Auto merge of #17110 - Veykril:cargo-script-mvp, r=Veykril

Cargo script mvp

Based on https://github.com/rust-lang/rust-analyzer/pull/15456,

As the original PR stated, detached files are still horrendous to work with.

10 files changed, 376 insertions, 143 deletions

diff --git a/crates/load-cargo/src/lib.rs b/crates/load-cargo/src/lib.rs
index ec37d88e607..31b0c8cdec5 100644
--- a/crates/load-cargo/src/lib.rs
+++ b/crates/load-cargo/src/lib.rs
@@ -335,7 +335,7 @@ fn load_crate_graph(
 ) -> RootDatabase {
     let (ProjectWorkspace::Cargo { toolchain, target_layout, .. }
     | ProjectWorkspace::Json { toolchain, target_layout, .. }
-    | ProjectWorkspace::DetachedFiles { toolchain, target_layout, .. }) = ws;
+    | ProjectWorkspace::DetachedFile { toolchain, target_layout, .. }) = ws;
 
     let lru_cap = std::env::var("RA_LRU_CAP").ok().and_then(|it| it.parse::<usize>().ok());
     let mut db = RootDatabase::new(lru_cap);
diff --git a/crates/project-model/src/cargo_workspace.rs b/crates/project-model/src/cargo_workspace.rs
index fd898ffa5c3..ff7cf144aa8 100644
--- a/crates/project-model/src/cargo_workspace.rs
+++ b/crates/project-model/src/cargo_workspace.rs
@@ -305,6 +305,12 @@ impl CargoWorkspace {
                     .collect(),
             );
         }
+        // The manifest is a rust file, so this means its a script manifest
+        if cargo_toml.extension().is_some_and(|ext| ext == "rs") {
+            // Deliberately don't set up RUSTC_BOOTSTRAP or a nightly override here, the user should
+            // opt into it themselves.
+            other_options.push("-Zscript".to_owned());
+        }
         meta.other_options(other_options);
 
         // FIXME: Fetching metadata is a slow process, as it might require
@@ -373,11 +379,12 @@ impl CargoWorkspace {
             let is_local = source.is_none();
             let is_member = ws_members.contains(&id);
 
+            let manifest = AbsPathBuf::assert(manifest_path);
             let pkg = packages.alloc(PackageData {
                 id: id.repr.clone(),
                 name,
                 version,
-                manifest: AbsPathBuf::assert(manifest_path).try_into().unwrap(),
+                manifest: manifest.clone().try_into().unwrap(),
                 targets: Vec::new(),
                 is_local,
                 is_member,
@@ -400,11 +407,22 @@ impl CargoWorkspace {
             for meta_tgt in meta_targets {
                 let cargo_metadata::Target { name, kind, required_features, src_path, .. } =
                     meta_tgt;
+                let kind = TargetKind::new(&kind);
                 let tgt = targets.alloc(TargetData {
                     package: pkg,
                     name,
-                    root: AbsPathBuf::assert(src_path),
-                    kind: TargetKind::new(&kind),
+                    root: if kind == TargetKind::Bin
+                        && manifest.extension().is_some_and(|ext| ext == "rs")
+                    {
+                        // cargo strips the script part of a cargo script away and places the
+                        // modified manifest file into a special target dir which is then used as
+                        // the source path. We don't want that, we want the original here so map it
+                        // back
+                        manifest.clone()
+                    } else {
+                        AbsPathBuf::assert(src_path)
+                    },
+                    kind,
                     required_features,
                 });
                 pkg_data.targets.push(tgt);
diff --git a/crates/project-model/src/workspace.rs b/crates/project-model/src/workspace.rs
index a5e74763d70..98c5a02dcdc 100644
--- a/crates/project-model/src/workspace.rs
+++ b/crates/project-model/src/workspace.rs
@@ -99,9 +99,9 @@ pub enum ProjectWorkspace {
     // //
     /// Project with a set of disjoint files, not belonging to any particular workspace.
     /// Backed by basic sysroot crates for basic completion and highlighting.
-    DetachedFiles {
-        /// The set of detached files.
-        files: Vec<AbsPathBuf>,
+    DetachedFile {
+        /// The file in question.
+        file: AbsPathBuf,
         /// The sysroot loaded for this workspace.
         sysroot: Result<Sysroot, Option<String>>,
         /// Holds cfg flags for the current target. We get those by running
@@ -115,6 +115,8 @@ pub enum ProjectWorkspace {
         target_layout: TargetLayoutLoadResult,
         /// A set of cfg overrides for the files.
         cfg_overrides: CfgOverrides,
+        /// Is this file a cargo script file?
+        cargo_script: Option<CargoWorkspace>,
     },
 }
 
