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Distinguish tuple elements by index in mem_categorization. Fixes #5362.

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This commit is contained in:
Niko Matsakis 2013-05-17 21:12:50 -04:00
parent ff081980e7
commit 5ca383b777
8 changed files with 246 additions and 81 deletions
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1
src/librustc/middle/borrowck/check_loans.rs
View file

@ -400,6 +400,7 @@ pub impl<'self> CheckLoanCtxt<'self> {
cmt = b;
}
mc::cat_downcast(b) |
mc::cat_interior(b, _) => {
if cmt.mutbl == mc::McInherited {
cmt = b;

3
src/librustc/middle/borrowck/gather_loans/lifetime.rs
View file

@ -105,6 +105,7 @@ impl GuaranteeLifetimeContext {
}
}
mc::cat_downcast(base) |
mc::cat_deref(base, _, mc::uniq_ptr(*)) |
mc::cat_interior(base, _) => {
self.check(base, discr_scope)
@ -303,6 +304,7 @@ impl GuaranteeLifetimeContext {
mc::cat_deref(*) => {
false
}
r @ mc::cat_downcast(*) |
r @ mc::cat_interior(*) |
r @ mc::cat_stack_upvar(*) |
r @ mc::cat_discr(*) => {
@ -340,6 +342,7 @@ impl GuaranteeLifetimeContext {
mc::cat_deref(_, _, mc::region_ptr(_, r)) => {
r
}
mc::cat_downcast(cmt) |
mc::cat_deref(cmt, _, mc::uniq_ptr(*)) |
mc::cat_deref(cmt, _, mc::gc_ptr(*)) |
mc::cat_interior(cmt, _) |

19
src/librustc/middle/borrowck/gather_loans/restrictions.rs
View file

@ -80,24 +80,17 @@ impl RestrictionsContext {
set: restrictions}])
}
mc::cat_interior(cmt_base, i @ mc::interior_variant(_)) => {
mc::cat_downcast(cmt_base) => {
// When we borrow the interior of an enum, we have to
// ensure the enum itself is not mutated, because that
// could cause the type of the memory to change.
let result = self.compute(cmt_base, restrictions | RESTR_MUTATE);
self.extend(result, cmt.mutbl, LpInterior(i), restrictions)
self.compute(cmt_base, restrictions | RESTR_MUTATE)
}
mc::cat_interior(cmt_base, i @ mc::interior_tuple) |
mc::cat_interior(cmt_base, i @ mc::interior_anon_field) |
mc::cat_interior(cmt_base, i @ mc::interior_field(*)) |
mc::cat_interior(cmt_base, i @ mc::interior_index(*)) => {
// For all of these cases, overwriting the base would
// not change the type of the memory, so no additional
// restrictions are needed.
//
// FIXME(#5397) --- Mut fields are not treated soundly
// (hopefully they will just get phased out)
mc::cat_interior(cmt_base, i) => {
// Overwriting the base would not change the type of
// the memory, so no additional restrictions are
// needed.
let result = self.compute(cmt_base, restrictions);
self.extend(result, cmt.mutbl, LpInterior(i), restrictions)
}

28
src/librustc/middle/borrowck/mod.rs
View file

@ -236,8 +236,8 @@ pub enum LoanPath {
#[deriving(Eq)]
pub enum LoanPathElem {
LpDeref, // `*LV` in doc.rs
LpInterior(mc::interior_kind) // `LV.f` in doc.rs
LpDeref, // `*LV` in doc.rs
LpInterior(mc::InteriorKind) // `LV.f` in doc.rs
}
pub impl LoanPath {
@ -280,6 +280,7 @@ pub fn opt_loan_path(cmt: mc::cmt) -> Option<@LoanPath> {
|&lp| @LpExtend(lp, cmt.mutbl, LpInterior(ik)))
}
mc::cat_downcast(cmt_base) |
mc::cat_stack_upvar(cmt_base) |
mc::cat_discr(cmt_base, _) => {
opt_loan_path(cmt_base)
@ -616,24 +617,25 @@ pub impl BorrowckCtxt {
}
}
LpExtend(lp_base, _, LpInterior(mc::interior_field(fld))) => {
LpExtend(lp_base, _, LpInterior(mc::InteriorField(fname))) => {
self.append_loan_path_to_str_from_interior(lp_base, out);
str::push_char(out, '.');
str::push_str(out, *self.tcx.sess.intr().get(fld));
match fname {
mc::NamedField(fname) => {
str::push_char(out, '.');
str::push_str(out, *self.tcx.sess.intr().get(fname));
}
mc::PositionalField(idx) => {
str::push_char(out, '#'); // invent a notation here
str::push_str(out, idx.to_str());
}
}
}
LpExtend(lp_base, _, LpInterior(mc::interior_index(*))) => {
LpExtend(lp_base, _, LpInterior(mc::InteriorElement(_))) => {
self.append_loan_path_to_str_from_interior(lp_base, out);
str::push_str(out, "[]");
}
LpExtend(lp_base, _, LpInterior(mc::interior_tuple)) |
LpExtend(lp_base, _, LpInterior(mc::interior_anon_field)) |
LpExtend(lp_base, _, LpInterior(mc::interior_variant(_))) => {
self.append_loan_path_to_str_from_interior(lp_base, out);
str::push_str(out, ".(tuple)");
}
LpExtend(lp_base, _, LpDeref) => {
str::push_char(out, '*');
self.append_loan_path_to_str(lp_base, out);

