Merge #2381

2381: Add proc-macro crate type handling r=JasperDeSutter a=JasperDeSutter

Resolves the libproc_macro crate in crates that are the proc-macro type.
This doesn't seem the ideal implementation though, since the compiler still requires you to write `extern crate proc_macro;` (even in 2018 edition).

Co-authored-by: JasperDeSutter <jasper.desutter@gmail.com>

crates/ra_project_model/src/cargo_workspace.rs

@@ -54,11 +54,13 @@ struct TargetData {
     name: String,
     root: PathBuf,
     kind: TargetKind,
+    is_proc_macro: bool,
 }
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub enum TargetKind {
     Bin,
+    /// Any kind of Cargo lib crate-type (dylib, rlib, proc-macro, ...).
     Lib,
     Example,
     Test,
@@ -74,6 +76,7 @@ impl TargetKind {
                 "test" => TargetKind::Test,
                 "bench" => TargetKind::Bench,
                 "example" => TargetKind::Example,
+                "proc-macro" => TargetKind::Lib,
                 _ if kind.contains("lib") => TargetKind::Lib,
                 _ => continue,
             };
@@ -123,6 +126,9 @@ impl Target {
     pub fn kind(self, ws: &CargoWorkspace) -> TargetKind {
         ws.targets[self].kind
     }
+    pub fn is_proc_macro(self, ws: &CargoWorkspace) -> bool {
+        ws.targets[self].is_proc_macro
+    }
 }
 
 impl CargoWorkspace {
@@ -155,11 +161,13 @@ impl CargoWorkspace {
             let pkg_data = &mut packages[pkg];
             pkg_by_id.insert(id, pkg);
             for meta_tgt in meta_pkg.targets {
+                let is_proc_macro = meta_tgt.kind.as_slice() == &["proc-macro"];
                 let tgt = targets.alloc(TargetData {
                     pkg,
                     name: meta_tgt.name,
                     root: meta_tgt.src_path.clone(),
                     kind: TargetKind::new(meta_tgt.kind.as_slice()),
+                    is_proc_macro,
                 });
                 pkg_data.targets.push(tgt);
             }

crates/ra_project_model/src/lib.rs

@@ -211,6 +211,8 @@ impl ProjectWorkspace {
                 let libcore = sysroot.core().and_then(|it| sysroot_crates.get(&it).copied());
                 let liballoc = sysroot.alloc().and_then(|it| sysroot_crates.get(&it).copied());
                 let libstd = sysroot.std().and_then(|it| sysroot_crates.get(&it).copied());
+                let libproc_macro =
+                    sysroot.proc_macro().and_then(|it| sysroot_crates.get(&it).copied());
 
                 let mut pkg_to_lib_crate = FxHashMap::default();
                 let mut pkg_crates = FxHashMap::default();
@@ -237,6 +239,21 @@ impl ProjectWorkspace {
                                 lib_tgt = Some(crate_id);
                                 pkg_to_lib_crate.insert(pkg, crate_id);
                             }
+                            if tgt.is_proc_macro(&cargo) {
+                                if let Some(proc_macro) = libproc_macro {
+                                    if let Err(_) = crate_graph.add_dep(
+                                        crate_id,
+                                        "proc_macro".into(),
+                                        proc_macro,
+                                    ) {
+                                        log::error!(
+                                            "cyclic dependency on proc_macro for {}",
+                                            pkg.name(&cargo)
+                                        )
+                                    }
+                                }
+                            }
+
                             pkg_crates.entry(pkg).or_insert_with(Vec::new).push(crate_id);
                         }
                     }

crates/ra_project_model/src/sysroot.rs

@@ -39,6 +39,10 @@ impl Sysroot {
         self.by_name("std")
     }
 
+    pub fn proc_macro(&self) -> Option<SysrootCrate> {
+        self.by_name("proc_macro")
+    }
+
     pub fn crates<'a>(&'a self) -> impl Iterator<Item = SysrootCrate> + ExactSizeIterator + 'a {
         self.crates.iter().map(|(id, _data)| id)
     }
@@ -74,7 +78,7 @@ impl Sysroot {
             }
         }
         if let Some(alloc) = sysroot.by_name("alloc") {
-            if let Some(core) = sysroot.by_name("core") {
+            if let Some(core) = sysroot.core() {
                 sysroot.crates[alloc].deps.push(core);
             }
         }