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Auto merge of rust-lang#120663 - matthiaskrgr:rollup-fasba0u, r=matth…
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Rollup of 7 pull requests

Successful merges:

 - rust-lang#113833 (`std::error::Error` -> Trait Implementations: lifetimes consistency improvement)
 - rust-lang#115386 (PartialEq, PartialOrd: update and synchronize handling of transitive chains)
 - rust-lang#116284 (make matching on NaN a hard error, and remove the rest of illegal_floating_point_literal_pattern)
 - rust-lang#118960 (Add LocalWaker and ContextBuilder types to core, and LocalWake trait to alloc.)
 - rust-lang#120060 (Use the same mir-opt bless targets on all platforms)
 - rust-lang#120214 (match lowering: consistently lower bindings deepest-first)
 - rust-lang#120384 (Use `<T, U>` for array/slice equality `impl`s)

r? `@ghost`
`@rustbot` modify labels: rollup
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bors committed Feb 5, 2024
2 parents 8c0b4f6 + 94a1f2c commit dc75c5c
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Showing 77 changed files with 1,526 additions and 1,116 deletions.
4 changes: 4 additions & 0 deletions compiler/rustc_lint/src/lib.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -516,6 +516,10 @@ fn register_builtins(store: &mut LintStore) {
"converted into hard error, see PR #118649 \
<https://github.com/rust-lang/rust/pull/118649> for more information",
);
store.register_removed(
"illegal_floating_point_literal_pattern",
"no longer a warning, float patterns behave the same as `==`",
);
}

fn register_internals(store: &mut LintStore) {
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50 changes: 0 additions & 50 deletions compiler/rustc_lint_defs/src/builtin.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -45,7 +45,6 @@ declare_lint_pass! {
FUZZY_PROVENANCE_CASTS,
HIDDEN_GLOB_REEXPORTS,
ILL_FORMED_ATTRIBUTE_INPUT,
ILLEGAL_FLOATING_POINT_LITERAL_PATTERN,
INCOMPLETE_INCLUDE,
INDIRECT_STRUCTURAL_MATCH,
INEFFECTIVE_UNSTABLE_TRAIT_IMPL,
Expand Down Expand Up @@ -1873,55 +1872,6 @@ declare_lint! {
};
}

declare_lint! {
/// The `illegal_floating_point_literal_pattern` lint detects
/// floating-point literals used in patterns.
///
/// ### Example
///
/// ```rust
/// let x = 42.0;
///
/// match x {
/// 5.0 => {}
/// _ => {}
/// }
/// ```
///
/// {{produces}}
///
/// ### Explanation
///
/// Previous versions of the compiler accepted floating-point literals in
/// patterns, but it was later determined this was a mistake. The
/// semantics of comparing floating-point values may not be clear in a
/// pattern when contrasted with "structural equality". Typically you can
/// work around this by using a [match guard], such as:
///
/// ```rust
/// # let x = 42.0;
///
/// match x {
/// y if y == 5.0 => {}
/// _ => {}
/// }
/// ```
///
/// This is a [future-incompatible] lint to transition this to a hard
/// error in the future. See [issue #41620] for more details.
///
/// [issue #41620]: https://github.com/rust-lang/rust/issues/41620
/// [match guard]: https://doc.rust-lang.org/reference/expressions/match-expr.html#match-guards
/// [future-incompatible]: ../index.md#future-incompatible-lints
pub ILLEGAL_FLOATING_POINT_LITERAL_PATTERN,
Warn,
"floating-point literals cannot be used in patterns",
@future_incompatible = FutureIncompatibleInfo {
reason: FutureIncompatibilityReason::FutureReleaseErrorDontReportInDeps,
reference: "issue #41620 <https://github.com/rust-lang/rust/issues/41620>",
};
}

declare_lint! {
/// The `unstable_name_collisions` lint detects that you have used a name
/// that the standard library plans to add in the future.
Expand Down
4 changes: 2 additions & 2 deletions compiler/rustc_middle/src/mir/interpret/value.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -418,8 +418,8 @@ impl<'tcx, Prov: Provenance> Scalar<Prov> {