@@ -167,17 +169,20 @@ impl fmt::Debug for ProjectWorkspace {
                     .field("n_cfg_overrides", &cfg_overrides.len());
                 debug_struct.finish()
             }
-            ProjectWorkspace::DetachedFiles {
-                files,
+            ProjectWorkspace::DetachedFile {
+                file,
                 sysroot,
                 rustc_cfg,
                 toolchain,
                 target_layout,
                 cfg_overrides,
+                cargo_script,
             } => f
                 .debug_struct("DetachedFiles")
-                .field("n_files", &files.len())
+                .field("file", &file)
+                .field("cargo_script", &cargo_script.is_some())
                 .field("sysroot", &sysroot.is_ok())
+                .field("cargo_script", &cargo_script.is_some())
                 .field("n_rustc_cfg", &rustc_cfg.len())
                 .field("toolchain", &toolchain)
                 .field("data_layout", &target_layout)
@@ -431,52 +436,79 @@ impl ProjectWorkspace {
     pub fn load_detached_files(
         detached_files: Vec<AbsPathBuf>,
         config: &CargoConfig,
-    ) -> anyhow::Result<ProjectWorkspace> {
-        let dir = detached_files
-            .first()
-            .and_then(|it| it.parent())
-            .ok_or_else(|| format_err!("No detached files to load"))?;
-        let sysroot = match &config.sysroot {
-            Some(RustLibSource::Path(path)) => {
-                Sysroot::with_sysroot_dir(path.clone(), config.sysroot_query_metadata)
-                    .map_err(|e| Some(format!("Failed to find sysroot at {path}:{e}")))
-            }
-            Some(RustLibSource::Discover) => Sysroot::discover(
-                dir,
-                &config.extra_env,
-                config.sysroot_query_metadata,
-            )
-            .map_err(|e| {
-                Some(format!("Failed to find sysroot for {dir}. Is rust-src installed? {e}"))
-            }),
-            None => Err(None),
-        };
+    ) -> Vec<anyhow::Result<ProjectWorkspace>> {
+        detached_files
+            .into_iter()
+            .map(|detached_file| {
+                let dir = detached_file
+                    .parent()
+                    .ok_or_else(|| format_err!("detached file has no parent"))?;
+                let sysroot = match &config.sysroot {
+                    Some(RustLibSource::Path(path)) => {
+                        Sysroot::with_sysroot_dir(path.clone(), config.sysroot_query_metadata)
+                            .map_err(|e| Some(format!("Failed to find sysroot at {path}:{e}")))
+                    }
+                    Some(RustLibSource::Discover) => {
+                        Sysroot::discover(dir, &config.extra_env, config.sysroot_query_metadata)
+                            .map_err(|e| {
+                                Some(format!(
+                                    "Failed to find sysroot for {dir}. Is rust-src installed? {e}"
+                                ))
+                            })
+                    }
+                    None => Err(None),
+                };
 
-        let sysroot_ref = sysroot.as_ref().ok();
-        let toolchain =
-            match get_toolchain_version(dir, sysroot_ref, Tool::Rustc, &config.extra_env, "rustc ")
-            {
-                Ok(it) => it,
-                Err(e) => {
-                    tracing::error!("{e}");
-                    None
-                }
-            };
+                let sysroot_ref = sysroot.as_ref().ok();
+                let toolchain = match get_toolchain_version(
+                    dir,
+                    sysroot_ref,
+                    Tool::Rustc,
+                    &config.extra_env,
+                    "rustc ",
+                ) {
+                    Ok(it) => it,
+                    Err(e) => {
+                        tracing::error!("{e}");
+                        None
+                    }
+                };
 
-        let rustc_cfg = rustc_cfg::get(None, &config.extra_env, RustcCfgConfig::Rustc(sysroot_ref));
-        let data_layout = target_data_layout::get(
-            RustcDataLayoutConfig::Rustc(sysroot_ref),
-            None,
-            &config.extra_env,
-        );
-        Ok(ProjectWorkspace::DetachedFiles {
-            files: detached_files,
-            sysroot,
-            rustc_cfg,
-            toolchain,
-            target_layout: data_layout.map(Arc::from).map_err(|it| Arc::from(it.to_string())),
-            cfg_overrides: config.cfg_overrides.clone(),
-        })
+                let rustc_cfg =
+                    rustc_cfg::get(None, &config.extra_env, RustcCfgConfig::Rustc(sysroot_ref));
+                let data_layout = target_data_layout::get(
+                    RustcDataLayoutConfig::Rustc(sysroot_ref),
+                    None,
+                    &config.extra_env,
+                );
+
+                let cargo_script = ManifestPath::try_from(detached_file.clone())
+                    .ok()
+                    .and_then(|file| {
+                        CargoWorkspace::fetch_metadata(
+                            &file,
+                            file.parent(),
+                            config,
+                            sysroot_ref,
+                            &|_| (),
+                        )
+                        .ok()
+                    })
+                    .map(CargoWorkspace::new);
+
+                Ok(ProjectWorkspace::DetachedFile {
+                    file: detached_file,
+                    sysroot,
+                    rustc_cfg,
+                    toolchain,
+                    target_layout: data_layout
+                        .map(Arc::from)
+                        .map_err(|it| Arc::from(it.to_string())),
+                    cfg_overrides: config.cfg_overrides.clone(),
+                    cargo_script,
+                })
+            })
+            .collect()
     }
 
