29 files changed, 350 insertions, 183 deletions

diff --git a/Cargo.lock b/Cargo.lock
index 505263c64..ea2c1aed7 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1158,6 +1158,15 @@ dependencies = [
 [[package]]
 name = "proc_macro_test"
 version = "0.0.0"
+dependencies = [
+ "cargo_metadata",
+ "proc_macro_test_impl",
+ "toolchain",
+]
+
+[[package]]
+name = "proc_macro_test_impl"
+version = "0.0.0"
 
 [[package]]
 name = "profile"
@@ -1170,6 +1179,7 @@ dependencies = [
  "once_cell",
  "perf-event",
  "tikv-jemalloc-ctl",
+ "winapi",
 ]
 
 [[package]]
diff --git a/Cargo.toml b/Cargo.toml
index 32ba3923b..4d6908fa9 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,7 @@
 [workspace]
 resolver = "2"
 members = ["xtask/", "lib/*", "crates/*"]
+exclude = ["crates/proc_macro_test/imp"]
 
 [profile.dev]
 # Disabling debug info speeds up builds a bunch,
diff --git a/crates/base_db/src/lib.rs b/crates/base_db/src/lib.rs
index 62bf2a4b2..54baa3a63 100644
--- a/crates/base_db/src/lib.rs
+++ b/crates/base_db/src/lib.rs
@@ -120,6 +120,7 @@ impl<T: SourceDatabaseExt> FileLoader for FileLoaderDelegate<&'_ T> {
     }
 
     fn relevant_crates(&self, file_id: FileId) -> Arc<FxHashSet<CrateId>> {
+        let _p = profile::span("relevant_crates");
         let source_root = self.0.file_source_root(file_id);
         self.0.source_root_crates(source_root)
     }
diff --git a/crates/hir/src/lib.rs b/crates/hir/src/lib.rs
index debc3ee62..b9c1dc44d 100644
--- a/crates/hir/src/lib.rs
+++ b/crates/hir/src/lib.rs
@@ -191,6 +191,7 @@ impl Crate {
         db: &dyn DefDatabase,
         query: import_map::Query,
     ) -> impl Iterator<Item = Either<ModuleDef, MacroDef>> {
+        let _p = profile::span("query_external_importables");
         import_map::search_dependencies(db, self.into(), query).into_iter().map(|item| match item {
             ItemInNs::Types(mod_id) | ItemInNs::Values(mod_id) => Either::Left(mod_id.into()),
             ItemInNs::Macros(mac_id) => Either::Right(mac_id.into()),
@@ -2185,6 +2186,7 @@ impl Type {
         name: Option<&Name>,
         mut callback: impl FnMut(&Ty, Function) -> Option<T>,
     ) -> Option<T> {
+        let _p = profile::span("iterate_method_candidates");
         // There should be no inference vars in types passed here
         // FIXME check that?
         // FIXME replace Unknown by bound vars here
@@ -2218,6 +2220,7 @@ impl Type {
         name: Option<&Name>,
         mut callback: impl FnMut(&Ty, AssocItem) -> Option<T>,
     ) -> Option<T> {
+        let _p = profile::span("iterate_path_candidates");
         let canonical = hir_ty::replace_errors_with_variables(&self.ty);
 
         let env = self.env.clone();
@@ -2255,6 +2258,7 @@ impl Type {
         &'a self,
         db: &'a dyn HirDatabase,
     ) -> impl Iterator<Item = Trait> + 'a {
+        let _p = profile::span("applicable_inherent_traits");
         self.autoderef(db)
             .filter_map(|derefed_type| derefed_type.ty.dyn_trait())
             .flat_map(move |dyn_trait_id| hir_ty::all_super_traits(db.upcast(), dyn_trait_id))
diff --git a/crates/hir_def/src/import_map.rs b/crates/hir_def/src/import_map.rs
index 960cabb5f..404e3e153 100644
--- a/crates/hir_def/src/import_map.rs
+++ b/crates/hir_def/src/import_map.rs
@@ -1,6 +1,6 @@
 //! A map of all publicly exported items in a crate.
 
-use std::{cmp::Ordering, fmt, hash::BuildHasherDefault, sync::Arc};
+use std::{fmt, hash::BuildHasherDefault, sync::Arc};
 
 use base_db::CrateId;
 use fst::{self, Streamer};
@@ -69,81 +69,11 @@ pub struct ImportMap {
 impl ImportMap {
     pub fn import_map_query(db: &dyn DefDatabase, krate: CrateId) -> Arc<Self> {
         let _p = profile::span("import_map_query");
-        let def_map = db.crate_def_map(krate);
-        let mut import_map = Self::default();
-
-        // We look only into modules that are public(ly reexported), starting with the crate root.
-        let empty = ImportPath { segments: vec![] };
-        let root = def_map.module_id(def_map.root());
-        let mut worklist = vec![(root, empty)];
-        while let Some((module, mod_path)) = worklist.pop() {
-            let ext_def_map;
-            let mod_data = if module.krate == krate {
-                &def_map[module.local_id]
-            } else {
-                // The crate might reexport a module defined in another crate.
-                ext_def_map = module.def_map(db);
-                &ext_def_map[module.local_id]
-            };
-
-            let visible_items = mod_data.scope.entries().filter_map(|(name, per_ns)| {
-                let per_ns = per_ns.filter_visibility(|vis| vis == Visibility::Public);
-                if per_ns.is_none() {
-                    None
-                } else {
-                    Some((name, per_ns))
-                }
-            });
-
-            for (name, per_ns) in visible_items {
-                let mk_path = || {
-                    let mut path = mod_path.clone();
-                    path.segments.push(name.clone());
-                    path
-                };
-
-                for item in per_ns.iter_items() {
-                    let path = mk_path();
-                    let path_len = path.len();
-                    let import_info =
-                        ImportInfo { path, container: module, is_trait_assoc_item: false };
-
-                    if let Some(ModuleDefId::TraitId(tr)) = item.as_module_def_id() {
-                        import_map.collect_trait_assoc_items(
-                            db,
-                            tr,
-                            matches!(item, ItemInNs::Types(_)),
-                            &import_info,
-                        );
-                    }
 
