add name resolution from the old impl

unlike the old impl, this also handles macro imports across crates

9 files changed, 739 insertions, 185 deletions

diff --git a/crates/ra_hir/src/nameres/crate_def_map.rs b/crates/ra_hir/src/nameres/crate_def_map.rs
index ea9b4fb50..483878c78 100644
--- a/crates/ra_hir/src/nameres/crate_def_map.rs
+++ b/crates/ra_hir/src/nameres/crate_def_map.rs
@@ -40,16 +40,21 @@
 /// syntax.
 ///
 /// TBD;
+
 mod raw;
 mod collector;
+#[cfg(test)]
+mod tests;
 
 use rustc_hash::FxHashMap;
-use ra_arena::{Arena};
+use test_utils::tested_by;
+use ra_arena::Arena;
 
 use crate::{
-    Name,
+    Name, Module, Path, PathKind, ModuleDef, Crate,
+    PersistentHirDatabase,
     module_tree::ModuleId,
-    nameres::ModuleScope,
+    nameres::{ModuleScope, ResolveMode, ResolvePathResult, PerNs, Edition, ReachedFixedPoint},
 };
 
 #[derive(Default, Debug)]
@@ -62,143 +67,202 @@ struct ModuleData {
 /// Contans all top-level defs from a macro-expanded crate
 #[derive(Debug)]
 pub(crate) struct CrateDefMap {
+    krate: Crate,
+    edition: Edition,
+    /// The prelude module for this crate. This either comes from an import
+    /// marked with the `prelude_import` attribute, or (in the normal case) from
+    /// a dependency (`std` or `core`).
+    prelude: Option<Module>,
+    extern_prelude: FxHashMap<Name, ModuleDef>,
     root: ModuleId,
     modules: Arena<ModuleId, ModuleData>,
+    public_macros: FxHashMap<Name, mbe::MacroRules>,
 }
 
-#[cfg(test)]
-mod tests {
-    use std::sync::Arc;
-
-    use ra_db::SourceDatabase;
-    use insta::assert_snapshot_matches;
-
-    use crate::{Crate, mock::MockDatabase, nameres::Resolution};
-
-    use super::*;
-
-    fn compute_crate_def_map(fixture: &str) -> Arc<CrateDefMap> {
-        let db = MockDatabase::with_files(fixture);
-        let crate_id = db.crate_graph().iter().next().unwrap();
-        let krate = Crate { crate_id };
-        collector::crate_def_map_query(&db, krate)
+impl std::ops::Index<ModuleId> for CrateDefMap {
+    type Output = ModuleScope;
+    fn index(&self, id: ModuleId) -> &ModuleScope {
+        &self.modules[id].scope
     }
+}
 
