wire sysroot into crate graph

crates/ra_lsp_server/src/project_model/sysroot.rs

@@ -20,7 +20,7 @@ impl_arena_id!(SysrootCrate);
 #[derive(Debug, Clone)]
 struct SysrootCrateData {
     name: SmolStr,
-    path: PathBuf,
+    root: PathBuf,
     deps: Vec<SysrootCrate>,
 }
 
@@ -29,6 +29,10 @@ impl Sysroot {
         self.by_name("std")
     }
 
+    pub(crate) fn crates<'a>(&'a self) -> impl Iterator<Item = SysrootCrate> + 'a {
+        self.crates.iter().map(|(id, _data)| id)
+    }
+
     pub(super) fn discover(cargo_toml: &Path) -> Result<Sysroot> {
         let rustc_output = Command::new("rustc")
             .current_dir(cargo_toml.parent().unwrap())
@@ -45,11 +49,11 @@ impl Sysroot {
             crates: Arena::default(),
         };
         for name in SYSROOT_CRATES.trim().lines() {
-            let path = src.join(format!("lib{}", name)).join("lib.rs");
-            if path.exists() {
+            let root = src.join(format!("lib{}", name)).join("lib.rs");
+            if root.exists() {
                 sysroot.crates.alloc(SysrootCrateData {
                     name: name.into(),
-                    path,
+                    root,
                     deps: Vec::new(),
                 });
             }
@@ -72,6 +76,21 @@ impl Sysroot {
     }
 }
 
+impl SysrootCrate {
+    pub(crate) fn name(self, sysroot: &Sysroot) -> &SmolStr {
+        &sysroot.crates[self].name
+    }
+    pub(crate) fn root(self, sysroot: &Sysroot) -> &Path {
+        sysroot.crates[self].root.as_path()
+    }
+    pub(crate) fn root_dir(self, sysroot: &Sysroot) -> &Path {
+        self.root(sysroot).parent().unwrap()
+    }
+    pub(crate) fn deps<'a>(self, sysroot: &'a Sysroot) -> impl Iterator<Item = SysrootCrate> + 'a {
+        sysroot.crates[self].deps.iter().map(|&it| it)
+    }
+}
+
 const SYSROOT_CRATES: &str = "
 std
 core

crates/ra_lsp_server/src/server_world.rs

@@ -44,7 +44,12 @@ impl ServerWorldState {
             for pkg in ws.cargo.packages() {
                 roots.push(pkg.root(&ws.cargo).to_path_buf());
             }
+            for krate in ws.sysroot.crates() {
+                roots.push(krate.root_dir(&ws.sysroot).to_path_buf())
+            }
         }
+        roots.sort();
+        roots.dedup();
         let roots_to_scan = roots.len();
         let (mut vfs, roots) = Vfs::new(roots);
         for r in roots {
@@ -53,16 +58,43 @@ impl ServerWorldState {
         }
 
         let mut crate_graph = CrateGraph::default();
-        let mut pkg_to_lib_crate = FxHashMap::default();
-        let mut pkg_crates = FxHashMap::default();
         for ws in workspaces.iter() {
+            // First, load std
+            let mut sysroot_crates = FxHashMap::default();
+            for krate in ws.sysroot.crates() {
+                if let Some(file_id) = vfs.load(krate.root(&ws.sysroot)) {
+                    let file_id = FileId(file_id.0.into());
+                    sysroot_crates.insert(krate, crate_graph.add_crate_root(file_id));
+                }
+            }
+            for from in ws.sysroot.crates() {
+                for to in from.deps(&ws.sysroot) {
+                    let name = to.name(&ws.sysroot);
+                    if let (Some(&from), Some(&to)) =
+                        (sysroot_crates.get(&from), sysroot_crates.get(&to))
+                    {
+                        crate_graph.add_dep(from, name.clone(), to);
+                    }
+                }
+            }
+
+            let libstd = ws
+                .sysroot
+                .std()
+                .and_then(|it| sysroot_crates.get(&it).map(|&it| it));
+
+            let mut pkg_to_lib_crate = FxHashMap::default();
+            let mut pkg_crates = FxHashMap::default();
+            // Next, create crates for each package, target pair
             for pkg in ws.cargo.packages() {
+                let mut lib_tgt = None;
                 for tgt in pkg.targets(&ws.cargo) {
                     let root = tgt.root(&ws.cargo);
                     if let Some(file_id) = vfs.load(root) {
                         let file_id = FileId(file_id.0.into());
                         let crate_id = crate_graph.add_crate_root(file_id);
                         if tgt.kind(&ws.cargo) == TargetKind::Lib {
+                            lib_tgt = Some(crate_id);
                             pkg_to_lib_crate.insert(pkg, crate_id);
                         }
                         pkg_crates
@@ -71,7 +103,22 @@ impl ServerWorldState {
                             .push(crate_id);
                     }
                 }
+
+                // Set deps to the std and to the lib target of the current package
+                for &from in pkg_crates.get(&pkg).into_iter().flatten() {
+                    if let Some(to) = lib_tgt {
+                        if to != from {
+                            crate_graph.add_dep(from, pkg.name(&ws.cargo).into(), to);
+                        }
+                    }
+                    if let Some(std) = libstd {
+                        crate_graph.add_dep(from, "std".into(), std);
+                    }
+                }
             }
+
+            // Now add a dep ednge from all targets of upstream to the lib
+            // target of downstream.
             for pkg in ws.cargo.packages() {
                 for dep in pkg.dependencies(&ws.cargo) {
                     if let Some(&to) = pkg_to_lib_crate.get(&dep.pkg) {