-                    match import_map.map.entry(item) {
-                        Entry::Vacant(entry) => {
-                            entry.insert(import_info);
-                        }
-                        Entry::Occupied(mut entry) => {
-                            // If the new path is shorter, prefer that one.
-                            if path_len < entry.get().path.len() {
-                                *entry.get_mut() = import_info;
-                            } else {
-                                continue;
-                            }
-                        }
-                    }
-
-                    // If we've just added a path to a module, descend into it. We might traverse
-                    // modules multiple times, but only if the new path to it is shorter than the
-                    // first (else we `continue` above).
-                    if let Some(ModuleDefId::ModuleId(mod_id)) = item.as_module_def_id() {
-                        worklist.push((mod_id, mk_path()));
-                    }
-                }
-            }
-        }
+        let mut import_map = collect_import_map(db, krate);
 
         let mut importables = import_map.map.iter().collect::<Vec<_>>();
-
-        importables.sort_by(cmp);
+        importables.sort_by_cached_key(|(_, import_info)| fst_path(&import_info.path));
 
         // Build the FST, taking care not to insert duplicate values.
 
@@ -151,13 +81,13 @@ impl ImportMap {
         let mut last_batch_start = 0;
 
         for idx in 0..importables.len() {
-            if let Some(next_item) = importables.get(idx + 1) {
-                if cmp(&importables[last_batch_start], next_item) == Ordering::Equal {
+            let key = fst_path(&importables[last_batch_start].1.path);
+            if let Some((_, next_import_info)) = importables.get(idx + 1) {
+                if key == fst_path(&next_import_info.path) {
                     continue;
                 }
             }
 
-            let key = fst_path(&importables[last_batch_start].1.path);
             builder.insert(key, last_batch_start as u64).unwrap();
 
             last_batch_start = idx + 1;
@@ -185,6 +115,7 @@ impl ImportMap {
         is_type_in_ns: bool,
         original_import_info: &ImportInfo,
     ) {
+        let _p = profile::span("collect_trait_assoc_items");
         for (assoc_item_name, item) in &db.trait_data(tr).items {
             let module_def_id = match item {
                 AssocItemId::FunctionId(f) => ModuleDefId::from(*f),
@@ -210,6 +141,84 @@ impl ImportMap {
     }
 }
 
+fn collect_import_map(db: &dyn DefDatabase, krate: CrateId) -> ImportMap {
+    let _p = profile::span("collect_import_map");
+
+    let def_map = db.crate_def_map(krate);
+    let mut import_map = ImportMap::default();
+
+    // We look only into modules that are public(ly reexported), starting with the crate root.
+    let empty = ImportPath { segments: vec![] };
+    let root = def_map.module_id(def_map.root());
+    let mut worklist = vec![(root, empty)];
+    while let Some((module, mod_path)) = worklist.pop() {
+        let ext_def_map;
+        let mod_data = if module.krate == krate {
+            &def_map[module.local_id]
+        } else {
+            // The crate might reexport a module defined in another crate.
+            ext_def_map = module.def_map(db);
+            &ext_def_map[module.local_id]
+        };
+
+        let visible_items = mod_data.scope.entries().filter_map(|(name, per_ns)| {
+            let per_ns = per_ns.filter_visibility(|vis| vis == Visibility::Public);
+            if per_ns.is_none() {
+                None
+            } else {
+                Some((name, per_ns))
+            }
+        });
+
+        for (name, per_ns) in visible_items {
+            let mk_path = || {
+                let mut path = mod_path.clone();
+                path.segments.push(name.clone());
+                path
+            };
+
+            for item in per_ns.iter_items() {
+                let path = mk_path();
+                let path_len = path.len();
+                let import_info =
+                    ImportInfo { path, container: module, is_trait_assoc_item: false };
+
+                if let Some(ModuleDefId::TraitId(tr)) = item.as_module_def_id() {
+                    import_map.collect_trait_assoc_items(
+                        db,
+                        tr,
+                        matches!(item, ItemInNs::Types(_)),
+                        &import_info,
+                    );
+                }
+
+                match import_map.map.entry(item) {
+                    Entry::Vacant(entry) => {
+                        entry.insert(import_info);
+                    }
+                    Entry::Occupied(mut entry) => {
+                        // If the new path is shorter, prefer that one.
+                        if path_len < entry.get().path.len() {
+                            *entry.get_mut() = import_info;
+                        } else {
+                            continue;
+                        }
+                    }
+                }
+
+                // If we've just added a path to a module, descend into it. We might traverse
+                // modules multiple times, but only if the new path to it is shorter than the
+                // first (else we `continue` above).
+                if let Some(ModuleDefId::ModuleId(mod_id)) = item.as_module_def_id() {
+                    worklist.push((mod_id, mk_path()));
+                }
+            }
+        }
+    }
+
+    import_map
+}
+
 impl PartialEq for ImportMap {
     fn eq(&self, other: &Self) -> bool {
         // `fst` and `importables` are built from `map`, so we don't need to compare them.
@@ -240,17 +249,12 @@ impl fmt::Debug for ImportMap {
 }
 
