Struct scale_info::Field

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pub struct Field<T: Form = MetaForm> {
    pub name: Option<T::String>,
    pub ty: T::Type,
    pub type_name: Option<T::String>,
    pub docs: Vec<T::String>,
}
Expand description

A field of a struct-like data type.

Name is optional so it can represent both named and unnamed fields.

This can be a named field of a struct type or an enum struct variant, or an unnamed field of a tuple struct.

§Type name

The type_name field contains a string which is the name of the type of the field as it appears in the source code. The exact contents and format of the type name are not specified, but in practice will be the name of any valid type for a field e.g.

  • Concrete types e.g "u32", "bool", "Foo" etc.
  • Type parameters e.g "T", "U"
  • Generic types e.g "Vec<u32>", "Vec<T>"
  • Associated types e.g. "T::MyType", "<T as MyTrait>::MyType"
  • Type aliases e.g. "MyTypeAlias", "MyTypeAlias<T>"
  • Other built in Rust types e.g. arrays, references etc.

Note that the type name doesn’t correspond to the underlying type of the field, unless using a concrete type directly. Any given type may be referred to by multiple field type names, when using generic type parameters and type aliases.

This is intended for informational and diagnostic purposes only. Although it is possible to infer certain properties e.g. whether a type name is a type alias, there are no guarantees provided, and the type name representation may change.

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§name: Option<T::String>

The name of the field. None for unnamed fields.

§ty: T::Type

The type of the field.

§type_name: Option<T::String>

The name of the type of the field as it appears in the source code.

§docs: Vec<T::String>

Documentation

Implementations§

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impl<T> Field<T>
where T: Form,

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pub fn builder() -> FieldBuilder<T>

Returns a new FieldBuilder for constructing a field.

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pub fn new( name: Option<T::String>, ty: T::Type, type_name: Option<T::String>, docs: Vec<T::String>, ) -> Self

Creates a new field.

Use this constructor if you want to instantiate from a given meta type.

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impl<T> Field<T>
where T: Form,

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pub fn name(&self) -> Option<&T::String>

👎Deprecated since 2.5.0: Prefer to access the fields directly; this getter will be removed in the next major version

Returns the name of the field. None for unnamed fields.

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pub fn ty(&self) -> &T::Type

👎Deprecated since 2.5.0: Prefer to access the fields directly; this getter will be removed in the next major version

Returns the type of the field.

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pub fn type_name(&self) -> Option<&T::String>

👎Deprecated since 2.5.0: Prefer to access the fields directly; this getter will be removed in the next major version

Returns a string which is the name of the type of the field as it appears in the source code. The exact contents and format of the type name are not specified, but in practice will be the name of any valid type for a field. This is intended for informational and diagnostic purposes only.

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pub fn docs(&self) -> &[T::String]

👎Deprecated since 2.5.0: Prefer to access the fields directly; this getter will be removed in the next major version

Returns the documentation of the field.

Trait Implementations§

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impl<T: Clone + Form> Clone for Field<T>
where T::String: Clone, T::Type: Clone,

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fn clone(&self) -> Field<T>

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
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impl<T: Debug + Form> Debug for Field<T>
where T::String: Debug, T::Type: Debug,

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

Formats the value using the given formatter. Read more
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impl<T: Form> Decode for Field<T>
where Option<T::String>: Decode, T::Type: Decode, Vec<T::String>: Decode,

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fn decode<__CodecInputEdqy: Input>( __codec_input_edqy: &mut __CodecInputEdqy, ) -> Result<Self, Error>

Attempt to deserialise the value from input.
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fn decode_into<I>( input: &mut I, dst: &mut MaybeUninit<Self>, ) -> Result<DecodeFinished, Error>
where I: Input,

Attempt to deserialize the value from input into a pre-allocated piece of memory. Read more
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fn skip<I>(input: &mut I) -> Result<(), Error>
where I: Input,

Attempt to skip the encoded value from input. Read more
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fn encoded_fixed_size() -> Option<usize>

Returns the fixed encoded size of the type. Read more
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impl<'de, T: Form> Deserialize<'de> for Field<T>

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fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>
where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer. Read more
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impl<T: Form> Encode for Field<T>
where Option<T::String>: Encode, T::Type: Encode, Vec<T::String>: Encode,

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fn size_hint(&self) -> usize

