3 files changed, 64 insertions, 9 deletions

diff --git a/crates/ra_project_model/src/cargo_workspace.rs b/crates/ra_project_model/src/cargo_workspace.rs
index c7f9bd873..291594e2a 100644
--- a/crates/ra_project_model/src/cargo_workspace.rs
+++ b/crates/ra_project_model/src/cargo_workspace.rs
@@ -83,6 +83,7 @@ pub struct PackageData {
     pub edition: Edition,
     pub features: Vec<String>,
     pub out_dir: Option<PathBuf>,
+    pub proc_macro_dylib_path: Option<PathBuf>,
 }
 
 #[derive(Debug, Clone)]
@@ -158,8 +159,11 @@ impl CargoWorkspace {
         })?;
 
         let mut out_dir_by_id = FxHashMap::default();
+        let mut proc_macro_dylib_paths = FxHashMap::default();
         if cargo_features.load_out_dirs_from_check {
-            out_dir_by_id = load_out_dirs(cargo_toml, cargo_features);
+            let resources = load_extern_resources(cargo_toml, cargo_features);
+            out_dir_by_id = resources.out_dirs;
+            proc_macro_dylib_paths = resources.proc_dylib_paths;
         }
 
         let mut pkg_by_id = FxHashMap::default();
@@ -183,6 +187,7 @@ impl CargoWorkspace {
                 dependencies: Vec::new(),
                 features: Vec::new(),
                 out_dir: out_dir_by_id.get(&id).cloned(),
+                proc_macro_dylib_path: proc_macro_dylib_paths.get(&id).cloned(),
             });
             let pkg_data = &mut packages[pkg];
             pkg_by_id.insert(id, pkg);
@@ -246,10 +251,13 @@ impl CargoWorkspace {
     }
 }
 
-pub fn load_out_dirs(
-    cargo_toml: &Path,
-    cargo_features: &CargoFeatures,
-) -> FxHashMap<PackageId, PathBuf> {
+#[derive(Debug, Clone, Default)]
+pub struct ExternResources {
+    out_dirs: FxHashMap<PackageId, PathBuf>,
+    proc_dylib_paths: FxHashMap<PackageId, PathBuf>,
+}
+
+pub fn load_extern_resources(cargo_toml: &Path, cargo_features: &CargoFeatures) -> ExternResources {
     let mut args: Vec<String> = vec![
         "check".to_string(),
         "--message-format=json".to_string(),
@@ -267,14 +275,21 @@ pub fn load_out_dirs(
         args.extend(cargo_features.features.iter().cloned());
     }
 
-    let mut acc = FxHashMap::default();
+    let mut acc = ExternResources::default();
     let res = run_cargo(&args, cargo_toml.parent(), &mut |message| {
         match message {
             Message::BuildScriptExecuted(BuildScript { package_id, out_dir, .. }) => {
-                acc.insert(package_id, out_dir);
+                acc.out_dirs.insert(package_id, out_dir);
             }
 
-            Message::CompilerArtifact(_) => (),
+            Message::CompilerArtifact(message) => {
+                if message.target.kind.contains(&"proc-macro".to_string()) {
+                    let package_id = message.package_id;
+                    if let Some(filename) = message.filenames.get(0) {
+                        acc.proc_dylib_paths.insert(package_id, filename.clone());
+                    }
+                }
+            }
             Message::CompilerMessage(_) => (),
             Message::Unknown => (),
         }
diff --git a/crates/ra_project_model/src/json_project.rs b/crates/ra_project_model/src/json_project.rs
index 336446e58..b030c8a6a 100644
--- a/crates/ra_project_model/src/json_project.rs
+++ b/crates/ra_project_model/src/json_project.rs
@@ -23,6 +23,7 @@ pub struct Crate {
     pub(crate) atom_cfgs: FxHashSet<String>,
     pub(crate) key_value_cfgs: FxHashMap<String, String>,
     pub(crate) out_dir: Option<PathBuf>,
+    pub(crate) proc_macro_dylib_path: Option<PathBuf>,
 }
 
