pub enum Transparency {
    Transparent,
    SemiTransparent,
    Opaque,
}
Expand description

A property of a macro expansion that determines how identifiers produced by that expansion are resolved.

Variants

Transparent

Identifier produced by a transparent expansion is always resolved at call-site. Call-site spans in procedural macros, hygiene opt-out in macro should use this.

SemiTransparent

Identifier produced by a semi-transparent expansion may be resolved either at call-site or at definition-site. If it’s a local variable, label or $crate then it’s resolved at def-site. Otherwise it’s resolved at call-site. macro_rules macros behave like this, built-in macros currently behave like this too, but that’s an implementation detail.

Opaque

Identifier produced by an opaque expansion is always resolved at definition-site. Def-site spans in procedural macros, identifiers from macro by default use this.

Trait Implementations

Returns a copy of the value. Read more
Performs copy-assignment from source. Read more
Formats the value using the given formatter. Read more
Feeds this value into the given Hasher. Read more
Feeds a slice of this type into the given Hasher. Read more
This method tests for self and other values to be equal, and is used by ==. Read more
This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason. Read more
This method returns an ordering between self and other values if one exists. Read more
This method tests less than (for self and other) and is used by the < operator. Read more
This method tests less than or equal to (for self and other) and is used by the <= operator. Read more
This method tests greater than (for self and other) and is used by the > operator. Read more
This method tests greater than or equal to (for self and other) and is used by the >= operator. Read more

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: 1 byte

Size for each variant:

  • Transparent: 0 bytes
  • SemiTransparent: 0 bytes
  • Opaque: 0 bytes