From e7ca6e1b47ce31ad544cd8f0eb7e5cd47b325e63 Mon Sep 17 00:00:00 2001 From: Jack Huey <31162821+jackh726@users.noreply.github.com> Date: Tue, 30 Aug 2022 21:50:22 -0400 Subject: [PATCH] Use Predicate ConstraintCategory when normalizing --- .../rustc_borrowck/src/constraints/mod.rs | 5 +-- .../src/diagnostics/region_errors.rs | 20 +++++++--- .../src/type_check/canonical.rs | 22 ++++++++-- compiler/rustc_borrowck/src/type_check/mod.rs | 4 ++ .../src/traits/query/normalize.rs | 3 +- .../bugs/hrtb-implied-2.rs | 40 +++++++++++++++++++ .../bugs/hrtb-implied-2.stderr | 22 ++++++++++ .../bugs/hrtb-implied-3.rs | 23 +++++++++++ .../bugs/hrtb-implied-3.stderr | 22 ++++++++++ .../trait-objects.extended.stderr | 2 + .../hrtb-just-for-static.stderr | 6 +++ .../hrtb-perfect-forwarding.stderr | 6 +++ src/test/ui/issues/issue-26217.stderr | 6 +++ src/test/ui/nll/type-test-universe.stderr | 6 +++ 14 files changed, 172 insertions(+), 15 deletions(-) create mode 100644 src/test/ui/generic-associated-types/bugs/hrtb-implied-2.rs create mode 100644 src/test/ui/generic-associated-types/bugs/hrtb-implied-2.stderr create mode 100644 src/test/ui/generic-associated-types/bugs/hrtb-implied-3.rs create mode 100644 src/test/ui/generic-associated-types/bugs/hrtb-implied-3.stderr diff --git a/compiler/rustc_borrowck/src/constraints/mod.rs b/compiler/rustc_borrowck/src/constraints/mod.rs index 6d323b03cdaa3..df04128135b89 100644 --- a/compiler/rustc_borrowck/src/constraints/mod.rs +++ b/compiler/rustc_borrowck/src/constraints/mod.rs @@ -21,10 +21,7 @@ pub(crate) struct OutlivesConstraintSet<'tcx> { impl<'tcx> OutlivesConstraintSet<'tcx> { pub(crate) fn push(&mut self, constraint: OutlivesConstraint<'tcx>) { - debug!( - "OutlivesConstraintSet::push({:?}: {:?} @ {:?}", - constraint.sup, constraint.sub, constraint.locations - ); + debug!("OutlivesConstraintSet::push({:?})", constraint); if constraint.sup == constraint.sub { // 'a: 'a is pretty uninteresting return; diff --git a/compiler/rustc_borrowck/src/diagnostics/region_errors.rs b/compiler/rustc_borrowck/src/diagnostics/region_errors.rs index c276719c227b0..34be2874fcb73 100644 --- a/compiler/rustc_borrowck/src/diagnostics/region_errors.rs +++ b/compiler/rustc_borrowck/src/diagnostics/region_errors.rs @@ -31,7 +31,7 @@ use crate::session_diagnostics::{ }; use super::{OutlivesSuggestionBuilder, RegionName}; -use crate::region_infer::BlameConstraint; +use crate::region_infer::{BlameConstraint, ExtraConstraintInfo}; use crate::{ nll::ConstraintDescription, region_infer::{values::RegionElement, TypeTest}, @@ -354,12 +354,11 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> { ) { debug!("report_region_error(fr={:?}, outlived_fr={:?})", fr, outlived_fr); - let BlameConstraint { category, cause, variance_info, .. } = self - .regioncx - .best_blame_constraint(fr, fr_origin, |r| { + let (blame_constraint, extra_info) = + self.regioncx.best_blame_constraint(fr, fr_origin, |r| { self.regioncx.provides_universal_region(r, fr, outlived_fr) - }) - .0; + }); + let BlameConstraint { category, cause, variance_info, .. } = blame_constraint; debug!("report_region_error: category={:?} {:?} {:?}", category, cause, variance_info); @@ -468,6 +467,14 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> { } } + for extra in extra_info { + match extra { + ExtraConstraintInfo::PlaceholderFromPredicate(span) => { + diag.span_note(span, format!