If possible give a hint of expected size of the encoding. Read more
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fn encode_to<__CodecOutputEdqy: Output + ?Sized>( &self, __codec_dest_edqy: &mut __CodecOutputEdqy, )

Convert self to a slice and append it to the destination.
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fn encode(&self) -> Vec<u8>

Convert self to an owned vector.
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fn using_encoded<R, F>(&self, f: F) -> R
where F: FnOnce(&[u8]) -> R,

Convert self to a slice and then invoke the given closure with it.
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fn encoded_size(&self) -> usize

Calculates the encoded size. Read more
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impl IntoPortable for Field

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type Output = Field<PortableForm>

The portable version of Self.
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fn into_portable(self, registry: &mut Registry) -> Self::Output

Convert self to the portable form by using the registry for caching.
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impl<T: Ord + Form> Ord for Field<T>
where T::String: Ord, T::Type: Ord,

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fn cmp(&self, other: &Field<T>) -> Ordering

This method returns an Ordering between self and other. Read more
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fn max(self, other: Self) -> Self
where Self: Sized,

Compares and returns the maximum of two values. Read more
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fn min(self, other: Self) -> Self
where Self: Sized,

Compares and returns the minimum of two values. Read more
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fn clamp(self, min: Self, max: Self) -> Self
where Self: Sized + PartialOrd,

Restrict a value to a certain interval. Read more
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impl<T: PartialEq + Form> PartialEq for Field<T>
where T::String: PartialEq, T::Type: PartialEq,

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fn eq(&self, other: &Field<T>) -> bool

This method tests for self and other values to be equal, and is used by ==.
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fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.
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impl<T: PartialOrd + Form> PartialOrd for Field<T>

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fn partial_cmp(&self, other: &Field<T>) -> Option<Ordering>

This method returns an ordering between self and other values if one exists. Read more
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fn lt(&self, other: &Rhs) -> bool

This method tests less than (for self and other) and is used by the < operator. Read more
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fn le(&self, other: &Rhs) -> bool

This method tests less than or equal to (for self and other) and is used by the <= operator. Read more
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fn gt(&self, other: &Rhs) -> bool

This method tests greater than (for self and other) and is used by the > operator. Read more
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fn ge(&self, other: &Rhs) -> bool

This method tests greater than or equal to (for self and other) and is used by the >= operator. Read more
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impl<T: Form> Serialize for Field<T>
where T::Type: Serialize, T::String: Serialize,

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fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>
where __S: Serializer,

Serialize this value into the given Serde serializer. Read more
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impl<T: Form> EncodeLike for Field<T>
where Option<T::String>: Encode, T::Type: Encode, Vec<T::String>: Encode,

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impl<T: Eq + Form> Eq for Field<T>
where T::String: Eq, T::Type: Eq,

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impl<T: Form> StructuralPartialEq for Field<T>

Auto Trait Implementations§

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impl<T> Freeze for Field<T>
where <T as Form>::Type: Freeze, <T as Form>::String: Freeze,

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impl<T> RefUnwindSafe for Field<T>
where <T as Form>::Type: RefUnwindSafe, <T as Form>::String: RefUnwindSafe,

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impl<T> Send for Field<T>
where <T as Form>::Type: Send, <T as Form>::String: Send,

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impl<T> Sync for Field<T>
where <T as Form>::Type: Sync, <T as Form>::String: Sync,

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impl<T> Unpin for Field<T>
where <T as Form>::Type: Unpin, <T as Form>::String: Unpin,

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impl<T> UnwindSafe for Field<T>
where <T as Form>::Type: UnwindSafe, <T as Form>::String: UnwindSafe,

Blanket Implementations§

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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> CloneToUninit for T
where T: Clone,

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default unsafe fn clone_to_uninit(&self, dst: *mut T)

🔬This is a nightly-only experimental API. (clone_to_uninit)
Performs copy-assignment from self to dst. Read more
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impl<T> Conv for T

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fn conv<T>(self) -> T
where Self: Into<T>,

Converts self into T using Into<T>. Read more
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impl<T> DecodeAll for T
where T: Decode,

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fn decode_all(input: &mut &[u8]) -> Result<T, Error>

Decode Self and consume all of the given input data. Read more
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impl<T> DecodeLimit for T
where T: Decode,

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fn decode_all_with_depth_limit( limit: u32, input: &mut &[u8], ) -> Result<T, Error>

