Gate #[test] expansion under cfg(test).

This will mean users opting to not activate `cfg(test)` will lose IDE experience on them, which is quite unfortunate, but this is unavoidable if we want to avoid false positives on e.g. diagnostics. The real fix is to provide IDE experience even for cfg'ed out code, but this is out of scope for this PR.

Author: ChayimFriedman2

crates/cfg/src/lib.rs

@@ -49,6 +49,10 @@ impl CfgOptions {
         cfg.fold(&|atom| self.enabled.contains(atom))
     }
 
+    pub fn check_atom(&self, cfg: &CfgAtom) -> bool {
+        self.enabled.contains(cfg)
+    }
+
     pub fn insert_atom(&mut self, key: Symbol) {
         self.enabled.insert(CfgAtom::Flag(key));
     }

crates/hir-def/src/nameres/collector.rs

@@ -6,7 +6,7 @@
 use std::{cmp::Ordering, iter, mem, ops::Not};
 
 use base_db::{CrateId, CrateOrigin, Dependency, LangCrateOrigin};
-use cfg::{CfgExpr, CfgOptions};
+use cfg::{CfgAtom, CfgExpr, CfgOptions};
 use either::Either;
 use hir_expand::{
     attrs::{Attr, AttrId},
@@ -1324,13 +1324,21 @@ impl DefCollector<'_> {
                     };
 
                     // Skip #[test]/#[bench] expansion, which would merely result in more memory usage
-                    // due to duplicating functions into macro expansions
+                    // due to duplicating functions into macro expansions, but only if `cfg(test)` is active,
+                    // otherwise they are expanded to nothing and this can impact e.g. diagnostics (due to things
+                    // being cfg'ed out).
+                    // Ideally we will just expand them to nothing here. But we are only collecting macro calls,
+                    // not expanding them, so we have no way to do that.
                     if matches!(
                         def.kind,
                         MacroDefKind::BuiltInAttr(_, expander)
                         if expander.is_test() || expander.is_bench()
                     ) {
-                        return recollect_without(self);
+                        let test_is_active =
+                            self.cfg_options.check_atom(&CfgAtom::Flag(sym::test.clone()));
+                        if test_is_active {
+                            return recollect_without(self);
+                        }
                     }
 
                     let call_id = || {

crates/hir-expand/src/builtin/attr_macro.rs

@@ -4,6 +4,8 @@ use span::{MacroCallId, Span};
 
 use crate::{db::ExpandDatabase, name, tt, ExpandResult, MacroCallKind};
 
+use super::quote;
+
 macro_rules! register_builtin {
     ($(($name:ident, $variant:ident) => $expand:ident),* ) => {
         #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
@@ -52,15 +54,15 @@ impl BuiltinAttrExpander {
 }
 
 register_builtin! {
-    (bench, Bench) => dummy_attr_expand,
+    (bench, Bench) => dummy_gate_test_expand,
     (cfg_accessible, CfgAccessible) => dummy_attr_expand,
     (cfg_eval, CfgEval) => dummy_attr_expand,
     (derive, Derive) => derive_expand,
     // derive const is equivalent to derive for our proposes.
     (derive_const, DeriveConst) => derive_expand,
     (global_allocator, GlobalAllocator) => dummy_attr_expand,
-    (test, Test) => dummy_attr_expand,
-    (test_case, TestCase) => dummy_attr_expand
+    (test, Test) => dummy_gate_test_expand,
+    (test_case, TestCase) => dummy_gate_test_expand
 }
 
 pub fn find_builtin_attr(ident: &name::Name) -> Option<BuiltinAttrExpander> {
@@ -76,6 +78,19 @@ fn dummy_attr_expand(
     ExpandResult::ok(tt.clone())
 }
 
+fn dummy_gate_test_expand(
+    _db: &dyn ExpandDatabase,
+    _id: MacroCallId,
+    tt: &tt::Subtree,
+    span: Span,
+) -> ExpandResult<tt::Subtree> {
+    let result = quote::quote! { span=>
+        #[cfg(test)]
+        #tt
+    };
+    ExpandResult::ok(result)
+}
+
 /// We generate a very specific expansion here, as we do not actually expand the `#[derive]` attribute
 /// itself in name res, but we do want to expand it to something for the IDE layer, so that the input
 /// derive attributes can be downmapped, and resolved as proper paths.