 fn fst_path(path: &ImportPath) -> String {
+    let _p = profile::span("fst_path");
     let mut s = path.to_string();
     s.make_ascii_lowercase();
     s
 }
 
-fn cmp((_, lhs): &(&ItemInNs, &ImportInfo), (_, rhs): &(&ItemInNs, &ImportInfo)) -> Ordering {
-    let lhs_str = fst_path(&lhs.path);
-    let rhs_str = fst_path(&rhs.path);
-    lhs_str.cmp(&rhs_str)
-}
-
 #[derive(Debug, Eq, PartialEq, Hash)]
 pub enum ImportKind {
     Module,
@@ -338,6 +342,7 @@ impl Query {
     }
 
     fn import_matches(&self, import: &ImportInfo, enforce_lowercase: bool) -> bool {
+        let _p = profile::span("import_map::Query::import_matches");
         if import.is_trait_assoc_item {
             if self.exclude_import_kinds.contains(&ImportKind::AssociatedItem) {
                 return false;
diff --git a/crates/hir_def/src/lang_item.rs b/crates/hir_def/src/lang_item.rs
index 9e90f745c..3a45cbfa1 100644
--- a/crates/hir_def/src/lang_item.rs
+++ b/crates/hir_def/src/lang_item.rs
@@ -141,6 +141,7 @@ impl LangItems {
     ) where
         T: Into<AttrDefId> + Copy,
     {
+        let _p = profile::span("collect_lang_item");
         if let Some(lang_item_name) = lang_attr(db, item) {
             self.items.entry(lang_item_name).or_insert_with(|| constructor(item));
         }
diff --git a/crates/hir_def/src/per_ns.rs b/crates/hir_def/src/per_ns.rs
index a594afce6..a9f13cb82 100644
--- a/crates/hir_def/src/per_ns.rs
+++ b/crates/hir_def/src/per_ns.rs
@@ -62,6 +62,7 @@ impl PerNs {
     }
 
     pub fn filter_visibility(self, mut f: impl FnMut(Visibility) -> bool) -> PerNs {
+        let _p = profile::span("PerNs::filter_visibility");
         PerNs {
             types: self.types.filter(|(_, v)| f(*v)),
             values: self.values.filter(|(_, v)| f(*v)),
@@ -86,6 +87,7 @@ impl PerNs {
     }
 
     pub fn iter_items(self) -> impl Iterator<Item = ItemInNs> {
+        let _p = profile::span("PerNs::iter_items");
         self.types
             .map(|it| ItemInNs::Types(it.0))
             .into_iter()
diff --git a/crates/ide/src/prime_caches.rs b/crates/ide/src/prime_caches.rs
index d912a01b8..36801c964 100644
--- a/crates/ide/src/prime_caches.rs
+++ b/crates/ide/src/prime_caches.rs
@@ -33,14 +33,15 @@ pub(crate) fn prime_caches(db: &RootDatabase, cb: &(dyn Fn(PrimeCachesProgress)
     // FIXME: This would be easy to parallelize, since it's in the ideal ordering for that.
     // Unfortunately rayon prevents panics from propagation out of a `scope`, which breaks
     // cancellation, so we cannot use rayon.
-    for (i, krate) in topo.iter().enumerate() {
-        let crate_name = graph[*krate].display_name.as_deref().unwrap_or_default().to_string();
+    for (i, &crate_id) in topo.iter().enumerate() {
+        let crate_name = graph[crate_id].display_name.as_deref().unwrap_or_default().to_string();
 
         cb(PrimeCachesProgress::StartedOnCrate {
             on_crate: crate_name,
             n_done: i,
             n_total: topo.len(),
         });
-        db.crate_def_map(*krate);
+        db.crate_def_map(crate_id);
+        db.import_map(crate_id);
     }
 }
diff --git a/crates/ide/src/references.rs b/crates/ide/src/references.rs
index ae492a264..f8b64a669 100644
--- a/crates/ide/src/references.rs
+++ b/crates/ide/src/references.rs
@@ -1380,4 +1380,24 @@ lib::foo!();
             "#]],
         );
     }
+
+    #[test]
+    fn macro_doesnt_reference_attribute_on_call() {
+        check(
+            r#"
+macro_rules! m {
+    () => {};
+}
+
+#[proc_macro_test::attr_noop]
+m$0!();
+
+"#,
+            expect![[r#"
+                m Macro FileId(0) 0..32 13..14
+
+                FileId(0) 64..65
+            "#]],
+        );
+    }
 }
diff --git a/crates/ide_assists/src/handlers/change_visibility.rs b/crates/ide_assists/src/handlers/change_visibility.rs
index d7e39b2ae..ed936667f 100644
--- a/crates/ide_assists/src/handlers/change_visibility.rs
+++ b/crates/ide_assists/src/handlers/change_visibility.rs
@@ -1,7 +1,9 @@
 use syntax::{
     ast::{self, NameOwner, VisibilityOwner},
     AstNode,
-    SyntaxKind::{CONST, ENUM, FN, MODULE, STATIC, STRUCT, TRAIT, TYPE_ALIAS, VISIBILITY},
+    SyntaxKind::{
+        CONST, ENUM, FN, MACRO_DEF, MODULE, STATIC, STRUCT, TRAIT, TYPE_ALIAS, USE, VISIBILITY,
+    },
     T,
 };
 