161
src/librustc/middle/mem_categorization.rs
View file

@ -66,9 +66,12 @@ pub enum categorization {
cat_local(ast::node_id), // local variable
cat_arg(ast::node_id), // formal argument
cat_deref(cmt, uint, ptr_kind), // deref of a ptr
cat_interior(cmt, interior_kind), // something interior
cat_interior(cmt, InteriorKind), // something interior: field, tuple, etc
cat_downcast(cmt), // selects a particular enum variant (*)
cat_discr(cmt, ast::node_id), // match discriminant (see preserve())
cat_self(ast::node_id), // explicit `self`
// (*) downcast is only required if the enum has more than one variant
}
#[deriving(Eq)]
@ -89,14 +92,15 @@ pub enum ptr_kind {
// We use the term "interior" to mean "something reachable from the
// base without a pointer dereference", e.g. a field
#[deriving(Eq)]
pub enum interior_kind {
interior_tuple, // elt in a tuple
interior_anon_field, // anonymous field (in e.g.
// struct Foo(int, int);
interior_variant(ast::def_id), // internals to a variant of given enum
interior_field(ast::ident), // name of field
interior_index(ty::t, // type of vec/str/etc being deref'd
ast::mutability) // mutability of vec content
pub enum InteriorKind {
InteriorField(FieldName),
InteriorElement(ty::t), // ty::t is the type of the vec/str
}
#[deriving(Eq)]
pub enum FieldName {
NamedField(ast::ident),
PositionalField(uint)
}
#[deriving(Eq)]
@ -134,7 +138,10 @@ pub type cmt = @cmt_;
// We pun on *T to mean both actual deref of a ptr as well
// as accessing of components:
pub enum deref_kind {deref_ptr(ptr_kind), deref_interior(interior_kind)}
pub enum deref_kind {
deref_ptr(ptr_kind),
deref_interior(InteriorKind),
}
// Categorizes a derefable type. Note that we include vectors and strings as
// derefable (we model an index as the combination of a deref and then a
@ -176,20 +183,14 @@ pub fn opt_deref_kind(t: ty::t) -> Option<deref_kind> {
Some(deref_ptr(unsafe_ptr))
}
ty::ty_enum(did, _) => {
Some(deref_interior(interior_variant(did)))
}
ty::ty_struct(_, _) => {
Some(deref_interior(interior_anon_field))
}
ty::ty_evec(mt, ty::vstore_fixed(_)) => {
Some(deref_interior(interior_index(t, mt.mutbl)))
ty::ty_enum(*) |
ty::ty_struct(*) => { // newtype
Some(deref_interior(InteriorField(PositionalField(0))))
}
ty::ty_evec(_, ty::vstore_fixed(_)) |
ty::ty_estr(ty::vstore_fixed(_)) => {
Some(deref_interior(interior_index(t, m_imm)))
Some(deref_interior(InteriorElement(t)))
}
_ => None
@ -579,7 +580,7 @@ pub impl mem_categorization_ctxt {
@cmt_ {
id: node.id(),
span: node.span(),
cat: cat_interior(base_cmt, interior_field(f_name)),
cat: cat_interior(base_cmt, InteriorField(NamedField(f_name))),
mutbl: base_cmt.mutbl.inherit(),
ty: f_ty
}
@ -737,15 +738,16 @@ pub impl mem_categorization_ctxt {
}
};
fn interior<N: ast_node>(elt: N, of_cmt: cmt,
vect: ty::t, mutbl: MutabilityCategory,
fn interior<N: ast_node>(elt: N,
of_cmt: cmt,
vec_ty: ty::t,
mutbl: MutabilityCategory,
mt: ty::mt) -> cmt
{
let interior = interior_index(vect, mt.mutbl);
@cmt_ {
id:elt.id(),
span:elt.span(),
cat:cat_interior(of_cmt, interior),
cat:cat_interior(of_cmt, InteriorElement(vec_ty)),
mutbl:mutbl,
ty:mt.ty
}
@ -756,7 +758,7 @@ pub impl mem_categorization_ctxt {
node: N,
base_cmt: cmt,
interior_ty: ty::t,
interior: interior_kind) -> cmt {
interior: InteriorKind) -> cmt {
@cmt_ {
id: node.id(),
span: node.span(),
@ -766,6 +768,19 @@ pub impl mem_categorization_ctxt {
}
}
fn cat_downcast<N:ast_node>(&self,
node: N,
base_cmt: cmt,
downcast_ty: ty::t) -> cmt {
@cmt_ {
id: node.id(),
span: node.span(),
cat: cat_downcast(base_cmt),
mutbl: base_cmt.mutbl.inherit(),
ty: downcast_ty
}
}
fn cat_pattern(&self,
cmt: cmt,
pat: @ast::pat,
@ -835,21 +850,34 @@ pub impl mem_categorization_ctxt {
match self.tcx.def_map.find(&pat.id) {
Some(&ast::def_variant(enum_did, _)) => {
