pub enum Constructor<Cx: PatCx> {
Show 20 variants
Struct,
Variant(Cx::VariantIdx),
Ref,
Slice(Slice),
UnionField,
Bool(bool),
IntRange(IntRange),
F16Range(IeeeFloat<HalfS>, IeeeFloat<HalfS>, RangeEnd),
F32Range(IeeeFloat<SingleS>, IeeeFloat<SingleS>, RangeEnd),
F64Range(IeeeFloat<DoubleS>, IeeeFloat<DoubleS>, RangeEnd),
F128Range(IeeeFloat<QuadS>, IeeeFloat<QuadS>, RangeEnd),
Str(Cx::StrLit),
Opaque(OpaqueId),
Or,
Wildcard,
Never,
NonExhaustive,
Hidden,
Missing,
PrivateUninhabited,
}Expand description
A value can be decomposed into a constructor applied to some fields. This struct represents
the constructor. See also Fields.
pat_constructor retrieves the constructor corresponding to a pattern.
specialize_constructor returns the list of fields corresponding to a pattern, given a
constructor. Constructor::apply reconstructs the pattern from a pair of Constructor and
Fields.
Variants§
Struct
Tuples and structs.
Variant(Cx::VariantIdx)
Enum variants.
Ref
References
Slice(Slice)
Array and slice patterns.
UnionField
Union field accesses.
Bool(bool)
Booleans
IntRange(IntRange)
Ranges of integer literal values (2, 2..=5 or 2..5).
F16Range(IeeeFloat<HalfS>, IeeeFloat<HalfS>, RangeEnd)
Ranges of floating-point literal values (2.0..=5.2).
F32Range(IeeeFloat<SingleS>, IeeeFloat<SingleS>, RangeEnd)
F64Range(IeeeFloat<DoubleS>, IeeeFloat<DoubleS>, RangeEnd)
F128Range(IeeeFloat<QuadS>, IeeeFloat<QuadS>, RangeEnd)
Str(Cx::StrLit)
String literals. Strings are not quite the same as &[u8] so we treat them separately.
Opaque(OpaqueId)
Constants that must not be matched structurally. They are treated as black boxes for the
purposes of exhaustiveness: we must not inspect them, and they don’t count towards making a
match exhaustive.
Carries an id that must be unique within a match. We need this to ensure the invariants of
SplitConstructorSet.
Or
Or-pattern.
Wildcard
Wildcard pattern.
Never
Never pattern. Only used in WitnessPat. An actual never pattern should be lowered as
Wildcard.
NonExhaustive
Fake extra constructor for enums that aren’t allowed to be matched exhaustively. Also used
for those types for which we cannot list constructors explicitly, like f64 and str. Only
used in WitnessPat.
Hidden
Fake extra constructor for variants that should not be mentioned in diagnostics. We use this
for variants behind an unstable gate as well as #[doc(hidden)] ones. Only used in
WitnessPat.
Missing
Fake extra constructor for constructors that are not seen in the matrix, as explained at the top of the file. Only used for specialization.
PrivateUninhabited
Fake extra constructor that indicates and empty field that is private. When we encounter one we skip the column entirely so we don’t observe its emptiness. Only used for specialization.