Merge #9128

9128: feat: expand procedural attribute macros r=jonas-schievink a=jonas-schievink

This adds experimental support for attribute macros. They can be enabled by setting `rust-analyzer.experimental.procAttrMacros` to `true`.

Known issues:
* Tokens aren't remapped, presumably because we edit the input syntax tree (this causes IDE features to not work inside items with attribute macros on them)
* Macro errors aren't reported correctly

Closes https://github.com/rust-analyzer/rust-analyzer/issues/8971
Fixes https://github.com/rust-analyzer/rust-analyzer/issues/8964 / https://github.com/la10736/rstest/issues/120
Fixes https://github.com/rust-analyzer/rust-analyzer/issues/2984
Fixes https://github.com/rust-analyzer/rust-analyzer/issues/5412
Fixes https://github.com/rust-analyzer/rust-analyzer/issues/6029
Fixes https://github.com/rust-analyzer/rust-analyzer/issues/6687

https://github.com/rust-analyzer/rust-analyzer/issues/6740 is still not fixed – we now expand `#[proc_macro_hack]`, but fail to expand the resulting `proc_macro_call!()` macro.

Co-authored-by: Jonas Schievink <[email protected]>

1 files changed, 6 insertions, 1 deletions

diff --git a/crates/hir_expand/src/proc_macro.rs b/crates/hir_expand/src/proc_macro.rs
index d5643393a..dbe1b446e 100644
--- a/crates/hir_expand/src/proc_macro.rs
+++ b/crates/hir_expand/src/proc_macro.rs
@@ -28,11 +28,16 @@ impl ProcMacroExpander {
         Self { krate, proc_macro_id: None }
     }
 
+    pub fn is_dummy(&self) -> bool {
+        self.proc_macro_id.is_none()
+    }
+
     pub fn expand(
         self,
         db: &dyn AstDatabase,
         calling_crate: CrateId,
         tt: &tt::Subtree,
+        attr_arg: Option<&tt::Subtree>,
     ) -> Result<tt::Subtree, mbe::ExpandError> {
         match self.proc_macro_id {
             Some(id) => {
@@ -46,7 +51,7 @@ impl ProcMacroExpander {
                 // Proc macros have access to the environment variables of the invoking crate.
                 let env = &krate_graph[calling_crate].env;
 
-                proc_macro.expander.expand(&tt, None, &env).map_err(mbe::ExpandError::from)
+                proc_macro.expander.expand(&tt, attr_arg, &env).map_err(mbe::ExpandError::from)
             }
             None => Err(mbe::ExpandError::UnresolvedProcMacro),
         }