Add config setting which allows adding additional include paths to the VFS.

crates/project-model/src/cargo_workspace.rs

@@ -92,6 +92,8 @@ pub struct CargoConfig {
     pub sysroot_src: Option<AbsPathBuf>,
     /// rustc private crate source
     pub rustc_source: Option<RustLibSource>,
+    /// Extra includes to add to the VFS.
+    pub extra_includes: Vec<AbsPathBuf>,
     pub cfg_overrides: CfgOverrides,
     /// Invoke `cargo check` through the RUSTC_WRAPPER.
     pub wrap_rustc_in_build_scripts: bool,

crates/project-model/src/tests.rs

@@ -49,6 +49,7 @@ fn load_workspace_from_metadata(file: &str) -> ProjectWorkspace {
         rustc_cfg: Vec::new(),
         toolchain: None,
         target_layout: Err("target_data_layout not loaded".into()),
+        extra_includes: Vec::new(),
     }
 }
 
@@ -63,6 +64,7 @@ fn load_rust_project(file: &str) -> (CrateGraph, ProcMacroPaths) {
         toolchain: None,
         target_layout: Err(Arc::from("test has no data layout")),
         cfg_overrides: Default::default(),
+        extra_includes: Vec::new(),
     };
     to_crate_graph(project_workspace, &mut Default::default())
 }
@@ -284,6 +286,7 @@ fn smoke_test_real_sysroot_cargo() {
         cfg_overrides: Default::default(),
         toolchain: None,
         target_layout: Err("target_data_layout not loaded".into()),
+        extra_includes: Vec::new(),
     };
     project_workspace.to_crate_graph(
         &mut {

crates/project-model/src/workspace.rs

@@ -63,6 +63,8 @@ pub struct ProjectWorkspace {
     pub target_layout: TargetLayoutLoadResult,
     /// A set of cfg overrides for this workspace.
     pub cfg_overrides: CfgOverrides,
+    /// Additional includes to add for the VFS.
+    pub extra_includes: Vec<AbsPathBuf>,
 }
 
 #[derive(Clone)]
@@ -104,7 +106,15 @@ pub enum ProjectWorkspaceKind {
 impl fmt::Debug for ProjectWorkspace {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         // Make sure this isn't too verbose.
-        let Self { kind, sysroot, rustc_cfg, toolchain, target_layout, cfg_overrides } = self;
+        let Self {
+            kind,
+            sysroot,
+            rustc_cfg,
+            toolchain,
+            target_layout,
+            cfg_overrides,
+            extra_includes,
+        } = self;
         match kind {
             ProjectWorkspaceKind::Cargo { cargo, error: _, build_scripts, rustc, set_test } => f
                 .debug_struct("Cargo")
@@ -117,6 +127,7 @@ impl fmt::Debug for ProjectWorkspace {
                 )
                 .field("n_rustc_cfg", &rustc_cfg.len())
                 .field("n_cfg_overrides", &cfg_overrides.len())
+                .field("n_extra_includes", &extra_includes.len())
                 .field("toolchain", &toolchain)
                 .field("data_layout", &target_layout)
                 .field("set_test", set_test)
@@ -130,7 +141,8 @@ impl fmt::Debug for ProjectWorkspace {
                     .field("n_rustc_cfg", &rustc_cfg.len())
                     .field("toolchain", &toolchain)
                     .field("data_layout", &target_layout)
-                    .field("n_cfg_overrides", &cfg_overrides.len());
+                    .field("n_cfg_overrides", &cfg_overrides.len())
+                    .field("n_extra_includes", &extra_includes.len());
 
                 debug_struct.finish()
             }
@@ -144,6 +156,7 @@ impl fmt::Debug for ProjectWorkspace {
                 .field("toolchain", &toolchain)
                 .field("data_layout", &target_layout)
                 .field("n_cfg_overrides", &cfg_overrides.len())
+                .field("n_extra_includes", &extra_includes.len())
                 .field("set_test", set_test)
                 .finish(),
         }
@@ -320,6 +333,7 @@ impl ProjectWorkspace {
             cfg_overrides,
             toolchain,
             target_layout: data_layout.map(Arc::from).map_err(|it| Arc::from(it.to_string())),
+            extra_includes: config.extra_includes.clone(),
         })
     }
 
@@ -340,6 +354,7 @@ impl ProjectWorkspace {
             toolchain,
             target_layout: data_layout.map(Arc::from).map_err(|it| Arc::from(it.to_string())),
             cfg_overrides: config.cfg_overrides.clone(),
+            extra_includes: config.extra_includes.clone(),
         }
     }
 