-    fn render_crate_def_map(map: &CrateDefMap) -> String {
-        let mut buf = String::new();
-        go(&mut buf, map, "\ncrate", map.root);
-        return buf;
-
-        fn go(buf: &mut String, map: &CrateDefMap, path: &str, module: ModuleId) {
-            *buf += path;
-            *buf += "\n";
-            for (name, res) in map.modules[module].scope.items.iter() {
-                *buf += &format!("{}: {}\n", name, dump_resolution(res))
+impl CrateDefMap {
+    // Returns Yes if we are sure that additions to `ItemMap` wouldn't change
+    // the result.
+    #[allow(unused)]
+    fn resolve_path_fp(
+        &self,
+        db: &impl PersistentHirDatabase,
+        mode: ResolveMode,
+        original_module: ModuleId,
+        path: &Path,
+    ) -> ResolvePathResult {
+        let mut segments = path.segments.iter().enumerate();
+        let mut curr_per_ns: PerNs<ModuleDef> = match path.kind {
+            PathKind::Crate => {
+                PerNs::types(Module { krate: self.krate, module_id: self.root }.into())
             }
-            for (name, child) in map.modules[module].children.iter() {
-                let path = path.to_string() + &format!("::{}", name);
-                go(buf, map, &path, *child);
+            PathKind::Self_ => {
+                PerNs::types(Module { krate: self.krate, module_id: original_module }.into())
             }
-        }
-
-        fn dump_resolution(resolution: &Resolution) -> &'static str {
-            match (resolution.def.types.is_some(), resolution.def.values.is_some()) {
-                (true, true) => "t v",
-                (true, false) => "t",
-                (false, true) => "v",
-                (false, false) => "_",
+            // plain import or absolute path in 2015: crate-relative with
+            // fallback to extern prelude (with the simplification in
+            // rust-lang/rust#57745)
+            // TODO there must be a nicer way to write this condition
+            PathKind::Plain | PathKind::Abs
+                if self.edition == Edition::Edition2015
+                    && (path.kind == PathKind::Abs || mode == ResolveMode::Import) =>
+            {
+                let segment = match segments.next() {
+                    Some((_, segment)) => segment,
+                    None => return ResolvePathResult::empty(ReachedFixedPoint::Yes),
+                };
+                log::debug!("resolving {:?} in crate root (+ extern prelude)", segment);
+                self.resolve_name_in_crate_root_or_extern_prelude(&segment.name)
+            }
+            PathKind::Plain => {
+                let segment = match segments.next() {
+                    Some((_, segment)) => segment,
+                    None => return ResolvePathResult::empty(ReachedFixedPoint::Yes),
+                };
+                log::debug!("resolving {:?} in module", segment);
+                self.resolve_name_in_module(db, original_module, &segment.name)
+            }
+            PathKind::Super => {
+                if let Some(p) = self.modules[original_module].parent {
+                    PerNs::types(Module { krate: self.krate, module_id: p }.into())
+                } else {
+                    log::debug!("super path in root module");
+                    return ResolvePathResult::empty(ReachedFixedPoint::Yes);
+                }
+            }
+            PathKind::Abs => {
+                // 2018-style absolute path -- only extern prelude
+                let segment = match segments.next() {
+                    Some((_, segment)) => segment,
+                    None => return ResolvePathResult::empty(ReachedFixedPoint::Yes),
+                };
+                if let Some(def) = self.extern_prelude.get(&segment.name) {
+                    log::debug!("absolute path {:?} resolved to crate {:?}", path, def);
+                    PerNs::types(*def)
+                } else {
+                    return ResolvePathResult::empty(ReachedFixedPoint::No); // extern crate declarations can add to the extern prelude
+                }
             }
+        };
+
+        for (i, segment) in segments {
+            let curr = match curr_per_ns.as_ref().take_types() {
+                Some(r) => r,
+                None => {
+                    // we still have path segments left, but the path so far
+                    // didn't resolve in the types namespace => no resolution
+                    // (don't break here because `curr_per_ns` might contain
+                    // something in the value namespace, and it would be wrong
+                    // to return that)
+                    return ResolvePathResult::empty(ReachedFixedPoint::No);
+                }
+            };
+            // resolve segment in curr
+
+            curr_per_ns = match curr {
+                ModuleDef::Module(module) => {
+                    if module.krate != self.krate {
+                        let path = Path {
+                            segments: path.segments[i..].iter().cloned().collect(),
+                            kind: PathKind::Self_,
+                        };
+                        log::debug!("resolving {:?} in other crate", path);
+                        let item_map = db.item_map(module.krate);
+                        let (def, s) = item_map.resolve_path(db, *module, &path);
+                        return ResolvePathResult::with(
+                            def,
+                            ReachedFixedPoint::Yes,
+                            s.map(|s| s + i),
+                        );
+                    }
+
+                    match self[module.module_id].items.get(&segment.name) {
+                        Some(res) if !res.def.is_none() => res.def,
+                        _ => {
+                            log::debug!("path segment {:?} not found", segment.name);
+                            return ResolvePathResult::empty(ReachedFixedPoint::No);
+                        }
+                    }
+                }
+                ModuleDef::Enum(e) => {
+                    // enum variant
+                    tested_by!(item_map_enum_importing);
+                    match e.variant(db, &segment.name) {
+                        Some(variant) => PerNs::both(variant.into(), variant.into()),
+                        None => {
+                            return ResolvePathResult::with(
+                                PerNs::types((*e).into()),
+                                ReachedFixedPoint::Yes,
+                                Some(i),
+                            );
+                        }
+                    }
+                }
+                s => {
+                    // could be an inherent method call in UFCS form
+                    // (`Struct::method`), or some other kind of associated item
+                    log::debug!(
+                        "path segment {:?} resolved to non-module {:?}, but is not last",
+                        segment.name,
+                        curr,
+                    );
+
+                    return ResolvePathResult::with(
+                        PerNs::types((*s).into()),
+                        ReachedFixedPoint::Yes,
+                        Some(i),
+                    );
+                }
+            };
         }
+        ResolvePathResult::with(curr_per_ns, ReachedFixedPoint::Yes, None)
     }
 
-    fn def_map(fixtute: &str) -> String {
-        let dm = compute_crate_def_map(fixtute);
-        render_crate_def_map(&dm)
+    fn resolve_name_in_crate_root_or_extern_prelude(&self, name: &Name) -> PerNs<ModuleDef> {
+        let from_crate_root = self[self.root].items.get(name).map_or(PerNs::none(), |it| it.def);
+        let from_extern_prelude = self.resolve_name_in_extern_prelude(name);
+
+        from_crate_root.or(from_extern_prelude)
     }
 
-    #[test]
-    fn crate_def_map_smoke_test() {
-        let map = def_map(
-            "
-            //- /lib.rs
-            mod foo;
-            struct S;
-
-            //- /foo/mod.rs
-            pub mod bar;
-            fn f() {}
-
-            //- /foo/bar.rs
-            pub struct Baz;
-            enum E { V }
-        ",
-        );
-        assert_snapshot_matches!(
-        map,
-            @r###"
-crate
-S: t v
-
-crate::foo
-f: v
-
-crate::foo::bar
-Baz: t v
-E: t
-"###
-        )
+    fn resolve_name_in_module(
+        &self,
+        db: &impl PersistentHirDatabase,
+        module: ModuleId,
+        name: &Name,
+    ) -> PerNs<ModuleDef> {
+        // Resolve in:
+        //  - current module / scope
+        //  - extern prelude
+        //  - std prelude
+        let from_scope = self[module].items.get(name).map_or(PerNs::none(), |it| it.def);
+        let from_extern_prelude =
+            self.extern_prelude.get(name).map_or(PerNs::none(), |&it| PerNs::types(it));
+        let from_prelude = self.resolve_in_prelude(db, name);
+
+        from_scope.or(from_extern_prelude).or(from_prelude)
     }
 
