Async Loading outdir and proc-macro

4 files changed, 235 insertions, 154 deletions

diff --git a/crates/project_model/src/build_data.rs b/crates/project_model/src/build_data.rs
index 3ff347e2c..a5c564e0a 100644
--- a/crates/project_model/src/build_data.rs
+++ b/crates/project_model/src/build_data.rs
@@ -5,10 +5,11 @@ use std::{
     io::BufReader,
     path::{Path, PathBuf},
     process::{Command, Stdio},
+    sync::Arc,
 };
 
 use anyhow::Result;
-use cargo_metadata::{BuildScript, Message, Package, PackageId};
+use cargo_metadata::{BuildScript, Message};
 use itertools::Itertools;
 use paths::{AbsPath, AbsPathBuf};
 use rustc_hash::FxHashMap;
@@ -16,150 +17,195 @@ use stdx::JodChild;
 
 use crate::{cfg_flag::CfgFlag, CargoConfig};
 
-#[derive(Debug, Clone, Default)]
-pub(crate) struct BuildDataMap {
-    data: FxHashMap<PackageId, BuildData>,
-}
 #[derive(Debug, Clone, Default, PartialEq, Eq)]
-pub struct BuildData {
+pub(crate) struct BuildData {
     /// List of config flags defined by this package's build script
-    pub cfgs: Vec<CfgFlag>,
+    pub(crate) cfgs: Vec<CfgFlag>,
     /// List of cargo-related environment variables with their value
     ///
     /// If the package has a build script which defines environment variables,
     /// they can also be found here.
-    pub envs: Vec<(String, String)>,
+    pub(crate) envs: Vec<(String, String)>,
     /// Directory where a build script might place its output
-    pub out_dir: Option<AbsPathBuf>,
+    pub(crate) out_dir: Option<AbsPathBuf>,
     /// Path to the proc-macro library file if this package exposes proc-macros
-    pub proc_macro_dylib_path: Option<AbsPathBuf>,
+    pub(crate) proc_macro_dylib_path: Option<AbsPathBuf>,
 }
 
-impl BuildDataMap {
-    pub(crate) fn new(
-        cargo_toml: &AbsPath,
-        cargo_features: &CargoConfig,
-        packages: &Vec<Package>,
-        progress: &dyn Fn(String),
-    ) -> Result<BuildDataMap> {
-        let mut cmd = Command::new(toolchain::cargo());
-        cmd.args(&["check", "--workspace", "--message-format=json", "--manifest-path"])
-            .arg(cargo_toml.as_ref());
-
-        // --all-targets includes tests, benches and examples in addition to the
-        // default lib and bins. This is an independent concept from the --targets
-        // flag below.
-        cmd.arg("--all-targets");
-
-        if let Some(target) = &cargo_features.target {
-            cmd.args(&["--target", target]);
-        }
+#[derive(Clone, Debug)]
+pub(crate) struct BuildDataConfig {
+    cargo_toml: AbsPathBuf,
+    cargo_features: CargoConfig,
+    packages: Arc<Vec<cargo_metadata::Package>>,
+}
 
-        if cargo_features.all_features {
-            cmd.arg("--all-features");
-        } else {
-            if cargo_features.no_default_features {
-                // FIXME: `NoDefaultFeatures` is mutual exclusive with `SomeFeatures`
-                // https://github.com/oli-obk/cargo_metadata/issues/79
-                cmd.arg("--no-default-features");
-            }
-            if !cargo_features.features.is_empty() {
-                cmd.arg("--features");
-                cmd.arg(cargo_features.features.join(" "));
-            }
-        }
+impl PartialEq for BuildDataConfig {
+    fn eq(&self, other: &Self) -> bool {
+        Arc::ptr_eq(&self.packages, &other.packages)
+    }
+}
 