crates/load-cargo/src/lib.rs

@@ -30,7 +30,6 @@ pub struct LoadCargoConfig {
     pub load_out_dirs_from_check: bool,
     pub with_proc_macro_server: ProcMacroServerChoice,
     pub prefill_caches: bool,
-    pub set_test: bool,
 }
 
 #[derive(Debug, Clone, PartialEq, Eq)]
@@ -100,7 +99,6 @@ pub fn load_workspace(
             vfs.file_id(&path)
         },
         extra_env,
-        load_config.set_test,
     );
     let proc_macros = {
         let proc_macro_server = match &proc_macro_server {
@@ -528,12 +526,11 @@ mod tests {
     #[test]
     fn test_loading_rust_analyzer() {
         let path = Path::new(env!("CARGO_MANIFEST_DIR")).parent().unwrap().parent().unwrap();
-        let cargo_config = CargoConfig::default();
+        let cargo_config = CargoConfig { set_test: true, ..CargoConfig::default() };
         let load_cargo_config = LoadCargoConfig {
             load_out_dirs_from_check: false,
             with_proc_macro_server: ProcMacroServerChoice::None,
             prefill_caches: false,
-            set_test: true,
         };
         let (db, _vfs, _proc_macro) =
             load_workspace_at(path, &cargo_config, &load_cargo_config, &|_| {}).unwrap();

crates/project-model/src/cargo_workspace.rs

@@ -100,6 +100,7 @@ pub struct CargoConfig {
     pub invocation_strategy: InvocationStrategy,
     /// Optional path to use instead of `target` when building
     pub target_dir: Option<Utf8PathBuf>,
+    pub set_test: bool,
 }
 
 pub type Package = Idx<PackageData>;

crates/project-model/src/tests.rs

@@ -35,6 +35,7 @@ fn load_cargo_with_overrides(
             rustc: Err(None),
             cargo_config_extra_env: Default::default(),
             error: None,
+            set_test: true,
         },
         cfg_overrides,
         sysroot: Sysroot::empty(),
@@ -136,7 +137,6 @@ fn to_crate_graph(project_workspace: ProjectWorkspace) -> (CrateGraph, ProcMacro
             }
         },
         &Default::default(),
-        true,
     )
 }
 
@@ -243,6 +243,7 @@ fn smoke_test_real_sysroot_cargo() {
             rustc: Err(None),
             cargo_config_extra_env: Default::default(),
             error: None,
+            set_test: true,
         },
         sysroot,
         rustc_cfg: Vec::new(),
@@ -258,6 +259,5 @@ fn smoke_test_real_sysroot_cargo() {
             }
         },
         &Default::default(),
-        true,
     );
 }

crates/project-model/src/workspace.rs

@@ -78,6 +78,7 @@ pub enum ProjectWorkspaceKind {
         rustc: Result<Box<(CargoWorkspace, WorkspaceBuildScripts)>, Option<String>>,
         /// Environment variables set in the `.cargo/config` file.
         cargo_config_extra_env: FxHashMap<String, String>,
+        set_test: bool,
     },
     /// Project workspace was specified using a `rust-project.json` file.
     Json(ProjectJson),
@@ -98,6 +99,7 @@ pub enum ProjectWorkspaceKind {
         cargo: Option<(CargoWorkspace, WorkspaceBuildScripts, Option<Arc<anyhow::Error>>)>,
         /// Environment variables set in the `.cargo/config` file.
         cargo_config_extra_env: FxHashMap<String, String>,
+        set_test: bool,
     },
 }
 
