Trait PatCx

pub trait PatCx: Sized + Debug {
    type Ty: Clone + Debug;
    type Error: Debug;
    type VariantIdx: Clone + Idx + Debug;
    type StrLit: Clone + PartialEq + Debug;
    type ArmData: Copy + Clone + Debug;
    type PatData: Clone;

    // Required methods
    fn is_exhaustive_patterns_feature_on(&self) -> bool;
    fn ctor_arity(&self, ctor: &Constructor<Self>, ty: &Self::Ty) -> usize;
    fn ctor_sub_tys(
        &self,
        ctor: &Constructor<Self>,
        ty: &Self::Ty,
    ) -> impl Iterator<Item = (Self::Ty, PrivateUninhabitedField)> + ExactSizeIterator;
    fn ctors_for_ty(
        &self,
        ty: &Self::Ty,
    ) -> Result<ConstructorSet<Self>, Self::Error>;
    fn write_variant_name(
        f: &mut Formatter<'_>,
        ctor: &Constructor<Self>,
        ty: &Self::Ty,
    ) -> Result;
    fn bug(&self, fmt: Arguments<'_>) -> Self::Error;
    fn complexity_exceeded(&self) -> Result<(), Self::Error>;
    fn report_mixed_deref_pat_ctors(
        &self,
        deref_pat: &DeconstructedPat<Self>,
        normal_pat: &DeconstructedPat<Self>,
    ) -> Self::Error;

    // Provided methods
    fn exhaustive_witnesses(&self) -> bool { ... }
    fn lint_overlapping_range_endpoints(
        &self,
        _pat: &DeconstructedPat<Self>,
        _overlaps_on: IntRange,
        _overlaps_with: &[&DeconstructedPat<Self>],
    ) { ... }
    fn lint_non_contiguous_range_endpoints(
        &self,
        _pat: &DeconstructedPat<Self>,
        _gap: IntRange,
        _gapped_with: &[&DeconstructedPat<Self>],
    ) { ... }
    fn match_may_contain_deref_pats(&self) -> bool { ... }
}

Context that provides type information about constructors.

Most of the crate is parameterized on a type that implements this trait.

Required Associated Types

type Ty: Clone + Debug

The type of a pattern.

type Error: Debug

Errors that can abort analysis.

type VariantIdx: Clone + Idx + Debug

The index of an enum variant.

type StrLit: Clone + PartialEq + Debug

A string literal

type ArmData: Copy + Clone + Debug

Extra data to store in a match arm.

type PatData: Clone

Extra data to store in a pattern.

Required Methods

fn is_exhaustive_patterns_feature_on(&self) -> bool

fn ctor_arity(&self, ctor: &Constructor<Self>, ty: &Self::Ty) -> usize

The number of fields for this constructor.

fn ctor_sub_tys( &self, ctor: &Constructor<Self>, ty: &Self::Ty, ) -> impl Iterator<Item = (Self::Ty, PrivateUninhabitedField)> + ExactSizeIterator

The types of the fields for this constructor. The result must contain ctor_arity() fields.

fn ctors_for_ty( &self, ty: &Self::Ty, ) -> Result<ConstructorSet<Self>, Self::Error>

The set of all the constructors for ty.

This must follow the invariants of ConstructorSet

fn write_variant_name( f: &mut Formatter<'_>, ctor: &Constructor<Self>, ty: &Self::Ty, ) -> Result

Write the name of the variant represented by pat. Used for the best-effort Debug impl of DeconstructedPat. Only invoqued when pat.ctor() is Struct | Variant(_) | UnionField.

fn bug(&self, fmt: Arguments<'_>) -> Self::Error

Raise a bug.

fn complexity_exceeded(&self) -> Result<(), Self::Error>

The maximum pattern complexity limit was reached.

fn report_mixed_deref_pat_ctors( &self, deref_pat: &DeconstructedPat<Self>, normal_pat: &DeconstructedPat<Self>, ) -> Self::Error

The current implementation of deref patterns requires that they can’t match on the same place as a normal constructor. Since this isn’t caught by type-checking, we check it in the PatCx before running the analysis. This reports an error if the check fails.

Provided Methods

fn exhaustive_witnesses(&self) -> bool

Whether to ensure the non-exhaustiveness witnesses we report for a complete set. This is false by default to avoid some exponential blowup cases such as https://github.com/rust-lang/rust/issues/118437.

fn lint_overlapping_range_endpoints( &self, _pat: &DeconstructedPat<Self>, _overlaps_on: IntRange, _overlaps_with: &[&DeconstructedPat<Self>], )

Lint that the range pat overlapped with all the ranges in overlaps_with, where the range they overlapped over is overlaps_on. We only detect singleton overlaps. The default implementation does nothing.

fn lint_non_contiguous_range_endpoints( &self, _pat: &DeconstructedPat<Self>, _gap: IntRange, _gapped_with: &[&DeconstructedPat<Self>], )

Lint that there is a gap gap between pat and all of gapped_with such that the gap is not matched by another range. If gapped_with is empty, then gap is T::MAX. We only detect singleton gaps. The default implementation does nothing.

fn match_may_contain_deref_pats(&self) -> bool

Check if we may need to perform additional deref-pattern-specific validation.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors