Function sub_namespace_match 

fn sub_namespace_match(
    db: &dyn SourceDatabase,
    macro_id: MacroId,
    expected: Option<MacroSubNs>,
) -> bool

Quoted from rustc: 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.