4 files changed, 55 insertions, 34 deletions

diff --git a/crates/hir/src/attrs.rs b/crates/hir/src/attrs.rs
index 99fb65bac..9e6a3e155 100644
--- a/crates/hir/src/attrs.rs
+++ b/crates/hir/src/attrs.rs
@@ -2,6 +2,7 @@
 use hir_def::{
     attr::{Attrs, Documentation},
     path::ModPath,
+    per_ns::PerNs,
     resolver::HasResolver,
     AttrDefId, GenericParamId, ModuleDefId,
 };
@@ -112,6 +113,11 @@ fn resolve_doc_path(
     let path = ast::Path::parse(link).ok()?;
     let modpath = ModPath::from_src(path, &Hygiene::new_unhygienic()).unwrap();
     let resolved = resolver.resolve_module_path_in_items(db.upcast(), &modpath);
+    if resolved == PerNs::none() {
+        if let Some(trait_id) = resolver.resolve_module_path_in_trait_items(db.upcast(), &modpath) {
+            return Some(ModuleDefId::TraitId(trait_id));
+        };
+    }
     let def = match ns {
         Some(Namespace::Types) => resolved.take_types()?,
         Some(Namespace::Values) => resolved.take_values()?,
diff --git a/crates/hir/src/code_model.rs b/crates/hir/src/code_model.rs
index aaa7013b6..d9b4cdfce 100644
--- a/crates/hir/src/code_model.rs
+++ b/crates/hir/src/code_model.rs
@@ -270,18 +270,18 @@ impl ModuleDef {
             None => return,
         };
 
-        hir_ty::diagnostics::validate_module_item(db, module.id.krate, id, sink)
+        hir_ty::diagnostics::validate_module_item(db, module.id.krate(), id, sink)
     }
 }
 
 impl Module {
     pub(crate) fn new(krate: Crate, crate_module_id: LocalModuleId) -> Module {
-        Module { id: ModuleId { krate: krate.id, local_id: crate_module_id } }
+        Module { id: ModuleId::top_level(krate.id, crate_module_id) }
     }
 
     /// Name of this module.
     pub fn name(self, db: &dyn HirDatabase) -> Option<Name> {
-        let def_map = db.crate_def_map(self.id.krate);
+        let def_map = self.id.def_map(db.upcast());
         let parent = def_map[self.id.local_id].parent?;
         def_map[parent].children.iter().find_map(|(name, module_id)| {
             if *module_id == self.id.local_id {
@@ -294,20 +294,20 @@ impl Module {
 
     /// Returns the crate this module is part of.
     pub fn krate(self) -> Crate {
-        Crate { id: self.id.krate }
+        Crate { id: self.id.krate() }
     }
 
     /// Topmost parent of this module. Every module has a `crate_root`, but some
     /// might be missing `krate`. This can happen if a module's file is not included
     /// in the module tree of any target in `Cargo.toml`.
     pub fn crate_root(self, db: &dyn HirDatabase) -> Module {
-        let def_map = db.crate_def_map(self.id.krate);
+        let def_map = db.crate_def_map(self.id.krate());
         self.with_module_id(def_map.root())
     }
 
     /// Iterates over all child modules.
     pub fn children(self, db: &dyn HirDatabase) -> impl Iterator<Item = Module> {
-        let def_map = db.crate_def_map(self.id.krate);
+        let def_map = self.id.def_map(db.upcast());
         let children = def_map[self.id.local_id]
             .children
             .iter()
@@ -318,7 +318,8 @@ impl Module {
 
