Trait wasmtime_environ::__core::fmt::Display

1.0.0 · source ·
pub trait Display {
    // Required method
    fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>;
}
Expand description

Format trait for an empty format, {}.

Implementing this trait for a type will automatically implement the ToString trait for the type, allowing the usage of the .to_string() method. Prefer implementing the Display trait for a type, rather than ToString.

Display is similar to Debug, but Display is for user-facing output, and so cannot be derived.

For more information on formatters, see the module-level documentation.

§Internationalization

Because a type can only have one Display implementation, it is often preferable to only implement Display when there is a single most “obvious” way that values can be formatted as text. This could mean formatting according to the “invariant” culture and “undefined” locale, or it could mean that the type display is designed for a specific culture/locale, such as developer logs.

If not all values have a justifiably canonical textual format or if you want to support alternative formats not covered by the standard set of possible formatting traits, the most flexible approach is display adapters: methods like str::escape_default or Path::display which create a wrapper implementing Display to output the specific display format.

§Examples

Implementing Display on a type:

use std::fmt;

struct Point {
    x: i32,
    y: i32,
}

impl fmt::Display for Point {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "({}, {})", self.x, self.y)
    }
}

let origin = Point { x: 0, y: 0 };

assert_eq!(format!("The origin is: {origin}"), "The origin is: (0, 0)");

Required Methods§

1.0.0 · source

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

Formats the value using the given formatter.

§Errors

This function should return Err if, and only if, the provided Formatter returns Err. String formatting is considered an infallible operation; this function only returns a Result because writing to the underlying stream might fail and it must provide a way to propagate the fact that an error has occurred back up the stack.

§Examples
use std::fmt;

struct Position {
    longitude: f32,
    latitude: f32,
}

impl fmt::Display for Position {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "({}, {})", self.longitude, self.latitude)
    }
}

assert_eq!(
    "(1.987, 2.983)",
    format!("{}", Position { longitude: 1.987, latitude: 2.983, }),
);

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impl Display for gimli::read::Error

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impl Display for ConvertError

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impl Display for gimli::write::Error

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impl Display for leb128::read::Error

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impl Display for Level

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impl Display for LevelFilter

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impl Display for postcard::error::Error

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impl Display for CollectionAllocErr

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impl Display for target_lexicon::parse_error::ParseError

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impl Display for Aarch64Architecture

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impl Display for Architecture

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impl Display for ArmArchitecture

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impl Display for BinaryFormat

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impl Display for Environment

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impl Display for Mips32Architecture

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impl Display for Mips64Architecture

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impl Display for OperatingSystem

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impl Display for Riscv32Architecture

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impl Display for Riscv64Architecture

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impl Display for Vendor

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impl Display for X86_32Architecture

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impl Display for PrimitiveValType

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impl Display for StorageType

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impl Display for UnpackedIndex

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impl Display for ValType

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impl Display for CompileError

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impl Display for EngineOrModuleTypeIndex

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impl Display for FlagValue<'_>

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impl Display for Trap

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impl Display for WasmCompositeType

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impl Display for WasmError

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impl Display for WasmHeapType

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impl Display for WasmStorageType

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impl Display for WasmValType

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impl Display for AsciiChar

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impl Display for Infallible

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impl Display for IpAddr

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impl Display for SocketAddr

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impl Display for VarError

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impl Display for ErrorKind

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impl Display for RecvTimeoutError

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impl Display for TryRecvError

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impl Display for bool

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impl Display for char

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impl Display for f32

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impl Display for f64

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impl Display for i8

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impl Display for i16

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impl Display for i32

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impl Display for i64

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impl Display for i128

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impl Display for isize

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impl Display for !