-        cmd.stdout(Stdio::piped()).stderr(Stdio::null()).stdin(Stdio::null());
-
-        let mut child = cmd.spawn().map(JodChild)?;
-        let child_stdout = child.stdout.take().unwrap();
-        let stdout = BufReader::new(child_stdout);
-
-        let mut res = BuildDataMap::default();
-        for message in cargo_metadata::Message::parse_stream(stdout) {
-            if let Ok(message) = message {
-                match message {
-                    Message::BuildScriptExecuted(BuildScript {
-                        package_id,
-                        out_dir,
-                        cfgs,
-                        env,
-                        ..
-                    }) => {
-                        let cfgs = {
-                            let mut acc = Vec::new();
-                            for cfg in cfgs {
-                                match cfg.parse::<CfgFlag>() {
-                                    Ok(it) => acc.push(it),
-                                    Err(err) => {
-                                        anyhow::bail!("invalid cfg from cargo-metadata: {}", err)
-                                    }
-                                };
-                            }
-                            acc
-                        };
-                        let res = res.data.entry(package_id.clone()).or_default();
-                        // cargo_metadata crate returns default (empty) path for
-                        // older cargos, which is not absolute, so work around that.
-                        if out_dir != PathBuf::default() {
-                            let out_dir = AbsPathBuf::assert(out_dir);
-                            res.out_dir = Some(out_dir);
-                            res.cfgs = cfgs;
-                        }
+impl Eq for BuildDataConfig {}
 
-                        res.envs = env;
-                    }
-                    Message::CompilerArtifact(message) => {
-                        progress(format!("metadata {}", message.target.name));
-
-                        if message.target.kind.contains(&"proc-macro".to_string()) {
-                            let package_id = message.package_id;
-                            // Skip rmeta file
-                            if let Some(filename) =
-                                message.filenames.iter().find(|name| is_dylib(name))
-                            {
-                                let filename = AbsPathBuf::assert(filename.clone());
-                                let res = res.data.entry(package_id.clone()).or_default();
-                                res.proc_macro_dylib_path = Some(filename);
-                            }
-                        }
-                    }
-                    Message::CompilerMessage(message) => {
-                        progress(message.target.name.clone());
-                    }
-                    Message::Unknown => (),
-                    Message::BuildFinished(_) => {}
-                    Message::TextLine(_) => {}
-                }
-            }
+#[derive(Debug, Default)]
+pub struct BuildDataCollector {
+    configs: FxHashMap<AbsPathBuf, BuildDataConfig>,
+}
+
+#[derive(Debug, Default, PartialEq, Eq)]
+pub struct BuildDataResult {
+    data: FxHashMap<AbsPathBuf, BuildDataMap>,
+}
+
+pub(crate) type BuildDataMap = FxHashMap<String, BuildData>;
+
+impl BuildDataCollector {
+    pub(crate) fn add_config(&mut self, workspace_root: &AbsPath, config: BuildDataConfig) {
+        self.configs.insert(workspace_root.to_path_buf().clone(), config);
+    }
+
+    pub fn collect(&mut self, progress: &dyn Fn(String)) -> Result<BuildDataResult> {
+        let mut res = BuildDataResult::default();
+        for (path, config) in self.configs.iter() {
+            res.data.insert(
+                path.clone(),
+                collect_from_workspace(
+                    &config.cargo_toml,
+                    &config.cargo_features,
+                    &config.packages,
+                    progress,
+                )?,
+            );
         }
-        res.inject_cargo_env(packages);
         Ok(res)
     }
+}
+
+impl BuildDataResult {
+    pub(crate) fn get(&self, root: &AbsPath) -> Option<&BuildDataMap> {
+        self.data.get(&root.to_path_buf())
+    }
+}
 
-    pub(crate) fn with_cargo_env(packages: &Vec<Package>) -> Self {
-        let mut res = Self::default();
-        res.inject_cargo_env(packages);
-        res
+impl BuildDataConfig {
+    pub(crate) fn new(
+        cargo_toml: AbsPathBuf,
+        cargo_features: CargoConfig,
+        packages: Arc<Vec<cargo_metadata::Package>>,
+    ) -> Self {
+        Self { cargo_toml, cargo_features, packages }
     }
+}
 
-    pub(crate) fn get(&self, id: &PackageId) -> Option<&BuildData> {
-        self.data.get(id)
+fn collect_from_workspace(
+    cargo_toml: &AbsPath,
+    cargo_features: &CargoConfig,
+    packages: &Vec<cargo_metadata::Package>,
+    progress: &dyn Fn(String),
+) -> Result<BuildDataMap> {
+    let mut cmd = Command::new(toolchain::cargo());
+    cmd.args(&["check", "--workspace", "--message-format=json", "--manifest-path"])
+        .arg(cargo_toml.as_ref());
+
+    // --all-targets includes tests, benches and examples in addition to the
+    // default lib and bins. This is an independent concept from the --targets
+    // flag below.
+    cmd.arg("--all-targets");
+
+    if let Some(target) = &cargo_features.target {
+        cmd.args(&["--target", target]);
     }
 