-    #[test]
-    fn macro_rules_are_globally_visible() {
-        let map = def_map(
-            "
-            //- /lib.rs
-            macro_rules! structs {
-                ($($i:ident),*) => {
-                    $(struct $i { field: u32 } )*
-                }
-            }
-            structs!(Foo);
-            mod nested;
-
-            //- /nested.rs
-            structs!(Bar, Baz);
-        ",
-        );
-        assert_snapshot_matches!(map, @r###"
-crate
-Foo: t v
-
-crate::nested
-Bar: t v
-Baz: t v
-"###);
+    fn resolve_name_in_extern_prelude(&self, name: &Name) -> PerNs<ModuleDef> {
+        self.extern_prelude.get(name).map_or(PerNs::none(), |&it| PerNs::types(it))
     }
 
-    #[test]
-    fn macro_rules_can_define_modules() {
-        let map = def_map(
-            "
-            //- /lib.rs
-            macro_rules! m {
-                ($name:ident) => { mod $name;  }
-            }
-            m!(n1);
-
-            //- /n1.rs
-            m!(n2)
-            //- /n1/n2.rs
-            struct X;
-        ",
-        );
-        assert_snapshot_matches!(map, @r###"
-crate
-
-crate::n1
-
-crate::n1::n2
-X: t v
-"###);
+    fn resolve_in_prelude(&self, db: &impl PersistentHirDatabase, name: &Name) -> PerNs<ModuleDef> {
+        if let Some(prelude) = self.prelude {
+            let resolution = if prelude.krate == self.krate {
+                self[prelude.module_id].items.get(name).cloned()
+            } else {
+                db.item_map(prelude.krate)[prelude.module_id].items.get(name).cloned()
+            };
+            resolution.map(|r| r.def).unwrap_or_else(PerNs::none)
+        } else {
+            PerNs::none()
+        }
     }
 }
diff --git a/crates/ra_hir/src/nameres/crate_def_map/collector.rs b/crates/ra_hir/src/nameres/crate_def_map/collector.rs
index 46bef3dbe..cd328b755 100644
--- a/crates/ra_hir/src/nameres/crate_def_map/collector.rs
+++ b/crates/ra_hir/src/nameres/crate_def_map/collector.rs
@@ -2,12 +2,13 @@ use std::sync::Arc;
 
 use rustc_hash::FxHashMap;
 use ra_arena::Arena;
+use test_utils::tested_by;
 
 use crate::{
     Function, Module, Struct, Enum, Const, Static, Trait, TypeAlias,
     Crate, PersistentHirDatabase, HirFileId, Name, Path,
     KnownName,
-    nameres::{Resolution, PerNs, ModuleDef, ReachedFixedPoint},
+    nameres::{Resolution, PerNs, ModuleDef, ReachedFixedPoint, ResolveMode},
     ids::{AstItemDef, LocationCtx, MacroCallLoc, SourceItemId, MacroCallId},
     module_tree::resolve_module_declaration,
 };
@@ -19,12 +20,41 @@ pub(crate) fn crate_def_map_query(
     db: &impl PersistentHirDatabase,
     krate: Crate,
 ) -> Arc<CrateDefMap> {
-    let mut modules: Arena<ModuleId, ModuleData> = Arena::default();
-    let root = modules.alloc(ModuleData::default());
+    let mut def_map = {
+        let edition = krate.edition(db);
+        let mut modules: Arena<ModuleId, ModuleData> = Arena::default();
+        let root = modules.alloc(ModuleData::default());
+        CrateDefMap {
+            krate,
+            edition,
+            extern_prelude: FxHashMap::default(),
+            prelude: None,
+            root,
+            modules,
+            public_macros: FxHashMap::default(),
+        }
+    };
+
+    // populate external prelude
+    for dep in krate.dependencies(db) {
+        log::debug!("crate dep {:?} -> {:?}", dep.name, dep.krate);
+        if let Some(module) = dep.krate.root_module(db) {
+            def_map.extern_prelude.insert(dep.name.clone(), module.into());
+        }
+        // look for the prelude
+        if def_map.prelude.is_none() {
+            let item_map = db.item_map(dep.krate);
+            if item_map.prelude.is_some() {
+                def_map.prelude = item_map.prelude;
+            }
+        }
+    }
+
     let mut collector = DefCollector {
         db,
         krate,
-        def_map: CrateDefMap { modules, root },
+        def_map,
+        glob_imports: FxHashMap::default(),
         unresolved_imports: Vec::new(),
         unexpanded_macros: Vec::new(),
         global_macro_scope: FxHashMap::default(),
@@ -39,8 +69,9 @@ struct DefCollector<DB> {
     db: DB,
     krate: Crate,
     def_map: CrateDefMap,
-    unresolved_imports: Vec<(ModuleId, raw::Import)>,
-    unexpanded_macros: Vec<(ModuleId, MacroCallId, tt::Subtree)>,
+    glob_imports: FxHashMap<ModuleId, Vec<(ModuleId, raw::ImportId)>>,
+    unresolved_imports: Vec<(ModuleId, raw::ImportId, raw::ImportData)>,
+    unexpanded_macros: Vec<(ModuleId, MacroCallId, Path, tt::Subtree)>,
     global_macro_scope: FxHashMap<Name, mbe::MacroRules>,
 }
 
