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Fix multiple mutable autoderefs with Box

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Closes #26205.
This commit is contained in:
Andrew Paseltiner 2015-09-03 13:10:34 -04:00
parent 1661947014
commit b8dad48435
15 changed files with 93 additions and 50 deletions
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2
src/librustc/middle/check_match.rs
View File

@ -664,7 +664,7 @@ fn is_useful(cx: &MatchCheckCtxt,
match real_pat.node {
hir::PatIdent(hir::BindByRef(..), _, _) => {
left_ty.builtin_deref(false).unwrap().ty
left_ty.builtin_deref(false, NoPreference).unwrap().ty
}
_ => left_ty,
}

6
src/librustc/middle/mem_categorization.rs
View File

@ -400,7 +400,7 @@ impl<'t, 'a,'tcx> MemCategorizationContext<'t, 'a, 'tcx> {
// a bind-by-ref means that the base_ty will be the type of the ident itself,
// but what we want here is the type of the underlying value being borrowed.
// So peel off one-level, turning the &T into T.
match base_ty.builtin_deref(false) {
match base_ty.builtin_deref(false, ty::NoPreference) {
Some(t) => t.ty,
None => { return Err(()); }
}
@ -897,7 +897,7 @@ impl<'t, 'a,'tcx> MemCategorizationContext<'t, 'a, 'tcx> {
None => base_cmt
};
let base_cmt_ty = base_cmt.ty;
match base_cmt_ty.builtin_deref(true) {
match base_cmt_ty.builtin_deref(true, ty::NoPreference) {
Some(mt) => {
let ret = self.cat_deref_common(node, base_cmt, deref_cnt,
mt.ty,
@ -1044,7 +1044,7 @@ impl<'t, 'a,'tcx> MemCategorizationContext<'t, 'a, 'tcx> {
span:elt.span(),
cat:cat_deref(base_cmt.clone(), 0, ptr),
mutbl:m,
ty: match base_cmt.ty.builtin_deref(false) {
ty: match base_cmt.ty.builtin_deref(false, ty::NoPreference) {
Some(mt) => mt.ty,
None => self.tcx().sess.bug("Found non-derefable type")
},

25
src/librustc/middle/ty.rs
View File

@ -29,6 +29,7 @@ pub use self::BoundRegion::*;
pub use self::TypeVariants::*;
pub use self::IntVarValue::*;
pub use self::CopyImplementationError::*;
pub use self::LvaluePreference::*;
pub use self::BuiltinBound::Send as BoundSend;
pub use self::BuiltinBound::Sized as BoundSized;
@ -4828,6 +4829,21 @@ impl<'tcx> TyS<'tcx> {
}
}
#[derive(Copy, Clone, Debug, PartialEq, Eq)]
pub enum LvaluePreference {
PreferMutLvalue,
NoPreference
}
impl LvaluePreference {
pub fn from_mutbl(m: hir::Mutability) -> Self {
match m {
hir::MutMutable => PreferMutLvalue,
hir::MutImmutable => NoPreference,
}
}
}
/// Describes whether a type is representable. For types that are not
/// representable, 'SelfRecursive' and 'ContainsRecursive' are used to
/// distinguish between types that are recursive with themselves and types that
@ -5073,12 +5089,15 @@ impl<'tcx> TyS<'tcx> {
//
// The parameter `explicit` indicates if this is an *explicit* dereference.
// Some types---notably unsafe ptrs---can only be dereferenced explicitly.
pub fn builtin_deref(&self, explicit: bool) -> Option<TypeAndMut<'tcx>> {
pub fn builtin_deref(&self, explicit: bool, pref: LvaluePreference)
-> Option<TypeAndMut<'tcx>>
{
match self.sty {
TyBox(ty) => {
Some(TypeAndMut {
ty: ty,
mutbl: hir::MutImmutable,
mutbl:
if pref == PreferMutLvalue { hir::MutMutable } else { hir::MutImmutable },
})
},
TyRef(_, mt) => Some(mt),
@ -5183,7 +5202,7 @@ impl<'tcx> TyS<'tcx> {
}
None => {}
}
match adjusted_ty.builtin_deref(true) {
match adjusted_ty.builtin_deref(true, NoPreference) {
Some(mt) => { adjusted_ty = mt.ty; }
None => {
cx.sess.span_bug(

