Enum rustc_trait_selection::infer::canonical::CanonicalVarKind

source · 
pub enum CanonicalVarKind<'tcx> {
    Ty(CanonicalTyVarKind),
    PlaceholderTy(Placeholder<BoundVar>),
    Region(UniverseIndex),
    PlaceholderRegion(Placeholder<BoundRegionKind>),
    Const(UniverseIndex, Ty<'tcx>),
    PlaceholderConst(Placeholder<BoundVar>, Ty<'tcx>),
}
Expand description

Describes the “kind” of the canonical variable. This is a “kind” in the type-theory sense of the term – i.e., a “meta” type system that analyzes type-like values.

Variants§

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Ty(CanonicalTyVarKind)

Some kind of type inference variable.

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PlaceholderTy(Placeholder<BoundVar>)

A “placeholder” that represents “any type”.

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Region(UniverseIndex)

Region variable '?R.

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PlaceholderRegion(Placeholder<BoundRegionKind>)

A “placeholder” that represents “any region”. Created when you are solving a goal like for<'a> T: Foo<'a> to represent the bound region 'a.

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Const(UniverseIndex, Ty<'tcx>)

Some kind of const inference variable.

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PlaceholderConst(Placeholder<BoundVar>, Ty<'tcx>)

A “placeholder” that represents “any const”.

Auto Trait Implementations§

Blanket Implementations§

Gets the TypeId of self. Read more
Immutably borrows from an owned value. Read more
Mutably borrows from an owned value. Read more

Returns the argument unchanged.

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

The resulting type after obtaining ownership.
Creates owned data from borrowed data, usually by cloning. Read more
Uses borrowed data to replace owned data, usually by cloning. Read more
The type returned in the event of a conversion error.
Performs the conversion.
The type returned in the event of a conversion error.
Performs the conversion.

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: 24 bytes

Size for each variant:

  • Ty: 4 bytes
  • PlaceholderTy: 16 bytes
  • Region: 4 bytes
  • PlaceholderRegion: 24 bytes
  • Const: 24 bytes
  • PlaceholderConst: 24 bytes