[][src]Struct rustc::ty::fold::HasEscapingRegionsVisitor

struct HasEscapingRegionsVisitor {
    outer_index: DebruijnIndex,
}
🔬 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?

An "escaping region" is a bound region whose binder is not part of t.

So, for example, consider a type like the following, which has two binders:

for<'a> fn(x: for<'b> fn(&'a isize, &'b isize)) ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ outer scope ^~~~~~~~~~~~~~~~~~~~~~~~~~~~ inner scope

This type has bound regions ('a, 'b), but it does not have escaping regions, because the binders of both 'a and 'b are part of the type itself. However, if we consider the inner fn type, that type has an escaping region: 'a.

Note that what I'm calling an "escaping region" is often just called a "free region". However, we already use the term "free region". It refers to the regions that we use to represent bound regions on a fn definition while we are typechecking its body.

To clarify, conceptually there is no particular difference between an "escaping" region and a "free" region. However, there is a big difference in practice. Basically, when "entering" a binding level, one is generally required to do some sort of processing to a bound region, such as replacing it with a fresh/skolemized region, or making an entry in the environment to represent the scope to which it is attached, etc. An escaping region represents a bound region for which this processing has not yet been done.

Fields

🔬 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?

Anything bound by outer_index or "above" is escaping

Trait Implementations

impl<'tcx> TypeVisitor<'tcx> for HasEscapingRegionsVisitor
[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?

🔬 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?

Auto Trait Implementations

impl Send for HasEscapingRegionsVisitor

impl Sync for HasEscapingRegionsVisitor

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> 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)

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?

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