From 20679b11662908315bc2600b5103f60103a4b0ae Mon Sep 17 00:00:00 2001 From: Michael Goulet Date: Sat, 25 Mar 2023 23:34:49 +0000 Subject: [PATCH 1/2] Still-further-specializable projections are ambiguous --- .../src/solve/project_goals.rs | 2 +- .../specialization-unconstrained.rs | 22 ++++++++++++++++ .../specialization-unconstrained.stderr | 25 +++++++++++++++++++ 3 files changed, 48 insertions(+), 1 deletion(-) create mode 100644 tests/ui/traits/new-solver/specialization-unconstrained.rs create mode 100644 tests/ui/traits/new-solver/specialization-unconstrained.stderr diff --git a/compiler/rustc_trait_selection/src/solve/project_goals.rs b/compiler/rustc_trait_selection/src/solve/project_goals.rs index 525b3105538d0..14c5b83c6ca72 100644 --- a/compiler/rustc_trait_selection/src/solve/project_goals.rs +++ b/compiler/rustc_trait_selection/src/solve/project_goals.rs @@ -174,7 +174,7 @@ impl<'tcx> assembly::GoalKind<'tcx> for ProjectionPredicate<'tcx> { goal.predicate.def_id(), impl_def_id )? else { - return ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes); + return ecx.evaluate_added_goals_and_make_canonical_response(Certainty::AMBIGUOUS); }; if !assoc_def.item.defaultness(tcx).has_value() { diff --git a/tests/ui/traits/new-solver/specialization-unconstrained.rs b/tests/ui/traits/new-solver/specialization-unconstrained.rs new file mode 100644 index 0000000000000..02150689ee5c3 --- /dev/null +++ b/tests/ui/traits/new-solver/specialization-unconstrained.rs @@ -0,0 +1,22 @@ +// compile-flags: -Ztrait-solver=next + +#![feature(specialization)] +//~^ WARN the feature `specialization` is incomplete + +// Do not treat the RHS of a projection-goal as an unconstrained `Certainty::Yes` response +// if the impl is still further specializable. + +trait Default { + type Id; +} + +impl Default for T { + default type Id = T; +} + +fn test, U>() {} + +fn main() { + test::(); + //~^ ERROR cannot satisfy `::Id == ()` +} diff --git a/tests/ui/traits/new-solver/specialization-unconstrained.stderr b/tests/ui/traits/new-solver/specialization-unconstrained.stderr new file mode 100644 index 0000000000000..910925cbaeb0d --- /dev/null +++ b/tests/ui/traits/new-solver/specialization-unconstrained.stderr @@ -0,0 +1,25 @@ +warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes + --> $DIR/specialization-unconstrained.rs:3:12 + | +LL | #![feature(specialization)] + | ^^^^^^^^^^^^^^ + | + = note: see issue #31844 for more information + = help: consider using `min_specialization` instead, which is more stable and complete + = note: `#[warn(incomplete_features)]` on by default + +error[E0284]: type annotations needed: cannot satisfy `::Id == ()` + --> $DIR/specialization-unconstrained.rs:20:5 + | +LL | test::(); + | ^^^^^^^^^^^^^^^ cannot satisfy `::Id == ()` + | +note: required by a bound in `test` + --> $DIR/specialization-unconstrained.rs:17:20 + | +LL | fn test, U>() {} + | ^^^^^^ required by this bound in `test` + +error: aborting due to previous error; 1 warning emitted + +For more information about this error, try `rustc --explain E0284`. From 3310f72db9205d23f7900d85055c5cd0eec17814 Mon Sep 17 00:00:00 2001 From: Michael Goulet Date: Sun, 26 Mar 2023 00:02:24 +0000 Subject: [PATCH 2/2] transmute test --- compiler/rustc_middle/src/ty/mod.rs | 4 +-- .../new-solver/specialization-transmute.rs | 30 ++++++++++++++++++ .../specialization-transmute.stderr | 31 +++++++++++++++++++ 3 files changed, 63 insertions(+), 2 deletions(-) create mode 100644 tests/ui/traits/new-solver/specialization-transmute.rs create mode 100644 tests/ui/traits/new-solver/specialization-transmute.stderr diff --git a/compiler/rustc_middle/src/ty/mod.rs b/compiler/rustc_middle/src/ty/mod.rs index e3cd5cca785aa..c6a56df5a5eee 100644 --- a/compiler/rustc_middle/src/ty/mod.rs +++ b/compiler/rustc_middle/src/ty/mod.rs @@ -653,8 +653,8 @@ pub enum AliasRelationDirection { impl std::fmt::Display for AliasRelationDirection { fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result { match self { - AliasRelationDirection::Equate => write!(f, " == "), - AliasRelationDirection::Subtype => write!(f, " <: "), + AliasRelationDirection::Equate => write!(f, "=="), + AliasRelationDirection::Subtype => write!(f, "<:"), } } } diff --git a/tests/ui/traits/new-solver/specialization-transmute.rs b/tests/ui/traits/new-solver/specialization-transmute.rs new file mode 100644 index 0000000000000..a54701df4ef7e --- /dev/null +++ b/tests/ui/traits/new-solver/specialization-transmute.rs @@ -0,0 +1,30 @@ +// compile-flags: -Ztrait-solver=next + +#![feature(specialization)] +//~^ WARN the feature `specialization` is incomplete + +trait Default { + type Id; + + fn intu(&self) -> &Self::Id; +} + +impl Default for T { + default type Id = T; + + fn intu(&self) -> &Self::Id { + self + //~^ ERROR cannot satisfy `T <: ::Id` + } +} + +fn transmute, U: Copy>(t: T) -> U { + *t.intu() +} + +use std::num::NonZeroU8; +fn main() { + let s = transmute::>(0); + //~^ ERROR cannot satisfy `::Id == Option + assert_eq!(s, None); +} diff --git a/tests/ui/traits/new-solver/specialization-transmute.stderr b/tests/ui/traits/new-solver/specialization-transmute.stderr new file mode 100644 index 0000000000000..e67c56afc0d0c --- /dev/null +++ b/tests/ui/traits/new-solver/specialization-transmute.stderr @@ -0,0 +1,31 @@ +warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes + --> $DIR/specialization-transmute.rs:3:12 + | +LL | #![feature(specialization)] + | ^^^^^^^^^^^^^^ + | + = note: see issue #31844 for more information + = help: consider using `min_specialization` instead, which is more stable and complete + = note: `#[warn(incomplete_features)]` on by default + +error[E0284]: type annotations needed: cannot satisfy `T <: ::Id` + --> $DIR/specialization-transmute.rs:16:9 + | +LL | self + | ^^^^ cannot satisfy `T <: ::Id` + +error[E0284]: type annotations needed: cannot satisfy `::Id == Option` + --> $DIR/specialization-transmute.rs:27:13 + | +LL | let s = transmute::>(0); + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot satisfy `::Id == Option` + | +note: required by a bound in `transmute` + --> $DIR/specialization-transmute.rs:21:25 + | +LL | fn transmute, U: Copy>(t: T) -> U { + | ^^^^^^ required by this bound in `transmute` + +error: aborting due to 2 previous errors; 1 warning emitted + +For more information about this error, try `rustc --explain E0284`.