-    fn inject_cargo_env(&mut self, packages: &Vec<Package>) {
-        for meta_pkg in packages {
-            let resource = self.data.entry(meta_pkg.id.clone()).or_default();
-            inject_cargo_env(meta_pkg, &mut resource.envs);
+    if cargo_features.all_features {
+        cmd.arg("--all-features");
+    } else {
+        if cargo_features.no_default_features {
+            // FIXME: `NoDefaultFeatures` is mutual exclusive with `SomeFeatures`
+            // https://github.com/oli-obk/cargo_metadata/issues/79
+            cmd.arg("--no-default-features");
+        }
+        if !cargo_features.features.is_empty() {
+            cmd.arg("--features");
+            cmd.arg(cargo_features.features.join(" "));
+        }
+    }
+
+    cmd.stdout(Stdio::piped()).stderr(Stdio::null()).stdin(Stdio::null());
 
-            if let Some(out_dir) = &resource.out_dir {
-                // NOTE: cargo and rustc seem to hide non-UTF-8 strings from env! and option_env!()
-                if let Some(out_dir) = out_dir.to_str().map(|s| s.to_owned()) {
-                    resource.envs.push(("OUT_DIR".to_string(), out_dir));
+    let mut child = cmd.spawn().map(JodChild)?;
+    let child_stdout = child.stdout.take().unwrap();
+    let stdout = BufReader::new(child_stdout);
+
+    let mut res = BuildDataMap::default();
+    for message in cargo_metadata::Message::parse_stream(stdout) {
+        if let Ok(message) = message {
+            match message {
+                Message::BuildScriptExecuted(BuildScript {
+                    package_id,
+                    out_dir,
+                    cfgs,
+                    env,
+                    ..
+                }) => {
+                    let cfgs = {
+                        let mut acc = Vec::new();
+                        for cfg in cfgs {
+                            match cfg.parse::<CfgFlag>() {
+                                Ok(it) => acc.push(it),
+                                Err(err) => {
+                                    anyhow::bail!("invalid cfg from cargo-metadata: {}", err)
+                                }
+                            };
+                        }
+                        acc
+                    };
+                    let res = res.entry(package_id.repr.clone()).or_default();
+                    // cargo_metadata crate returns default (empty) path for
+                    // older cargos, which is not absolute, so work around that.
+                    if out_dir != PathBuf::default() {
+                        let out_dir = AbsPathBuf::assert(out_dir);
+                        res.out_dir = Some(out_dir);
+                        res.cfgs = cfgs;
+                    }
+
+                    res.envs = env;
+                }
+                Message::CompilerArtifact(message) => {
+                    progress(format!("metadata {}", message.target.name));
+
+                    if message.target.kind.contains(&"proc-macro".to_string()) {
+                        let package_id = message.package_id;
+                        // Skip rmeta file
+                        if let Some(filename) = message.filenames.iter().find(|name| is_dylib(name))
+                        {
+                            let filename = AbsPathBuf::assert(filename.clone());
+                            let res = res.entry(package_id.repr.clone()).or_default();
+                            res.proc_macro_dylib_path = Some(filename);
+                        }
+                    }
+                }
+                Message::CompilerMessage(message) => {
+                    progress(message.target.name.clone());
                 }
+                Message::Unknown => (),
+                Message::BuildFinished(_) => {}
+                Message::TextLine(_) => {}
             }
         }
     }
+
+    for package in packages {
+        let build_data = res.entry(package.id.repr.clone()).or_default();
+        inject_cargo_env(package, build_data);
+        if let Some(out_dir) = &build_data.out_dir {
+            // NOTE: cargo and rustc seem to hide non-UTF-8 strings from env! and option_env!()
+            if let Some(out_dir) = out_dir.to_str().map(|s| s.to_owned()) {
+                build_data.envs.push(("OUT_DIR".to_string(), out_dir));
+            }
+        }
+    }
+
+    Ok(res)
 }
 