@@ -112,6 +114,7 @@ impl fmt::Debug for ProjectWorkspace {
                 build_scripts,
                 rustc,
                 cargo_config_extra_env,
+                set_test,
             } => f
                 .debug_struct("Cargo")
                 .field("root", &cargo.workspace_root().file_name())
@@ -126,6 +129,7 @@ impl fmt::Debug for ProjectWorkspace {
                 .field("toolchain", &toolchain)
                 .field("data_layout", &target_layout)
                 .field("cargo_config_extra_env", &cargo_config_extra_env)
+                .field("set_test", set_test)
                 .field("build_scripts", &build_scripts.error().unwrap_or("ok"))
                 .finish(),
             ProjectWorkspaceKind::Json(project) => {
@@ -137,12 +141,14 @@ impl fmt::Debug for ProjectWorkspace {
                     .field("toolchain", &toolchain)
                     .field("data_layout", &target_layout)
                     .field("n_cfg_overrides", &cfg_overrides.len());
+
                 debug_struct.finish()
             }
             ProjectWorkspaceKind::DetachedFile {
                 file,
                 cargo: cargo_script,
                 cargo_config_extra_env,
+                set_test,
             } => f
                 .debug_struct("DetachedFiles")
                 .field("file", &file)
@@ -154,6 +160,7 @@ impl fmt::Debug for ProjectWorkspace {
                 .field("data_layout", &target_layout)
                 .field("n_cfg_overrides", &cfg_overrides.len())
                 .field("cargo_config_extra_env", &cargo_config_extra_env)
+                .field("set_test", set_test)
                 .finish(),
         }
     }
@@ -329,6 +336,7 @@ impl ProjectWorkspace {
                         rustc,
                         cargo_config_extra_env,
                         error: error.map(Arc::new),
+                        set_test: config.set_test,
                     },
                     sysroot,
                     rustc_cfg,
@@ -423,6 +431,7 @@ impl ProjectWorkspace {
                 file: detached_file.to_owned(),
                 cargo: cargo_script,
                 cargo_config_extra_env,
+                set_test: config.set_test,
             },
             sysroot,
             rustc_cfg,
@@ -609,6 +618,7 @@ impl ProjectWorkspace {
                 build_scripts,
                 cargo_config_extra_env: _,
                 error: _,
+                set_test: _,
             } => {
                 cargo
                     .packages()
@@ -728,7 +738,6 @@ impl ProjectWorkspace {
         &self,
         load: FileLoader<'_>,
         extra_env: &FxHashMap<String, String>,
-        set_test: bool,
     ) -> (CrateGraph, ProcMacroPaths) {
         let _p = tracing::info_span!("ProjectWorkspace::to_crate_graph").entered();
 
@@ -742,7 +751,6 @@ impl ProjectWorkspace {
                     sysroot,
                     extra_env,
                     cfg_overrides,
-                    set_test,
                 ),
                 sysroot,
             ),
@@ -752,6 +760,7 @@ impl ProjectWorkspace {
                 build_scripts,
                 cargo_config_extra_env: _,
                 error: _,
+                set_test,
             } => (
                 cargo_to_crate_graph(
                     load,
@@ -761,11 +770,11 @@ impl ProjectWorkspace {
                     rustc_cfg.clone(),
                     cfg_overrides,
                     build_scripts,
-                    set_test,
+                    *set_test,
                 ),
                 sysroot,
             ),
-            ProjectWorkspaceKind::DetachedFile { file, cargo: cargo_script, .. } => (
+            ProjectWorkspaceKind::DetachedFile { file, cargo: cargo_script, set_test, .. } => (
                 if let Some((cargo, build_scripts, _)) = cargo_script {
                     cargo_to_crate_graph(
                         &mut |path| load(path),
@@ -775,7 +784,7 @@ impl ProjectWorkspace {
                         rustc_cfg.clone(),
                         cfg_overrides,
                         build_scripts,
-                        set_test,
+                        *set_test,
                     )
                 } else {
                     detached_file_to_crate_graph(
@@ -784,7 +793,7 @@ impl ProjectWorkspace {
                         file,
                         sysroot,
                         cfg_overrides,
-                        set_test,
+                        *set_test,
                     )
                 },
                 sysroot,
@@ -818,13 +827,15 @@ impl ProjectWorkspace {
                     cargo_config_extra_env,
                     build_scripts: _,
                     error: _,
+                    set_test: _,
                 },
                 ProjectWorkspaceKind::Cargo {
                     cargo: o_cargo,
                     rustc: o_rustc,
                     cargo_config_extra_env: o_cargo_config_extra_env,
                     build_scripts: _,
                     error: _,
+                    set_test: _,
                 },
             ) => {
                 cargo == o_cargo
@@ -839,11 +850,13 @@ impl ProjectWorkspace {
                     file,
                     cargo: Some((cargo_script, _, _)),
                     cargo_config_extra_env,
+                    set_test: _,
                 },
                 ProjectWorkspaceKind::DetachedFile {
                     file: o_file,
                     cargo: Some((o_cargo_script, _, _)),
                     cargo_config_extra_env: o_cargo_config_extra_env,
+                    set_test: _,
                 },
             ) => {
                 file == o_file
@@ -875,12 +888,11 @@ fn project_json_to_crate_graph(
     sysroot: &Sysroot,
     extra_env: &FxHashMap<String, String>,
     override_cfg: &CfgOverrides,
-    set_test: bool,
 ) -> (CrateGraph, ProcMacroPaths) {
     let mut res = (CrateGraph::default(), ProcMacroPaths::default());
     let (crate_graph, proc_macros) = &mut res;
     let (public_deps, libproc_macro) =
-        sysroot_to_crate_graph(crate_graph, sysroot, rustc_cfg.clone(), load, set_test);
+        sysroot_to_crate_graph(crate_graph, sysroot, rustc_cfg.clone(), load);
 