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impl Display for str

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impl Display for u8

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impl Display for u16

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impl Display for u32

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impl Display for u64

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impl Display for u128

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impl Display for usize

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impl Display for allocator_api2::stable::alloc::AllocError

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impl Display for allocator_api2::stable::raw_vec::TryReserveError

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impl Display for anyhow::Error

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impl Display for bitflags::parser::ParseError

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impl Display for DwAccess

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impl Display for DwAddr

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impl Display for DwAt

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impl Display for DwAte

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impl Display for DwCc

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impl Display for DwCfa

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impl Display for DwChildren

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impl Display for DwDefaulted

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impl Display for DwDs

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impl Display for DwDsc

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impl Display for DwEhPe

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impl Display for DwEnd

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impl Display for DwForm

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impl Display for DwId

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impl Display for DwIdx

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impl Display for DwInl

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impl Display for DwLang

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impl Display for DwLle

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impl Display for DwLnct

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impl Display for DwLne

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impl Display for DwLns

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impl Display for DwMacro

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impl Display for DwOp

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impl Display for DwOrd

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impl Display for DwRle

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impl Display for DwSect

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impl Display for DwSectV2

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impl Display for DwTag

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impl Display for DwUt

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impl Display for DwVirtuality

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impl Display for DwVis

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impl Display for indexmap::TryReserveError

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impl Display for ParseLevelError

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impl Display for SetLoggerError

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impl Display for object::read::Error

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impl Display for SectionIndex

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impl Display for SymbolIndex

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impl Display for object::write::Error

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impl Display for semver::parse::Error

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impl Display for BuildMetadata

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impl Display for Comparator

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impl Display for Prerelease

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impl Display for Version

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impl Display for VersionReq

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impl Display for serde::de::value::Error

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impl Display for Triple

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impl Display for ColorChoiceParseError

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impl Display for ParseColorError

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impl Display for BinaryReaderError

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impl Display for CompositeType

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impl Display for PackedIndex

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impl Display for RefType

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impl Display for SubType

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impl Display for ComponentName

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impl Display for KebabStr

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impl Display for KebabString

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impl Display for String

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impl Display for SizeOverflow

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impl Display for WasmArrayType

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impl Display for WasmFieldType

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impl Display for WasmFuncType

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impl Display for WasmRefType

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impl Display for WasmStructType

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impl Display for WasmSubType

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impl Display for wasmtime_environ::__core::alloc::AllocError

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impl Display for LayoutError

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impl Display for TryFromSliceError

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impl Display for wasmtime_environ::__core::ascii::EscapeDefault

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impl Display for BorrowError

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impl Display for BorrowMutError

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impl Display for CharTryFromError

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impl Display for DecodeUtf16Error

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impl Display for wasmtime_environ::__core::char::EscapeDebug

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impl Display for wasmtime_environ::__core::char::EscapeDefault

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impl Display for wasmtime_environ::__core::char::EscapeUnicode

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impl Display for ParseCharError

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impl Display for ToLowercase

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impl Display for ToUppercase

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impl Display for TryFromCharError

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impl Display for FromBytesUntilNulError

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impl Display for FromBytesWithNulError

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impl Display for AddrParseError

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impl Display for Ipv4Addr

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impl Display for Ipv6Addr

Writes an Ipv6Addr, conforming to the canonical style described by RFC 5952.

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impl Display for SocketAddrV4

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impl Display for SocketAddrV6

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impl Display for ParseFloatError

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impl Display for ParseIntError

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impl Display for TryFromIntError

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impl Display for Location<'_>

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impl Display for PanicInfo<'_>

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impl Display for PanicMessage<'_>

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impl Display for ParseBoolError

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impl Display for Utf8Error

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impl Display for TryFromFloatSecsError

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impl Display for UnorderedKeyError

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impl Display for alloc::collections::TryReserveError

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impl Display for FromVecWithNulError

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impl Display for IntoStringError

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impl Display for NulError

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impl Display for FromUtf8Error

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impl Display for FromUtf16Error

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impl Display for Backtrace

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impl Display for JoinPathsError

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impl Display for std::ffi::os_str::Display<'_>

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impl Display for WriterPanicked

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impl Display for std::io::error::Error

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impl Display for PanicHookInfo<'_>

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impl Display for std::path::Display<'_>

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impl Display for StripPrefixError

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impl Display for ExitStatus

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impl Display for ExitStatusError

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impl Display for RecvError

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impl Display for AccessError

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impl Display for SystemTimeError

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impl Display for Arguments<'_>

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impl Display for wasmtime_environ::__core::fmt::Error

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impl Display for dyn Expected + '_

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impl<'a> Display for Unexpected<'a>

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impl<'a> Display for EscapeAscii<'a>

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impl<'a> Display for wasmtime_environ::__core::str::EscapeDebug<'a>

