Go to definition doesn't work for unqualified function-like proc macros

[lnicola]

// using the unzip-n crate

use unzip_n::unzip_n;

unzip_n!(3); // trigger go to def here
unzip_n::unzip_n!(4); // this one works

fn main() {}

[AdnoC]

Issue is that hir::MacroDef does not have an ast-node when it is for a proc-macro. (See https://rust-lang.zulipchat.com/#narrow/stream/185405-t-compiler.2Fwg-rls-2.2E0/topic/proc-macro.20no.20ast-node). When doing unzip_n::unzip_n!(4) we classify it as a function rather than a macro. And this for some reason works.

Specifically, the NameRefClass for unzip_n!(3) is

Definition(Macro(MacroDef { id: MacroDefId { krate: CrateId(53), ast_id: None, kind: ProcMacro(ProcMacroExpander { krate: CrateId(53), proc_macro_id: None }), local_inner: false } }))

and the NameRefClass for unizp_n::unzip_n!(4) is

Definition(ModuleDef(Function(Function { id: FunctionId(1115) })))

[jonas-schievink]

This was fixed by #8088, I'll try to add a test