Auto merge of #69145 - matthewjasper:mir-typeck-static-ty, r=nikomatsakis
Fix MIR typeck soundness holes * Check types of static items * Always check lifetime bounds of `Copy` impls r? @nikomatsakis closes #69114
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bfb96048b5
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@ -313,6 +313,7 @@ impl<'a, 'b, 'tcx> Visitor<'tcx> for TypeVerifier<'a, 'b, 'tcx> {
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);
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}
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} else {
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let tcx = self.tcx();
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if let ty::ConstKind::Unevaluated(def_id, substs, promoted) = constant.literal.val {
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if let Some(promoted) = promoted {
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let check_err = |verifier: &mut TypeVerifier<'a, 'b, 'tcx>,
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@ -362,10 +363,23 @@ impl<'a, 'b, 'tcx> Visitor<'tcx> for TypeVerifier<'a, 'b, 'tcx> {
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);
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}
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}
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}
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if let ty::FnDef(def_id, substs) = constant.literal.ty.kind {
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let tcx = self.tcx();
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} else if let Some(static_def_id) = constant.check_static_ptr(tcx) {
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let unnormalized_ty = tcx.type_of(static_def_id);
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let locations = location.to_locations();
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let normalized_ty = self.cx.normalize(unnormalized_ty, locations);
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let literal_ty = constant.literal.ty.builtin_deref(true).unwrap().ty;
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if let Err(terr) = self.cx.eq_types(
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normalized_ty,
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literal_ty,
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locations,
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ConstraintCategory::Boring,
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) {
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span_mirbug!(self, constant, "bad static type {:?} ({:?})", constant, terr);
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}
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}
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if let ty::FnDef(def_id, substs) = constant.literal.ty.kind {
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let instantiated_predicates = tcx.predicates_of(def_id).instantiate(tcx, substs);
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self.cx.normalize_and_prove_instantiated_predicates(
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instantiated_predicates,
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@ -470,33 +484,6 @@ impl<'a, 'b, 'tcx> TypeVerifier<'a, 'b, 'tcx> {
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let mut place_ty = PlaceTy::from_ty(self.body.local_decls[place.local].ty);
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if place.projection.is_empty() {
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if let PlaceContext::NonMutatingUse(NonMutatingUseContext::Copy) = context {
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let tcx = self.tcx();
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let trait_ref = ty::TraitRef {
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def_id: tcx.lang_items().copy_trait().unwrap(),
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substs: tcx.mk_substs_trait(place_ty.ty, &[]),
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};
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// To have a `Copy` operand, the type `T` of the
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// value must be `Copy`. Note that we prove that `T: Copy`,
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// rather than using the `is_copy_modulo_regions`
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// test. This is important because
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// `is_copy_modulo_regions` ignores the resulting region
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// obligations and assumes they pass. This can result in
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// bounds from `Copy` impls being unsoundly ignored (e.g.,
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// #29149). Note that we decide to use `Copy` before knowing
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// whether the bounds fully apply: in effect, the rule is
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// that if a value of some type could implement `Copy`, then
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// it must.
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self.cx.prove_trait_ref(
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trait_ref,
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location.to_locations(),
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ConstraintCategory::CopyBound,
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);
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}
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}
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for elem in place.projection.iter() {
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if place_ty.variant_index.is_none() {
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if place_ty.ty.references_error() {
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@ -507,6 +494,31 @@ impl<'a, 'b, 'tcx> TypeVerifier<'a, 'b, 'tcx> {
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place_ty = self.sanitize_projection(place_ty, elem, place, location)
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}
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if let PlaceContext::NonMutatingUse(NonMutatingUseContext::Copy) = context {
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let tcx = self.tcx();
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let trait_ref = ty::TraitRef {
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def_id: tcx.lang_items().copy_trait().unwrap(),
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substs: tcx.mk_substs_trait(place_ty.ty, &[]),
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};
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// To have a `Copy` operand, the type `T` of the
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// value must be `Copy`. Note that we prove that `T: Copy`,
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// rather than using the `is_copy_modulo_regions`
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// test. This is important because
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// `is_copy_modulo_regions` ignores the resulting region
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// obligations and assumes they pass. This can result in
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// bounds from `Copy` impls being unsoundly ignored (e.g.,
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// #29149). Note that we decide to use `Copy` before knowing
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// whether the bounds fully apply: in effect, the rule is
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// that if a value of some type could implement `Copy`, then
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// it must.