@@ -83,8 +114,11 @@ where
         }
     }
 
-    fn define_macro(&mut self, name: Name, tt: &tt::Subtree) {
+    fn define_macro(&mut self, name: Name, tt: &tt::Subtree, export: bool) {
         if let Ok(rules) = mbe::MacroRules::parse(tt) {
+            if export {
+                self.def_map.public_macros.insert(name.clone(), rules.clone());
+            }
             self.global_macro_scope.insert(name, rules);
         }
     }
@@ -94,22 +128,218 @@ where
     }
 
     fn resolve_imports(&mut self) -> ReachedFixedPoint {
+        let mut imports = std::mem::replace(&mut self.unresolved_imports, Vec::new());
+        let mut resolved = Vec::new();
+        imports.retain(|(module_id, import, import_data)| {
+            let (def, fp) = self.resolve_import(*module_id, import_data);
+            if fp == ReachedFixedPoint::Yes {
+                resolved.push((*module_id, def, *import, import_data.clone()))
+            }
+            fp == ReachedFixedPoint::No
+        });
+        self.unresolved_imports = imports;
         // Resolves imports, filling-in module scopes
-        ReachedFixedPoint::Yes
+        let result =
+            if resolved.is_empty() { ReachedFixedPoint::Yes } else { ReachedFixedPoint::No };
+        for (module_id, def, import, import_data) in resolved {
+            self.record_resolved_import(module_id, def, import, &import_data)
+        }
+        result
     }
 
-    fn resolve_macros(&mut self) -> ReachedFixedPoint {
-        // Resolve macros, calling into `expand_macro` to actually do the
-        // expansion.
-        ReachedFixedPoint::Yes
+    fn resolve_import(
+        &mut self,
+        module_id: ModuleId,
+        import: &raw::ImportData,
+    ) -> (PerNs<ModuleDef>, ReachedFixedPoint) {
+        log::debug!("resolving import: {:?} ({:?})", import, self.def_map.edition);
+        if import.is_extern_crate {
+            let res = self.def_map.resolve_name_in_extern_prelude(
+                &import
+                    .path
+                    .as_ident()
+                    .expect("extern crate should have been desugared to one-element path"),
+            );
+            // FIXME: why do we return No here?
+            (res, if res.is_none() { ReachedFixedPoint::No } else { ReachedFixedPoint::Yes })
+        } else {
+            let res =
+                self.def_map.resolve_path_fp(self.db, ResolveMode::Import, module_id, &import.path);
+
+            (res.resolved_def, res.reached_fixedpoint)
+        }
+    }
+
+    fn record_resolved_import(
+        &mut self,
+        module_id: ModuleId,
+        def: PerNs<ModuleDef>,
+        import_id: raw::ImportId,
+        import: &raw::ImportData,
+    ) {
+        if import.is_glob {
+            log::debug!("glob import: {:?}", import);
+            match def.take_types() {
+                Some(ModuleDef::Module(m)) => {
+                    if import.is_prelude {
+                        tested_by!(std_prelude);
+                        self.def_map.prelude = Some(m);
+                    } else if m.krate != self.krate {
+                        tested_by!(glob_across_crates);
+                        // glob import from other crate => we can just import everything once
+                        let item_map = self.db.item_map(m.krate);
+                        let scope = &item_map[m.module_id];
+                        let items = scope
+                            .items
+                            .iter()
+                            .map(|(name, res)| (name.clone(), res.clone()))
+                            .collect::<Vec<_>>();
+                        self.update(module_id, Some(import_id), &items);
+                    } else {
+                        // glob import from same crate => we do an initial
+                        // import, and then need to propagate any further
+                        // additions
+                        let scope = &self.def_map[m.module_id];
+                        let items = scope
+                            .items
+                            .iter()
+                            .map(|(name, res)| (name.clone(), res.clone()))
+                            .collect::<Vec<_>>();
+                        self.update(module_id, Some(import_id), &items);
+                        // record the glob import in case we add further items
+                        self.glob_imports
+                            .entry(m.module_id)
+                            .or_default()
+                            .push((module_id, import_id));
+                    }
+                }
+                Some(ModuleDef::Enum(e)) => {
+                    tested_by!(glob_enum);
+                    // glob import from enum => just import all the variants
+                    let variants = e.variants(self.db);
+                    let resolutions = variants
+                        .into_iter()
+                        .filter_map(|variant| {
+                            let res = Resolution {
+                                def: PerNs::both(variant.into(), variant.into()),
+                                import: Some(import_id),
+                            };
+                            let name = variant.name(self.db)?;
+                            Some((name, res))
+                        })
+                        .collect::<Vec<_>>();
+                    self.update(module_id, Some(import_id), &resolutions);
+                }
+                Some(d) => {
+                    log::debug!("glob import {:?} from non-module/enum {:?}", import, d);
+                }
+                None => {
+                    log::debug!("glob import {:?} didn't resolve as type", import);
+                }
+            }
+        } else {
+            let last_segment = import.path.segments.last().unwrap();
+            let name = import.alias.clone().unwrap_or_else(|| last_segment.name.clone());
+            log::debug!("resolved import {:?} ({:?}) to {:?}", name, import, def);
+
+            // extern crates in the crate root are special-cased to insert entries into the extern prelude: rust-lang/rust#54658
+            if let Some(root_module) = self.krate.root_module(self.db) {
+                if import.is_extern_crate && module_id == root_module.module_id {
+                    if let Some(def) = def.take_types() {
+                        self.def_map.extern_prelude.insert(name.clone(), def);
+                    }
+                }
+            }
+            let resolution = Resolution { def, import: Some(import_id) };
+            self.update(module_id, None, &[(name, resolution)]);
+        }
+    }
+
+    fn update(
+        &mut self,
+        module_id: ModuleId,
+        import: Option<raw::ImportId>,
+        resolutions: &[(Name, Resolution)],
+    ) {
+        self.update_recursive(module_id, import, resolutions, 0)
     }
 