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impl<'a> Display for wasmtime_environ::__core::str::EscapeDefault<'a>

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impl<'a> Display for wasmtime_environ::__core::str::EscapeUnicode<'a>

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impl<'a, K, V> Display for std::collections::hash::map::OccupiedError<'a, K, V>
where K: Debug, V: Debug,

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impl<'a, K, V, A> Display for alloc::collections::btree::map::entry::OccupiedError<'a, K, V, A>
where K: Debug + Ord, V: Debug, A: Allocator + Clone,

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impl<'a, K, V, S, A> Display for hashbrown::map::OccupiedError<'a, K, V, S, A>
where K: Debug, V: Debug, A: Allocator,

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impl<B> Display for Cow<'_, B>
where B: Display + ToOwned + ?Sized, <B as ToOwned>::Owned: Display,

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impl<E> Display for Report<E>
where E: Error,

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impl<F> Display for FromFn<F>
where F: Fn(&mut Formatter<'_>) -> Result<(), Error>,

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impl<K, V, S, A> Display for hashbrown::map::OccupiedError<'_, K, V, S, A>
where K: Debug, V: Debug, A: Allocator,

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impl<O> Display for F32<O>
where O: ByteOrder,

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impl<O> Display for F64<O>
where O: ByteOrder,

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impl<O> Display for I16<O>
where O: ByteOrder,

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impl<O> Display for I32<O>
where O: ByteOrder,

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impl<O> Display for I64<O>
where O: ByteOrder,

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impl<O> Display for I128<O>
where O: ByteOrder,

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impl<O> Display for U16<O>
where O: ByteOrder,

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impl<O> Display for U32<O>
where O: ByteOrder,

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impl<O> Display for U64<O>
where O: ByteOrder,

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impl<O> Display for U128<O>
where O: ByteOrder,

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impl<Ptr> Display for Pin<Ptr>
where Ptr: Display,

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impl<T> Display for TrySendError<T>

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impl<T> Display for TryLockError<T>

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impl<T> Display for &T
where T: Display + ?Sized,

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impl<T> Display for &mut T
where T: Display + ?Sized,

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impl<T> Display for Unalign<T>
where T: Unaligned + Display,

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impl<T> Display for wasmtime_environ::__core::cell::Ref<'_, T>
where T: Display + ?Sized,

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impl<T> Display for RefMut<'_, T>
where T: Display + ?Sized,

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impl<T> Display for NonZero<T>

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impl<T> Display for Saturating<T>
where T: Display,

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impl<T> Display for Wrapping<T>
where T: Display,

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impl<T> Display for ThinBox<T>
where T: Display + ?Sized,

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impl<T> Display for SendError<T>

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impl<T> Display for MappedMutexGuard<'_, T>
where T: Display + ?Sized,

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impl<T> Display for MutexGuard<'_, T>
where T: Display + ?Sized,

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impl<T> Display for PoisonError<T>

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impl<T> Display for ReentrantLockGuard<'_, T>
where T: Display + ?Sized,

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impl<T> Display for MappedRwLockReadGuard<'_, T>
where T: Display + ?Sized,

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impl<T> Display for MappedRwLockWriteGuard<'_, T>
where T: Display + ?Sized,

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impl<T> Display for RwLockReadGuard<'_, T>
where T: Display + ?Sized,

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impl<T> Display for RwLockWriteGuard<'_, T>
where T: Display + ?Sized,

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impl<T, A> Display for allocator_api2::stable::boxed::Box<T, A>
where T: Display + ?Sized, A: Allocator,

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impl<T, A> Display for wasmtime_environ::prelude::Box<T, A>
where T: Display + ?Sized, A: Allocator,

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impl<T, A> Display for Rc<T, A>
where T: Display + ?Sized, A: Allocator,

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impl<T, A> Display for Arc<T, A>
where T: Display + ?Sized, A: Allocator,

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impl<T, B> Display for zerocopy::Ref<B, [T]>
where B: ByteSlice, T: FromBytes, [T]: Display,

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impl<T, B> Display for zerocopy::Ref<B, T>
where B: ByteSlice, T: FromBytes + Display,

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impl<W> Display for IntoInnerError<W>

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impl<const N: usize> Display for GetManyMutError<N>