
opname: ast::Name,
trait_did: Option<DefId>,
lhs_expr: &'a hir::Expr)
-> Result<Ty<'tcx>,()>
{
debug!("lookup_op_method(expr={:?}, lhs_ty={:?}, opname={:?}, \
trait_did={:?}, lhs_expr={:?})",
expr,
@ -397,28 +387,30 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
trait_did,
lhs_expr);
let method = match trait_did {
Some(trait_did) => {
self.lookup_method_in_trait_adjusted(expr.span,
opname,
trait_did,
lhs_ty,
Some(other_tys))
}
None => None
};
let method = trait_did.and_then(|trait_did| {
let opname = Symbol::intern(opname);
self.lookup_method_in_trait(expr.span, opname, trait_did, lhs_ty, Some(other_tys))
});
match method {
Some(ok) => {
let (autoref, method) = self.register_infer_ok_obligations(ok);
let method = self.register_infer_ok_obligations(ok);
self.select_obligations_where_possible();
self.apply_adjustment(lhs_expr.id, Adjustment {
kind: Adjust::Deref(vec![]),
autoref,
unsize: false,
target: method.sig.inputs()[0]
});
let (lhs_by_ref, _rhs_by_ref) = match op {
Op::Binary(_, IsAssign::Yes) => (true, false),
Op::Binary(op, _) if !op.node.is_by_value() => (true, true),
Op::Binary(..) | Op::Unary(_) => (false, false),
};
if lhs_by_ref {
if let ty::TyRef(region, mt) = method.sig.inputs()[0].sty {
let autoref = Adjustment {
kind: Adjust::Borrow(AutoBorrow::Ref(region, mt.mutbl)),
target: method.sig.inputs()[0]
};
self.apply_adjustments(lhs_expr, vec![autoref]);
}
}
self.write_method_call(expr.id, method);
Ok(method.sig.output())
@ -493,6 +485,12 @@ enum IsAssign {
Yes,
}
#[derive(Clone, Copy, Debug)]
enum Op {
Binary(hir::BinOp, IsAssign),
Unary(hir::UnOp),
}
/// Returns true if this is a built-in arithmetic operation (e.g. u32
/// + u32, i16x4 == i16x4) and false if these types would have to be
/// overloaded to be legal. There are two reasons that we distinguish