 // FIXME: File a better way to know if it is a dylib
@@ -173,7 +219,9 @@ fn is_dylib(path: &Path) -> bool {
 /// Recreates the compile-time environment variables that Cargo sets.
 ///
 /// Should be synced with <https://doc.rust-lang.org/cargo/reference/environment-variables.html#environment-variables-cargo-sets-for-crates>
-fn inject_cargo_env(package: &cargo_metadata::Package, env: &mut Vec<(String, String)>) {
+fn inject_cargo_env(package: &cargo_metadata::Package, build_data: &mut BuildData) {
+    let env = &mut build_data.envs;
+
     // FIXME: Missing variables:
     // CARGO_PKG_HOMEPAGE, CARGO_CRATE_NAME, CARGO_BIN_NAME, CARGO_BIN_EXE_<name>
 
diff --git a/crates/project_model/src/cargo_workspace.rs b/crates/project_model/src/cargo_workspace.rs
index c8a5333c4..f47898b9b 100644
--- a/crates/project_model/src/cargo_workspace.rs
+++ b/crates/project_model/src/cargo_workspace.rs
@@ -1,6 +1,6 @@
 //! FIXME: write short doc here
 
-use std::{convert::TryInto, ops, process::Command};
+use std::{convert::TryInto, ops, process::Command, sync::Arc};
 
 use anyhow::{Context, Result};
 use base_db::Edition;
@@ -9,7 +9,7 @@ use la_arena::{Arena, Idx};
 use paths::{AbsPath, AbsPathBuf};
 use rustc_hash::FxHashMap;
 
-use crate::build_data::{BuildData, BuildDataMap};
+use crate::build_data::BuildDataConfig;
 use crate::utf8_stdout;
 
 /// `CargoWorkspace` represents the logical structure of, well, a Cargo
@@ -27,6 +27,7 @@ pub struct CargoWorkspace {
     packages: Arena<PackageData>,
     targets: Arena<TargetData>,
     workspace_root: AbsPathBuf,
+    build_data_config: BuildDataConfig,
 }
 
 impl ops::Index<Package> for CargoWorkspace {
@@ -55,9 +56,6 @@ pub struct CargoConfig {
     /// This will be ignored if `cargo_all_features` is true.
     pub features: Vec<String>,
 
-    /// Runs cargo check on launch to figure out the correct values of OUT_DIR
-    pub load_out_dirs_from_check: bool,
-
     /// rustc target
     pub target: Option<String>,
 
@@ -94,8 +92,8 @@ pub struct PackageData {
     pub features: FxHashMap<String, Vec<String>>,
     /// List of features enabled on this package
     pub active_features: Vec<String>,
-    /// Build script related data for this package
-    pub build_data: BuildData,
+    // String representation of package id
+    pub id: String,
 }
 
 #[derive(Debug, Clone, Eq, PartialEq)]
@@ -228,12 +226,6 @@ impl CargoWorkspace {
             )
         })?;
 
-        let resources = if config.load_out_dirs_from_check {
-            BuildDataMap::new(cargo_toml, config, &meta.packages, progress)?
-        } else {
-            BuildDataMap::with_cargo_env(&meta.packages)
-        };
-
         let mut pkg_by_id = FxHashMap::default();
         let mut packages = Arena::default();
         let mut targets = Arena::default();
@@ -241,10 +233,7 @@ impl CargoWorkspace {
         let ws_members = &meta.workspace_members;
 
         meta.packages.sort_by(|a, b| a.id.cmp(&b.id));
-        for meta_pkg in meta.packages {
-            let id = meta_pkg.id.clone();
-            let build_data = resources.get(&id).cloned().unwrap_or_default();
-
+        for meta_pkg in &meta.packages {
             let cargo_metadata::Package { id, edition, name, manifest_path, version, .. } =
                 meta_pkg;
             let is_member = ws_members.contains(&id);
@@ -252,24 +241,24 @@ impl CargoWorkspace {
                 .parse::<Edition>()
                 .with_context(|| format!("Failed to parse edition {}", edition))?;
             let pkg = packages.alloc(PackageData {
-                name,
+                id: id.repr.clone(),
+                name: name.clone(),
                 version: version.to_string(),
-                manifest: AbsPathBuf::assert(manifest_path),
+                manifest: AbsPathBuf::assert(manifest_path.clone()),
                 targets: Vec::new(),
                 is_member,
                 edition,
                 dependencies: Vec::new(),
-                features: meta_pkg.features.into_iter().collect(),
+                features: meta_pkg.features.clone().into_iter().collect(),
                 active_features: Vec::new(),
-                build_data,
             });
             let pkg_data = &mut packages[pkg];
             pkg_by_id.insert(id, pkg);
-            for meta_tgt in meta_pkg.targets {
+            for meta_tgt in &meta_pkg.targets {
                 let is_proc_macro = meta_tgt.kind.as_slice() == ["proc-macro"];
                 let tgt = targets.alloc(TargetData {
                     package: pkg,
-                    name: meta_tgt.name,
+                    name: meta_tgt.name.clone(),
                     root: AbsPathBuf::assert(meta_tgt.src_path.clone()),
                     kind: TargetKind::new(meta_tgt.kind.as_slice()),
                     is_proc_macro,
@@ -308,7 +297,13 @@ impl CargoWorkspace {
         }
 