@@ -37,12 +39,15 @@ fn add_vis(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
                 | T![enum]
                 | T![trait]
                 | T![type]
+                | T![use]
+                | T![macro]
         )
     });
 
     let (offset, target) = if let Some(keyword) = item_keyword {
         let parent = keyword.parent()?;
-        let def_kws = vec![CONST, STATIC, TYPE_ALIAS, FN, MODULE, STRUCT, ENUM, TRAIT];
+        let def_kws =
+            vec![CONST, STATIC, TYPE_ALIAS, FN, MODULE, STRUCT, ENUM, TRAIT, USE, MACRO_DEF];
         // Parent is not a definition, can't add visibility
         if !def_kws.iter().any(|&def_kw| def_kw == parent.kind()) {
             return None;
@@ -122,6 +127,8 @@ mod tests {
         check_assist(change_visibility, "$0trait Foo {}", "pub(crate) trait Foo {}");
         check_assist(change_visibility, "m$0od {}", "pub(crate) mod {}");
         check_assist(change_visibility, "unsafe f$0n foo() {}", "pub(crate) unsafe fn foo() {}");
+        check_assist(change_visibility, "$0macro foo() {}", "pub(crate) macro foo() {}");
+        check_assist(change_visibility, "$0use foo;", "pub(crate) use foo;");
     }
 
     #[test]
diff --git a/crates/ide_assists/src/handlers/remove_unused_param.rs b/crates/ide_assists/src/handlers/remove_unused_param.rs
index 2699d2861..fabfe7e93 100644
--- a/crates/ide_assists/src/handlers/remove_unused_param.rs
+++ b/crates/ide_assists/src/handlers/remove_unused_param.rs
@@ -37,8 +37,20 @@ pub(crate) fn remove_unused_param(acc: &mut Assists, ctx: &AssistContext) -> Opt
         _ => return None,
     };
     let func = param.syntax().ancestors().find_map(ast::Fn::cast)?;
-    let param_position = func.param_list()?.params().position(|it| it == param)?;
 
+    // check if fn is in impl Trait for ..
+    if func
+        .syntax()
+        .parent() // AssocItemList
+        .and_then(|x| x.parent())
+        .and_then(ast::Impl::cast)
+        .map_or(false, |imp| imp.trait_().is_some())
+    {
+        cov_mark::hit!(trait_impl);
+        return None;
+    }
+
+    let param_position = func.param_list()?.params().position(|it| it == param)?;
     let fn_def = {
         let func = ctx.sema.to_def(&func)?;
         Definition::ModuleDef(func.into())
@@ -254,6 +266,22 @@ fn main() { foo(9, 2) }
     }
 
     #[test]
+    fn trait_impl() {
+        cov_mark::check!(trait_impl);
+        check_assist_not_applicable(
+            remove_unused_param,
+            r#"
+trait Trait {
+    fn foo(x: i32);
+}
+impl Trait for () {
+    fn foo($0x: i32) {}
+}
+"#,
+        );
+    }
+
+    #[test]
     fn remove_across_files() {
         check_assist(
             remove_unused_param,
diff --git a/crates/ide_db/src/defs.rs b/crates/ide_db/src/defs.rs
index 1dcccbb8b..1b69d72f9 100644
--- a/crates/ide_db/src/defs.rs
+++ b/crates/ide_db/src/defs.rs
@@ -357,9 +357,9 @@ impl NameRefClass {
             }
         }
 
-        if let Some(macro_call) = parent.ancestors().find_map(ast::MacroCall::cast) {
-            if let Some(path) = macro_call.path() {
-                if path.qualifier().is_none() {
+        if let Some(path) = name_ref.syntax().ancestors().find_map(ast::Path::cast) {
+            if path.qualifier().is_none() {
+                if let Some(macro_call) = path.syntax().parent().and_then(ast::MacroCall::cast) {
                     // Only use this to resolve single-segment macro calls like `foo!()`. Multi-segment
                     // paths are handled below (allowing `log$0::info!` to resolve to the log crate).
                     if let Some(macro_def) = sema.resolve_macro_call(&macro_call) {
@@ -367,9 +367,7 @@ impl NameRefClass {
                     }
                 }
             }
-        }
 
-        if let Some(path) = name_ref.syntax().ancestors().find_map(ast::Path::cast) {
             if let Some(resolved) = sema.resolve_path(&path) {
                 if path.syntax().parent().and_then(ast::Attr::cast).is_some() {
                     if let PathResolution::Def(ModuleDef::Function(func)) = resolved {
diff --git a/crates/ide_db/src/symbol_index.rs b/crates/ide_db/src/symbol_index.rs
index 5c372a7e5..000f87a85 100644
--- a/crates/ide_db/src/symbol_index.rs
+++ b/crates/ide_db/src/symbol_index.rs
@@ -197,6 +197,7 @@ pub fn world_symbols(db: &RootDatabase, query: Query) -> Vec<FileSymbol> {
 }
 
 pub fn crate_symbols(db: &RootDatabase, krate: CrateId, query: Query) -> Vec<FileSymbol> {
+    let _p = profile::span("crate_symbols").detail(|| format!("{:?}", query));
     // FIXME(#4842): This now depends on CrateDefMap, why not build the entire symbol index from
     // that instead?
 
