Enum rustc_expand::hygiene::Transparency

pub enum Transparency {
    Transparent,
    SemiTransparent,
    Opaque,
}

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.

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