     /// Runs the build scripts for this [`ProjectWorkspace`].
@@ -486,7 +518,13 @@ impl ProjectWorkspace {
         progress: &dyn Fn(String),
     ) -> anyhow::Result<WorkspaceBuildScripts> {
         match self {
-            ProjectWorkspace::Cargo { cargo, toolchain, sysroot, .. } => {
+            ProjectWorkspace::DetachedFile {
+                cargo_script: Some(cargo),
+                toolchain,
+                sysroot,
+                ..
+            }
+            | ProjectWorkspace::Cargo { cargo, toolchain, sysroot, .. } => {
                 WorkspaceBuildScripts::run_for_workspace(
                     config,
                     cargo,
@@ -498,9 +536,8 @@ impl ProjectWorkspace {
                     format!("Failed to run build scripts for {}", cargo.workspace_root())
                 })
             }
-            ProjectWorkspace::Json { .. } | ProjectWorkspace::DetachedFiles { .. } => {
-                Ok(WorkspaceBuildScripts::default())
-            }
+            ProjectWorkspace::DetachedFile { cargo_script: None, .. }
+            | ProjectWorkspace::Json { .. } => Ok(WorkspaceBuildScripts::default()),
         }
     }
 
@@ -556,11 +593,11 @@ impl ProjectWorkspace {
         }
     }
 
-    pub fn workspace_definition_path(&self) -> Option<&AbsPath> {
+    pub fn workspace_definition_path(&self) -> &AbsPath {
         match self {
-            ProjectWorkspace::Cargo { cargo, .. } => Some(cargo.workspace_root()),
-            ProjectWorkspace::Json { project, .. } => Some(project.path()),
-            ProjectWorkspace::DetachedFiles { .. } => None,
+            ProjectWorkspace::Cargo { cargo, .. } => cargo.workspace_root(),
+            ProjectWorkspace::Json { project, .. } => project.path(),
+            ProjectWorkspace::DetachedFile { file, .. } => file,
         }
     }
 
@@ -568,10 +605,10 @@ impl ProjectWorkspace {
         match self {
             ProjectWorkspace::Cargo { sysroot: Ok(sysroot), .. }
             | ProjectWorkspace::Json { sysroot: Ok(sysroot), .. }
-            | ProjectWorkspace::DetachedFiles { sysroot: Ok(sysroot), .. } => {
+            | ProjectWorkspace::DetachedFile { sysroot: Ok(sysroot), .. } => {
                 sysroot.discover_proc_macro_srv()
             }
-            ProjectWorkspace::DetachedFiles { .. } => {
+            ProjectWorkspace::DetachedFile { .. } => {
                 Err(anyhow::format_err!("cannot find proc-macro server, no sysroot was found"))
             }
             ProjectWorkspace::Cargo { cargo, .. } => Err(anyhow::format_err!(
@@ -702,15 +739,50 @@ impl ProjectWorkspace {
                     }))
                     .collect()
             }
-            ProjectWorkspace::DetachedFiles { files, sysroot, .. } => files
-                .iter()
-                .map(|detached_file| PackageRoot {
+            ProjectWorkspace::DetachedFile { file, cargo_script, sysroot, .. } => {
+                iter::once(PackageRoot {
                     is_local: true,
-                    include: vec![detached_file.clone()],
+                    include: vec![file.clone()],
                     exclude: Vec::new(),
                 })
+                .chain(cargo_script.iter().flat_map(|cargo| {
+                    cargo.packages().map(|pkg| {
+                        let is_local = cargo[pkg].is_local;
+                        let pkg_root = cargo[pkg].manifest.parent().to_path_buf();
+
+                        let mut include = vec![pkg_root.clone()];
+
+                        // In case target's path is manually set in Cargo.toml to be
+                        // outside the package root, add its parent as an extra include.
+                        // An example of this situation would look like this:
+                        //
+                        // ```toml
+                        // [lib]
+                        // path = "../../src/lib.rs"
+                        // ```
+                        let extra_targets = cargo[pkg]
+                            .targets
+                            .iter()
+                            .filter(|&&tgt| matches!(cargo[tgt].kind, TargetKind::Lib { .. }))
+                            .filter_map(|&tgt| cargo[tgt].root.parent())
+                            .map(|tgt| tgt.normalize().to_path_buf())
+                            .filter(|path| !path.starts_with(&pkg_root));
+                        include.extend(extra_targets);
+
+                        let mut exclude = vec![pkg_root.join(".git")];
+                        if is_local {
+                            exclude.push(pkg_root.join("target"));
+                        } else {
+                            exclude.push(pkg_root.join("tests"));
+                            exclude.push(pkg_root.join("examples"));
+                            exclude.push(pkg_root.join("benches"));
+                        }
+                        PackageRoot { is_local, include, exclude }
+                    })
+                }))
                 .chain(mk_sysroot(sysroot.as_ref()))
-                .collect(),
+                .collect()
+            }
         }
     }
 