@@ -321,6 +322,7 @@ impl SymbolIndex {
 
 impl Query {
     pub(crate) fn search(self, indices: &[&SymbolIndex]) -> Vec<FileSymbol> {
+        let _p = profile::span("symbol_index::Query::search");
         let mut op = fst::map::OpBuilder::new();
         for file_symbols in indices.iter() {
             let automaton = fst::automaton::Subsequence::new(&self.lowercased);
diff --git a/crates/proc_macro_srv/src/dylib.rs b/crates/proc_macro_srv/src/dylib.rs
index cccc53220..5133e7c50 100644
--- a/crates/proc_macro_srv/src/dylib.rs
+++ b/crates/proc_macro_srv/src/dylib.rs
@@ -188,7 +188,9 @@ impl Expander {
 /// Copy the dylib to temp directory to prevent locking in Windows
 #[cfg(windows)]
 fn ensure_file_with_lock_free_access(path: &Path) -> io::Result<PathBuf> {
-    use std::{ffi::OsString, time::SystemTime};
+    use std::collections::hash_map::RandomState;
+    use std::ffi::OsString;
+    use std::hash::{BuildHasher, Hasher};
 
     let mut to = std::env::temp_dir();
 
@@ -199,10 +201,11 @@ fn ensure_file_with_lock_free_access(path: &Path) -> io::Result<PathBuf> {
         )
     })?;
 
-    // generate a time deps unique number
-    let t = SystemTime::now().duration_since(std::time::UNIX_EPOCH).expect("Time went backwards");
+    // Generate a unique number by abusing `HashMap`'s hasher.
+    // Maybe this will also "inspire" a libs team member to finally put `rand` in libstd.
+    let t = RandomState::new().build_hasher().finish();
 
-    let mut unique_name = OsString::from(t.as_millis().to_string());
+    let mut unique_name = OsString::from(t.to_string());
     unique_name.push(file_name);
 
     to.push(unique_name);
diff --git a/crates/proc_macro_srv/src/tests/utils.rs b/crates/proc_macro_srv/src/tests/utils.rs
index 2e950c113..2c093aa0a 100644
--- a/crates/proc_macro_srv/src/tests/utils.rs
+++ b/crates/proc_macro_srv/src/tests/utils.rs
@@ -7,35 +7,8 @@ use proc_macro_api::ListMacrosTask;
 use std::str::FromStr;
 
 pub mod fixtures {
-    use cargo_metadata::Message;
-    use std::path::PathBuf;
-    use std::process::Command;
-
-    // Use current project metadata to get the proc-macro dylib path
     pub fn proc_macro_test_dylib_path() -> std::path::PathBuf {
-        let name = "proc_macro_test";
-        let version = "0.0.0";
-        let command = Command::new(toolchain::cargo())
-            .args(&["check", "--tests", "--message-format", "json"])
-            .output()
-            .unwrap()
-            .stdout;
-
-        for message in Message::parse_stream(command.as_slice()) {
-            match message.unwrap() {
-                Message::CompilerArtifact(artifact) => {
-                    if artifact.target.kind.contains(&"proc-macro".to_string()) {
-                        let repr = format!("{} {}", name, version);
-                        if artifact.package_id.repr.starts_with(&repr) {
-                            return PathBuf::from(&artifact.filenames[0]);
-                        }
-                    }
-                }
-                _ => (), // Unknown message
-            }
-        }
-
-        panic!("No proc-macro dylib for {} found!", name);
+        proc_macro_test::PROC_MACRO_TEST_LOCATION.into()
     }
 }
 
diff --git a/crates/proc_macro_test/Cargo.toml b/crates/proc_macro_test/Cargo.toml
index 753443be2..1a88e361e 100644
--- a/crates/proc_macro_test/Cargo.toml
+++ b/crates/proc_macro_test/Cargo.toml
@@ -8,4 +8,8 @@ publish = false
 