         let workspace_root = AbsPathBuf::assert(meta.workspace_root);
-        Ok(CargoWorkspace { packages, targets, workspace_root: workspace_root })
+        let build_data_config = BuildDataConfig::new(
+            cargo_toml.to_path_buf(),
+            config.clone(),
+            Arc::new(meta.packages.clone()),
+        );
+
+        Ok(CargoWorkspace { packages, targets, workspace_root, build_data_config })
     }
 
     pub fn packages<'a>(&'a self) -> impl Iterator<Item = Package> + ExactSizeIterator + 'a {
@@ -334,6 +329,10 @@ impl CargoWorkspace {
         }
     }
 
+    pub(crate) fn build_data_config(&self) -> &BuildDataConfig {
+        &self.build_data_config
+    }
+
     fn is_unique(&self, name: &str) -> bool {
         self.packages.iter().filter(|(_, v)| v.name == name).count() == 1
     }
diff --git a/crates/project_model/src/lib.rs b/crates/project_model/src/lib.rs
index 525c336e6..d712095a6 100644
--- a/crates/project_model/src/lib.rs
+++ b/crates/project_model/src/lib.rs
@@ -19,6 +19,7 @@ use paths::{AbsPath, AbsPathBuf};
 use rustc_hash::FxHashSet;
 
 pub use crate::{
+    build_data::{BuildDataCollector, BuildDataResult},
     cargo_workspace::{
         CargoConfig, CargoWorkspace, Package, PackageData, PackageDependency, Target, TargetData,
         TargetKind,
diff --git a/crates/project_model/src/workspace.rs b/crates/project_model/src/workspace.rs
index 559f4e7bf..c30861976 100644
--- a/crates/project_model/src/workspace.rs
+++ b/crates/project_model/src/workspace.rs
@@ -16,8 +16,13 @@ use proc_macro_api::ProcMacroClient;
 use rustc_hash::{FxHashMap, FxHashSet};
 
 use crate::{
-    cargo_workspace, cfg_flag::CfgFlag, rustc_cfg, sysroot::SysrootCrate, utf8_stdout, CargoConfig,
-    CargoWorkspace, ProjectJson, ProjectManifest, Sysroot, TargetKind,
+    build_data::{BuildData, BuildDataMap, BuildDataResult},
+    cargo_workspace,
+    cfg_flag::CfgFlag,
+    rustc_cfg,
+    sysroot::SysrootCrate,
+    utf8_stdout, BuildDataCollector, CargoConfig, CargoWorkspace, ProjectJson, ProjectManifest,
+    Sysroot, TargetKind,
 };
 
 /// `PackageRoot` describes a package root folder.
@@ -153,7 +158,7 @@ impl ProjectWorkspace {
     /// Returns the roots for the current `ProjectWorkspace`
     /// The return type contains the path and whether or not
     /// the root is a member of the current workspace
-    pub fn to_roots(&self) -> Vec<PackageRoot> {
+    pub fn to_roots(&self, build_data: Option<&BuildDataResult>) -> Vec<PackageRoot> {
         match self {
             ProjectWorkspace::Json { project, sysroot, rustc_cfg: _ } => project
                 .crates()
@@ -179,7 +184,12 @@ impl ProjectWorkspace {
                     let pkg_root = cargo[pkg].root().to_path_buf();
 
                     let mut include = vec![pkg_root.clone()];
-                    include.extend(cargo[pkg].build_data.out_dir.clone());
+                    include.extend(
+                        build_data
+                            .and_then(|it| it.get(cargo.workspace_root()))
+                            .and_then(|map| map.get(&cargo[pkg].id))
+                            .and_then(|it| it.out_dir.clone()),
+                    );
 