@@ -726,9 +798,10 @@ impl ProjectWorkspace {
                 let sysroot_package_len = sysroot.as_ref().map_or(0, |it| it.num_packages());
                 cargo.packages().len() + sysroot_package_len + rustc_package_len
             }
-            ProjectWorkspace::DetachedFiles { sysroot, files, .. } => {
+            ProjectWorkspace::DetachedFile { sysroot, cargo_script, .. } => {
                 let sysroot_package_len = sysroot.as_ref().map_or(0, |it| it.num_packages());
-                sysroot_package_len + files.len()
+                sysroot_package_len
+                    + cargo_script.as_ref().map_or(1, |cargo| cargo.packages().len())
             }
         }
     }
@@ -781,21 +854,34 @@ impl ProjectWorkspace {
                 ),
                 sysroot,
             ),
-            ProjectWorkspace::DetachedFiles {
-                files,
+            ProjectWorkspace::DetachedFile {
+                file,
                 sysroot,
                 rustc_cfg,
                 toolchain: _,
                 target_layout: _,
                 cfg_overrides,
+                cargo_script,
             } => (
-                detached_files_to_crate_graph(
-                    rustc_cfg.clone(),
-                    load,
-                    files,
-                    sysroot.as_ref().ok(),
-                    cfg_overrides,
-                ),
+                if let Some(cargo) = cargo_script {
+                    cargo_to_crate_graph(
+                        &mut |path| load(path),
+                        None,
+                        cargo,
+                        sysroot.as_ref().ok(),
+                        rustc_cfg.clone(),
+                        cfg_overrides,
+                        &WorkspaceBuildScripts::default(),
+                    )
+                } else {
+                    detached_file_to_crate_graph(
+                        rustc_cfg.clone(),
+                        load,
+                        file,
+                        sysroot.as_ref().ok(),
+                        cfg_overrides,
+                    )
+                },
                 sysroot,
             ),
         };
@@ -869,29 +955,32 @@ impl ProjectWorkspace {
                     && cfg_overrides == o_cfg_overrides
             }
             (
-                Self::DetachedFiles {
-                    files,
+                Self::DetachedFile {
+                    file,
                     sysroot,
                     rustc_cfg,
+                    cargo_script,
                     toolchain,
                     target_layout,
                     cfg_overrides,
                 },
-                Self::DetachedFiles {
-                    files: o_files,
+                Self::DetachedFile {
+                    file: o_file,
                     sysroot: o_sysroot,
                     rustc_cfg: o_rustc_cfg,
+                    cargo_script: o_cargo_script,
                     toolchain: o_toolchain,
                     target_layout: o_target_layout,
                     cfg_overrides: o_cfg_overrides,
                 },
             ) => {
-                files == o_files
+                file == o_file
                     && sysroot == o_sysroot
                     && rustc_cfg == o_rustc_cfg
                     && toolchain == o_toolchain
                     && target_layout == o_target_layout
                     && cfg_overrides == o_cfg_overrides
+                    && cargo_script == o_cargo_script
             }
             _ => false,
         }
@@ -1202,10 +1291,10 @@ fn cargo_to_crate_graph(
     res
 }
 
-fn detached_files_to_crate_graph(
+fn detached_file_to_crate_graph(
     rustc_cfg: Vec<CfgFlag>,
     load: FileLoader<'_>,
-    detached_files: &[AbsPathBuf],
+    detached_file: &AbsPathBuf,
     sysroot: Option<&Sysroot>,
     override_cfg: &CfgOverrides,
 ) -> (CrateGraph, ProcMacroPaths) {
@@ -1222,34 +1311,32 @@ fn detached_files_to_crate_graph(
     override_cfg.apply(&mut cfg_options, "");
     let cfg_options = Arc::new(cfg_options);
 