 [lib]
 doctest = false
-proc-macro = true
+
+[build-dependencies]
+proc_macro_test_impl = { path = "imp", version = "0.0.0" }
+toolchain = { path = "../toolchain", version = "0.0.0" }
+cargo_metadata = "0.13"
diff --git a/crates/proc_macro_test/build.rs b/crates/proc_macro_test/build.rs
new file mode 100644
index 000000000..4653a93dd
--- /dev/null
+++ b/crates/proc_macro_test/build.rs
@@ -0,0 +1,48 @@
+//! This will build the proc macro in `imp`, and copy the resulting dylib artifact into the
+//! `OUT_DIR`.
+//!
+//! `proc_macro_test` itself contains only a path to that artifact.
+
+use std::{
+    env, fs,
+    path::{Path, PathBuf},
+    process::Command,
+};
+
+use cargo_metadata::Message;
+
+fn main() {
+    let out_dir = env::var_os("OUT_DIR").unwrap();
+    let out_dir = Path::new(&out_dir);
+
+    let name = "proc_macro_test_impl";
+    let version = "0.0.0";
+    let output = Command::new(toolchain::cargo())
+        .current_dir("imp")
+        .args(&["build", "-p", "proc_macro_test_impl", "--message-format", "json"])
+        .output()
+        .unwrap();
+    assert!(output.status.success());
+
+    let mut artifact_path = None;
+    for message in Message::parse_stream(output.stdout.as_slice()) {
+        match message.unwrap() {
+            Message::CompilerArtifact(artifact) => {
+                if artifact.target.kind.contains(&"proc-macro".to_string()) {
+                    let repr = format!("{} {}", name, version);
+                    if artifact.package_id.repr.starts_with(&repr) {
+                        artifact_path = Some(PathBuf::from(&artifact.filenames[0]));
+                    }
+                }
+            }
+            _ => (), // Unknown message
+        }
+    }
+
+    let src_path = artifact_path.expect("no dylib for proc_macro_test_impl found");
+    let dest_path = out_dir.join(src_path.file_name().unwrap());
+    fs::copy(src_path, &dest_path).unwrap();
+
+    let info_path = out_dir.join("proc_macro_test_location.txt");
+    fs::write(info_path, dest_path.to_str().unwrap()).unwrap();
+}
diff --git a/crates/proc_macro_test/imp/.gitignore b/crates/proc_macro_test/imp/.gitignore
new file mode 100644
index 000000000..2c96eb1b6
--- /dev/null
+++ b/crates/proc_macro_test/imp/.gitignore
@@ -0,0 +1,2 @@
+target/
+Cargo.lock
diff --git a/crates/proc_macro_test/imp/Cargo.toml b/crates/proc_macro_test/imp/Cargo.toml
new file mode 100644
index 000000000..1c2e75401
--- /dev/null
+++ b/crates/proc_macro_test/imp/Cargo.toml
@@ -0,0 +1,17 @@
+[package]
+name = "proc_macro_test_impl"
+version = "0.0.0"
+license = "MIT OR Apache-2.0"
+authors = ["rust-analyzer developers"]
+edition = "2018"
+publish = false
+
+[lib]
+doctest = false
+proc-macro = true
+
+[workspace]
+
+[dependencies]
+# this crate should not have any dependencies, since it uses its own workspace,
+# and its own `Cargo.lock`
diff --git a/crates/proc_macro_test/imp/src/lib.rs b/crates/proc_macro_test/imp/src/lib.rs
new file mode 100644
index 000000000..4b26d2472
--- /dev/null
+++ b/crates/proc_macro_test/imp/src/lib.rs
@@ -0,0 +1,48 @@
+//! Exports a few trivial procedural macros for testing.
+
+use proc_macro::TokenStream;
+
+#[proc_macro]
+pub fn fn_like_noop(args: TokenStream) -> TokenStream {
+    args
+}
+
+#[proc_macro]
+pub fn fn_like_panic(args: TokenStream) -> TokenStream {
+    panic!("fn_like_panic!({})", args);
+}
+
+#[proc_macro]
+pub fn fn_like_error(args: TokenStream) -> TokenStream {
+    format!("compile_error!(\"fn_like_error!({})\");", args).parse().unwrap()
+}
+
+#[proc_macro_attribute]
+pub fn attr_noop(_args: TokenStream, item: TokenStream) -> TokenStream {
+    item
+}
+
+#[proc_macro_attribute]
+pub fn attr_panic(args: TokenStream, item: TokenStream) -> TokenStream {
+    panic!("#[attr_panic {}] {}", args, item);
+}
+
+#[proc_macro_attribute]
+pub fn attr_error(args: TokenStream, item: TokenStream) -> TokenStream {
+    format!("compile_error!(\"#[attr_error({})] {}\");", args, item).parse().unwrap()
+}
+
+#[proc_macro_derive(DeriveEmpty)]
+pub fn derive_empty(_item: TokenStream) -> TokenStream {
+    TokenStream::new()
+}
+
+#[proc_macro_derive(DerivePanic)]
+pub fn derive_panic(item: TokenStream) -> TokenStream {
+    panic!("#[derive(DerivePanic)] {}", item);
+}
+
+#[proc_macro_derive(DeriveError)]
+pub fn derive_error(item: TokenStream) -> TokenStream {
+    format!("compile_error!(\"#[derive(DeriveError)] {}\");", item).parse().unwrap()
+}
diff --git a/crates/proc_macro_test/src/lib.rs b/crates/proc_macro_test/src/lib.rs
index 4b26d2472..2edf23a63 100644
--- a/crates/proc_macro_test/src/lib.rs
+++ b/crates/proc_macro_test/src/lib.rs
@@ -1,48 +1,4 @@
 //! Exports a few trivial procedural macros for testing.
 