9
src/librustc_trans/trans/consts.rs
View File

@ -155,7 +155,7 @@ fn const_deref<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>,
v: ValueRef,
ty: Ty<'tcx>)
-> (ValueRef, Ty<'tcx>) {
match ty.builtin_deref(true) {
match ty.builtin_deref(true, ty::NoPreference) {
Some(mt) => {
if type_is_sized(cx.tcx(), mt.ty) {
(const_deref_ptr(cx, v), mt.ty)
@ -329,7 +329,7 @@ pub fn const_expr<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>,
param_substs,
&target);
let pointee_ty = ty.builtin_deref(true)
let pointee_ty = ty.builtin_deref(true, ty::NoPreference)
.expect("consts: unsizing got non-pointer type").ty;
let (base, old_info) = if !type_is_sized(cx.tcx(), pointee_ty) {
// Normally, the source is a thin pointer and we are
@ -344,7 +344,7 @@ pub fn const_expr<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>,
(llconst, None)
};
let unsized_ty = target.builtin_deref(true)
let unsized_ty = target.builtin_deref(true, ty::NoPreference)
.expect("consts: unsizing got non-pointer target type").ty;
let ptr_ty = type_of::in_memory_type_of(cx, unsized_ty).ptr_to();
let base = ptrcast(base, ptr_ty);
@ -642,7 +642,8 @@ fn const_expr_unadjusted<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>,
}
if type_is_fat_ptr(cx.tcx(), t_expr) {
// Fat pointer casts.
let t_cast_inner = t_cast.builtin_deref(true).expect("cast to non-pointer").ty;
let t_cast_inner =
t_cast.builtin_deref(true, ty::NoPreference).expect("cast to non-pointer").ty;
let ptr_ty = type_of::in_memory_type_of(cx, t_cast_inner).ptr_to();
let addr = ptrcast(const_get_elt(cx, v, &[abi::FAT_PTR_ADDR as u32]),
ptr_ty);

5
src/librustc_trans/trans/expr.rs
View File

@ -780,7 +780,7 @@ fn trans_index<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
let ref_ty = // invoked methods have LB regions instantiated:
bcx.tcx().no_late_bound_regions(&method_ty.fn_ret()).unwrap().unwrap();
let elt_ty = match ref_ty.builtin_deref(true) {
let elt_ty = match ref_ty.builtin_deref(true, ty::NoPreference) {
None => {
bcx.tcx().sess.span_bug(index_expr.span,
"index method didn't return a \
@ -1971,7 +1971,8 @@ pub fn cast_is_noop<'tcx>(tcx: &ty::ctxt<'tcx>,
return true;
}
match (t_in.builtin_deref(true), t_out.builtin_deref(true)) {
match (t_in.builtin_deref(true, ty::NoPreference),
t_out.builtin_deref(true, ty::NoPreference)) {
(Some(ty::TypeAndMut{ ty: t_in, .. }), Some(ty::TypeAndMut{ ty: t_out, .. })) => {
t_in == t_out
}

10
src/librustc_typeck/check/_match.rs
View File

@ -15,10 +15,10 @@ use middle::pat_util::{PatIdMap, pat_id_map, pat_is_binding};
use middle::pat_util::pat_is_resolved_const;
use middle::privacy::{AllPublic, LastMod};
use middle::subst::Substs;
use middle::ty::{self, Ty, HasTypeFlags};
use middle::ty::{self, Ty, HasTypeFlags, LvaluePreference};
use check::{check_expr, check_expr_has_type, check_expr_with_expectation};
use check::{check_expr_coercable_to_type, demand, FnCtxt, Expectation};
use check::{check_expr_with_lvalue_pref, LvaluePreference};
use check::{check_expr_with_lvalue_pref};
use check::{instantiate_path, resolve_ty_and_def_ufcs, structurally_resolved_type};
use require_same_types;
use util::nodemap::FnvHashMap;
@ -292,7 +292,7 @@ pub fn check_pat<'a, 'tcx>(pcx: &pat_ctxt<'a, 'tcx>,
let region = fcx.infcx().next_region_var(infer::PatternRegion(pat.span));
tcx.mk_ref(tcx.mk_region(region), ty::TypeAndMut {
ty: tcx.mk_slice(inner_ty),
mutbl: expected_ty.builtin_deref(true).map(|mt| mt.mutbl)
mutbl: expected_ty.builtin_deref(true, ty::NoPreference).map(|mt| mt.mutbl)
.unwrap_or(hir::MutImmutable)
})
}
@ -310,7 +310,7 @@ pub fn check_pat<'a, 'tcx>(pcx: &pat_ctxt<'a, 'tcx>,
}
if let Some(ref slice) = *slice {
let region = fcx.infcx().next_region_var(infer::PatternRegion(pat.span));
let mutbl = expected_ty.builtin_deref(true)
let mutbl = expected_ty.builtin_deref(true, ty::NoPreference)
.map_or(hir::MutImmutable, |mt| mt.mutbl);
let slice_ty = tcx.mk_ref(tcx.mk_region(region), ty::TypeAndMut {
@ -399,7 +399,7 @@ pub fn check_dereferencable<'a, 'tcx>(pcx: &pat_ctxt<'a, 'tcx>,
let tcx = pcx.fcx.ccx.tcx;
if pat_is_binding(&tcx.def_map, inner) {
let expected = fcx.infcx().shallow_resolve(expected);
expected.builtin_deref(true).map_or(true, |mt| match mt.ty.sty {
expected.builtin_deref(true, ty::NoPreference).map_or(true, |mt| match mt.ty.sty {
ty::TyTrait(_) => {
// This is "x = SomeTrait" being reduced from
// "let &x = &SomeTrait" or "let box x = Box<SomeTrait>", an error.