-    for detached_file in detached_files {
-        let file_id = match load(detached_file) {
-            Some(file_id) => file_id,
-            None => {
-                tracing::error!("Failed to load detached file {:?}", detached_file);
-                continue;
-            }
-        };
-        let display_name = detached_file
-            .file_stem()
-            .map(|file_stem| CrateDisplayName::from_canonical_name(file_stem.to_owned()));
-        let detached_file_crate = crate_graph.add_crate_root(
-            file_id,
-            Edition::CURRENT,
-            display_name.clone(),
-            None,
-            cfg_options.clone(),
-            None,
-            Env::default(),
-            false,
-            CrateOrigin::Local {
-                repo: None,
-                name: display_name.map(|n| n.canonical_name().to_owned()),
-            },
-        );
+    let file_id = match load(detached_file) {
+        Some(file_id) => file_id,
+        None => {
+            tracing::error!("Failed to load detached file {:?}", detached_file);
+            return (crate_graph, FxHashMap::default());
+        }
+    };
+    let display_name = detached_file
+        .file_stem()
+        .map(|file_stem| CrateDisplayName::from_canonical_name(file_stem.to_owned()));
+    let detached_file_crate = crate_graph.add_crate_root(
+        file_id,
+        Edition::CURRENT,
+        display_name.clone(),
+        None,
+        cfg_options.clone(),
+        None,
+        Env::default(),
+        false,
+        CrateOrigin::Local {
+            repo: None,
+            name: display_name.map(|n| n.canonical_name().to_owned()),
+        },
+    );
 
-        public_deps.add_to_crate_graph(&mut crate_graph, detached_file_crate);
-    }
+    public_deps.add_to_crate_graph(&mut crate_graph, detached_file_crate);
     (crate_graph, FxHashMap::default())
 }
 
diff --git a/crates/rust-analyzer/src/cli/rustc_tests.rs b/crates/rust-analyzer/src/cli/rustc_tests.rs
index 548dd4e70e5..2f9394d0ee1 100644
--- a/crates/rust-analyzer/src/cli/rustc_tests.rs
+++ b/crates/rust-analyzer/src/cli/rustc_tests.rs
@@ -75,13 +75,14 @@ impl Tester {
             &cargo_config.extra_env,
         );
 
-        let workspace = ProjectWorkspace::DetachedFiles {
-            files: vec![tmp_file],
+        let workspace = ProjectWorkspace::DetachedFile {
+            file: tmp_file,
             sysroot,
             rustc_cfg: vec![],
             toolchain: None,
             target_layout: data_layout.map(Arc::from).map_err(|it| Arc::from(it.to_string())),
             cfg_overrides: Default::default(),
+            cargo_script: None,
         };
         let load_cargo_config = LoadCargoConfig {
             load_out_dirs_from_check: false,
diff --git a/crates/rust-analyzer/src/global_state.rs b/crates/rust-analyzer/src/global_state.rs
index ec10bc7ccda..e9bca19af64 100644
--- a/crates/rust-analyzer/src/global_state.rs
+++ b/crates/rust-analyzer/src/global_state.rs
@@ -125,6 +125,7 @@ pub(crate) struct GlobalState {
     /// to invalidate any salsa caches.
     pub(crate) workspaces: Arc<Vec<ProjectWorkspace>>,
     pub(crate) crate_graph_file_dependencies: FxHashSet<vfs::VfsPath>,
+    pub(crate) detached_files: FxHashSet<vfs::AbsPathBuf>,
 
     // op queues
     pub(crate) fetch_workspaces_queue:
@@ -233,6 +234,7 @@ impl GlobalState {
 
             workspaces: Arc::from(Vec::new()),
             crate_graph_file_dependencies: FxHashSet::default(),
+            detached_files: FxHashSet::default(),
             fetch_workspaces_queue: OpQueue::default(),
             fetch_build_data_queue: OpQueue::default(),
             fetch_proc_macros_queue: OpQueue::default(),
@@ -519,7 +521,7 @@ impl GlobalStateSnapshot {
                 cargo.target_by_root(path).map(|it| (cargo, it))
             }
             ProjectWorkspace::Json { .. } => None,
-            ProjectWorkspace::DetachedFiles { .. } => None,
+            ProjectWorkspace::DetachedFile { .. } => None,
         })
     }
 
diff --git a/crates/rust-analyzer/src/handlers/notification.rs b/crates/rust-analyzer/src/handlers/notification.rs
index 68dc2cf2e29..4b8c3d06ce4 100644
--- a/crates/rust-analyzer/src/handlers/notification.rs
+++ b/crates/rust-analyzer/src/handlers/notification.rs
@@ -154,6 +154,10 @@ pub(crate) fn handle_did_save_text_document(
                 state
                     .fetch_workspaces_queue
                     .request_op(format!("workspace vfs file change saved {abs_path}"), false);
+            } else if state.detached_files.contains(abs_path) {
+                state
+                    .fetch_workspaces_queue
+                    .request_op(format!("detached file saved {abs_path}"), false);
             }
         }
 