128
src/librustc_typeck/check/regionck.rs
View File

@ -542,61 +542,10 @@ impl<'a, 'gcx, 'tcx> Visitor<'gcx> for RegionCtxt<'a, 'gcx, 'tcx> {
}
// Check any autoderefs or autorefs that appear.
let adjustment = self.tables.borrow().adjustments.get(&expr.id).map(|a| a.clone());
if let Some(adjustment) = adjustment {
debug!("adjustment={:?}", adjustment);
match adjustment.kind {
adjustment::Adjust::Deref(ref autoderefs) => {
let cmt = ignore_err!(self.constrain_autoderefs(expr, autoderefs));
if let Some(ref autoref) = adjustment.autoref {
self.link_autoref(expr, cmt, autoref);
// Require that the resulting region encompasses
// the current node.
//
// FIXME(#6268) remove to support nested method calls
self.type_of_node_must_outlive(infer::AutoBorrow(expr.span),
expr.id, expr_region);
}
}
/*
adjustment::AutoObject(_, ref bounds, ..) => {
// Determine if we are casting `expr` to a trait
// instance. If so, we have to be sure that the type
// of the source obeys the new region bound.
let source_ty = self.resolve_node_type(expr.id);
self.type_must_outlive(infer::RelateObjectBound(expr.span),
source_ty, bounds.region_bound);
}
*/
_ => {
assert!(adjustment.autoref.is_none());
}
}
// If necessary, constrain destructors in the unadjusted form of this
// expression.
let cmt_result = {
let mc = mc::MemCategorizationContext::new(self, &self.region_maps);
mc.cat_expr_unadjusted(expr)
};
match cmt_result {
Ok(head_cmt) => {
self.check_safety_of_rvalue_destructor_if_necessary(head_cmt,
expr.span);
}
Err(..) => {
self.tcx.sess.delay_span_bug(expr.span, "cat_expr_unadjusted Errd");
}
}
}
let cmt_result = self.constrain_adjustments(expr);
// If necessary, constrain destructors in this expression. This will be
// the adjusted form if there is an adjustment.
let cmt_result = {
let mc = mc::MemCategorizationContext::new(self, &self.region_maps);
mc.cat_expr(expr)
};
match cmt_result {
Ok(head_cmt) => {
self.check_safety_of_rvalue_destructor_if_necessary(head_cmt, expr.span);
@ -904,26 +853,35 @@ impl<'a, 'gcx, 'tcx> RegionCtxt<'a, 'gcx, 'tcx> {
}
}
/// Invoked on any auto-dereference that occurs. Checks that if this is a region pointer being
/// Invoked on any adjustments that occur. Checks that if this is a region pointer being
/// dereferenced, the lifetime of the pointer includes the deref expr.
fn constrain_autoderefs(&mut self,
deref_expr: &hir::Expr,
autoderefs: &[Option<adjustment::OverloadedDeref<'tcx>>])
-> mc::McResult<mc::cmt<'tcx>>
{
debug!("constrain_autoderefs(deref_expr={:?}, autoderefs={:?})",
deref_expr,
autoderefs);
fn constrain_adjustments(&mut self, expr: &hir::Expr) -> mc::McResult<mc::cmt<'tcx>> {
debug!("constrain_adjustments(expr={:?})", expr);
let mut cmt = {
let mc = mc::MemCategorizationContext::new(self, &self.region_maps);
mc.cat_expr_unadjusted(deref_expr)?
mc.cat_expr_unadjusted(expr)?
};
let r_deref_expr = self.tcx.node_scope_region(deref_expr.id);
for &overloaded in autoderefs {
if let Some(deref) = overloaded {
debug!("constrain_autoderefs: overloaded, {:?}", deref);
//NOTE(@jroesch): mixed RefCell borrow causes crash
let adjustments = self.tables.borrow().expr_adjustments(&expr).to_vec();
if adjustments.is_empty() {
return Ok(cmt);
}
debug!("constrain_adjustments: adjustments={:?}", adjustments);
// If necessary, constrain destructors in the unadjusted form of this
// expression.
self.check_safety_of_rvalue_destructor_if_necessary(cmt.clone(), expr.span);
let expr_region = self.tcx.node_scope_region(expr.id);
for adjustment in adjustments {
debug!("constrain_adjustments: adjustment={:?}, cmt={:?}",
adjustment, cmt);
if let adjustment::Adjust::Deref(Some(deref)) = adjustment.kind {
debug!("constrain_adjustments: overloaded deref: {:?}", deref);
// Treat overloaded autoderefs as if an AutoBorrow adjustment
// was applied on the base type, as that is always the case.
@ -932,33 +890,39 @@ impl<'a, 'gcx, 'tcx> RegionCtxt<'a, 'gcx, 'tcx> {
mutbl: deref.mutbl,
});
let output = self.tcx.mk_ref(deref.region, ty::TypeAndMut {
ty: deref.target,
ty: adjustment.target,
mutbl: deref.mutbl,
});
debug!("constrain_autoderefs: self_cmt={:?}", cmt);
self.link_region(deref_expr.span, deref.region,
self.link_region(expr.span, deref.region,
ty::BorrowKind::from_mutbl(deref.mutbl), cmt.clone());
// Specialized version of constrain_call.
self.type_must_outlive(infer::CallRcvr(deref_expr.span),
input, r_deref_expr);
self.type_must_outlive(infer::CallReturn(deref_expr.span),
output, r_deref_expr);
self.type_must_outlive(infer::CallRcvr(expr.span),
input, expr_region);
self.type_must_outlive(infer::CallReturn(expr.span),
output, expr_region);
}
if let adjustment::Adjust::Borrow(ref autoref) = adjustment.kind {
self.link_autoref(expr, cmt.clone(), autoref);
// Require that the resulting region encompasses
// the current node.
//
// FIXME(#6268) remove to support nested method calls
self.type_of_node_must_outlive(infer::AutoBorrow(expr.span),
expr.id, expr_region);
}
{
let mc = mc::MemCategorizationContext::new(self, &self.region_maps);
if let Some(deref) = overloaded {
cmt = mc.cat_overloaded_autoderef(deref_expr, deref)?;
} else {
cmt = mc.cat_deref(deref_expr, cmt, false)?;
}
cmt = mc.cat_expr_adjusted(expr, cmt, &adjustment)?;
}
if let Categorization::Deref(_, mc::BorrowedPtr(_, r_ptr)) = cmt.cat {
self.mk_subregion_due_to_dereference(deref_expr.span,
r_deref_expr, r_ptr);
self.mk_subregion_due_to_dereference(expr.span,
expr_region, r_ptr);
}
}
@ -1029,7 +993,9 @@ impl<'a, 'gcx, 'tcx> RegionCtxt<'a, 'gcx, 'tcx> {
// is going to fail anyway, so just stop here and let typeck
// report errors later on in the writeback phase.
let ty0 = self.resolve_node_type(id);
let ty = self.tables.borrow().adjustments.get(&id).map_or(ty0, |adj| adj.target);
let ty = self.tables.borrow().adjustments.get(&id)
.and_then(|adj| adj.last())
.map_or(ty0, |adj| adj.target);
let ty = self.resolve_type(ty);
debug!("constrain_regions_in_type_of_node(\
ty={}, ty0={}, id={}, minimum_lifetime={:?})",

2
src/librustc_typeck/lib.rs
View File

@ -73,12 +73,14 @@ This API is completely unstable and subject to change.
#![allow(non_camel_case_types)]
#![feature(advanced_slice_patterns)]
#![feature(box_patterns)]
#![feature(box_syntax)]
#![feature(conservative_impl_trait)]
#![feature(never_type)]
#![feature(quote)]
#![feature(rustc_diagnostic_macros)]
#![feature(slice_patterns)]
#![cfg_attr(stage0, unstable(feature = "rustc_private", issue = "27812"))]
#![cfg_attr(stage0, feature(rustc_private))]