("due to current limitations in the borrow checker, this implies a `'static` lifetime")); + } + } + } + self.buffer_error(diag); } @@ -559,6 +566,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> { /// LL | ref_obj(x) /// | ^^^^^^^^^^ `x` escapes the function body here /// ``` + #[instrument(level = "debug", skip(self))] fn report_escaping_data_error( &self, errci: &ErrorConstraintInfo<'tcx>, diff --git a/compiler/rustc_borrowck/src/type_check/canonical.rs b/compiler/rustc_borrowck/src/type_check/canonical.rs index 8a3972a12c543..9271a2f4dc718 100644 --- a/compiler/rustc_borrowck/src/type_check/canonical.rs +++ b/compiler/rustc_borrowck/src/type_check/canonical.rs @@ -104,6 +104,7 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> { ); } + #[instrument(level = "debug", skip(self))] pub(super) fn normalize_and_prove_instantiated_predicates( &mut self, // Keep this parameter for now, in case we start using @@ -118,8 +119,9 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> { .zip(instantiated_predicates.spans.into_iter()) { debug!(?predicate); - let predicate = self.normalize(predicate, locations); - self.prove_predicate(predicate, locations, ConstraintCategory::Predicate(span)); + let category = ConstraintCategory::Predicate(span); + let predicate = self.normalize_with_category(predicate, locations, category); + self.prove_predicate(predicate, locations, category); } } @@ -155,15 +157,27 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> { }) } - #[instrument(skip(self), level = "debug")] pub(super) fn normalize(&mut self, value: T, location: impl NormalizeLocation) -> T + where + T: type_op::normalize::Normalizable<'tcx> + fmt::Display + Copy + 'tcx, + { + self.normalize_with_category(value, location, ConstraintCategory::Boring) + } + + #[instrument(skip(self), level = "debug")] + pub(super) fn normalize_with_category( + &mut self, + value: T, + location: impl NormalizeLocation, + category: ConstraintCategory<'tcx>, + ) -> T where T: type_op::normalize::Normalizable<'tcx> + fmt::Display + Copy + 'tcx, { let param_env = self.param_env; self.fully_perform_op( location.to_locations(), - ConstraintCategory::Boring, + category, param_env.and(type_op::normalize::Normalize::new(value)), ) .unwrap_or_else(|NoSolution| { diff --git a/compiler/rustc_borrowck/src/type_check/mod.rs b/compiler/rustc_borrowck/src/type_check/mod.rs index 5f714cf723ba2..f41d70d384d8b 100644 --- a/compiler/rustc_borrowck/src/type_check/mod.rs +++ b/compiler/rustc_borrowck/src/type_check/mod.rs @@ -312,6 +312,8 @@ impl<'a, 'b, 'tcx> Visitor<'tcx> for TypeVerifier<'a, 'b, 'tcx> { } fn visit_constant(&mut self, constant: &Constant<'tcx>, location: Location) { + debug!(?constant, ?location, "visit_constant"); + self.super_constant(constant, location); let ty = self.sanitize_type(constant, constant.literal.ty()); @@ -1811,6 +1813,8 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> { } fn check_operand(&mut self, op: &Operand<'tcx>, location: Location) { + debug!(?op, ?location, "check_operand"); + if let Operand::Constant(constant) = op { let maybe_uneval = match constant.literal { ConstantKind::Ty(ct) => match ct.kind() { diff --git a/compiler/rustc_trait_selection/src/traits/query/normalize.rs b/compiler/rustc_trait_selection/src/traits/query/normalize.rs index f65fc5bad0d91..a3f8f4e2ed0ed 100644 --- a/compiler/rustc_trait_selection/src/traits/query/normalize.rs +++ b/compiler/rustc_trait_selection/src/traits/query/normalize.rs @@ -48,10 +48,11 @@ impl<'cx, 'tcx> AtExt<'tcx> for At<'cx, 'tcx> { T: TypeFoldable<'tcx>, { debug!( - "normalize::<{}>(value={:?}, param_env={:?})", + "normalize::<{}>(value={:?}, param_env={:?}, cause={:?