rustc_pattern_analysis

Trait PatCx

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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<'a>(
        &'a self,
        ctor: &'a Constructor<Self>,
        ty: &'a Self::Ty,
    ) -> impl Iterator<Item = (Self::Ty, PrivateUninhabitedField)> + ExactSizeIterator + Captures<'a>;
    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>;

    // Provided methods
    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>],
    ) { ... }
}
Expand description

Context that provides type information about constructors.

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

Required Associated Types§

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type Ty: Clone + Debug

The type of a pattern.

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type Error: Debug

Errors that can abort analysis.

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type VariantIdx: Clone + Idx + Debug

The index of an enum variant.

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type StrLit: Clone + PartialEq + Debug

A string literal

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type ArmData: Copy + Clone + Debug

Extra data to store in a match arm.

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type PatData: Clone

Extra data to store in a pattern.

Required Methods§

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fn is_exhaustive_patterns_feature_on(&self) -> bool

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

The number of fields for this constructor.

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

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

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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

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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.

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

Raise a bug.

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

The maximum pattern complexity limit was reached.

Provided Methods§

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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.

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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.

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§