[][src]Struct rustc::infer::region_constraints::RegionConstraintData

pub struct RegionConstraintData<'tcx> {
    pub constraints: BTreeMap<Constraint<'tcx>, SubregionOrigin<'tcx>>,
    pub verifys: Vec<Verify<'tcx>>,
    pub givens: FxHashSet<(Region<'tcx>, RegionVid)>,
}
🔬 This is a nightly-only experimental API. (rustc_private)

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The full set of region constraints gathered up by the collector. Describes constraints between the region variables and other regions, as well as other conditions that must be verified, or assumptions that can be made.

Fields

🔬 This is a nightly-only experimental API. (rustc_private)

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Constraints of the form A <= B, where either A or B can be a region variable (or neither, as it happens).

🔬 This is a nightly-only experimental API. (rustc_private)

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A "verify" is something that we need to verify after inference is done, but which does not directly affect inference in any way.

An example is a A <= B where neither A nor B are inference variables.

🔬 This is a nightly-only experimental API. (rustc_private)

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A "given" is a relationship that is known to hold. In particular, we often know from closure fn signatures that a particular free region must be a subregion of a region variable:

foo.iter().filter(<'a> |x: &'a &'b T| ...)

In situations like this, 'b is in fact a region variable introduced by the call to iter(), and 'a is a bound region on the closure (as indicated by the <'a> prefix). If we are naive, we wind up inferring that 'b must be 'static, because we require that it be greater than 'a and we do not know what 'a is precisely.

This hashmap is used to avoid that naive scenario. Basically we record the fact that 'a <= 'b is implied by the fn signature, and then ignore the constraint when solving equations. This is a bit of a hack but seems to work.

Methods

impl<'tcx> RegionConstraintData<'tcx>
[src]

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True if this region constraint data contains no constraints.

Trait Implementations

impl<'tcx> Debug for RegionConstraintData<'tcx>
[src]

Formats the value using the given formatter. Read more

impl<'tcx> Default for RegionConstraintData<'tcx>
[src]

Returns the "default value" for a type. Read more

impl<'tcx> Clone for RegionConstraintData<'tcx>
[src]

Returns a copy of the value. Read more

Performs copy-assignment from source. Read more

Auto Trait Implementations

impl<'tcx> !Send for RegionConstraintData<'tcx>

impl<'tcx> !Sync for RegionConstraintData<'tcx>

Blanket Implementations

impl<T> MaybeResult for T
[src]

🔬 This is a nightly-only experimental API. (rustc_private)

this crate is being loaded from the sysroot, an unstable location; did you mean to load this crate from crates.io via Cargo.toml instead?

🔬 This is a nightly-only experimental API. (rustc_private)

this crate is being loaded from the sysroot, an unstable location; did you mean to load this crate from crates.io via Cargo.toml instead?

impl<'a, T> Captures for T where
    T: ?Sized
[src]

impl<T> ToOwned for T where
    T: Clone
[src]

Creates owned data from borrowed data, usually by cloning. Read more

🔬 This is a nightly-only experimental API. (toowned_clone_into)

recently added

Uses borrowed data to replace owned data, usually by cloning. Read more

impl<T> From for T
[src]

Performs the conversion.

impl<T, U> Into for T where
    U: From<T>, 
[src]

Performs the conversion.

impl<T, U> TryFrom for T where
    T: From<U>, 
[src]

🔬 This is a nightly-only experimental API. (try_from)

The type returned in the event of a conversion error.

🔬 This is a nightly-only experimental API. (try_from)

Performs the conversion.

impl<T> Borrow for T where
    T: ?Sized
[src]

Important traits for &'a mut R

Immutably borrows from an owned value. Read more

impl<T, U> TryInto for T where
    U: TryFrom<T>, 
[src]

🔬 This is a nightly-only experimental API. (try_from)

The type returned in the event of a conversion error.

🔬 This is a nightly-only experimental API. (try_from)

Performs the conversion.

impl<T> BorrowMut for T where
    T: ?Sized
[src]

Important traits for &'a mut R

Mutably borrows from an owned value. Read more

impl<T> Any for T where
    T: 'static + ?Sized
[src]

🔬 This is a nightly-only experimental API. (get_type_id)

this method will likely be replaced by an associated static

Gets the TypeId of self. Read more

impl<E> SpecializationError for E
[src]

🔬 This is a nightly-only experimental API. (rustc_private)

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Create an error for a missing method specialization. Defaults to panicking with type, trait & method names. S is the encoder/decoder state type, T is the type being encoded/decoded, and the arguments are the names of the trait and method that should've been overridden. Read more

impl<T> Erased for T
[src]

impl<T> Send for T where
    T: ?Sized
[src]

impl<T> Sync for T where
    T: ?Sized
[src]

impl<T> Erased for T