3
src/librustc_typeck/check/callee.rs
View File

@ -18,7 +18,6 @@ use super::err_args;
use super::Expectation;
use super::expected_types_for_fn_args;
use super::FnCtxt;
use super::LvaluePreference;
use super::method;
use super::structurally_resolved_type;
use super::TupleArgumentsFlag;
@ -28,7 +27,7 @@ use super::write_call;
use CrateCtxt;
use middle::def_id::{DefId, LOCAL_CRATE};
use middle::infer;
use middle::ty::{self, Ty};
use middle::ty::{self, LvaluePreference, Ty};
use syntax::codemap::Span;
use syntax::parse::token;
use syntax::ptr::P;

4
src/librustc_typeck/check/coercion.rs
View File

@ -60,13 +60,13 @@
//! sort of a minor point so I've opted to leave it for later---after all
//! we may want to adjust precisely when coercions occur.
use check::{autoderef, FnCtxt, LvaluePreference, UnresolvedTypeAction};
use check::{autoderef, FnCtxt, UnresolvedTypeAction};
use middle::infer::{self, Coercion};
use middle::traits::{self, ObligationCause};
use middle::traits::{predicate_for_trait_def, report_selection_error};
use middle::ty::{AutoDerefRef, AdjustDerefRef};
use middle::ty::{self, TypeAndMut, Ty, TypeError};
use middle::ty::{self, LvaluePreference, TypeAndMut, Ty, TypeError};
use middle::ty_relate::RelateResult;
use util::common::indent;

6
src/librustc_typeck/check/method/confirm.rs
View File

@ -10,12 +10,12 @@
use super::probe;
use check::{self, FnCtxt, NoPreference, PreferMutLvalue, callee, demand};
use check::{self, FnCtxt, callee, demand};
use check::UnresolvedTypeAction;
use middle::def_id::DefId;
use middle::subst::{self};
use middle::traits;
use middle::ty::{self, Ty};
use middle::ty::{self, NoPreference, PreferMutLvalue, Ty};
use middle::ty_fold::TypeFoldable;
use middle::infer;
use middle::infer::InferCtxt;
@ -534,7 +534,7 @@ impl<'a,'tcx> ConfirmContext<'a,'tcx> {
}
Some(ty::AutoPtr(_, _)) => {
(adr.autoderefs, adr.unsize.map(|target| {
target.builtin_deref(false)
target.builtin_deref(false, NoPreference)
.expect("fixup: AutoPtr is not &T").ty
}))
}

4
src/librustc_typeck/check/method/probe.rs
View File

@ -14,13 +14,13 @@ use super::{CandidateSource, ImplSource, TraitSource};
use super::suggest;
use check;
use check::{FnCtxt, NoPreference, UnresolvedTypeAction};
use check::{FnCtxt, UnresolvedTypeAction};
use middle::def_id::DefId;
use middle::fast_reject;
use middle::subst;
use middle::subst::Subst;
use middle::traits;
use middle::ty::{self, RegionEscape, Ty, ToPolyTraitRef, TraitRef};
use middle::ty::{self, NoPreference, RegionEscape, Ty, ToPolyTraitRef, TraitRef};
use middle::ty::HasTypeFlags;
use middle::ty_fold::TypeFoldable;
use middle::infer;

2
src/librustc_typeck/check/method/suggest.rs
View File

@ -324,7 +324,7 @@ fn type_derefs_to_local<'a, 'tcx>(fcx: &FnCtxt<'a, 'tcx>,
}
check::autoderef(fcx, span, rcvr_ty, None,
check::UnresolvedTypeAction::Ignore, check::NoPreference,
check::UnresolvedTypeAction::Ignore, ty::NoPreference,
|ty, _| {
if is_local(ty) {
Some(())