-    #[allow(unused)]
-    fn expand_macro(&mut self, idx: usize, rules: &mbe::MacroRules) {
-        let (module_id, call_id, arg) = self.unexpanded_macros.swap_remove(idx);
-        if let Ok(tt) = rules.expand(&arg) {
-            self.collect_macro_expansion(module_id, call_id, tt);
+    fn update_recursive(
+        &mut self,
+        module_id: ModuleId,
+        import: Option<raw::ImportId>,
+        resolutions: &[(Name, Resolution)],
+        depth: usize,
+    ) {
+        if depth > 100 {
+            // prevent stack overflows (but this shouldn't be possible)
+            panic!("infinite recursion in glob imports!");
         }
+        let module_items = &mut self.def_map.modules[module_id].scope;
+        let mut changed = false;
+        for (name, res) in resolutions {
+            let existing = module_items.items.entry(name.clone()).or_default();
+            if existing.def.types.is_none() && res.def.types.is_some() {
+                existing.def.types = res.def.types;
+                existing.import = import.or(res.import);
+                changed = true;
+            }
+            if existing.def.values.is_none() && res.def.values.is_some() {
+                existing.def.values = res.def.values;
+                existing.import = import.or(res.import);
+                changed = true;
+            }
+        }
+        if !changed {
+            return;
+        }
+        let glob_imports = self
+            .glob_imports
+            .get(&module_id)
+            .into_iter()
+            .flat_map(|v| v.iter())
+            .cloned()
+            .collect::<Vec<_>>();
+        for (glob_importing_module, glob_import) in glob_imports {
+            // We pass the glob import so that the tracked import in those modules is that glob import
+            self.update_recursive(glob_importing_module, Some(glob_import), resolutions, depth + 1);
+        }
+    }
+
+    // XXX: this is just a pile of hacks now, because `PerNs` does not handle
+    // macro namespace.
+    fn resolve_macros(&mut self) -> ReachedFixedPoint {
+        let mut macros = std::mem::replace(&mut self.unexpanded_macros, Vec::new());
+        let mut resolved = Vec::new();
+        macros.retain(|(module_id, call_id, path, tt)| {
+            if path.segments.len() != 2 {
+                return true;
+            }
+            let crate_name = &path.segments[0].name;
+            let krate = match self.def_map.resolve_name_in_extern_prelude(crate_name).take_types() {
+                Some(ModuleDef::Module(m)) => m.krate(self.db),
+                _ => return true,
+            };
+            let krate = match krate {
+                Some(it) => it,
+                _ => return true,
+            };
+            // FIXME: this should be a proper query
+            let def_map = crate_def_map_query(self.db, krate);
+            let rules = def_map.public_macros.get(&path.segments[1].name).cloned();
+            resolved.push((*module_id, *call_id, rules, tt.clone()));
+            false
+        });
+        let res = if resolved.is_empty() { ReachedFixedPoint::Yes } else { ReachedFixedPoint::No };
+
+        for (module_id, macro_call_id, rules, arg) in resolved {
+            if let Some(rules) = rules {
+                if let Ok(tt) = rules.expand(&arg) {
+                    self.collect_macro_expansion(module_id, macro_call_id, tt);
+                }
+            }
+        }
+        res
     }
 
     fn collect_macro_expansion(
@@ -145,9 +375,11 @@ where
         for item in items {
             match *item {
                 raw::RawItem::Module(m) => self.collect_module(&self.raw_items[m]),
-                raw::RawItem::Import(import) => {
-                    self.def_collector.unresolved_imports.push((self.module_id, import))
-                }
+                raw::RawItem::Import(import) => self.def_collector.unresolved_imports.push((
+                    self.module_id,
+                    import,
+                    self.raw_items[import].clone(),
+                )),
                 raw::RawItem::Def(def) => self.define_def(&self.raw_items[def]),
                 raw::RawItem::Macro(mac) => self.collect_macro(&self.raw_items[mac]),
             }
@@ -216,14 +448,14 @@ where
             raw::DefKind::TypeAlias => PerNs::types(TypeAlias { id: id!() }.into()),
         };
         let resolution = Resolution { def, import: None };
-        self.def_collector.def_map.modules[self.module_id].scope.items.insert(name, resolution);
+        self.def_collector.update(self.module_id, None, &[(name, resolution)])
     }
 
     fn collect_macro(&mut self, mac: &raw::MacroData) {
         // Case 1: macro rules, define a macro in crate-global mutable scope
         if is_macro_rules(&mac.path) {
             if let Some(name) = &mac.name {
-                self.def_collector.define_macro(name.clone(), &mac.arg)
+                self.def_collector.define_macro(name.clone(), &mac.arg, mac.export)
             }
             return;
         }
@@ -247,7 +479,12 @@ where
         }
 