                     let mut exclude = vec![pkg_root.join(".git")];
                     if is_member {
@@ -219,6 +229,7 @@ impl ProjectWorkspace {
 
     pub fn to_crate_graph(
         &self,
+        build_data: Option<&BuildDataResult>,
         proc_macro_client: Option<&ProcMacroClient>,
         load: &mut dyn FnMut(&AbsPath) -> Option<FileId>,
     ) -> CrateGraph {
@@ -241,8 +252,10 @@ impl ProjectWorkspace {
                 &proc_macro_loader,
                 load,
                 cargo,
+                build_data.and_then(|it| it.get(cargo.workspace_root())),
                 sysroot,
                 rustc,
+                rustc.as_ref().zip(build_data).and_then(|(it, map)| map.get(it.workspace_root())),
             ),
         };
         if crate_graph.patch_cfg_if() {
@@ -252,6 +265,18 @@ impl ProjectWorkspace {
         }
         crate_graph
     }
+
+    pub fn collect_build_data_configs(&self, collector: &mut BuildDataCollector) {
+        match self {
+            ProjectWorkspace::Cargo { cargo, rustc, .. } => {
+                collector.add_config(&cargo.workspace_root(), cargo.build_data_config().clone());
+                if let Some(rustc) = rustc {
+                    collector.add_config(rustc.workspace_root(), rustc.build_data_config().clone());
+                }
+            }
+            _ => {}
+        }
+    }
 }
 
 fn project_json_to_crate_graph(
@@ -324,8 +349,10 @@ fn cargo_to_crate_graph(
     proc_macro_loader: &dyn Fn(&Path) -> Vec<ProcMacro>,
     load: &mut dyn FnMut(&AbsPath) -> Option<FileId>,
     cargo: &CargoWorkspace,
+    build_data_map: Option<&BuildDataMap>,
     sysroot: &Sysroot,
     rustc: &Option<CargoWorkspace>,
+    rustc_build_data_map: Option<&BuildDataMap>,
 ) -> CrateGraph {
     let _p = profile::span("cargo_to_crate_graph");
     let mut crate_graph = CrateGraph::default();
@@ -351,6 +378,7 @@ fn cargo_to_crate_graph(
                 let crate_id = add_target_crate_root(
                     &mut crate_graph,
                     &cargo[pkg],
+                    build_data_map.and_then(|it| it.get(&cargo[pkg].id)),
                     &cfg_options,
                     proc_macro_loader,
                     file_id,
@@ -427,6 +455,7 @@ fn cargo_to_crate_graph(
                     let crate_id = add_target_crate_root(
                         &mut crate_graph,
                         &rustc_workspace[pkg],
+                        rustc_build_data_map.and_then(|it| it.get(&rustc_workspace[pkg].id)),
                         &cfg_options,
                         proc_macro_loader,
                         file_id,
@@ -475,6 +504,7 @@ fn cargo_to_crate_graph(
 fn add_target_crate_root(
     crate_graph: &mut CrateGraph,
     pkg: &cargo_workspace::PackageData,
+    build_data: Option<&BuildData>,
     cfg_options: &CfgOptions,
     proc_macro_loader: &dyn Fn(&Path) -> Vec<ProcMacro>,
     file_id: FileId,
@@ -485,19 +515,22 @@ fn add_target_crate_root(
         for feature in pkg.active_features.iter() {
             opts.insert_key_value("feature".into(), feature.into());
         }
-        opts.extend(pkg.build_data.cfgs.iter().cloned());
+        if let Some(cfgs) = build_data.as_ref().map(|it| &it.cfgs) {
+            opts.extend(cfgs.iter().cloned());
+        }
         opts
     };
 
     let mut env = Env::default();
-    for (k, v) in &pkg.build_data.envs {
-        env.set(k, v.clone());
+    if let Some(envs) = build_data.map(|it| &it.envs) {
+        for (k, v) in envs {
+            env.set(k, v.clone());
+        }
     }
 
-    let proc_macro = pkg
-        .build_data
-        .proc_macro_dylib_path
+    let proc_macro = build_data
         .as_ref()
+        .and_then(|it| it.proc_macro_dylib_path.as_ref())
         .map(|it| proc_macro_loader(&it))
         .unwrap_or_default();