-use proc_macro::TokenStream;
-
-#[proc_macro]
-pub fn fn_like_noop(args: TokenStream) -> TokenStream {
-    args
-}
-
-#[proc_macro]
-pub fn fn_like_panic(args: TokenStream) -> TokenStream {
-    panic!("fn_like_panic!({})", args);
-}
-
-#[proc_macro]
-pub fn fn_like_error(args: TokenStream) -> TokenStream {
-    format!("compile_error!(\"fn_like_error!({})\");", args).parse().unwrap()
-}
-
-#[proc_macro_attribute]
-pub fn attr_noop(_args: TokenStream, item: TokenStream) -> TokenStream {
-    item
-}
-
-#[proc_macro_attribute]
-pub fn attr_panic(args: TokenStream, item: TokenStream) -> TokenStream {
-    panic!("#[attr_panic {}] {}", args, item);
-}
-
-#[proc_macro_attribute]
-pub fn attr_error(args: TokenStream, item: TokenStream) -> TokenStream {
-    format!("compile_error!(\"#[attr_error({})] {}\");", args, item).parse().unwrap()
-}
-
-#[proc_macro_derive(DeriveEmpty)]
-pub fn derive_empty(_item: TokenStream) -> TokenStream {
-    TokenStream::new()
-}
-
-#[proc_macro_derive(DerivePanic)]
-pub fn derive_panic(item: TokenStream) -> TokenStream {
-    panic!("#[derive(DerivePanic)] {}", item);
-}
-
-#[proc_macro_derive(DeriveError)]
-pub fn derive_error(item: TokenStream) -> TokenStream {
-    format!("compile_error!(\"#[derive(DeriveError)] {}\");", item).parse().unwrap()
-}
+pub static PROC_MACRO_TEST_LOCATION: &str =
+    include_str!(concat!(env!("OUT_DIR"), "/proc_macro_test_location.txt"));
diff --git a/crates/profile/Cargo.toml b/crates/profile/Cargo.toml
index 1a8c8f862..653d3d983 100644
--- a/crates/profile/Cargo.toml
+++ b/crates/profile/Cargo.toml
@@ -20,6 +20,9 @@ jemalloc-ctl = { version = "0.4.1", package = "tikv-jemalloc-ctl", optional = tr
 [target.'cfg(target_os = "linux")'.dependencies]
 perf-event = "0.4"
 
+[target.'cfg(windows)'.dependencies]
+winapi = { version = "0.3.8", features = ["psapi"] }
+
 [features]
 cpu_profiler = []
 jemalloc = ["jemalloc-ctl"]
diff --git a/crates/profile/src/memory_usage.rs b/crates/profile/src/memory_usage.rs
index 2917ded60..6ef58c9c1 100644
--- a/crates/profile/src/memory_usage.rs
+++ b/crates/profile/src/memory_usage.rs
@@ -35,6 +35,22 @@ impl MemoryUsage {
                 // Note: This is incredibly slow.
                 let alloc = unsafe { libc::mallinfo() }.uordblks as isize;
                 MemoryUsage { allocated: Bytes(alloc) }
+            } else if #[cfg(windows)] {
+                // There doesn't seem to be an API for determining heap usage, so we try to
+                // approximate that by using the Commit Charge value.
+
+                use winapi::um::processthreadsapi::*;
+                use winapi::um::psapi::*;
+                use std::mem::{MaybeUninit, size_of};
+
+                let proc = unsafe { GetCurrentProcess() };
+                let mut mem_counters = MaybeUninit::uninit();
+                let cb = size_of::<PROCESS_MEMORY_COUNTERS>();
+                let ret = unsafe { GetProcessMemoryInfo(proc, mem_counters.as_mut_ptr(), cb as u32) };
+                assert!(ret != 0);
+
+                let usage = unsafe { mem_counters.assume_init().PagefileUsage };
+                MemoryUsage { allocated: Bytes(usage as isize) }
             } else {
                 MemoryUsage { allocated: Bytes(0) }
             }
diff --git a/crates/rust-analyzer/src/cli.rs b/crates/rust-analyzer/src/cli.rs
index 76b666dc2..25ebcc0ec 100644
--- a/crates/rust-analyzer/src/cli.rs
+++ b/crates/rust-analyzer/src/cli.rs
@@ -16,7 +16,6 @@ use vfs::Vfs;
 pub use self::{
     analysis_stats::AnalysisStatsCmd,
     diagnostics::diagnostics,
-    load_cargo::{load_workspace, load_workspace_at, LoadCargoConfig},
     ssr::{apply_ssr_rules, search_for_patterns},
 };
 
diff --git a/crates/rust-analyzer/src/cli/analysis_stats.rs b/crates/rust-analyzer/src/cli/analysis_stats.rs
index 5364e907c..843c0ca37 100644
--- a/crates/rust-analyzer/src/cli/analysis_stats.rs
+++ b/crates/rust-analyzer/src/cli/analysis_stats.rs
@@ -70,6 +70,7 @@ impl AnalysisStatsCmd {
             load_out_dirs_from_check: self.enable_build_scripts,
             wrap_rustc: false,
             with_proc_macro: self.enable_proc_macros,
+            prefill_caches: false,
         };
         let (host, vfs, _proc_macro) =
             load_workspace_at(&self.path, &cargo_config, &load_cargo_config, &|_| {})?;
diff --git a/crates/rust-analyzer/src/cli/diagnostics.rs b/crates/rust-analyzer/src/cli/diagnostics.rs
index c33c8179c..dc9a390fe 100644
--- a/crates/rust-analyzer/src/cli/diagnostics.rs
+++ b/crates/rust-analyzer/src/cli/diagnostics.rs
@@ -34,8 +34,12 @@ pub fn diagnostics(
     with_proc_macro: bool,
 ) -> Result<()> {
     let cargo_config = Default::default();
-    let load_cargo_config =
-        LoadCargoConfig { load_out_dirs_from_check, with_proc_macro, wrap_rustc: false };
+    let load_cargo_config = LoadCargoConfig {
+        load_out_dirs_from_check,
+        with_proc_macro,
+        wrap_rustc: false,
+        prefill_caches: false,
+    };
     let (host, _vfs, _proc_macro) =
         load_workspace_at(path, &cargo_config, &load_cargo_config, &|_| {})?;
     let db = host.raw_database();
diff --git a/crates/rust-analyzer/src/cli/load_cargo.rs b/crates/rust-analyzer/src/cli/load_cargo.rs
index 8cee65478..19cb1c046 100644
--- a/crates/rust-analyzer/src/cli/load_cargo.rs
+++ b/crates/rust-analyzer/src/cli/load_cargo.rs
@@ -14,13 +14,14 @@ use vfs::{loader::Handle, AbsPath, AbsPathBuf};
 