         // Case 3: path to a macro from another crate, expand during name resolution
-        self.def_collector.unexpanded_macros.push((self.module_id, macro_call_id, mac.arg.clone()))
+        self.def_collector.unexpanded_macros.push((
+            self.module_id,
+            macro_call_id,
+            mac.path.clone(),
+            mac.arg.clone(),
+        ))
     }
 }
 
diff --git a/crates/ra_hir/src/nameres/crate_def_map/raw.rs b/crates/ra_hir/src/nameres/crate_def_map/raw.rs
index cec2484eb..fe832b8da 100644
--- a/crates/ra_hir/src/nameres/crate_def_map/raw.rs
+++ b/crates/ra_hir/src/nameres/crate_def_map/raw.rs
@@ -18,7 +18,7 @@ use crate::{
 #[derive(Default, PartialEq, Eq)]
 pub(crate) struct RawItems {
     modules: Arena<Module, ModuleData>,
-    imports: Arena<Import, ImportData>,
+    imports: Arena<ImportId, ImportData>,
     defs: Arena<Def, DefData>,
     macros: Arena<Macro, MacroData>,
     /// items for top-level module
@@ -60,9 +60,9 @@ impl Index<Module> for RawItems {
     }
 }
 
-impl Index<Import> for RawItems {
+impl Index<ImportId> for RawItems {
     type Output = ImportData;
-    fn index(&self, idx: Import) -> &ImportData {
+    fn index(&self, idx: ImportId) -> &ImportData {
         &self.imports[idx]
     }
 }
@@ -84,7 +84,7 @@ impl Index<Macro> for RawItems {
 #[derive(PartialEq, Eq, Clone, Copy)]
 pub(crate) enum RawItem {
     Module(Module),
-    Import(Import),
+    Import(ImportId),
     Def(Def),
     Macro(Macro),
 }
@@ -99,18 +99,8 @@ pub(crate) enum ModuleData {
     Definition { name: Name, items: Vec<RawItem> },
 }
 
-#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
-pub(crate) struct Import(RawId);
-impl_arena_id!(Import);
-
-#[derive(PartialEq, Eq)]
-pub(crate) struct ImportData {
-    path: Path,
-    alias: Option<Name>,
-    is_glob: bool,
-    is_prelude: bool,
-    is_extern_crate: bool,
-}
+pub(crate) use crate::nameres::lower::ImportId;
+pub(super) use crate::nameres::lower::ImportData;
 
 #[derive(Clone, Copy, PartialEq, Eq, Hash)]
 pub(crate) struct Def(RawId);
@@ -144,6 +134,7 @@ pub(crate) struct MacroData {
     pub(crate) path: Path,
     pub(crate) name: Option<Name>,
     pub(crate) arg: tt::Subtree,
+    pub(crate) export: bool,
 }
 
 struct RawItemsCollector {
@@ -215,9 +206,7 @@ impl RawItemsCollector {
     }
 
     fn add_use_item(&mut self, current_module: Option<Module>, use_item: &ast::UseItem) {
-        let is_prelude = use_item
-            .attrs()
-            .any(|attr| attr.as_atom().map(|s| s == "prelude_import").unwrap_or(false));
+        let is_prelude = use_item.has_atom_attr("prelude_import");
 
         Path::expand_use_item(use_item, |path, segment, alias| {
             let import = self.raw_items.imports.alloc(ImportData {
@@ -261,7 +250,8 @@ impl RawItemsCollector {
 
         let name = m.name().map(|it| it.as_name());
         let source_item_id = self.source_file_items.id_of_unchecked(m.syntax());
-        let m = self.raw_items.macros.alloc(MacroData { source_item_id, path, arg, name });
+        let export = m.has_atom_attr("macro_export");
+        let m = self.raw_items.macros.alloc(MacroData { source_item_id, path, arg, name, export });
         self.push_item(current_module, RawItem::Macro(m));
     }
 
