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Fix MIR typeck soundness holes #69145
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Original file line number | Diff line number | Diff line change |
---|---|---|
|
@@ -309,6 +309,7 @@ impl<'a, 'b, 'tcx> Visitor<'tcx> for TypeVerifier<'a, 'b, 'tcx> { | |
); | ||
} | ||
} else { | ||
let tcx = self.tcx(); | ||
if let ty::ConstKind::Unevaluated(def_id, substs, promoted) = constant.literal.val { | ||
if let Some(promoted) = promoted { | ||
let check_err = |verifier: &mut TypeVerifier<'a, 'b, 'tcx>, | ||
|
@@ -358,10 +359,23 @@ impl<'a, 'b, 'tcx> Visitor<'tcx> for TypeVerifier<'a, 'b, 'tcx> { | |
); | ||
} | ||
} | ||
} else if let Some(static_def_id) = constant.check_static_ptr(tcx) { | ||
let unnormalized_ty = tcx.type_of(static_def_id); | ||
let locations = location.to_locations(); | ||
let normalized_ty = self.cx.normalize(unnormalized_ty, locations); | ||
let literal_ty = constant.literal.ty.builtin_deref(true).unwrap().ty; | ||
|
||
if let Err(terr) = self.cx.eq_types( | ||
normalized_ty, | ||
literal_ty, | ||
locations, | ||
ConstraintCategory::Boring, | ||
) { | ||
span_mirbug!(self, constant, "bad static type {:?} ({:?})", constant, terr); | ||
} | ||
} | ||
if let ty::FnDef(def_id, substs) = constant.literal.ty.kind { | ||
let tcx = self.tcx(); | ||
|
||
if let ty::FnDef(def_id, substs) = constant.literal.ty.kind { | ||
let instantiated_predicates = tcx.predicates_of(def_id).instantiate(tcx, substs); | ||
self.cx.normalize_and_prove_instantiated_predicates( | ||
instantiated_predicates, | ||
|
@@ -466,33 +480,6 @@ impl<'a, 'b, 'tcx> TypeVerifier<'a, 'b, 'tcx> { | |
|
||
let mut place_ty = PlaceTy::from_ty(self.body.local_decls[place.local].ty); | ||
|
||
if place.projection.is_empty() { | ||
if let PlaceContext::NonMutatingUse(NonMutatingUseContext::Copy) = context { | ||
let tcx = self.tcx(); | ||
let trait_ref = ty::TraitRef { | ||
def_id: tcx.lang_items().copy_trait().unwrap(), | ||
substs: tcx.mk_substs_trait(place_ty.ty, &[]), | ||
}; | ||
|
||
// To have a `Copy` operand, the type `T` of the | ||
// value must be `Copy`. Note that we prove that `T: Copy`, | ||
// rather than using the `is_copy_modulo_regions` | ||
// test. This is important because | ||
// `is_copy_modulo_regions` ignores the resulting region | ||
// obligations and assumes they pass. This can result in | ||
// bounds from `Copy` impls being unsoundly ignored (e.g., | ||
// #29149). Note that we decide to use `Copy` before knowing | ||
// whether the bounds fully apply: in effect, the rule is | ||
// that if a value of some type could implement `Copy`, then | ||
// it must. | ||
self.cx.prove_trait_ref( | ||
trait_ref, | ||
location.to_locations(), | ||
ConstraintCategory::CopyBound, | ||
); | ||
} | ||
} | ||
|
||
for elem in place.projection.iter() { | ||
if place_ty.variant_index.is_none() { | ||
if place_ty.ty.references_error() { | ||
|
@@ -503,6 +490,31 @@ impl<'a, 'b, 'tcx> TypeVerifier<'a, 'b, 'tcx> { | |
place_ty = self.sanitize_projection(place_ty, elem, place, location) | ||
} | ||
|
||
if let PlaceContext::NonMutatingUse(NonMutatingUseContext::Copy) = context { | ||
There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more. The main change here is that we now do this for all places, right? I wonder why we didn't before? That just seems like a silly oversight to me. There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more. yes |
||
let tcx = self.tcx(); | ||
let trait_ref = ty::TraitRef { | ||
def_id: tcx.lang_items().copy_trait().unwrap(), | ||
substs: tcx.mk_substs_trait(place_ty.ty, &[]), | ||
}; | ||
|
||
// To have a `Copy` operand, the type `T` of the | ||
// value must be `Copy`. Note that we prove that `T: Copy`, | ||
// rather than using the `is_copy_modulo_regions` | ||
// test. This is important because | ||
// `is_copy_modulo_regions` ignores the resulting region | ||
// obligations and assumes they pass. This can result in | ||
// bounds from `Copy` impls being unsoundly ignored (e.g., | ||
// #29149). Note that we decide to use `Copy` before knowing | ||
// whether the bounds fully apply: in effect, the rule is | ||
// that if a value of some type could implement `Copy`, then | ||
// it must. | ||
self.cx.prove_trait_ref( | ||
trait_ref, | ||
location.to_locations(), | ||
ConstraintCategory::CopyBound, | ||
); | ||
} | ||
|
||
place_ty | ||
} | ||
|
||
|
12 changes: 12 additions & 0 deletions
12
src/test/ui/nll/do-not-ignore-lifetime-bounds-in-copy-proj.rs