     /// Finds a parent module.
     pub fn parent(self, db: &dyn HirDatabase) -> Option<Module> {
-        let def_map = db.crate_def_map(self.id.krate);
+        // FIXME: handle block expressions as modules (their parent is in a different DefMap)
+        let def_map = self.id.def_map(db.upcast());
         let parent_id = def_map[self.id.local_id].parent?;
         Some(self.with_module_id(parent_id))
     }
@@ -339,7 +340,7 @@ impl Module {
         db: &dyn HirDatabase,
         visible_from: Option<Module>,
     ) -> Vec<(Name, ScopeDef)> {
-        db.crate_def_map(self.id.krate)[self.id.local_id]
+        self.id.def_map(db.upcast())[self.id.local_id]
             .scope
             .entries()
             .filter_map(|(name, def)| {
@@ -362,14 +363,14 @@ impl Module {
     }
 
     pub fn visibility_of(self, db: &dyn HirDatabase, def: &ModuleDef) -> Option<Visibility> {
-        db.crate_def_map(self.id.krate)[self.id.local_id].scope.visibility_of(def.clone().into())
+        self.id.def_map(db.upcast())[self.id.local_id].scope.visibility_of(def.clone().into())
     }
 
     pub fn diagnostics(self, db: &dyn HirDatabase, sink: &mut DiagnosticSink) {
         let _p = profile::span("Module::diagnostics").detail(|| {
             format!("{:?}", self.name(db).map_or("<unknown>".into(), |name| name.to_string()))
         });
-        let crate_def_map = db.crate_def_map(self.id.krate);
+        let crate_def_map = self.id.def_map(db.upcast());
         crate_def_map.add_diagnostics(db.upcast(), self.id.local_id, sink);
         for decl in self.declarations(db) {
             match decl {
@@ -396,12 +397,12 @@ impl Module {
     }
 
     pub fn declarations(self, db: &dyn HirDatabase) -> Vec<ModuleDef> {
-        let def_map = db.crate_def_map(self.id.krate);
+        let def_map = self.id.def_map(db.upcast());
         def_map[self.id.local_id].scope.declarations().map(ModuleDef::from).collect()
     }
 
     pub fn impl_defs(self, db: &dyn HirDatabase) -> Vec<Impl> {
-        let def_map = db.crate_def_map(self.id.krate);
+        let def_map = self.id.def_map(db.upcast());
         def_map[self.id.local_id].scope.impls().map(Impl::from).collect()
     }
 
@@ -457,7 +458,7 @@ impl Field {
         };
         let substs = Substs::type_params(db, generic_def_id);
         let ty = db.field_types(var_id)[self.id].clone().subst(&substs);
-        Type::new(db, self.parent.module(db).id.krate, var_id, ty)
+        Type::new(db, self.parent.module(db).id.krate(), var_id, ty)
     }
 
     pub fn parent_def(&self, _db: &dyn HirDatabase) -> VariantDef {
@@ -502,7 +503,11 @@ impl Struct {
     }
 
     pub fn ty(self, db: &dyn HirDatabase) -> Type {
-        Type::from_def(db, self.id.lookup(db.upcast()).container.module(db.upcast()).krate, self.id)
+        Type::from_def(
+            db,
+            self.id.lookup(db.upcast()).container.module(db.upcast()).krate(),
+            self.id,
+        )
     }
 
     pub fn repr(self, db: &dyn HirDatabase) -> Option<ReprKind> {
@@ -533,7 +538,11 @@ impl Union {
     }
 
     pub fn ty(self, db: &dyn HirDatabase) -> Type {
-        Type::from_def(db, self.id.lookup(db.upcast()).container.module(db.upcast()).krate, self.id)
+        Type::from_def(
+            db,
+            self.id.lookup(db.upcast()).container.module(db.upcast()).krate(),
+            self.id,
+        )
     }
 
     pub fn fields(self, db: &dyn HirDatabase) -> Vec<Field> {
@@ -573,7 +582,11 @@ impl Enum {
     }
 
     pub fn ty(self, db: &dyn HirDatabase) -> Type {
-        Type::from_def(db, self.id.lookup(db.upcast()).container.module(db.upcast()).krate, self.id)
+        Type::from_def(
+            db,
+            self.id.lookup(db.upcast()).container.module(db.upcast()).krate(),
+            self.id,
+        )
     }
 }
 