@@ -303,7 +307,8 @@ fn run_flycheck(state: &mut GlobalState, vfs_path: VfsPath) -> bool {
                         }
                         None
                     }
-                    project_model::ProjectWorkspace::DetachedFiles { .. } => return None,
+                    // FIXME
+                    project_model::ProjectWorkspace::DetachedFile { .. } => return None,
                 };
                 Some((idx, package))
             });
diff --git a/crates/rust-analyzer/src/handlers/request.rs b/crates/rust-analyzer/src/handlers/request.rs
index 9c86704ba3e..cf97d7d9d23 100644
--- a/crates/rust-analyzer/src/handlers/request.rs
+++ b/crates/rust-analyzer/src/handlers/request.rs
@@ -101,7 +101,7 @@ pub(crate) fn handle_analyzer_status(
             "Workspace root folders: {:?}",
             snap.workspaces
                 .iter()
-                .flat_map(|ws| ws.workspace_definition_path())
+                .map(|ws| ws.workspace_definition_path())
                 .collect::<Vec<&AbsPath>>()
         );
     }
@@ -1761,7 +1761,9 @@ pub(crate) fn handle_open_docs(
     let ws_and_sysroot = snap.workspaces.iter().find_map(|ws| match ws {
         ProjectWorkspace::Cargo { cargo, sysroot, .. } => Some((cargo, sysroot.as_ref().ok())),
         ProjectWorkspace::Json { .. } => None,
-        ProjectWorkspace::DetachedFiles { .. } => None,
+        ProjectWorkspace::DetachedFile { cargo_script, sysroot, .. } => {
+            cargo_script.as_ref().zip(Some(sysroot.as_ref().ok()))
+        }
     });
 
     let (cargo, sysroot) = match ws_and_sysroot {
diff --git a/crates/rust-analyzer/src/reload.rs b/crates/rust-analyzer/src/reload.rs
index 00a61758f06..5d8a66cabc7 100644
--- a/crates/rust-analyzer/src/reload.rs
+++ b/crates/rust-analyzer/src/reload.rs
@@ -153,7 +153,7 @@ impl GlobalState {
         for ws in self.workspaces.iter() {
             let (ProjectWorkspace::Cargo { sysroot, .. }
             | ProjectWorkspace::Json { sysroot, .. }
-            | ProjectWorkspace::DetachedFiles { sysroot, .. }) = ws;
+            | ProjectWorkspace::DetachedFile { sysroot, .. }) = ws;
             match sysroot {
                 Err(None) => (),
                 Err(Some(e)) => {
@@ -255,7 +255,7 @@ impl GlobalState {
                 }
 
                 if !detached_files.is_empty() {
-                    workspaces.push(project_model::ProjectWorkspace::load_detached_files(
+                    workspaces.extend(project_model::ProjectWorkspace::load_detached_files(
                         detached_files,
                         &cargo_config,
                     ));
@@ -540,9 +540,6 @@ impl GlobalState {
     }
 
     fn recreate_crate_graph(&mut self, cause: String) {
-        // crate graph construction relies on these paths, record them so when one of them gets
-        // deleted or created we trigger a reconstruction of the crate graph
-        let mut crate_graph_file_dependencies = mem::take(&mut self.crate_graph_file_dependencies);
         self.report_progress(
             "Building CrateGraph",
             crate::lsp::utils::Progress::Begin,
@@ -551,13 +548,25 @@ impl GlobalState {
             None,
         );
 
+        // crate graph construction relies on these paths, record them so when one of them gets
+        // deleted or created we trigger a reconstruction of the crate graph
+        self.crate_graph_file_dependencies.clear();
+        self.detached_files = self
+            .workspaces
+            .iter()
+            .filter_map(|ws| match ws {
+                ProjectWorkspace::DetachedFile { file, .. } => Some(file.clone()),
+                _ => None,
+            })
+            .collect();
+
         let (crate_graph, proc_macro_paths, layouts, toolchains) = {
             // Create crate graph from all the workspaces
             let vfs = &mut self.vfs.write().0;
 
             let load = |path: &AbsPath| {
                 let vfs_path = vfs::VfsPath::from(path.to_path_buf());
-                crate_graph_file_dependencies.insert(vfs_path.clone());
+                self.crate_graph_file_dependencies.insert(vfs_path.clone());
                 vfs.file_id(&vfs_path)
             };
 
