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rustc_middle: Pretty-print negative bounds correctly

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This commit is contained in:
León Orell Valerian Liehr 2023-12-27 17:57:55 +01:00
parent 32cea61c86
commit 977546d3fc
No known key found for this signature in database
GPG Key ID: D17A07215F68E713
5 changed files with 173 additions and 21 deletions
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72
compiler/rustc_middle/src/ty/print/pretty.rs
View File

@ -912,7 +912,8 @@ pub trait PrettyPrinter<'tcx>: Printer<'tcx> + fmt::Write {
let mut traits = FxIndexMap::default();
let mut fn_traits = FxIndexMap::default();
let mut is_sized = false;
let mut has_sized_bound = false;
let mut has_negative_sized_bound = false;
let mut lifetimes = SmallVec::<[ty::Region<'tcx>; 1]>::new();
for (predicate, _) in bounds.iter_instantiated_copied(tcx, args) {
@ -922,13 +923,24 @@ pub trait PrettyPrinter<'tcx>: Printer<'tcx> + fmt::Write {
ty::ClauseKind::Trait(pred) => {
let trait_ref = bound_predicate.rebind(pred.trait_ref);
// Don't print + Sized, but rather + ?Sized if absent.
// Don't print `+ Sized`, but rather `+ ?Sized` if absent.
if Some(trait_ref.def_id()) == tcx.lang_items().sized_trait() {
is_sized = true;
continue;
match pred.polarity {
ty::ImplPolarity::Positive | ty::ImplPolarity::Reservation => {
has_sized_bound = true;
continue;
}
ty::ImplPolarity::Negative => has_negative_sized_bound = true,
}
}
self.insert_trait_and_projection(trait_ref, None, &mut traits, &mut fn_traits);
self.insert_trait_and_projection(
trait_ref,
pred.polarity,
None,
&mut traits,
&mut fn_traits,
);
}
ty::ClauseKind::Projection(pred) => {
let proj_ref = bound_predicate.rebind(pred);
@ -939,6 +951,7 @@ pub trait PrettyPrinter<'tcx>: Printer<'tcx> + fmt::Write {
self.insert_trait_and_projection(
trait_ref,
ty::ImplPolarity::Positive,
Some(proj_ty),
&mut traits,
&mut fn_traits,
@ -955,7 +968,7 @@ pub trait PrettyPrinter<'tcx>: Printer<'tcx> + fmt::Write {
let mut first = true;
// Insert parenthesis around (Fn(A, B) -> C) if the opaque ty has more than one other trait
let paren_needed = fn_traits.len() > 1 || traits.len() > 0 || !is_sized;
let paren_needed = fn_traits.len() > 1 || traits.len() > 0 || !has_sized_bound;
for (fn_once_trait_ref, entry) in fn_traits {
write!(self, "{}", if first { "" } else { " + " })?;
@ -1002,18 +1015,21 @@ pub trait PrettyPrinter<'tcx>: Printer<'tcx> + fmt::Write {
// trait_refs we collected in the OpaqueFnEntry as normal trait refs.
_ => {
if entry.has_fn_once {
traits.entry(fn_once_trait_ref).or_default().extend(
// Group the return ty with its def id, if we had one.
entry
.return_ty
.map(|ty| (tcx.require_lang_item(LangItem::FnOnce, None), ty)),
);
traits
.entry((fn_once_trait_ref, ty::ImplPolarity::Positive))
.or_default()