Decode Self and consume all of the given input data. Read more
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fn decode_with_depth_limit<I>(limit: u32, input: &mut I) -> Result<T, Error>
where I: Input,

Decode Self with the given maximum recursion depth and advance input by the number of bytes consumed. Read more
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impl<T> FmtForward for T

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fn fmt_binary(self) -> FmtBinary<Self>
where Self: Binary,

Causes self to use its Binary implementation when Debug-formatted.
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fn fmt_display(self) -> FmtDisplay<Self>
where Self: Display,

Causes self to use its Display implementation when Debug-formatted.
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fn fmt_lower_exp(self) -> FmtLowerExp<Self>
where Self: LowerExp,

Causes self to use its LowerExp implementation when Debug-formatted.
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fn fmt_lower_hex(self) -> FmtLowerHex<Self>
where Self: LowerHex,

Causes self to use its LowerHex implementation when Debug-formatted.
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fn fmt_octal(self) -> FmtOctal<Self>
where Self: Octal,

Causes self to use its Octal implementation when Debug-formatted.
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fn fmt_pointer(self) -> FmtPointer<Self>
where Self: Pointer,

Causes self to use its Pointer implementation when Debug-formatted.
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fn fmt_upper_exp(self) -> FmtUpperExp<Self>
where Self: UpperExp,

Causes self to use its UpperExp implementation when Debug-formatted.
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fn fmt_upper_hex(self) -> FmtUpperHex<Self>
where Self: UpperHex,

Causes self to use its UpperHex implementation when Debug-formatted.
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fn fmt_list(self) -> FmtList<Self>
where &'a Self: for<'a> IntoIterator,

Formats each item in a sequence. 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, U> Into<U> for T
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> KeyedVec for T
where T: Codec,

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fn to_keyed_vec(&self, prepend_key: &[u8]) -> Vec<u8>

Return an encoding of Self prepended by given slice.
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impl<T> Pipe for T
where T: ?Sized,

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fn pipe<R>(self, func: impl FnOnce(Self) -> R) -> R
where Self: Sized,

Pipes by value. This is generally the method you want to use. Read more
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fn pipe_ref<'a, R>(&'a self, func: impl FnOnce(&'a Self) -> R) -> R
where R: 'a,

Borrows self and passes that borrow into the pipe function. Read more
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fn pipe_ref_mut<'a, R>(&'a mut self, func: impl FnOnce(&'a mut Self) -> R) -> R
where R: 'a,

Mutably borrows self and passes that borrow into the pipe function. Read more
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fn pipe_borrow<'a, B, R>(&'a self, func: impl FnOnce(&'a B) -> R) -> R
where Self: Borrow<B>, B: 'a + ?Sized, R: 'a,

Borrows self, then passes self.borrow() into the pipe function. Read more
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fn pipe_borrow_mut<'a, B, R>( &'a mut self, func: impl FnOnce(&'a mut B) -> R, ) -> R
where Self: BorrowMut<B>, B: 'a + ?Sized, R: 'a,

Mutably borrows self, then passes self.borrow_mut() into the pipe function. Read more
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fn pipe_as_ref<'a, U, R>(&'a self, func: impl FnOnce(&'a U) -> R) -> R
where Self: AsRef<U>, U: 'a + ?Sized, R: 'a,

Borrows self, then passes self.as_ref() into the pipe function.
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fn pipe_as_mut<'a, U, R>(&'a mut self, func: impl FnOnce(&'a mut U) -> R) -> R
where Self: AsMut<U>, U: 'a + ?Sized, R: 'a,

Mutably borrows self, then passes self.as_mut() into the pipe function.
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fn pipe_deref<'a, T, R>(&'a self, func: impl FnOnce(&'a T) -> R) -> R
where Self: Deref<Target = T>, T: 'a + ?Sized, R: 'a,

Borrows self, then passes self.deref() into the pipe function.
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fn pipe_deref_mut<'a, T, R>( &'a mut self, func: impl FnOnce(&'a mut T) -> R, ) -> R
where Self: DerefMut<Target = T> + Deref, T: 'a + ?Sized, R: 'a,

Mutably borrows self, then passes self.deref_mut() into the pipe function.
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impl<T> Tap for T

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fn tap(self, func: impl FnOnce(&Self)) -> Self