     let r_a_cfg_flag = CfgAtom::Flag(sym::rust_analyzer.clone());
     let mut cfg_cache: FxHashMap<&str, Vec<CfgAtom>> = FxHashMap::default();
@@ -1000,7 +1012,7 @@ fn cargo_to_crate_graph(
     let crate_graph = &mut res.0;
     let proc_macros = &mut res.1;
     let (public_deps, libproc_macro) =
-        sysroot_to_crate_graph(crate_graph, sysroot, rustc_cfg.clone(), load, set_test);
+        sysroot_to_crate_graph(crate_graph, sysroot, rustc_cfg.clone(), load);
 
     let cfg_options = CfgOptions::from_iter(rustc_cfg);
 
@@ -1187,7 +1199,7 @@ fn detached_file_to_crate_graph(
     let _p = tracing::info_span!("detached_file_to_crate_graph").entered();
     let mut crate_graph = CrateGraph::default();
     let (public_deps, _libproc_macro) =
-        sysroot_to_crate_graph(&mut crate_graph, sysroot, rustc_cfg.clone(), load, set_test);
+        sysroot_to_crate_graph(&mut crate_graph, sysroot, rustc_cfg.clone(), load);
 
     let mut cfg_options = CfgOptions::from_iter(rustc_cfg);
     if set_test {
@@ -1416,7 +1428,6 @@ fn sysroot_to_crate_graph(
     sysroot: &Sysroot,
     rustc_cfg: Vec<CfgAtom>,
     load: FileLoader<'_>,
-    set_test: bool,
 ) -> (SysrootPublicDeps, Option<CrateId>) {
     let _p = tracing::info_span!("sysroot_to_crate_graph").entered();
     match sysroot.mode() {
@@ -1439,7 +1450,7 @@ fn sysroot_to_crate_graph(
                     ..Default::default()
                 },
                 &WorkspaceBuildScripts::default(),
-                set_test,
+                false,
             );
 
             let mut pub_deps = vec![];

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

@@ -65,6 +65,7 @@ impl flags::AnalysisStats {
                 false => Some(RustLibSource::Discover),
             },
             all_targets: true,
+            set_test: true,
             ..Default::default()
         };
         let no_progress = &|_| ();
@@ -84,7 +85,6 @@ impl flags::AnalysisStats {
                 ProcMacroServerChoice::Sysroot
             },
             prefill_caches: false,
-            set_test: true,
         };
 
         let build_scripts_time = if self.disable_build_scripts {

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

@@ -39,8 +39,6 @@ impl flags::Diagnostics {
             load_out_dirs_from_check: !self.disable_build_scripts,
             with_proc_macro_server,
             prefill_caches: false,
-            // We don't pass `--all-targets` so we also set `cfg(test)` to false.
-            set_test: false,
         };
         let (db, _vfs, _proc_macro) =
             load_workspace_at(&self.path, &cargo_config, &load_cargo_config, &|_| {})?;