#[inline]
pub fn to_float<F: Float>(self) -> InterpResult<'tcx, F> {
// Going through `to_uint` to check size and truncation.
Ok(F::from_bits(self.to_uint(Size::from_bits(F::BITS))?))
// Going through `to_bits` to check size and truncation.
Ok(F::from_bits(self.to_bits(Size::from_bits(F::BITS))?))
}

#[inline]
Expand Down
71 changes: 44 additions & 27 deletions compiler/rustc_middle/src/ty/consts/int.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -249,11 +249,6 @@ impl ScalarInt {
}
}

#[inline]
pub fn try_to_target_usize(&self, tcx: TyCtxt<'_>) -> Result<u64, Size> {
Ok(self.to_bits(tcx.data_layout.pointer_size)? as u64)
}

/// Tries to convert the `ScalarInt` to an unsigned integer of the given size.
/// Fails if the size of the `ScalarInt` is not equal to `size` and returns the
/// `ScalarInt`s size in that case.
Expand All @@ -262,56 +257,61 @@ impl ScalarInt {
self.to_bits(size)
}

// Tries to convert the `ScalarInt` to `bool`. Fails if the `size` of the `ScalarInt`
// in not equal to `Size { raw: 1 }` or if the value is not 0 or 1 and returns the `size`
// value of the `ScalarInt` in that case.
#[inline]
pub fn try_to_bool(self) -> Result<bool, Size> {
match self.try_to_u8()? {
0 => Ok(false),
1 => Ok(true),
_ => Err(self.size()),
}
}

// Tries to convert the `ScalarInt` to `u8`. Fails if the `size` of the `ScalarInt`
// in not equal to `Size { raw: 1 }` and returns the `size` value of the `ScalarInt` in
// that case.
#[inline]
pub fn try_to_u8(self) -> Result<u8, Size> {
self.to_bits(Size::from_bits(8)).map(|v| u8::try_from(v).unwrap())
self.try_to_uint(Size::from_bits(8)).map(|v| u8::try_from(v).unwrap())
}

/// Tries to convert the `ScalarInt` to `u16`. Fails if the size of the `ScalarInt`
/// in not equal to `Size { raw: 2 }` and returns the `size` value of the `ScalarInt` in
/// that case.
#[inline]
pub fn try_to_u16(self) -> Result<u16, Size> {
self.to_bits(Size::from_bits(16)).map(|v| u16::try_from(v).unwrap())
self.try_to_uint(Size::from_bits(16)).map(|v| u16::try_from(v).unwrap())
}

/// Tries to convert the `ScalarInt` to `u32`. Fails if the `size` of the `ScalarInt`
/// in not equal to `Size { raw: 4 }` and returns the `size` value of the `ScalarInt` in
/// that case.
#[inline]
pub fn try_to_u32(self) -> Result<u32, Size> {
self.to_bits(Size::from_bits(32)).map(|v| u32::try_from(v).unwrap())
self.try_to_uint(Size::from_bits(32)).map(|v| u32::try_from(v).unwrap())
}

/// Tries to convert the `ScalarInt` to `u64`. Fails if the `size` of the `ScalarInt`
/// in not equal to `Size { raw: 8 }` and returns the `size` value of the `ScalarInt` in
/// that case.
#[inline]
pub fn try_to_u64(self) -> Result<u64, Size> {
self.to_bits(Size::from_bits(64)).map(|v| u64::try_from(v).unwrap())
self.try_to_uint(Size::from_bits(64)).map(|v| u64::try_from(v).unwrap())
}

/// Tries to convert the `ScalarInt` to `u128`. Fails if the `size` of the `ScalarInt`
/// in not equal to `Size { raw: 16 }` and returns the `size` value of the `ScalarInt` in
/// that case.
#[inline]
pub fn try_to_u128(self) -> Result<u128, Size> {
self.to_bits(Size::from_bits(128))
self.try_to_uint(Size::from_bits(128))
}

#[inline]
pub fn try_to_target_usize(&self, tcx: TyCtxt<'_>) -> Result<u64, Size> {
self.try_to_uint(tcx.data_layout.pointer_size).map(|v| u64::try_from(v).unwrap())
}

// Tries to convert the `ScalarInt` to `bool`. Fails if the `size` of the `ScalarInt`
// in not equal to `Size { raw: 1 }` or if the value is not 0 or 1 and returns the `size`
// value of the `ScalarInt` in that case.
#[inline]
pub fn try_to_bool(self) -> Result<bool, Size> {
match self.try_to_u8()? {
0 => Ok(false),
1 => Ok(true),
_ => Err(self.size()),
}
}

