Enum rustc_expand::mbe::transcribe::LockstepIterSize
source · 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§
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
).
Constraint(usize, MacroRulesNormalizedIdent)
A MetaVar
with an actual MatchedSeq
. The length of the match and the name of the
meta-var are returned.
Contradiction(String)
Two Constraint
s on the same sequence had different lengths. This is an error.
Implementations§
source§impl LockstepIterSize
impl LockstepIterSize
sourcefn with(self, other: LockstepIterSize) -> LockstepIterSize
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§
source§impl Clone for LockstepIterSize
impl Clone for LockstepIterSize
source§fn clone(&self) -> LockstepIterSize
fn clone(&self) -> LockstepIterSize
1.0.0 · source§fn clone_from(&mut self, source: &Self)
fn clone_from(&mut self, source: &Self)
source
. Read moreAuto Trait Implementations§
impl RefUnwindSafe for LockstepIterSize
impl !Send for LockstepIterSize
impl !Sync for LockstepIterSize
impl Unpin for LockstepIterSize
impl UnwindSafe for LockstepIterSize
Blanket Implementations§
source§impl<T> BorrowMut<T> for Twhere
T: ?Sized,
impl<T> BorrowMut<T> for Twhere T: ?Sized,
source§fn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
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 bytesConstraint
: 20 bytesContradiction
: 28 bytes