 use crate::reload::{ProjectFolders, SourceRootConfig};
 
-pub struct LoadCargoConfig {
-    pub load_out_dirs_from_check: bool,
-    pub wrap_rustc: bool,
-    pub with_proc_macro: bool,
+pub(crate) struct LoadCargoConfig {
+    pub(crate) load_out_dirs_from_check: bool,
+    pub(crate) wrap_rustc: bool,
+    pub(crate) with_proc_macro: bool,
+    pub(crate) prefill_caches: bool,
 }
 
-pub fn load_workspace_at(
+pub(crate) fn load_workspace_at(
     root: &Path,
     cargo_config: &CargoConfig,
     load_config: &LoadCargoConfig,
@@ -33,7 +34,7 @@ pub fn load_workspace_at(
     load_workspace(workspace, load_config, progress)
 }
 
-pub fn load_workspace(
+fn load_workspace(
     ws: ProjectWorkspace,
     config: &LoadCargoConfig,
     progress: &dyn Fn(String),
@@ -82,6 +83,10 @@ pub fn load_workspace(
     log::debug!("crate graph: {:?}", crate_graph);
     let host =
         load_crate_graph(crate_graph, project_folders.source_root_config, &mut vfs, &receiver);
+
+    if config.prefill_caches {
+        host.analysis().prime_caches(|_| {})?;
+    }
     Ok((host, vfs, proc_macro_client))
 }
 
@@ -144,6 +149,7 @@ mod tests {
             load_out_dirs_from_check: false,
             wrap_rustc: false,
             with_proc_macro: false,
+            prefill_caches: false,
         };
         let (host, _vfs, _proc_macro) =
             load_workspace_at(path, &cargo_config, &load_cargo_config, &|_| {})?;
diff --git a/crates/rust-analyzer/src/cli/ssr.rs b/crates/rust-analyzer/src/cli/ssr.rs
index 1fd9b5a9b..0b3475e09 100644
--- a/crates/rust-analyzer/src/cli/ssr.rs
+++ b/crates/rust-analyzer/src/cli/ssr.rs
@@ -13,6 +13,7 @@ pub fn apply_ssr_rules(rules: Vec<SsrRule>) -> Result<()> {
         load_out_dirs_from_check: true,
         wrap_rustc: false,
         with_proc_macro: true,
+        prefill_caches: false,
     };
     let (host, vfs, _proc_macro) =
         load_workspace_at(&std::env::current_dir()?, &cargo_config, &load_cargo_config, &|_| {})?;
@@ -39,8 +40,12 @@ pub fn search_for_patterns(patterns: Vec<SsrPattern>, debug_snippet: Option<Stri
     use ide_db::base_db::SourceDatabaseExt;
     use ide_db::symbol_index::SymbolsDatabase;
     let cargo_config = Default::default();
-    let load_cargo_config =
-        LoadCargoConfig { load_out_dirs_from_check: true, wrap_rustc: true, with_proc_macro: true };
+    let load_cargo_config = LoadCargoConfig {
+        load_out_dirs_from_check: true,
+        wrap_rustc: true,
+        with_proc_macro: true,
+        prefill_caches: false,
+    };
     let (host, _vfs, _proc_macro) =
         load_workspace_at(&std::env::current_dir()?, &cargo_config, &load_cargo_config, &|_| {})?;
     let db = host.raw_database();
diff --git a/crates/rust-analyzer/src/integrated_benchmarks.rs b/crates/rust-analyzer/src/integrated_benchmarks.rs
index ec36a5f5c..8ddeb59f7 100644
--- a/crates/rust-analyzer/src/integrated_benchmarks.rs
+++ b/crates/rust-analyzer/src/integrated_benchmarks.rs
@@ -37,6 +37,7 @@ fn integrated_highlighting_benchmark() {
         load_out_dirs_from_check: true,
         wrap_rustc: false,
         with_proc_macro: false,
+        prefill_caches: false,
     };
 
     let (mut host, vfs, _proc_macro) = {
@@ -91,6 +92,7 @@ fn integrated_completion_benchmark() {
         load_out_dirs_from_check: true,
         wrap_rustc: false,
         with_proc_macro: false,
+        prefill_caches: true,
     };
 
     let (mut host, vfs, _proc_macro) = {