diff --git a/crates/ra_hir/src/nameres/crate_def_map/tests.rs b/crates/ra_hir/src/nameres/crate_def_map/tests.rs
new file mode 100644
index 000000000..a56dbaf90
--- /dev/null
+++ b/crates/ra_hir/src/nameres/crate_def_map/tests.rs
@@ -0,0 +1,265 @@
+use std::sync::Arc;
+
+use ra_db::SourceDatabase;
+use test_utils::covers;
+use insta::assert_snapshot_matches;
+
+use crate::{Crate, mock::{MockDatabase, CrateGraphFixture}, nameres::Resolution};
+
+use super::*;
+
+fn compute_crate_def_map(fixture: &str, graph: Option<CrateGraphFixture>) -> Arc<CrateDefMap> {
+    let mut db = MockDatabase::with_files(fixture);
+    if let Some(graph) = graph {
+        db.set_crate_graph_from_fixture(graph);
+    }
+    let crate_id = db.crate_graph().iter().next().unwrap();
+    let krate = Crate { crate_id };
+    collector::crate_def_map_query(&db, krate)
+}
+
+fn render_crate_def_map(map: &CrateDefMap) -> String {
+    let mut buf = String::new();
+    go(&mut buf, map, "\ncrate", map.root);
+    return buf;
+
+    fn go(buf: &mut String, map: &CrateDefMap, path: &str, module: ModuleId) {
+        *buf += path;
+        *buf += "\n";
+        for (name, res) in map.modules[module].scope.items.iter() {
+            *buf += &format!("{}: {}\n", name, dump_resolution(res))
+        }
+        for (name, child) in map.modules[module].children.iter() {
+            let path = path.to_string() + &format!("::{}", name);
+            go(buf, map, &path, *child);
+        }
+    }
+
+    fn dump_resolution(resolution: &Resolution) -> &'static str {
+        match (resolution.def.types.is_some(), resolution.def.values.is_some()) {
+            (true, true) => "t v",
+            (true, false) => "t",
+            (false, true) => "v",
+            (false, false) => "_",
+        }
+    }
+}
+
+fn def_map(fixtute: &str) -> String {
+    let dm = compute_crate_def_map(fixtute, None);
+    render_crate_def_map(&dm)
+}
+
+fn def_map_with_crate_graph(fixtute: &str, graph: CrateGraphFixture) -> String {
+    let dm = compute_crate_def_map(fixtute, Some(graph));
+    render_crate_def_map(&dm)
+}
+
+#[test]
+fn crate_def_map_smoke_test() {
+    let map = def_map(
+        "
+        //- /lib.rs
+        mod foo;
+        struct S;
+
+        //- /foo/mod.rs
+        pub mod bar;
+        fn f() {}
+
+        //- /foo/bar.rs
+        pub struct Baz;
+        enum E { V }
+        ",
+    );
+    assert_snapshot_matches!(map, @r###"
+crate
+S: t v
+
+crate::foo
+f: v
+
+crate::foo::bar
+Baz: t v
+E: t
+"###
+    )
+}
+
+#[test]
+fn macro_rules_are_globally_visible() {
+    let map = def_map(
+        "
+        //- /lib.rs
+        macro_rules! structs {
+            ($($i:ident),*) => {
+                $(struct $i { field: u32 } )*
+            }
+        }
+        structs!(Foo);
+        mod nested;
+
+        //- /nested.rs
+        structs!(Bar, Baz);
+        ",
+    );
+    assert_snapshot_matches!(map, @r###"
+crate
+Foo: t v
+
+crate::nested
+Bar: t v
+Baz: t v
+"###);
+}
+
+#[test]
+fn macro_rules_can_define_modules() {
+    let map = def_map(
+        "
+        //- /lib.rs
+        macro_rules! m {
+            ($name:ident) => { mod $name;  }
+        }
+        m!(n1);
+
+        //- /n1.rs
+        m!(n2)
+        //- /n1/n2.rs
+        struct X;
+        ",
+    );
+    assert_snapshot_matches!(map, @r###"
+crate
+
+crate::n1
+
+crate::n1::n2
+X: t v
+"###);
+}
+
+#[test]
+fn macro_rules_from_other_crates_are_visible() {
+    let map = def_map_with_crate_graph(
+        "
+        //- /main.rs
+        foo::structs!(Foo, Bar)
+        mod bar;
+
+        //- /bar.rs
+        use crate::*;
+
+        //- /lib.rs
+        #[macro_export]
+        macro_rules! structs {
+            ($($i:ident),*) => {
+                $(struct $i { field: u32 } )*
+            }
+        }
+        ",
+        crate_graph! {
+            "main": ("/main.rs", ["foo"]),
+            "foo": ("/lib.rs", []),
+        },
+    );
+    assert_snapshot_matches!(map, @r###"
+crate
+Foo: t v
+Bar: t v
+
+crate::bar
+Foo: t v
+Bar: t v
+"###);
+}
+
+#[test]
+fn std_prelude() {
+    covers!(std_prelude);
+    let map = def_map_with_crate_graph(
+        "
+        //- /main.rs
+        use Foo::*;
+
+        //- /lib.rs
+        mod prelude;
+        #[prelude_import]
+        use prelude::*;
+
+        //- /prelude.rs
+        pub enum Foo { Bar, Baz };
+        ",
+        crate_graph! {
+            "main": ("/main.rs", ["test_crate"]),
+            "test_crate": ("/lib.rs", []),
+        },
+    );
+    assert_snapshot_matches!(map, @r###"
+crate
+Bar: t v
+Baz: t v
+"###);
+}
+
+#[test]
+fn glob_across_crates() {
+    covers!(glob_across_crates);
+    let map = def_map_with_crate_graph(
+        "
+        //- /main.rs
+        use test_crate::*;
+
+        //- /lib.rs
+        pub struct Baz;
+        ",
+        crate_graph! {
+            "main": ("/main.rs", ["test_crate"]),
+            "test_crate": ("/lib.rs", []),
+        },
+    );
+    assert_snapshot_matches!(map, @r###"
+crate
+Baz: t v
+"###
+    );
+}
+
+#[test]
+fn item_map_enum_importing() {
+    covers!(item_map_enum_importing);
+    let map = def_map(
+        "
+        //- /lib.rs
+        enum E { V }
+        use self::E::V;
+        ",
+    );
+    assert_snapshot_matches!(map, @r###"
+crate
+V: t v
+E: t
+"###
+    );
+}
+
+#[test]
+fn glob_enum() {
+    covers!(glob_enum);
+    let map = def_map(
+        "
+        //- /lib.rs
+        enum Foo {
+            Bar, Baz
+        }
+        use self::Foo::*;
+        ",
+    );
+    assert_snapshot_matches!(map, @r###"
+crate
+Foo: t
+Bar: t v
+Baz: t v
+"###
+    );
+}
diff --git a/crates/ra_hir/src/nameres/lower.rs b/crates/ra_hir/src/nameres/lower.rs
index 56262ad6d..24707aed1 100644
--- a/crates/ra_hir/src/nameres/lower.rs
+++ b/crates/ra_hir/src/nameres/lower.rs
@@ -18,8 +18,8 @@ use crate::{
 pub struct ImportId(RawId);
 impl_arena_id!(ImportId);
 