// variant(x, y, z)
for subpats.each |&subpat| {
let downcast_cmt = {
if ty::enum_is_univariant(tcx, enum_did) {
cmt // univariant, no downcast needed
} else {
self.cat_downcast(pat, cmt, cmt.ty)
}
};
for subpats.eachi |i, &subpat| {
let subpat_ty = self.pat_ty(subpat); // see (*)
let subcmt =
self.cat_imm_interior(pat, cmt, subpat_ty,
interior_variant(enum_did));
self.cat_imm_interior(
pat, downcast_cmt, subpat_ty,
InteriorField(PositionalField(i)));
self.cat_pattern(subcmt, subpat, op);
}
}
Some(&ast::def_fn(*)) |
Some(&ast::def_struct(*)) => {
for subpats.each |&subpat| {
for subpats.eachi |i, &subpat| {
let subpat_ty = self.pat_ty(subpat); // see (*)
let cmt_field =
self.cat_imm_interior(pat, cmt, subpat_ty,
interior_anon_field);
self.cat_imm_interior(
pat, cmt, subpat_ty,
InteriorField(PositionalField(i)));
self.cat_pattern(cmt_field, subpat, op);
}
}
@ -885,10 +913,12 @@ pub impl mem_categorization_ctxt {
ast::pat_tup(ref subpats) => {
// (p1, ..., pN)
for subpats.each |&subpat| {
for subpats.eachi |i, &subpat| {
let subpat_ty = self.pat_ty(subpat); // see (*)
let subcmt = self.cat_imm_interior(pat, cmt, subpat_ty,
interior_tuple);
let subcmt =
self.cat_imm_interior(
pat, cmt, subpat_ty,
InteriorField(PositionalField(i)));
self.cat_pattern(subcmt, subpat, op);
}
}
@ -931,22 +961,37 @@ pub impl mem_categorization_ctxt {
fn cmt_to_str(&self, cmt: cmt) -> ~str {
match cmt.cat {
cat_static_item => ~"static item",
cat_implicit_self => ~"self reference",
cat_static_item => {
~"static item"
}
cat_implicit_self => {
~"self reference"
}
cat_copied_upvar(_) => {
~"captured outer variable in a heap closure"
}
cat_rvalue => ~"non-lvalue",
cat_local(_) => ~"local variable",
cat_self(_) => ~"self value",
cat_arg(*) => ~"argument",
cat_deref(_, _, pk) => fmt!("dereference of %s pointer",
ptr_sigil(pk)),
cat_interior(_, interior_field(*)) => ~"field",
cat_interior(_, interior_tuple) => ~"tuple content",
cat_interior(_, interior_anon_field) => ~"anonymous field",
cat_interior(_, interior_variant(_)) => ~"enum content",
cat_interior(_, interior_index(t, _)) => {
cat_rvalue => {
~"non-lvalue"
}
cat_local(_) => {
~"local variable"
}
cat_self(_) => {
~"self value"
}
cat_arg(*) => {
~"argument"
}
cat_deref(_, _, pk) => {
fmt!("dereference of %s pointer", ptr_sigil(pk))
}
cat_interior(_, InteriorField(NamedField(_))) => {
~"field"
}
cat_interior(_, InteriorField(PositionalField(_))) => {
~"anonymous field"
}
cat_interior(_, InteriorElement(t)) => {
match ty::get(t).sty {
ty::ty_evec(*) => ~"vec content",
ty::ty_estr(*) => ~"str content",
@ -959,6 +1004,9 @@ pub impl mem_categorization_ctxt {
cat_discr(cmt, _) => {
self.cmt_to_str(cmt)
}
cat_downcast(cmt) => {
self.cmt_to_str(cmt)
}
}
}
@ -1027,6 +1075,7 @@ pub impl cmt_ {
cat_deref(_, _, region_ptr(*)) => {
self
}
cat_downcast(b) |
cat_stack_upvar(b) |
cat_discr(b, _) |
cat_interior(b, _) |
@ -1075,6 +1124,7 @@ pub impl cmt_ {
Some(AliasableBorrowed(m))
}
cat_downcast(b) |
cat_stack_upvar(b) |
cat_deref(b, _, uniq_ptr(*)) |
cat_interior(b, _) |
@ -1114,6 +1164,9 @@ impl Repr for categorization {
cmt.cat.repr(tcx),
interior.repr(tcx))
}
cat_downcast(cmt) => {
fmt!("%s->(enum)", cmt.cat.repr(tcx))
}
cat_stack_upvar(cmt) |
cat_discr(cmt, _) => cmt.cat.repr(tcx)
}
@ -1129,14 +1182,12 @@ pub fn ptr_sigil(ptr: ptr_kind) -> ~str {
}
}
impl Repr for interior_kind {
impl Repr for InteriorKind {
fn repr(&self, tcx: ty::ctxt) -> ~str {
match *self {
interior_field(fld) => copy *tcx.sess.str_of(fld),
interior_index(*) => ~"[]",
interior_tuple => ~"()",
interior_anon_field => ~"<anonymous field>",
interior_variant(_) => ~"<enum>"
InteriorField(NamedField(fld)) => copy *tcx.sess.str_of(fld),
InteriorField(PositionalField(i)) => fmt!("#%?", i),
InteriorElement(_) => ~"[]",
}
}
}