.extend(
// Group the return ty with its def id, if we had one.
entry.return_ty.map(|ty| {
(tcx.require_lang_item(LangItem::FnOnce, None), ty)
}),
);
}
if let Some(trait_ref) = entry.fn_mut_trait_ref {
traits.entry(trait_ref).or_default();
traits.entry((trait_ref, ty::ImplPolarity::Positive)).or_default();
}
if let Some(trait_ref) = entry.fn_trait_ref {
traits.entry(trait_ref).or_default();
traits.entry((trait_ref, ty::ImplPolarity::Positive)).or_default();
}
}
}
@ -1023,11 +1039,15 @@ pub trait PrettyPrinter<'tcx>: Printer<'tcx> + fmt::Write {
}
// Print the rest of the trait types (that aren't Fn* family of traits)
for (trait_ref, assoc_items) in traits {
for ((trait_ref, polarity), assoc_items) in traits {
write!(self, "{}", if first { "" } else { " + " })?;
self.wrap_binder(&trait_ref, |trait_ref, cx| {
define_scoped_cx!(cx);
if polarity == ty::ImplPolarity::Negative {
p!("!");
}
p!(print(trait_ref.print_only_trait_name()));
let generics = tcx.generics_of(trait_ref.def_id);
@ -1094,9 +1114,15 @@ pub trait PrettyPrinter<'tcx>: Printer<'tcx> + fmt::Write {
})?;
}
if !is_sized {
write!(self, "{}?Sized", if first { "" } else { " + " })?;
} else if first {
let add_sized = has_sized_bound && (first || has_negative_sized_bound);
let add_maybe_sized = !has_sized_bound && !has_negative_sized_bound;
if add_sized || add_maybe_sized {
if !first {
write!(self, " + ")?;
}
if add_maybe_sized {
write!(self, "?")?;
}
write!(self, "Sized")?;
}
@ -1128,9 +1154,10 @@ pub trait PrettyPrinter<'tcx>: Printer<'tcx> + fmt::Write {
fn insert_trait_and_projection(
&mut self,
trait_ref: ty::PolyTraitRef<'tcx>,
polarity: ty::ImplPolarity,
proj_ty: Option<(DefId, ty::Binder<'tcx, Term<'tcx>>)>,
traits: &mut FxIndexMap<
ty::PolyTraitRef<'tcx>,
(ty::PolyTraitRef<'tcx>, ty::ImplPolarity),
FxIndexMap<DefId, ty::Binder<'tcx, Term<'tcx>>>,
>,
fn_traits: &mut FxIndexMap<ty::PolyTraitRef<'tcx>, OpaqueFnEntry<'tcx>>,
@ -1139,7 +1166,10 @@ pub trait PrettyPrinter<'tcx>: Printer<'tcx> + fmt::Write {
// If our trait_ref is FnOnce or any of its children, project it onto the parent FnOnce
// super-trait ref and record it there.
if let Some(fn_once_trait) = self.tcx().lang_items().fn_once_trait() {
// We skip negative Fn* bounds since they can't use parenthetical notation anyway.
if polarity == ty::ImplPolarity::Positive
&& let Some(fn_once_trait) = self.tcx().lang_items().fn_once_trait()
{
// If we have a FnOnce, then insert it into
if trait_def_id == fn_once_trait {
let entry = fn_traits.entry(trait_ref).or_default();
@ -1167,7 +1197,7 @@ pub trait PrettyPrinter<'tcx>: Printer<'tcx> + fmt::Write {
}
// Otherwise, just group our traits and projection types.
traits.entry(trait_ref).or_default().extend(proj_ty);
traits.entry((trait_ref, polarity)).or_default().extend(proj_ty);
}
fn pretty_print_inherent_projection(