-#[derive(Debug, PartialEq, Eq)]
-pub(super) struct ImportData {
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct ImportData {
     pub(super) path: Path,
     pub(super) alias: Option<Name>,
     pub(super) is_glob: bool,
diff --git a/crates/ra_mbe/src/lib.rs b/crates/ra_mbe/src/lib.rs
index 2c75b7b4f..989308626 100644
--- a/crates/ra_mbe/src/lib.rs
+++ b/crates/ra_mbe/src/lib.rs
@@ -42,7 +42,7 @@ pub use crate::syntax_bridge::{ast_to_token_tree, token_tree_to_ast_item_list};
 /// be very confusing is that AST has almost exactly the same shape as
 /// `tt::TokenTree`, but there's a crucial difference: in macro rules, `$ident`
 /// and `$()*` have special meaning (see `Var` and `Repeat` data structures)
-#[derive(Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq)]
 pub struct MacroRules {
     pub(crate) rules: Vec<Rule>,
 }
@@ -56,13 +56,13 @@ impl MacroRules {
     }
 }
 
-#[derive(Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq)]
 pub(crate) struct Rule {
     pub(crate) lhs: Subtree,
     pub(crate) rhs: Subtree,
 }
 
-#[derive(Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq)]
 pub(crate) enum TokenTree {
     Leaf(Leaf),
     Subtree(Subtree),
@@ -70,7 +70,7 @@ pub(crate) enum TokenTree {
 }
 impl_froms!(TokenTree: Leaf, Subtree, Repeat);
 
-#[derive(Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq)]
 pub(crate) enum Leaf {
     Literal(Literal),
     Punct(Punct),
@@ -79,37 +79,37 @@ pub(crate) enum Leaf {
 }
 impl_froms!(Leaf: Literal, Punct, Ident, Var);
 
-#[derive(Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq)]
 pub(crate) struct Subtree {
     pub(crate) delimiter: Delimiter,
     pub(crate) token_trees: Vec<TokenTree>,
 }
 
-#[derive(Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq)]
 pub(crate) struct Repeat {
     pub(crate) subtree: Subtree,
     pub(crate) kind: RepeatKind,
     pub(crate) separator: Option<char>,
 }
 
-#[derive(Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq)]
 pub(crate) enum RepeatKind {
     ZeroOrMore,
     OneOrMore,
     ZeroOrOne,
 }
 
-#[derive(Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq)]
 pub(crate) struct Literal {
     pub(crate) text: SmolStr,
 }
 
-#[derive(Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq)]
 pub(crate) struct Ident {
     pub(crate) text: SmolStr,
 }
 
-#[derive(Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq)]
 pub(crate) struct Var {
     pub(crate) text: SmolStr,
     pub(crate) kind: Option<SmolStr>,
diff --git a/crates/ra_syntax/src/ast.rs b/crates/ra_syntax/src/ast.rs
index 81c709bfb..d8c2cb063 100644
--- a/crates/ra_syntax/src/ast.rs
+++ b/crates/ra_syntax/src/ast.rs
@@ -114,6 +114,9 @@ pub trait AttrsOwner: AstNode {
     fn attrs(&self) -> AstChildren<Attr> {
         children(self)
     }
+    fn has_atom_attr(&self, atom: &str) -> bool {
+        self.attrs().filter_map(|x| x.as_atom()).any(|x| x == atom)
+    }
 }
 
 pub trait DocCommentsOwner: AstNode {
@@ -153,12 +156,6 @@ pub trait DocCommentsOwner: AstNode {
     }
 }
 
-impl FnDef {
-    pub fn has_atom_attr(&self, atom: &str) -> bool {
-        self.attrs().filter_map(|x| x.as_atom()).any(|x| x == atom)
-    }
-}
-
 impl Attr {
     pub fn is_inner(&self) -> bool {
         let tt = match self.value() {
diff --git a/crates/ra_syntax/src/ast/generated.rs b/crates/ra_syntax/src/ast/generated.rs
index 7572225b8..54b72f8c5 100644
--- a/crates/ra_syntax/src/ast/generated.rs
+++ b/crates/ra_syntax/src/ast/generated.rs
@@ -2108,6 +2108,7 @@ impl ToOwned for MacroCall {
 
 
 impl ast::NameOwner for MacroCall {}
+impl ast::AttrsOwner for MacroCall {}
 impl MacroCall {
     pub fn token_tree(&self) -> Option<&TokenTree> {
         super::child_opt(self)
diff --git a/crates/ra_syntax/src/grammar.ron b/crates/ra_syntax/src/grammar.ron
index 66f1339c1..4f8e19bd0 100644
--- a/crates/ra_syntax/src/grammar.ron
+++ b/crates/ra_syntax/src/grammar.ron
@@ -557,7 +557,7 @@ Grammar(
         "Name": (),
         "NameRef": (),
         "MacroCall": (
-            traits: [ "NameOwner" ],
+            traits: [ "NameOwner", "AttrsOwner" ],
             options: [ "TokenTree", "Path" ],
         ),
         "Attr": ( options: [ ["value", "TokenTree"] ] ),