@@ -577,7 +586,6 @@ impl GlobalState {
         change.set_target_data_layouts(layouts);
         change.set_toolchains(toolchains);
         self.analysis_host.apply_change(change);
-        self.crate_graph_file_dependencies = crate_graph_file_dependencies;
         self.report_progress(
             "Building CrateGraph",
             crate::lsp::utils::Progress::End,
@@ -674,7 +682,8 @@ impl GlobalState {
                                 _ => None,
                             }
                         }
-                        ProjectWorkspace::DetachedFiles { .. } => None,
+                        // FIXME
+                        ProjectWorkspace::DetachedFile { .. } => None,
                     })
                     .map(|(id, root, sysroot_root)| {
                         let sender = sender.clone();
@@ -713,15 +722,9 @@ pub fn ws_to_crate_graph(
         let (other, mut crate_proc_macros) = ws.to_crate_graph(&mut load, extra_env);
         let num_layouts = layouts.len();
         let num_toolchains = toolchains.len();
-        let (toolchain, layout) = match ws {
-            ProjectWorkspace::Cargo { toolchain, target_layout, .. }
-            | ProjectWorkspace::Json { toolchain, target_layout, .. } => {
-                (toolchain.clone(), target_layout.clone())
-            }
-            ProjectWorkspace::DetachedFiles { .. } => {
-                (None, Err("detached files have no layout".into()))
-            }
-        };
+        let (ProjectWorkspace::Cargo { toolchain, target_layout, .. }
+        | ProjectWorkspace::Json { toolchain, target_layout, .. }
+        | ProjectWorkspace::DetachedFile { toolchain, target_layout, .. }) = ws;
 
         let mapping = crate_graph.extend(
             other,
@@ -730,7 +733,7 @@ pub fn ws_to_crate_graph(
                 // if the newly created crate graph's layout is equal to the crate of the merged graph, then
                 // we can merge the crates.
                 let id = cg_id.into_raw().into_u32() as usize;
-                layouts[id] == layout && toolchains[id] == toolchain && cg_data == o_data
+                layouts[id] == *target_layout && toolchains[id] == *toolchain && cg_data == o_data
             },
         );
         // Populate the side tables for the newly merged crates
@@ -742,13 +745,13 @@ pub fn ws_to_crate_graph(
                 if layouts.len() <= idx {
                     layouts.resize(idx + 1, e.clone());
                 }
-                layouts[idx].clone_from(&layout);
+                layouts[idx].clone_from(target_layout);
             }
             if idx >= num_toolchains {
                 if toolchains.len() <= idx {
                     toolchains.resize(idx + 1, None);
                 }
-                toolchains[idx].clone_from(&toolchain);
+                toolchains[idx].clone_from(toolchain);
             }
         });
         proc_macro_paths.push(crate_proc_macros);
diff --git a/crates/rust-analyzer/tests/slow-tests/main.rs b/crates/rust-analyzer/tests/slow-tests/main.rs
index 786a80c4a68..b87f02947bf 100644
--- a/crates/rust-analyzer/tests/slow-tests/main.rs
+++ b/crates/rust-analyzer/tests/slow-tests/main.rs
@@ -118,6 +118,105 @@ fn f() {
 }
 
