Enum rustc_typeck::check::diverges::Diverges

pub enum Diverges {
    Maybe,
    Always {
        span: Span,
        custom_note: Option<&'static str>,
    },
    WarnedAlways,
}

Tracks whether executing a node may exit normally (versus return/break/panic, which “diverge”, leaving dead code in their wake). Tracked semi-automatically (through type variables marked as diverging), with some manual adjustments for control-flow primitives (approximating a CFG).

Variants

Maybe

Potentially unknown, some cases converge, others require a CFG to determine them.

Always

Definitely known to diverge and therefore not reach the next sibling or its parent.

Fields of Always

span: Span

The Span points to the expression that caused us to diverge (e.g. return, break, etc).

custom_note: Option<&'static str>

In some cases (e.g. a match expression where all arms diverge), we may be able to provide a more informative message to the user. If this is None, a default message will be generated, which is suitable for most cases.

WarnedAlways

Same as Always but with a reachability warning already emitted.

Implementations

impl Diverges

pub(super) fn always(span: Span) -> Diverges

Creates a Diverges::Always with the provided span and the default note message.

pub(super) fn is_always(self) -> bool

Trait Implementations

impl BitAnd<Diverges> for Diverges

type Output = Self

The resulting type after applying the & operator.

fn bitand(self, other: Self) -> Self

Performs the & operation.

impl BitAndAssign<Diverges> for Diverges

fn bitand_assign(&mut self, other: Self)

Performs the &= operation.

impl BitOr<Diverges> for Diverges

type Output = Self

The resulting type after applying the | operator.

fn bitor(self, other: Self) -> Self

Performs the | operation.

impl BitOrAssign<Diverges> for Diverges

fn bitor_assign(&mut self, other: Self)

Performs the |= operation.

impl Clone for Diverges

fn clone(&self) -> Diverges

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for Diverges

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

Formats the value using the given formatter.

impl Ord for Diverges

fn cmp(&self, other: &Diverges) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

Restrict a value to a certain interval.

impl PartialEq<Diverges> for Diverges

fn eq(&self, other: &Diverges) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Diverges) -> bool

This method tests for !=.

impl PartialOrd<Diverges> for Diverges

fn partial_cmp(&self, other: &Diverges) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

This method tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

This method tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

This method tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

This method tests greater than or equal to (for self and other) and is used by the >= operator.

impl Copy for Diverges

impl Eq for Diverges

impl StructuralEq for Diverges

impl StructuralPartialEq for Diverges

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: 32 bytes

Size for each variant:

• Maybe: 0 bytes
• Always: 28 bytes
• WarnedAlways: 0 bytes