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@@ -0,0 +1,12 @@ | ||
// Test that the 'static bound from the Copy impl is respected. Regression test for #29149. | ||
|
||
#[derive(Clone)] | ||
struct Foo<'a>(&'a u32); | ||
impl Copy for Foo<'static> {} | ||
|
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fn main() { | ||
let s = 2; | ||
let a = (Foo(&s),); //~ ERROR `s` does not live long enough [E0597] | ||
drop(a.0); | ||
drop(a.0); | ||
} |
14 changes: 14 additions & 0 deletions
14
src/test/ui/nll/do-not-ignore-lifetime-bounds-in-copy-proj.stderr
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@@ -0,0 +1,14 @@ | ||
error[E0597]: `s` does not live long enough | ||
--> $DIR/do-not-ignore-lifetime-bounds-in-copy-proj.rs:9:18 | ||
| | ||
LL | let a = (Foo(&s),); | ||
| ^^ borrowed value does not live long enough | ||
LL | drop(a.0); | ||
| --- copying this value requires that `s` is borrowed for `'static` | ||
LL | drop(a.0); | ||
LL | } | ||
| - `s` dropped here while still borrowed | ||
|
||
error: aborting due to previous error | ||
|
||
For more information about this error, try `rustc --explain E0597`. |
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Original file line number | Diff line number | Diff line change |
---|---|---|
@@ -0,0 +1,30 @@ | ||
// Check that borrowck ensures that `static mut` items have the expected type. | ||
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static FOO: u8 = 42; | ||
static mut BAR: &'static u8 = &FOO; | ||
static mut BAR_ELIDED: &u8 = &FOO; | ||
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fn main() { | ||
unsafe { | ||
println!("{} {}", BAR, BAR_ELIDED); | ||
set_bar(); | ||
set_bar_elided(); | ||
println!("{} {}", BAR, BAR_ELIDED); | ||
} | ||
} | ||
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fn set_bar() { | ||
let n = 42; | ||
unsafe { | ||
BAR = &n; | ||
//~^ ERROR does not live long enough | ||
} | ||
} | ||
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fn set_bar_elided() { | ||
let n = 42; | ||
unsafe { | ||
BAR_ELIDED = &n; | ||
//~^ ERROR does not live long enough | ||
} | ||
} |
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Original file line number | Diff line number | Diff line change |
---|---|---|
@@ -0,0 +1,27 @@ | ||
error[E0597]: `n` does not live long enough | ||
--> $DIR/issue-69114-static-mut-ty.rs:19:15 | ||
| | ||
LL | BAR = &n; | ||
| ------^^ | ||
| | | | ||
| | borrowed value does not live long enough | ||
| assignment requires that `n` is borrowed for `'static` | ||
... | ||
LL | } | ||
| - `n` dropped here while still borrowed | ||
|
||
error[E0597]: `n` does not live long enough | ||
--> $DIR/issue-69114-static-mut-ty.rs:27:22 | ||
| | ||
LL | BAR_ELIDED = &n; | ||
| -------------^^ | ||
| | | | ||
| | borrowed value does not live long enough | ||
| assignment requires that `n` is borrowed for `'static` | ||
... | ||
LL | } | ||
| - `n` dropped here while still borrowed | ||
|
||
error: aborting due to 2 previous errors | ||
|
||
For more information about this error, try `rustc --explain E0597`. |
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@@ -0,0 +1,9 @@ | ||
// Check that borrowck ensures that `static` items have the expected type. | ||
|
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static FOO: &'static (dyn Fn(&'static u8) + Send + Sync) = &drop; | ||
|
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fn main() { | ||
let n = 42; | ||
FOO(&n); | ||
//~^ ERROR does not live long enough | ||
} |
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Original file line number | Diff line number | Diff line change |
---|---|---|
@@ -0,0 +1,15 @@ | ||
error[E0597]: `n` does not live long enough | ||
--> $DIR/issue-69114-static-ty.rs:7:9 | ||
| | ||
LL | FOO(&n); | ||
| ----^^- | ||
| | | | ||
| | borrowed value does not live long enough | ||
| argument requires that `n` is borrowed for `'static` | ||
LL | | ||
LL | } | ||
| - `n` dropped here while still borrowed | ||
|
||
error: aborting due to previous error | ||
|
||
For more information about this error, try `rustc --explain E0597`. |
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This is another thing where I don't understand why the new
static
representation doesn't result in correctness by default.There was a problem hiding this comment.
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Could MIR building inject a
UserTypeAnnotation
forstatic
references/pointers? (note that I don't want to block this PR, any fix here should be equivalent, so we can clean it up later)