A bunch of methods and structures more or less related to resolving macros and
interface provided by
Resolver to macro expander.
Binding produced by a
macro_rulesitem. Not modularized, can shadow previous
The scope introduced by a
macro_rules!macro. This starts at the macro’s definition and ends at the end of the macro’s parent module (named or unnamed), or even further if it escapes with
#[macro_use]. Some macro invocations need to introduce
macro_rulesscopes too because they can potentially expand into macro definitions.
Macro namespace is separated into two sub-namespaces, one for bang macros and one for attribute-like macros (attributes, derives). We ignore resolutions from one sub-namespace when searching names in scope for another.
macro_rules!scopes are always kept by reference and inside a cell. The reason is that we update scopes with value
invoc_idgets 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.