Type Alias rustc_resolve::macros::MacroRulesScopeRef
source · pub(crate) type MacroRulesScopeRef<'a> = Interned<'a, Cell<MacroRulesScope<'a>>>;
Expand description
macro_rules!
scopes are always kept by reference and inside a cell.
The reason is that we update scopes with value MacroRulesScope::Invocation(invoc_id)
in-place after invoc_id
gets expanded.
This helps to avoid uncontrollable growth of macro_rules!
scope chains,
which usually grow linearly with the number of macro invocations
in a module (including derives) and hurt performance.
Aliased Type§
struct MacroRulesScopeRef<'a>(pub &'a Cell<MacroRulesScope<'a>>, pub PrivateZst);
Fields§
§0: &'a Cell<MacroRulesScope<'a>>
§1: PrivateZst
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: 8 bytes