37
src/test/compile-fail/borrowck-anon-fields-struct.rs Normal file
View file

@ -0,0 +1,37 @@
// Tests that we are able to distinguish when loans borrow different
// anonymous fields of an tuple vs the same anonymous field.
struct Y(uint, uint);
fn distinct_variant() {
let mut y = Y(1, 2);
let a = match y {
Y(ref mut a, _) => a
};
let b = match y {
Y(_, ref mut b) => b
};
*a += 1;
*b += 1;
}
fn same_variant() {
let mut y = Y(1, 2);
let a = match y {
Y(ref mut a, _) => a
};
let b = match y {
Y(ref mut b, _) => b //~ ERROR cannot borrow
};
*a += 1;
*b += 1;
}
fn main() {
}

35
src/test/compile-fail/borrowck-anon-fields-tuple.rs Normal file
View file

@ -0,0 +1,35 @@
// Tests that we are able to distinguish when loans borrow different
// anonymous fields of a tuple vs the same anonymous field.
fn distinct_variant() {
let mut y = (1, 2);
let a = match y {
(ref mut a, _) => a
};
let b = match y {
(_, ref mut b) => b
};
*a += 1;
*b += 1;
}
fn same_variant() {
let mut y = (1, 2);
let a = match y {
(ref mut a, _) => a
};
let b = match y {
(ref mut b, _) => b //~ ERROR cannot borrow
};
*a += 1;
*b += 1;
}
fn main() {
}

43
src/test/compile-fail/borrowck-anon-fields-variant.rs Normal file
View file

@ -0,0 +1,43 @@
// Tests that we are able to distinguish when loans borrow different
// anonymous fields of an enum variant vs the same anonymous field.
enum Foo {
X, Y(uint, uint)
}
fn distinct_variant() {
let mut y = Y(1, 2);
let a = match y {
Y(ref mut a, _) => a,
X => fail!()
};
let b = match y {
Y(_, ref mut b) => b,
X => fail!()
};
*a += 1;
*b += 1;
}
fn same_variant() {
let mut y = Y(1, 2);
let a = match y {
Y(ref mut a, _) => a,
X => fail!()
};
let b = match y {
Y(ref mut b, _) => b, //~ ERROR cannot borrow
X => fail!()
};
*a += 1;
*b += 1;
}
fn main() {
}