Enum rustc_feature::UnstableFeatures

pub enum UnstableFeatures {
    Disallow,
    Allow,
    Cheat,
}

Variants

Disallow

Hard errors for unstable features are active, as on beta/stable channels.

Allow

Allow features to be activated, as on nightly.

Cheat

Errors are bypassed for bootstrapping. This is required any time during the build that feature-related lints are set to warn or above because the build turns on warnings-as-errors and uses lots of unstable features. As a result, this is always required for building Rust itself.

Implementations

impl UnstableFeatures

pub fn from_environment(krate: Option<&str>) -> Self

This takes into account RUSTC_BOOTSTRAP.

If krate is Some, then setting RUSTC_BOOTSTRAP=krate will enable the nightly features. Otherwise, only RUSTC_BOOTSTRAP=1 will work.

pub fn is_nightly_build(&self) -> bool

Trait Implementations

impl Clone for UnstableFeatures

fn clone(&self) -> UnstableFeatures

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for UnstableFeatures

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Hash for UnstableFeatures

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)where
    H: Hasher,
    Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Copy for UnstableFeatures

Layout

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...) attributes. Please see the Rust Reference’s “Type Layout” chapter for details on type layout guarantees.

Size: 1 byte

Size for each variant:

• Disallow: 0 bytes
• Allow: 0 bytes
• Cheat: 0 bytes