 #[test]
+fn completes_items_from_standard_library_in_cargo_script() {
+    // this test requires nightly so CI can't run it
+    if skip_slow_tests() || std::env::var("CI").is_ok() {
+        return;
+    }
+
+    let server = Project::with_fixture(
+        r#"
+//- /dependency/Cargo.toml
+[package]
+name = "dependency"
+version = "0.1.0"
+//- /dependency/src/lib.rs
+pub struct SpecialHashMap;
+//- /dependency2/Cargo.toml
+[package]
+name = "dependency2"
+version = "0.1.0"
+//- /dependency2/src/lib.rs
+pub struct SpecialHashMap2;
+//- /src/lib.rs
+#!/usr/bin/env -S cargo +nightly -Zscript
+---
+[dependencies]
+dependency = { path = "../dependency" }
+---
+use dependency::Spam;
+use dependency2::Spam;
+"#,
+    )
+    .with_config(serde_json::json!({
+        "cargo": { "sysroot": null },
+    }))
+    .server()
+    .wait_until_workspace_is_loaded();
+
+    let res = server.send_request::<Completion>(CompletionParams {
+        text_document_position: TextDocumentPositionParams::new(
+            server.doc_id("src/lib.rs"),
+            Position::new(5, 18),
+        ),
+        context: None,
+        partial_result_params: PartialResultParams::default(),
+        work_done_progress_params: WorkDoneProgressParams::default(),
+    });
+    assert!(res.to_string().contains("SpecialHashMap"), "{}", res.to_string());
+
+    let res = server.send_request::<Completion>(CompletionParams {
+        text_document_position: TextDocumentPositionParams::new(
+            server.doc_id("src/lib.rs"),
+            Position::new(6, 18),
+        ),
+        context: None,
+        partial_result_params: PartialResultParams::default(),
+        work_done_progress_params: WorkDoneProgressParams::default(),
+    });
+    assert!(!res.to_string().contains("SpecialHashMap"));
+
+    server.write_file_and_save(
+        "src/lib.rs",
+        r#"#!/usr/bin/env -S cargo +nightly -Zscript
+---
+[dependencies]
+dependency2 = { path = "../dependency2" }
+---
+use dependency::Spam;
+use dependency2::Spam;
+"#
+        .to_owned(),
+    );
+
+    let server = server.wait_until_workspace_is_loaded();
+
+    std::thread::sleep(std::time::Duration::from_secs(3));
+
+    let res = server.send_request::<Completion>(CompletionParams {
+        text_document_position: TextDocumentPositionParams::new(
+            server.doc_id("src/lib.rs"),
+            Position::new(5, 18),
+        ),
+        context: None,
+        partial_result_params: PartialResultParams::default(),
+        work_done_progress_params: WorkDoneProgressParams::default(),
+    });
+    assert!(!res.to_string().contains("SpecialHashMap"));
+
+    let res = server.send_request::<Completion>(CompletionParams {
+        text_document_position: TextDocumentPositionParams::new(
+            server.doc_id("src/lib.rs"),
+            Position::new(6, 18),
+        ),
+        context: None,
+        partial_result_params: PartialResultParams::default(),
+        work_done_progress_params: WorkDoneProgressParams::default(),
+    });
+    assert!(res.to_string().contains("SpecialHashMap"));
+}
+
+#[test]
 fn test_runnables_project() {
     if skip_slow_tests() {
         return;
diff --git a/crates/rust-analyzer/tests/slow-tests/support.rs b/crates/rust-analyzer/tests/slow-tests/support.rs
index c6778bf6564..f04962a7a27 100644
--- a/crates/rust-analyzer/tests/slow-tests/support.rs
+++ b/crates/rust-analyzer/tests/slow-tests/support.rs
@@ -125,7 +125,7 @@ impl Project<'_> {
         }
 
         let mut config = Config::new(
-            tmp_dir_path,
+            tmp_dir_path.clone(),
             lsp_types::ClientCapabilities {
                 workspace: Some(lsp_types::WorkspaceClientCapabilities {
                     did_change_watched_files: Some(
@@ -185,10 +185,14 @@ impl Project<'_> {
             roots,
             None,
         );
-        config.update(self.config).expect("invalid config");
+        // TODO: don't hardcode src/lib.rs as detached file
+        let mut c = self.config;
+        let p = tmp_dir_path.join("src/lib.rs").to_string();
+        c["detachedFiles"] = serde_json::json!([p]);
+        config.update(c).expect("invalid config");
         config.rediscover_workspaces();
 
-        Server::new(tmp_dir, config)
+        Server::new(tmp_dir.keep(), config)
     }
 }
 
@@ -283,6 +287,7 @@ impl Server {
         }
     }
 
+    #[track_caller]
     pub(crate) fn send_request<R>(&self, params: R::Params) -> Value
     where
         R: lsp_types::request::Request,
@@ -294,6 +299,7 @@ impl Server {
         let r = Request::new(id.into(), R::METHOD.to_owned(), params);
         self.send_request_(r)
     }
+    #[track_caller]
     fn send_request_(&self, r: Request) -> Value {
         let id = r.id.clone();
         self.client.sender.send(r.clone().into()).unwrap();
@@ -374,6 +380,16 @@ impl Server {
     pub(crate) fn path(&self) -> &Utf8Path {
         self.dir.path()
     }
+
+    pub(crate) fn write_file_and_save(&self, path: &str, text: String) {
+        fs::write(self.dir.path().join(path), &text).unwrap();
+        self.notification::<lsp_types::notification::DidSaveTextDocument>(
+            lsp_types::DidSaveTextDocumentParams {
+                text_document: self.doc_id(path),
+                text: Some(text),
+            },
+        )
+    }
 }
 
 impl Drop for Server {