/// Tries to convert the `ScalarInt` to a signed integer of the given size.
Expand Down Expand Up @@ -357,6 +357,27 @@ impl ScalarInt {
pub fn try_to_i128(self) -> Result<i128, Size> {
self.try_to_int(Size::from_bits(128))
}

#[inline]
pub fn try_to_target_isize(&self, tcx: TyCtxt<'_>) -> Result<i64, Size> {
self.try_to_int(tcx.data_layout.pointer_size).map(|v| i64::try_from(v).unwrap())
}

#[inline]
pub fn try_to_float<F: Float>(self) -> Result<F, Size> {
// Going through `to_uint` to check size and truncation.
Ok(F::from_bits(self.to_bits(Size::from_bits(F::BITS))?))
}

#[inline]
pub fn try_to_f32(self) -> Result<Single, Size> {
self.try_to_float()
}

#[inline]
pub fn try_to_f64(self) -> Result<Double, Size> {
self.try_to_float()
}
}

macro_rules! from {
Expand Down Expand Up @@ -399,11 +420,7 @@ impl TryFrom<ScalarInt> for bool {
type Error = Size;
#[inline]
fn try_from(int: ScalarInt) -> Result<Self, Size> {
int.to_bits(Size::from_bytes(1)).and_then(|u| match u {
0 => Ok(false),
1 => Ok(true),
_ => Err(Size::from_bytes(1)),
})
int.try_to_bool()
}
}

Expand Down
6 changes: 4 additions & 2 deletions compiler/rustc_mir_build/messages.ftl
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Original file line number Diff line number Diff line change
Expand Up @@ -107,8 +107,6 @@ mir_build_extern_static_requires_unsafe_unsafe_op_in_unsafe_fn_allowed =
.note = extern statics are not controlled by the Rust type system: invalid data, aliasing violations or data races will cause undefined behavior
.label = use of extern static
mir_build_float_pattern = floating-point types cannot be used in patterns
mir_build_indirect_structural_match =
to use a constant of type `{$non_sm_ty}` in a pattern, `{$non_sm_ty}` must be annotated with `#[derive(PartialEq)]`
Expand Down Expand Up @@ -232,6 +230,10 @@ mir_build_mutation_of_layout_constrained_field_requires_unsafe_unsafe_op_in_unsa
.note = mutating layout constrained fields cannot statically be checked for valid values
.label = mutation of layout constrained field
mir_build_nan_pattern = cannot use NaN in patterns
.note = NaNs compare inequal to everything, even themselves, so this pattern would never match
.help = try using the `is_nan` method instead
mir_build_non_const_path = runtime values cannot be referenced in patterns
mir_build_non_empty_never_pattern =
Expand Down
107 changes: 53 additions & 54 deletions compiler/rustc_mir_build/src/build/matches/simplify.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -40,43 +40,39 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
&mut self,
candidate: &mut Candidate<'pat, 'tcx>,
) -> bool {
// repeatedly simplify match pairs until fixed point is reached
debug!("{candidate:#?}");

// existing_bindings and new_bindings exists to keep the semantics in order.
// Reversing the binding order for bindings after `@` changes the binding order in places
// it shouldn't be changed, for example `let (Some(a), Some(b)) = (x, y)`
// In order to please the borrow checker, in a pattern like `x @ pat` we must lower the
// bindings in `pat` before `x`. E.g. (#69971):
//
// struct NonCopyStruct {
// copy_field: u32,
// }
//
// fn foo1(x: NonCopyStruct) {
// let y @ NonCopyStruct { copy_field: z } = x;
// // the above should turn into
// let z = x.copy_field;
// let y = x;
// }
//
// To avoid this, the binding occurs in the following manner:
// * the bindings for one iteration of the following loop occurs in order (i.e. left to
// right)
// * the bindings from the previous iteration of the loop is prepended to the bindings from
// the current iteration (in the implementation this is done by mem::swap and extend)
// * after all iterations, these new bindings are then appended to the bindings that were
// preexisting (i.e. `candidate.binding` when the function was called).
// We can't just reverse the binding order, because we must preserve pattern-order
// otherwise, e.g. in `let (Some(a), Some(b)) = (x, y)`. Our rule then is: deepest-first,
// and bindings at the same depth stay in source order.
//
// To do this, every time around the loop we prepend the newly found bindings to the
// bindings we already had.
//
// example:
// candidate.bindings = [1, 2, 3]
// binding in iter 1: [4, 5]
// binding in iter 2: [6, 7]
// bindings in iter 1: [4, 5]
// bindings in iter 2: [6, 7]
//
// final binding: [1, 2, 3, 6, 7, 4, 5]
let mut existing_bindings = mem::take(&mut candidate.bindings);
let mut new_bindings = Vec::new();
// final bindings: [6, 7, 4, 5, 1, 2, 3]
let mut accumulated_bindings = mem::take(&mut candidate.bindings);
// Repeatedly simplify match pairs until fixed point is reached
loop {
let match_pairs = mem::take(&mut candidate.match_pairs);