23
tests/ui/traits/negative-bounds/opaque-type-unsatisfied-bound.rs Normal file
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@ -0,0 +1,23 @@
// compile-flags: -Znext-solver
#![feature(negative_bounds, negative_impls)]
trait Trait {}
impl !Trait for () {}
fn produce() -> impl !Trait {}
fn consume(_: impl Trait) {}
fn main() {
consume(produce()); //~ ERROR the trait bound `impl !Trait: Trait` is not satisfied
}
fn weird0() -> impl Sized + !Sized {}
//~^ ERROR mismatched types
//~| ERROR type mismatch resolving `() == impl !Sized + Sized`
fn weird1() -> impl !Sized + Sized {}
//~^ ERROR mismatched types
//~| ERROR type mismatch resolving `() == impl !Sized + Sized`
fn weird2() -> impl !Sized {}
//~^ ERROR mismatched types
//~| ERROR type mismatch resolving `() == impl !Sized`

69
tests/ui/traits/negative-bounds/opaque-type-unsatisfied-bound.stderr Normal file
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@ -0,0 +1,69 @@
error[E0308]: mismatched types
--> $DIR/opaque-type-unsatisfied-bound.rs:15:36
|
LL | fn weird0() -> impl Sized + !Sized {}
| ------------------- ^^ types differ
| |
| the expected opaque type
|
= note: expected opaque type `impl !Sized + Sized`
found unit type `()`
error[E0271]: type mismatch resolving `() == impl !Sized + Sized`
--> $DIR/opaque-type-unsatisfied-bound.rs:15:16
|
LL | fn weird0() -> impl Sized + !Sized {}
| ^^^^^^^^^^^^^^^^^^^ types differ
error[E0308]: mismatched types
--> $DIR/opaque-type-unsatisfied-bound.rs:18:36
|
LL | fn weird1() -> impl !Sized + Sized {}
| ------------------- ^^ types differ
| |
| the expected opaque type
|
= note: expected opaque type `impl !Sized + Sized`
found unit type `()`
error[E0271]: type mismatch resolving `() == impl !Sized + Sized`
--> $DIR/opaque-type-unsatisfied-bound.rs:18:16
|
LL | fn weird1() -> impl !Sized + Sized {}
| ^^^^^^^^^^^^^^^^^^^ types differ
error[E0308]: mismatched types
--> $DIR/opaque-type-unsatisfied-bound.rs:21:28
|
LL | fn weird2() -> impl !Sized {}
| ----------- ^^ types differ
| |
| the expected opaque type
|
= note: expected opaque type `impl !Sized`
found unit type `()`
error[E0271]: type mismatch resolving `() == impl !Sized`
--> $DIR/opaque-type-unsatisfied-bound.rs:21:16
|
LL | fn weird2() -> impl !Sized {}
| ^^^^^^^^^^^ types differ
error[E0277]: the trait bound `impl !Trait: Trait` is not satisfied
--> $DIR/opaque-type-unsatisfied-bound.rs:12:13
|
LL | consume(produce());
| ------- ^^^^^^^^^ the trait `Trait` is not implemented for `impl !Trait`
| |
| required by a bound introduced by this call
|
note: required by a bound in `consume`
--> $DIR/opaque-type-unsatisfied-bound.rs:9:20
|
LL | fn consume(_: impl Trait) {}
| ^^^^^ required by this bound in `consume`
error: aborting due to 7 previous errors
Some errors have detailed explanations: E0271, E0277, E0308.
For more information about an error, try `rustc --explain E0271`.

9
tests/ui/traits/negative-bounds/opaque-type-unsatisfied-fn-bound.rs Normal file
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@ -0,0 +1,9 @@
// compile-flags: -Znext-solver
#![feature(negative_bounds, unboxed_closures)]
fn produce() -> impl !Fn<(u32,)> {}
//~^ ERROR mismatched types
//~| ERROR type mismatch resolving `() == impl !Fn<(u32,)>`
fn main() {}

21
tests/ui/traits/negative-bounds/opaque-type-unsatisfied-fn-bound.stderr Normal file
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@ -0,0 +1,21 @@
error[E0308]: mismatched types
--> $DIR/opaque-type-unsatisfied-fn-bound.rs:5:34
|
LL | fn produce() -> impl !Fn<(u32,)> {}
| ---------------- ^^ types differ
| |
| the expected opaque type
|
= note: expected opaque type `impl !Fn<(u32,)>`
found unit type `()`
error[E0271]: type mismatch resolving `() == impl !Fn<(u32,)>`
--> $DIR/opaque-type-unsatisfied-fn-bound.rs:5:17
|
LL | fn produce() -> impl !Fn<(u32,)> {}
| ^^^^^^^^^^^^^^^^ types differ
error: aborting due to 2 previous errors
Some errors have detailed explanations: E0271, E0308.
For more information about an error, try `rustc --explain E0271`.