Struct rustc_target::abi::FieldIdx
source · pub struct FieldIdx {
private: u32,
}
Expand description
The source-order index of a field in a variant.
This is how most code after type checking refers to fields, rather than using names (as names have hygiene complications and more complex lookup).
Particularly for repr(Rust)
types, this may not be the same as layout order.
(It is for repr(C)
struct
s, however.)
For example, in the following types,
enum Demo1 {
Variant0 { a: Never, b: i32 } = 100,
Variant1 { c: u8, d: u64 } = 10,
}
struct Demo2 { e: u8, f: u16, g: u8 }
b
is FieldIdx(1)
in VariantIdx(0)
,
d
is FieldIdx(1)
in VariantIdx(1)
, and
f
is FieldIdx(1)
in VariantIdx(0)
.
Fields§
§private: u32
Implementations§
source§impl FieldIdx
impl FieldIdx
sourcepub const MAX_AS_U32: u32 = 4_294_967_040u32
pub const MAX_AS_U32: u32 = 4_294_967_040u32
Maximum value the index can take, as a u32
.
sourcepub const fn from_usize(value: usize) -> Self
pub const fn from_usize(value: usize) -> Self
sourcepub const unsafe fn from_u32_unchecked(value: u32) -> Self
pub const unsafe fn from_u32_unchecked(value: u32) -> Self
Creates a new index from a given u32
.
Safety
The provided value must be less than or equal to the maximum value for the newtype. Providing a value outside this range is undefined due to layout restrictions.
Prefer using from_u32
.
Trait Implementations§
source§impl<__CTX> HashStable<__CTX> for FieldIdxwhere
__CTX: HashStableContext,
impl<__CTX> HashStable<__CTX> for FieldIdxwhere __CTX: HashStableContext,
fn hash_stable(&self, __hcx: &mut __CTX, __hasher: &mut StableHasher)
source§impl Ord for FieldIdx
impl Ord for FieldIdx
source§impl PartialEq<FieldIdx> for FieldIdx
impl PartialEq<FieldIdx> for FieldIdx
source§impl PartialOrd<FieldIdx> for FieldIdx
impl PartialOrd<FieldIdx> for FieldIdx
1.0.0 · source§fn le(&self, other: &Rhs) -> bool
fn le(&self, other: &Rhs) -> bool
self
and other
) and is used by the <=
operator. Read moresource§impl Step for FieldIdx
impl Step for FieldIdx
source§fn steps_between(start: &Self, end: &Self) -> Option<usize>
fn steps_between(start: &Self, end: &Self) -> Option<usize>
step_trait
)source§fn forward_checked(start: Self, u: usize) -> Option<Self>
fn forward_checked(start: Self, u: usize) -> Option<Self>
step_trait
)source§fn backward_checked(start: Self, u: usize) -> Option<Self>
fn backward_checked(start: Self, u: usize) -> Option<Self>
step_trait
)source§fn forward(start: Self, count: usize) -> Self
fn forward(start: Self, count: usize) -> Self
step_trait
)source§unsafe fn forward_unchecked(start: Self, count: usize) -> Self
unsafe fn forward_unchecked(start: Self, count: usize) -> Self
step_trait
)source§fn backward(start: Self, count: usize) -> Self
fn backward(start: Self, count: usize) -> Self
step_trait
)source§unsafe fn backward_unchecked(start: Self, count: usize) -> Self
unsafe fn backward_unchecked(start: Self, count: usize) -> Self
step_trait
)impl Copy for FieldIdx
impl Eq for FieldIdx
impl StructuralEq for FieldIdx
impl StructuralPartialEq for FieldIdx
impl TrustedStep for FieldIdx
Auto Trait Implementations§
impl RefUnwindSafe for FieldIdx
impl Send for FieldIdx
impl Sync for FieldIdx
impl Unpin for FieldIdx
impl UnwindSafe for FieldIdx
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: 4 bytes