Immutable access to a value. Read more
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fn tap_mut(self, func: impl FnOnce(&mut Self)) -> Self

Mutable access to a value. Read more
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fn tap_borrow<B>(self, func: impl FnOnce(&B)) -> Self
where Self: Borrow<B>, B: ?Sized,

Immutable access to the Borrow<B> of a value. Read more
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fn tap_borrow_mut<B>(self, func: impl FnOnce(&mut B)) -> Self
where Self: BorrowMut<B>, B: ?Sized,

Mutable access to the BorrowMut<B> of a value. Read more
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fn tap_ref<R>(self, func: impl FnOnce(&R)) -> Self
where Self: AsRef<R>, R: ?Sized,

Immutable access to the AsRef<R> view of a value. Read more
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fn tap_ref_mut<R>(self, func: impl FnOnce(&mut R)) -> Self
where Self: AsMut<R>, R: ?Sized,

Mutable access to the AsMut<R> view of a value. Read more
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fn tap_deref<T>(self, func: impl FnOnce(&T)) -> Self
where Self: Deref<Target = T>, T: ?Sized,

Immutable access to the Deref::Target of a value. Read more
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fn tap_deref_mut<T>(self, func: impl FnOnce(&mut T)) -> Self
where Self: DerefMut<Target = T> + Deref, T: ?Sized,

Mutable access to the Deref::Target of a value. Read more
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fn tap_dbg(self, func: impl FnOnce(&Self)) -> Self

Calls .tap() only in debug builds, and is erased in release builds.
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fn tap_mut_dbg(self, func: impl FnOnce(&mut Self)) -> Self

Calls .tap_mut() only in debug builds, and is erased in release builds.
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fn tap_borrow_dbg<B>(self, func: impl FnOnce(&B)) -> Self
where Self: Borrow<B>, B: ?Sized,

Calls .tap_borrow() only in debug builds, and is erased in release builds.
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fn tap_borrow_mut_dbg<B>(self, func: impl FnOnce(&mut B)) -> Self
where Self: BorrowMut<B>, B: ?Sized,

Calls .tap_borrow_mut() only in debug builds, and is erased in release builds.
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fn tap_ref_dbg<R>(self, func: impl FnOnce(&R)) -> Self
where Self: AsRef<R>, R: ?Sized,

Calls .tap_ref() only in debug builds, and is erased in release builds.
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fn tap_ref_mut_dbg<R>(self, func: impl FnOnce(&mut R)) -> Self
where Self: AsMut<R>, R: ?Sized,

Calls .tap_ref_mut() only in debug builds, and is erased in release builds.
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fn tap_deref_dbg<T>(self, func: impl FnOnce(&T)) -> Self
where Self: Deref<Target = T>, T: ?Sized,

Calls .tap_deref() only in debug builds, and is erased in release builds.
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fn tap_deref_mut_dbg<T>(self, func: impl FnOnce(&mut T)) -> Self
where Self: DerefMut<Target = T> + Deref, T: ?Sized,

Calls .tap_deref_mut() only in debug builds, and is erased in release builds.
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impl<T> ToOwned for T
where T: Clone,

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type Owned = T

The resulting type after obtaining ownership.
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fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
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fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
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impl<T> TryConv for T

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fn try_conv<T>(self) -> Result<T, Self::Error>
where Self: TryInto<T>,

Attempts to convert self into T using TryInto<T>. Read more
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impl<T, U> TryFrom<U> for T
where U: Into<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
where U: TryFrom<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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impl<S> Codec for S
where S: Decode + Encode,

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impl<T> DeserializeOwned for T
where T: for<'de> Deserialize<'de>,

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impl<T> EncodeLike<&&T> for T
where T: Encode,

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impl<T> EncodeLike<&T> for T
where T: Encode,

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impl<T> EncodeLike<&mut T> for T
where T: Encode,

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impl<T> EncodeLike<Arc<T>> for T
where T: Encode,

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impl<T> EncodeLike<Box<T>> for T
where T: Encode,

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impl<'a, T> EncodeLike<Cow<'a, T>> for T
where T: ToOwned + Encode,

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impl<T> EncodeLike<Rc<T>> for T
where T: Encode,

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impl<S> FullCodec for S
where S: Decode + FullEncode,

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impl<S> FullEncode for S
where S: Encode + EncodeLike,

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impl<T> JsonSchemaMaybe for T