@@ -399,6 +414,7 @@ impl ProjectWorkspace {
             toolchain,
             target_layout: data_layout.map(Arc::from).map_err(|it| Arc::from(it.to_string())),
             cfg_overrides: config.cfg_overrides.clone(),
+            extra_includes: config.extra_includes.clone(),
         })
     }
 
@@ -565,7 +581,13 @@ impl ProjectWorkspace {
 
                     PackageRoot {
                         is_local: krate.is_workspace_member,
-                        include: krate.include.iter().cloned().chain(build_file).collect(),
+                        include: krate
+                            .include
+                            .iter()
+                            .cloned()
+                            .chain(build_file)
+                            .chain(self.extra_includes.iter().cloned())
+                            .collect(),
                         exclude: krate.exclude.clone(),
                     }
                 })
@@ -603,6 +625,8 @@ impl ProjectWorkspace {
 
                         let mut exclude = vec![pkg_root.join(".git")];
                         if is_local {
+                            include.extend(self.extra_includes.iter().cloned());
+
                             exclude.push(pkg_root.join("target"));
                         } else {
                             exclude.push(pkg_root.join("tests"));
@@ -661,6 +685,8 @@ impl ProjectWorkspace {
 
                         let mut exclude = vec![pkg_root.join(".git")];
                         if is_local {
+                            include.extend(self.extra_includes.iter().cloned());
+
                             exclude.push(pkg_root.join("target"));
                         } else {
                             exclude.push(pkg_root.join("tests"));

crates/rust-analyzer/src/cli/rustc_tests.rs

@@ -93,6 +93,7 @@ impl Tester {
             toolchain: None,
             target_layout: data_layout.map(Arc::from).map_err(|it| Arc::from(it.to_string())),
             cfg_overrides: Default::default(),
+            extra_includes: vec![],
         };
         let load_cargo_config = LoadCargoConfig {
             load_out_dirs_from_check: false,

crates/rust-analyzer/src/config.rs

@@ -728,6 +728,10 @@ config_data! {
         /// available on a nightly build.
         rustfmt_rangeFormatting_enable: bool = false,
 
+        /// Additional paths to include in the VFS. Generally for code that is
+        /// generated or otherwise managed by a build system outside of Cargo,
+        /// though Cargo might be the eventual consumer.
+        vfs_extraIncludes: Vec<String> = vec![],
 
         /// Workspace symbol search kind.
         workspace_symbol_search_kind: WorkspaceSymbolSearchKindDef = WorkspaceSymbolSearchKindDef::OnlyTypes,
@@ -1926,6 +1930,13 @@ impl Config {
         });
         let sysroot_src =
             self.cargo_sysrootSrc(source_root).as_ref().map(|sysroot| self.root_path.join(sysroot));
+        let extra_includes = self
+            .vfs_extraIncludes(source_root)
+            .iter()
+            .map(String::as_str)
+            .map(AbsPathBuf::try_from)
+            .filter_map(Result::ok)
+            .collect();
 
         CargoConfig {
             all_targets: *self.cargo_allTargets(source_root),
@@ -1940,6 +1951,7 @@ impl Config {
             sysroot,
             sysroot_src,
             rustc_source,
+            extra_includes,
             cfg_overrides: project_model::CfgOverrides {
                 global: CfgDiff::new(
                     self.cargo_cfgs(source_root)

docs/user/generated_config.adoc

@@ -1051,6 +1051,13 @@ Show documentation.
 --
 Specify the characters to exclude from triggering typing assists. The default trigger characters are `.`, `=`, `<`, `>`, `{`, and `(`.
 --
+[[rust-analyzer.vfs.extraIncludes]]rust-analyzer.vfs.extraIncludes (default: `[]`)::
++
+--
+Additional paths to include in the VFS. Generally for code that is
+generated or otherwise managed by a build system outside of Cargo,
+though Cargo might be the eventual consumer.
+--
 [[rust-analyzer.workspace.discoverConfig]]rust-analyzer.workspace.discoverConfig (default: `null`)::
 +
 --

editors/code/package.json

@@ -2718,6 +2718,19 @@
                     }
                 }
             },
+            {
+                "title": "vfs",
+                "properties": {
+                    "rust-analyzer.vfs.extraIncludes": {
+                        "markdownDescription": "Additional paths to include in the VFS. Generally for code that is\ngenerated or otherwise managed by a build system outside of Cargo,\nthough Cargo might be the eventual consumer.",
+                        "default": [],
+                        "type": "array",
+                        "items": {
+                            "type": "string"
+                        }
+                    }
+                }
+            },
             {
                 "title": "workspace",
                 "properties": {