@@ -632,7 +645,7 @@ impl Adt {
     /// general set of completions, but will not look very nice when printed.
     pub fn ty(self, db: &dyn HirDatabase) -> Type {
         let id = AdtId::from(self);
-        Type::from_def(db, id.module(db.upcast()).krate, id)
+        Type::from_def(db, id.module(db.upcast()).krate(), id)
     }
 
     pub fn module(self, db: &dyn HirDatabase) -> Module {
@@ -750,7 +763,7 @@ impl Function {
         let ctx = hir_ty::TyLoweringContext::new(db, &resolver);
         let environment = TraitEnvironment::lower(db, &resolver);
         Type {
-            krate: self.id.lookup(db.upcast()).container.module(db.upcast()).krate,
+            krate: self.id.lookup(db.upcast()).container.module(db.upcast()).krate(),
             ty: InEnvironment { value: Ty::from_hir_ext(&ctx, ret_type).0, environment },
         }
     }
@@ -771,7 +784,7 @@ impl Function {
             .iter()
             .map(|type_ref| {
                 let ty = Type {
-                    krate: self.id.lookup(db.upcast()).container.module(db.upcast()).krate,
+                    krate: self.id.lookup(db.upcast()).container.module(db.upcast()).krate(),
                     ty: InEnvironment {
                         value: Ty::from_hir_ext(&ctx, type_ref).0,
                         environment: environment.clone(),
@@ -795,7 +808,7 @@ impl Function {
     }
 
     pub fn diagnostics(self, db: &dyn HirDatabase, sink: &mut DiagnosticSink) {
-        let krate = self.module(db).id.krate;
+        let krate = self.module(db).id.krate();
         hir_def::diagnostics::validate_body(db.upcast(), self.id.into(), sink);
         hir_ty::diagnostics::validate_module_item(db, krate, self.id.into(), sink);
         hir_ty::diagnostics::validate_body(db, self.id.into(), sink);
@@ -973,7 +986,7 @@ impl TypeAlias {
     }
 
     pub fn ty(self, db: &dyn HirDatabase) -> Type {
-        Type::from_def(db, self.id.lookup(db.upcast()).module(db.upcast()).krate, self.id)
+        Type::from_def(db, self.id.lookup(db.upcast()).module(db.upcast()).krate(), self.id)
     }
 
     pub fn name(self, db: &dyn HirDatabase) -> Name {
@@ -1230,7 +1243,7 @@ impl Local {
         let def = DefWithBodyId::from(self.parent);
         let infer = db.infer(def);
         let ty = infer[self.pat_id].clone();
-        let krate = def.module(db.upcast()).krate;
+        let krate = def.module(db.upcast()).krate();
         Type::new(db, krate, def, ty)
     }
 
@@ -1318,7 +1331,7 @@ impl TypeParam {
         let environment = TraitEnvironment::lower(db, &resolver);
         let ty = Ty::Placeholder(self.id);
         Type {
-            krate: self.id.parent.module(db.upcast()).krate,
+            krate: self.id.parent.module(db.upcast()).krate(),
             ty: InEnvironment { value: ty, environment },
         }
     }
@@ -1344,7 +1357,7 @@ impl TypeParam {
         let subst = Substs::type_params(db, self.id.parent);
         let ty = ty.subst(&subst.prefix(local_idx));
         Some(Type {
-            krate: self.id.parent.module(db.upcast()).krate,
+            krate: self.id.parent.module(db.upcast()).krate(),
             ty: InEnvironment { value: ty, environment },
         })
     }
@@ -1405,7 +1418,7 @@ impl ConstParam {
 
     pub fn ty(self, db: &dyn HirDatabase) -> Type {
         let def = self.id.parent;
-        let krate = def.module(db.upcast()).krate;
+        let krate = def.module(db.upcast()).krate();
         Type::new(db, krate, def, db.const_param_ty(self.id))
     }
 }
@@ -1440,7 +1453,7 @@ impl Impl {
         let environment = TraitEnvironment::lower(db, &resolver);
         let ty = Ty::from_hir(&ctx, &impl_data.target_type);
         Type {
-            krate: self.id.lookup(db.upcast()).container.module(db.upcast()).krate,
+            krate: self.id.lookup(db.upcast()).container.module(db.upcast()).krate(),
             ty: InEnvironment { value: ty, environment },
         }
     }
@@ -1458,7 +1471,7 @@ impl Impl {
     }
 