23
src/librustc_typeck/check/mod.rs
View File

@ -76,7 +76,6 @@ type parameter).
*/
pub use self::LvaluePreference::*;
pub use self::Expectation::*;
pub use self::compare_method::{compare_impl_method, compare_const_impl};
use self::TupleArgumentsFlag::*;
@ -95,6 +94,7 @@ use middle::subst::{self, Subst, Substs, VecPerParamSpace, ParamSpace, TypeSpace
use middle::traits::{self, report_fulfillment_errors};
use middle::ty::{FnSig, GenericPredicates, TypeScheme};
use middle::ty::{Disr, ParamTy, ParameterEnvironment};
use middle::ty::{LvaluePreference, NoPreference, PreferMutLvalue};
use middle::ty::{self, HasTypeFlags, RegionEscape, ToPolyTraitRef, Ty};
use middle::ty::{MethodCall, MethodCallee};
use middle::ty_fold::{TypeFolder, TypeFoldable};
@ -2086,21 +2086,6 @@ impl<'a, 'tcx> RegionScope for FnCtxt<'a, 'tcx> {
}
}
#[derive(Copy, Clone, Debug, PartialEq, Eq)]
pub enum LvaluePreference {
PreferMutLvalue,
NoPreference
}
impl LvaluePreference {
pub fn from_mutbl(m: hir::Mutability) -> Self {
match m {
hir::MutMutable => PreferMutLvalue,
hir::MutImmutable => NoPreference,
}
}
}
/// Whether `autoderef` requires types to resolve.
#[derive(Copy, Clone, Debug, PartialEq, Eq)]
pub enum UnresolvedTypeAction {
@ -2156,7 +2141,7 @@ pub fn autoderef<'a, 'tcx, T, F>(fcx: &FnCtxt<'a, 'tcx>,
}
// Otherwise, deref if type is derefable:
let mt = match resolved_t.builtin_deref(false) {
let mt = match resolved_t.builtin_deref(false, lvalue_pref) {
Some(mt) => Some(mt),
None => {
let method_call =
@ -2245,7 +2230,7 @@ fn make_overloaded_lvalue_return_type<'a, 'tcx>(fcx: &FnCtxt<'a, 'tcx>,
}
// method returns &T, but the type as visible to user is T, so deref
ret_ty.builtin_deref(true)
ret_ty.builtin_deref(true, NoPreference)
}
None => None,
}
@ -3293,7 +3278,7 @@ fn check_expr_with_unifier<'a, 'tcx, F>(fcx: &FnCtxt<'a, 'tcx>,
}
hir::UnDeref => {
oprnd_t = structurally_resolved_type(fcx, expr.span, oprnd_t);
oprnd_t = match oprnd_t.builtin_deref(true) {
oprnd_t = match oprnd_t.builtin_deref(true, NoPreference) {
Some(mt) => mt.ty,
None => match try_overloaded_deref(fcx, expr.span,
Some(MethodCall::expr(expr.id)),

3
src/librustc_typeck/check/op.rs
View File

@ -17,12 +17,11 @@ use super::{
demand,
method,
FnCtxt,
PreferMutLvalue,
structurally_resolved_type,
};
use middle::def_id::DefId;
use middle::traits;
use middle::ty::{Ty, HasTypeFlags};
use middle::ty::{Ty, HasTypeFlags, PreferMutLvalue};
use syntax::ast;
use syntax::parse::token;
use rustc_front::hir;

2
src/librustc_typeck/check/regionck.rs
View File

@ -1031,7 +1031,7 @@ fn constrain_autoderefs<'a, 'tcx>(rcx: &mut Rcx<'a, 'tcx>,
r_deref_expr, *r_ptr);
}
match derefd_ty.builtin_deref(true) {
match derefd_ty.builtin_deref(true, ty::NoPreference) {
Some(mt) => derefd_ty = mt.ty,
/* if this type can't be dereferenced, then there's already an error
in the session saying so. Just bail out for now */

39
src/test/run-pass/issue-26205.rs Normal file
View File

@ -0,0 +1,39 @@
// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
use std::ops::{Deref, DerefMut};
struct Foo;
impl Foo {
fn foo_mut(&mut self) {}
}
struct Bar(Foo);
impl Deref for Bar {
type Target = Foo;
fn deref(&self) -> &Foo {
&self.0
}
}
impl DerefMut for Bar {
fn deref_mut(&mut self) -> &mut Foo {
&mut self.0
}
}
fn test(mut bar: Box<Bar>) {
bar.foo_mut();
}
fn main() {}