Enum rustc_typeck::check::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(in check) fn always(
    span: Span
) -> Diverges

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

pub(in check) fn is_always(
    self
) -> bool

Trait Implementations

impl BitAnd<Diverges> for Diverges

type Output = Self

The resulting type after applying the & operator.

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

Performs the & operation.

impl BitAndAssign<Diverges> for Diverges

pub 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.

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

Performs the | operation.

impl BitOrAssign<Diverges> for Diverges

pub fn bitor_assign(&mut self, other: Self)

Performs the |= operation.

impl Clone for Diverges

pub fn clone(&self) -> Diverges

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Copy for Diverges

impl Debug for Diverges

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

Formats the value using the given formatter.

impl Eq for Diverges

impl Ord for Diverges

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

This method returns an Ordering between self and other.

#[must_use]pub fn max(self, other: Self) -> Self

Compares and returns the maximum of two values.

#[must_use]pub fn min(self, other: Self) -> Self

Compares and returns the minimum of two values.

#[must_use]pub fn clamp(self, min: Self, max: Self) -> Self

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

Restrict a value to a certain interval.

impl PartialEq<Diverges> for Diverges

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

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

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

This method tests for !=.

impl PartialOrd<Diverges> for Diverges

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

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

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

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

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

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

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

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

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

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

impl StructuralEq for Diverges

impl StructuralPartialEq for Diverges