})", std::any::type_name::(), value, self.param_env, + self.cause, ); if !needs_normalization(&value, self.param_env.reveal()) { return Ok(Normalized { value, obligations: vec![] }); diff --git a/src/test/ui/generic-associated-types/bugs/hrtb-implied-2.rs b/src/test/ui/generic-associated-types/bugs/hrtb-implied-2.rs new file mode 100644 index 0000000000000..8e6c5348e71ca --- /dev/null +++ b/src/test/ui/generic-associated-types/bugs/hrtb-implied-2.rs @@ -0,0 +1,40 @@ +// check-fail +// known-bug + +// This gives us problems because `for<'a> I::Item<'a>: Debug` should mean "for +// all 'a where I::Item<'a> is WF", but really means "for all 'a possible" + +trait LendingIterator: Sized { + type Item<'a> + where + Self: 'a; + fn next(&mut self) -> Self::Item<'_>; +} +fn fails(iter: &mut I, f: F) -> bool +where + F: FnMut(I::Item<'_>), +{ + let mut iter2 = Eat(iter, f); + let _next = iter2.next(); + //~^ borrowed data escapes + true +} +impl LendingIterator for &mut I { + type Item<'a> = I::Item<'a> where Self:'a; + fn next(&mut self) -> Self::Item<'_> { + (**self).next() + } +} + +struct Eat(I, F); +impl Iterator for Eat +where + F: FnMut(I::Item<'_>), +{ + type Item = (); + fn next(&mut self) -> Option { + None + } +} + +fn main() {} diff --git a/src/test/ui/generic-associated-types/bugs/hrtb-implied-2.stderr b/src/test/ui/generic-associated-types/bugs/hrtb-implied-2.stderr new file mode 100644 index 0000000000000..1ee270398de4d --- /dev/null +++ b/src/test/ui/generic-associated-types/bugs/hrtb-implied-2.stderr @@ -0,0 +1,22 @@ +error[E0521]: borrowed data escapes outside of function + --> $DIR/hrtb-implied-2.rs:18:17 + | +LL | fn fails(iter: &mut I, f: F) -> bool + | ---- - let's call the lifetime of this reference `'1` + | | + | `iter` is a reference that is only valid in the function body +... +LL | let _next = iter2.next(); + | ^^^^^^^^^^^^ + | | + | `iter` escapes the function body here + | argument requires that `'1` must outlive `'static` + | + = note: requirement occurs because of a mutable reference to `Eat<&mut I, F>` + = note: mutable references are invariant over their type parameter + = help: see for more information about variance + = note: due to current limitations in the borrow checker, this implies a `'static` lifetime + +error: aborting due to previous error + +For more information about this error, try `rustc --explain E0521`. diff --git a/src/test/ui/generic-associated-types/bugs/hrtb-implied-3.rs b/src/test/ui/generic-associated-types/bugs/hrtb-implied-3.rs new file mode 100644 index 0000000000000..bc9e6c8aea85e --- /dev/null +++ b/src/test/ui/generic-associated-types/bugs/hrtb-implied-3.rs @@ -0,0 +1,23 @@ +trait LendingIterator { + type Item<'a> + where + Self: 'a; +} + +impl LendingIterator for &str { + type Item<'a> = () where Self:'a; +} + +fn trivial_bound(_: I) +where + I: LendingIterator, + for<'a> I::Item<'a>: Sized, +{ +} + +fn fails(iter: &str) { + trivial_bound(iter); + //~^ borrowed data escapes +} + +fn main() {} diff --git a/src/test/ui/generic-associated-types/bugs/hrtb-implied-3.stderr b/src/test/ui/generic-associated-types/bugs/hrtb-implied-3.stderr new file mode 100644 index 0000000000000..c67e02437cd8d --- /dev/null +++ b/src/test/ui/generic-associated-types/bugs/hrtb-implied-3.stderr @@ -0,0 +1,22 @@ +error[E0521]: borrowed data escapes outside of function + --> $DIR/hrtb-implied-3.rs:19:5 + | +LL | fn fails(iter: &str) { + | ---- - let's call the lifetime of this reference `'1` + | | + | `iter` is a reference that is only valid in the function body +LL | trivial_bound(iter); + | ^^^^^^^^^^^^^^^^^^^ + | | + | `iter` escapes the function body here + | argument requires that `'1` must outlive `'static` + | +note: due to current limitations in the borrow checker, this implies a `'static` lifetime + --> $DIR/hrtb-implied-3.rs:14:26 + | +LL | for<'a> I::Item<'a>: Sized, + | ^^^^^ + +error: aborting due to previous error + +For more information about this error, try `rustc --explain E0521`. diff --git a/src/test/ui/generic-associated-types/trait-objects.extended.stderr b/src/test/ui/generic-associated-types/trait-objects.extended.stderr index 086177cc106dc..45b64d2b02483 100644 --- a/src/test/ui/generic-associated-types/trait-objects.extended.stderr +++ b/src/test/ui/generic-associated-types/trait-objects.extended.stderr @@ -11,6 +11,8 @@ LL | x.size_hint().0 | | | `x` escapes the function body here | argument requires that `'1` must outlive `'static` + | + = note: due to current limitations in the borrow checker, this implies a `'static` lifetime error: aborting due to previous error diff --git a/src/test/ui/higher-rank-trait-bounds/hrtb-just-for-static.stderr b/src/test/ui/higher-rank-trait-bounds/hrtb-just-for-static.stderr index b4312091edb27..31e11e1283516 100644 --- a/src/test/ui/higher-rank-trait-bounds/hrtb-just-for-static.stderr +++ b/src/test/ui/higher-rank-trait-bounds/hrtb-just-for-static.stderr @@ -14,6 +14,12 @@ LL | fn give_some<'a>() { | -- lifetime `'a` defined here LL | want_hrtb::<&'a u32>() | ^^^^^^^^^^^^^^^^^^^^ requires that `'a` must outlive `'static` + | +note: due to current limitations in the borrow checker, this implies a `'static` lifetime + --> $DIR/hrtb-just-for-static.rs:9:15 + | +LL | where T : for<'a> Foo<&'a isize> + | ^^^^^^^^^^^^^^^^^^^^^^ error: implementation of `Foo` is not general enough --> $DIR/hrtb-just-for-static.rs:30:5 diff --git a/src/test/ui/higher-rank-trait-bounds/hrtb-perfect-forwarding.stderr b/src/test/ui/higher-rank-trait-bounds/hrtb-perfect-forwarding.stderr index 1461e7fd2ddd7..5e75a4cc8afa5 100644 --- a/src/test/ui/higher-rank-trait-bounds/hrtb-perfect-forwarding.stderr +++ b/src/test/ui/higher-rank-trait-bounds/hrtb-perfect-forwarding.stderr @@ -46,6 +46,12 @@ LL | fn foo_hrtb_bar_not<'b, T>(mut t: T) ... LL | foo_hrtb_bar_not(&mut t); | ^^^^^^^^^^^^^^^^^^^^^^^^ requires that `'b` must outlive `'static` + | +note: due to current limitations in the borrow checker, this implies a `'static` lifetime + --> $DIR/hrtb-perfect-forwarding.rs:37:8 + | +LL | T: for<'a> Foo<&'a isize> + Bar<&'b isize>, + | ^^^^^^^^^^^^^^^^^^^^^^ error: implementation of `Bar` is not general enough --> $DIR/hrtb-perfect-forwarding.rs:43:5 diff --git a/src/test/ui/issues/issue-26217.stderr b/src/test/ui/issues/issue-26217.stderr index c7601caacdca3..73c772205c3da 100644 --- a/src/test/ui/issues/issue-26217.stderr +++ b/src/test/ui/issues/issue-26217.stderr @@ -5,6 +5,12 @@ LL | fn bar<'a>() { | -- lifetime `'a` defined here LL | foo::<&'a i32>(); | ^^^^^^^^^^^^^^ requires that `'a` must outlive `'static` + | +note: due to current limitations in the borrow checker, this implies a `'static` lifetime + --> $DIR/issue-26217.rs:1:30 + | +LL | fn foo() where for<'a> T: 'a {} + | ^^ error: aborting due to previous error diff --git a/src/test/ui/nll/type-test-universe.stderr b/src/test/ui/nll/type-test-universe.stderr index 242486c360a80..31e17d64b8caf 100644 --- a/src/test/ui/nll/type-test-universe.stderr +++ b/src/test/ui/nll/type-test-universe.stderr @@ -11,6 +11,12 @@ LL | fn test2<'a>() { | -- lifetime `'a` defined here LL | outlives_forall::>(); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ requires that `'a` must outlive `'static` + | +note: due to current limitations in the borrow checker, this implies a `'static` lifetime + --> $DIR/type-test-universe.rs:6:16 + | +LL | for<'u> T: 'u, + | ^^ error: aborting due to 2 previous errors