     pub fn krate(self, db: &dyn HirDatabase) -> Crate {
-        Crate { id: self.module(db).id.krate }
+        Crate { id: self.module(db).id.krate() }
     }
 
     pub fn is_builtin_derive(self, db: &dyn HirDatabase) -> Option<InFile<ast::Attr>> {
diff --git a/crates/hir/src/has_source.rs b/crates/hir/src/has_source.rs
index 7c57d8378..262002671 100644
--- a/crates/hir/src/has_source.rs
+++ b/crates/hir/src/has_source.rs
@@ -24,12 +24,12 @@ pub trait HasSource {
 impl Module {
     /// Returns a node which defines this module. That is, a file or a `mod foo {}` with items.
     pub fn definition_source(self, db: &dyn HirDatabase) -> InFile<ModuleSource> {
-        let def_map = db.crate_def_map(self.id.krate);
+        let def_map = self.id.def_map(db.upcast());
         def_map[self.id.local_id].definition_source(db.upcast())
     }
 
     pub fn is_mod_rs(self, db: &dyn HirDatabase) -> bool {
-        let def_map = db.crate_def_map(self.id.krate);
+        let def_map = self.id.def_map(db.upcast());
         match def_map[self.id.local_id].origin {
             ModuleOrigin::File { is_mod_rs, .. } => is_mod_rs,
             _ => false,
@@ -39,7 +39,7 @@ impl Module {
     /// Returns a node which declares this module, either a `mod foo;` or a `mod foo {}`.
     /// `None` for the crate root.
     pub fn declaration_source(self, db: &dyn HirDatabase) -> Option<InFile<ast::Module>> {
-        let def_map = db.crate_def_map(self.id.krate);
+        let def_map = self.id.def_map(db.upcast());
         def_map[self.id.local_id].declaration_source(db.upcast())
     }
 }
diff --git a/crates/hir/src/semantics/source_to_def.rs b/crates/hir/src/semantics/source_to_def.rs
index 9bf60c72a..faede3269 100644
--- a/crates/hir/src/semantics/source_to_def.rs
+++ b/crates/hir/src/semantics/source_to_def.rs
@@ -31,11 +31,12 @@ impl SourceToDefCtx<'_, '_> {
     pub(super) fn file_to_def(&mut self, file: FileId) -> Option<ModuleId> {
         let _p = profile::span("SourceBinder::to_module_def");
         let (krate, local_id) = self.db.relevant_crates(file).iter().find_map(|&crate_id| {
+            // FIXME: inner items
             let crate_def_map = self.db.crate_def_map(crate_id);
             let local_id = crate_def_map.modules_for_file(file).next()?;
             Some((crate_id, local_id))
         })?;
-        Some(ModuleId { krate, local_id })
+        Some(ModuleId::top_level(krate, local_id))
     }
 
     pub(super) fn module_to_def(&mut self, src: InFile<ast::Module>) -> Option<ModuleId> {
@@ -60,9 +61,10 @@ impl SourceToDefCtx<'_, '_> {
         }?;
 
         let child_name = src.value.name()?.as_name();
-        let def_map = self.db.crate_def_map(parent_module.krate);
+        let def_map = parent_module.def_map(self.db.upcast());
         let child_id = *def_map[parent_module.local_id].children.get(&child_name)?;
-        Some(ModuleId { krate: parent_module.krate, local_id: child_id })
+        // FIXME: handle block expression modules
+        Some(ModuleId::top_level(parent_module.krate(), child_id))
     }
 
     pub(super) fn trait_to_def(&mut self, src: InFile<ast::Trait>) -> Option<TraitId> {
@@ -185,7 +187,7 @@ impl SourceToDefCtx<'_, '_> {
     ) -> Option<MacroDefId> {
         let kind = MacroDefKind::Declarative;
         let file_id = src.file_id.original_file(self.db.upcast());
-        let krate = self.file_to_def(file_id)?.krate;
+        let krate = self.file_to_def(file_id)?.krate();
         let file_ast_id = self.db.ast_id_map(src.file_id).ast_id(&src.value);
         let ast_id = Some(AstId::new(src.file_id, file_ast_id.upcast()));
         Some(MacroDefId { krate, ast_id, kind, local_inner: false })