Enum rustc_expand::mbe::transcribe::LockstepIterSize

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enum LockstepIterSize {
    Unconstrained,
    Constraint(usize, MacroRulesNormalizedIdent),
    Contradiction(String),
}
Expand description

An accumulator over a TokenTree to be used with fold. During transcription, we need to make sure that the size of each sequence and all of its nested sequences are the same as the sizes of all the matched (nested) sequences in the macro invocation. If they don’t match, somebody has made a mistake (either the macro writer or caller).

Variants§

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Unconstrained

No constraints on length of matcher. This is true for any TokenTree variants except a MetaVar with an actual MatchedSeq (as opposed to a MatchedNonterminal).

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Constraint(usize, MacroRulesNormalizedIdent)

A MetaVar with an actual MatchedSeq. The length of the match and the name of the meta-var are returned.

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Contradiction(String)

Two Constraints on the same sequence had different lengths. This is an error.

Implementations§

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impl LockstepIterSize

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fn with(self, other: LockstepIterSize) -> LockstepIterSize

Find incompatibilities in matcher/invocation sizes.

  • Unconstrained is compatible with everything.
  • Contradiction is incompatible with everything.
  • Constraint(len) is only compatible with other constraints of the same length.

Trait Implementations§

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impl Clone for LockstepIterSize

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fn clone(&self) -> LockstepIterSize

Returns a copy of the value. Read more
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fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more

Auto Trait Implementations§

Blanket Implementations§

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impl<T> Aligned for T

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const ALIGN: Alignment = _

Alignment of Self.
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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T, R> CollectAndApply<T, R> for T

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fn collect_and_apply<I, F>(iter: I, f: F) -> R
where I: Iterator<Item = T>, F: FnOnce(&[T]) -> R,

Equivalent to f(&iter.collect::<Vec<_>>()).

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type Output = R

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impl<T> Filterable for T

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fn filterable( self, filter_name: &'static str ) -> RequestFilterDataProvider<T, fn(_: DataRequest<'_>) -> bool>

Creates a filterable data provider with the given name for debugging. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T> Instrument for T

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fn instrument(self, span: Span) -> Instrumented<Self>

Instruments this type with the provided Span, returning an Instrumented wrapper. Read more
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fn in_current_span(self) -> Instrumented<Self>

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where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T> Pointable for T

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const ALIGN: usize = _

The alignment of pointer.
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type Init = T

The type for initializers.
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unsafe fn init(init: <T as Pointable>::Init) -> usize

Initializes a with the given initializer. Read more
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unsafe fn deref<'a>(ptr: usize) -> &'a T

Dereferences the given pointer. Read more
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Mutably dereferences the given pointer. Read more
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unsafe fn drop(ptr: usize)

Drops the object pointed to by the given pointer. Read more
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type Output = T

Should always be Self
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The resulting type after obtaining ownership.
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fn clone_into(&self, target: &mut T)

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impl<T, U> TryFrom<U> for T
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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.
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fn vzip(self) -> V

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where S: Into<Dispatch>,

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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:

  • Unconstrained: 0 bytes
  • Constraint: 20 bytes
  • Contradiction: 28 bytes