if let [MatchPair { pattern: Pat { kind: PatKind::Or { pats }, .. }, place }] =
&*match_pairs
{
existing_bindings.extend_from_slice(&new_bindings);
mem::swap(&mut candidate.bindings, &mut existing_bindings);
candidate.subcandidates = self.create_or_subcandidates(candidate, place, pats);
return true;
}

let mut changed = false;
for match_pair in match_pairs {
for match_pair in mem::take(&mut candidate.match_pairs) {
match self.simplify_match_pair(match_pair, candidate) {
Ok(()) => {
changed = true;
Expand All @@ -86,36 +82,39 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
}
}
}
// Avoid issue #69971: the binding order should be right to left if there are more
// bindings after `@` to please the borrow checker
// Ex
// struct NonCopyStruct {
// copy_field: u32,
// }
//
// fn foo1(x: NonCopyStruct) {
// let y @ NonCopyStruct { copy_field: z } = x;
// // the above should turn into
// let z = x.copy_field;
// let y = x;
// }
candidate.bindings.extend_from_slice(&new_bindings);
mem::swap(&mut candidate.bindings, &mut new_bindings);

// This does: accumulated_bindings = candidate.bindings.take() ++ accumulated_bindings
candidate.bindings.extend_from_slice(&accumulated_bindings);
mem::swap(&mut candidate.bindings, &mut accumulated_bindings);
candidate.bindings.clear();

if !changed {
existing_bindings.extend_from_slice(&new_bindings);
mem::swap(&mut candidate.bindings, &mut existing_bindings);
// Move or-patterns to the end, because they can result in us
// creating additional candidates, so we want to test them as
// late as possible.
candidate
.match_pairs
.sort_by_key(|pair| matches!(pair.pattern.kind, PatKind::Or { .. }));
debug!(simplified = ?candidate, "simplify_candidate");
return false; // if we were not able to simplify any, done.
// If we were not able to simplify anymore, done.
break;
}
}

// Store computed bindings back in `candidate`.
mem::swap(&mut candidate.bindings, &mut accumulated_bindings);

let did_expand_or =
if let [MatchPair { pattern: Pat { kind: PatKind::Or { pats }, .. }, place }] =
&*candidate.match_pairs
{
candidate.subcandidates = self.create_or_subcandidates(candidate, place, pats);
candidate.match_pairs.clear();
true
} else {
false
};

// Move or-patterns to the end, because they can result in us
// creating additional candidates, so we want to test them as
// late as possible.
candidate.match_pairs.sort_by_key(|pair| matches!(pair.pattern.kind, PatKind::Or { .. }));
debug!(simplified = ?candidate, "simplify_candidate");

did_expand_or
}

/// Given `candidate` that has a single or-pattern for its match-pairs,
Expand Down
11 changes: 8 additions & 3 deletions compiler/rustc_mir_build/src/errors.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -780,9 +780,14 @@ pub struct UnsizedPattern<'tcx> {
pub non_sm_ty: Ty<'tcx>,
}

#[derive(LintDiagnostic)]
#[diag(mir_build_float_pattern)]
pub struct FloatPattern;
#[derive(Diagnostic)]
#[diag(mir_build_nan_pattern)]
#[note]
#[help]
pub struct NaNPattern {
#[primary_span]
pub span: Span,
}

#[derive(LintDiagnostic)]
#[diag(mir_build_pointer_pattern)]
Expand Down
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