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self.cx.prove_trait_ref(
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trait_ref,
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location.to_locations(),
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ConstraintCategory::CopyBound,
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);
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}
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place_ty
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}
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@ -0,0 +1,12 @@
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// Test that the 'static bound from the Copy impl is respected. Regression test for #29149.
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#[derive(Clone)]
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struct Foo<'a>(&'a u32);
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impl Copy for Foo<'static> {}
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fn main() {
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let s = 2;
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let a = (Foo(&s),); //~ ERROR `s` does not live long enough [E0597]
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drop(a.0);
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drop(a.0);
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}
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@ -0,0 +1,14 @@
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error[E0597]: `s` does not live long enough
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--> $DIR/do-not-ignore-lifetime-bounds-in-copy-proj.rs:9:18
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LL | let a = (Foo(&s),);
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| ^^ borrowed value does not live long enough
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LL | drop(a.0);
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| --- copying this value requires that `s` is borrowed for `'static`
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LL | drop(a.0);
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LL | }
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| - `s` dropped here while still borrowed
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error: aborting due to previous error
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For more information about this error, try `rustc --explain E0597`.
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@ -0,0 +1,30 @@
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// Check that borrowck ensures that `static mut` items have the expected type.
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static FOO: u8 = 42;
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static mut BAR: &'static u8 = &FOO;
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static mut BAR_ELIDED: &u8 = &FOO;
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fn main() {
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unsafe {
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println!("{} {}", BAR, BAR_ELIDED);
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set_bar();
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set_bar_elided();
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println!("{} {}", BAR, BAR_ELIDED);
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}
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}
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fn set_bar() {
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let n = 42;
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unsafe {
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BAR = &n;
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//~^ ERROR does not live long enough
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}
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}
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fn set_bar_elided() {
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let n = 42;
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unsafe {
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BAR_ELIDED = &n;
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//~^ ERROR does not live long enough
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}
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}
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@ -0,0 +1,27 @@
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error[E0597]: `n` does not live long enough
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--> $DIR/issue-69114-static-mut-ty.rs:19:15
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LL | BAR = &n;
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| ------^^
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| | |
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| | borrowed value does not live long enough
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| assignment requires that `n` is borrowed for `'static`
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...
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LL | }
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| - `n` dropped here while still borrowed
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error[E0597]: `n` does not live long enough
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--> $DIR/issue-69114-static-mut-ty.rs:27:22
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LL | BAR_ELIDED = &n;
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| -------------^^
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| | |
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| | borrowed value does not live long enough
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| assignment requires that `n` is borrowed for `'static`
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...
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LL | }
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| - `n` dropped here while still borrowed
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error: aborting due to 2 previous errors
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For more information about this error, try `rustc --explain E0597`.
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@ -0,0 +1,9 @@
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// 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() {
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let n = 42;
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FOO(&n);
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//~^ ERROR does not live long enough
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}
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@ -0,0 +1,15 @@
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error[E0597]: `n` does not live long enough
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--> $DIR/issue-69114-static-ty.rs:7:9
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LL | FOO(&n);
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| ----^^-
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| | |
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| | borrowed value does not live long enough
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| argument requires that `n` is borrowed for `'static`
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LL |
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LL | }
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| - `n` dropped here while still borrowed
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error: aborting due to previous error
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For more information about this error, try `rustc --explain E0597`.
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