 #[derive(Clone, Copy, Debug, Deserialize)]
diff --git a/crates/ra_project_model/src/lib.rs b/crates/ra_project_model/src/lib.rs
index a3ef9acdc..444d3bb3f 100644
--- a/crates/ra_project_model/src/lib.rs
+++ b/crates/ra_project_model/src/lib.rs
@@ -23,6 +23,7 @@ pub use crate::{
     json_project::JsonProject,
     sysroot::Sysroot,
 };
+pub use ra_proc_macro::ProcMacroClient;
 
 #[derive(Clone, PartialEq, Eq, Hash, Debug)]
 pub struct CargoTomlNotFoundError {
@@ -173,6 +174,29 @@ impl ProjectWorkspace {
         }
     }
 
+    pub fn proc_macro_dylib_paths(&self) -> Vec<PathBuf> {
+        match self {
+            ProjectWorkspace::Json { project } => {
+                let mut proc_macro_dylib_paths = Vec::with_capacity(project.crates.len());
+                for krate in &project.crates {
+                    if let Some(out_dir) = &krate.proc_macro_dylib_path {
+                        proc_macro_dylib_paths.push(out_dir.to_path_buf());
+                    }
+                }
+                proc_macro_dylib_paths
+            }
+            ProjectWorkspace::Cargo { cargo, sysroot: _sysroot } => {
+                let mut proc_macro_dylib_paths = Vec::with_capacity(cargo.packages().len());
+                for pkg in cargo.packages() {
+                    if let Some(dylib_path) = &cargo[pkg].proc_macro_dylib_path {
+                        proc_macro_dylib_paths.push(dylib_path.to_path_buf());
+                    }
+                }
+                proc_macro_dylib_paths
+            }
+        }
+    }
+
     pub fn n_packages(&self) -> usize {
         match self {
             ProjectWorkspace::Json { project } => project.crates.len(),
@@ -186,6 +210,7 @@ impl ProjectWorkspace {
         &self,
         default_cfg_options: &CfgOptions,
         extern_source_roots: &FxHashMap<PathBuf, ExternSourceId>,
+        proc_macro_client: &ProcMacroClient,
         load: &mut dyn FnMut(&Path) -> Option<FileId>,
     ) -> CrateGraph {
         let mut crate_graph = CrateGraph::default();
@@ -219,7 +244,10 @@ impl ProjectWorkspace {
                                 extern_source.set_extern_path(&out_dir, extern_source_id);
                             }
                         }
-
+                        let proc_macro = krate
+                            .proc_macro_dylib_path
+                            .clone()
+                            .map(|it| proc_macro_client.by_dylib_path(&it));
                         // FIXME: No crate name in json definition such that we cannot add OUT_DIR to env
                         crates.insert(
                             crate_id,
@@ -231,6 +259,7 @@ impl ProjectWorkspace {
                                 cfg_options,
                                 env,
                                 extern_source,
+                                proc_macro.unwrap_or_default(),
                             ),
                         );
                     }
@@ -270,6 +299,8 @@ impl ProjectWorkspace {
 
                         let env = Env::default();
                         let extern_source = ExternSource::default();
+                        let proc_macro = vec![];
+
                         let crate_id = crate_graph.add_crate_root(
                             file_id,
                             Edition::Edition2018,
@@ -280,6 +311,7 @@ impl ProjectWorkspace {
                             cfg_options,
                             env,
                             extern_source,
+                            proc_macro,
                         );
                         sysroot_crates.insert(krate, crate_id);
                     }
@@ -327,6 +359,12 @@ impl ProjectWorkspace {
                                     extern_source.set_extern_path(&out_dir, extern_source_id);
                                 }
                             }
+                            let proc_macro = cargo[pkg]
+                                .proc_macro_dylib_path
+                                .as_ref()
+                                .map(|it| proc_macro_client.by_dylib_path(&it))
+                                .unwrap_or_default();
+
                             let crate_id = crate_graph.add_crate_root(
                                 file_id,
                                 edition,
@@ -334,6 +372,7 @@ impl ProjectWorkspace {
                                 cfg_options,
                                 env,
                                 extern_source,
+                                proc_macro.clone(),
                             );
                             if cargo[tgt].kind == TargetKind::Lib {
                                 lib_tgt = Some((crate_id, cargo[tgt].name.clone()));