3 files changed, 44 insertions, 2 deletions

diff --git a/crates/ide_db/src/defs.rs b/crates/ide_db/src/defs.rs
index ff612b7d0..f86e5ce93 100644
--- a/crates/ide_db/src/defs.rs
+++ b/crates/ide_db/src/defs.rs
@@ -70,7 +70,7 @@ impl Definition {
                 hir::ModuleDef::Static(it) => it.name(db)?,
                 hir::ModuleDef::Trait(it) => it.name(db),
                 hir::ModuleDef::TypeAlias(it) => it.name(db),
-                hir::ModuleDef::BuiltinType(_) => return None,
+                hir::ModuleDef::BuiltinType(it) => it.name(),
             },
             Definition::SelfType(_) => return None,
             Definition::Local(it) => it.name(db)?,
diff --git a/crates/ide_db/src/helpers.rs b/crates/ide_db/src/helpers.rs
index 3c95d3cff..9992a92bd 100644
--- a/crates/ide_db/src/helpers.rs
+++ b/crates/ide_db/src/helpers.rs
@@ -2,6 +2,10 @@
 pub mod insert_use;
 pub mod import_assets;
 
+use std::collections::VecDeque;
+
+use base_db::FileId;
+use either::Either;
 use hir::{Crate, Enum, ItemInNs, MacroDef, Module, ModuleDef, Name, ScopeDef, Semantics, Trait};
 use syntax::ast::{self, make};
 
@@ -39,6 +43,30 @@ pub fn mod_path_to_ast(path: &hir::ModPath) -> ast::Path {
     make::path_from_segments(segments, is_abs)
 }
 
+/// Iterates all `ModuleDef`s and `Impl` blocks of the given file.
+pub fn visit_file_defs(
+    sema: &Semantics<RootDatabase>,
+    file_id: FileId,
+    cb: &mut dyn FnMut(Either<hir::ModuleDef, hir::Impl>),
+) {
+    let db = sema.db;
+    let module = match sema.to_module_def(file_id) {
+        Some(it) => it,
+        None => return,
+    };
+    let mut defs: VecDeque<_> = module.declarations(db).into();
+    while let Some(def) = defs.pop_front() {
+        if let ModuleDef::Module(submodule) = def {
+            if let hir::ModuleSource::Module(_) = submodule.definition_source(db).value {
+                defs.extend(submodule.declarations(db));
+                submodule.impl_defs(db).into_iter().for_each(|impl_| cb(Either::Right(impl_)));
+            }
+        }
+        cb(Either::Left(def));
+    }
+    module.impl_defs(db).into_iter().for_each(|impl_| cb(Either::Right(impl_)));
+}
+
 /// Helps with finding well-know things inside the standard library. This is
 /// somewhat similar to the known paths infra inside hir, but it different; We
 /// want to make sure that IDE specific paths don't become interesting inside
diff --git a/crates/ide_db/src/search.rs b/crates/ide_db/src/search.rs
index fa18703e1..d00a8b6e7 100644
--- a/crates/ide_db/src/search.rs
+++ b/crates/ide_db/src/search.rs
@@ -6,7 +6,7 @@
 
 use std::{convert::TryInto, mem};
 
-use base_db::{FileId, FileRange, SourceDatabaseExt};
+use base_db::{FileId, FileRange, SourceDatabase, SourceDatabaseExt};
 use hir::{DefWithBody, HasSource, Module, ModuleSource, Semantics, Visibility};
 use once_cell::unsync::Lazy;
 use rustc_hash::FxHashMap;
@@ -138,6 +138,20 @@ impl IntoIterator for SearchScope {
 impl Definition {
     fn search_scope(&self, db: &RootDatabase) -> SearchScope {
         let _p = profile::span("search_scope");
+
+        if let Definition::ModuleDef(hir::ModuleDef::BuiltinType(_)) = self {
+            let mut res = FxHashMap::default();
+
+            let graph = db.crate_graph();
+            for krate in graph.iter() {
+                let root_file = graph[krate].root_file_id;
+                let source_root_id = db.file_source_root(root_file);
+                let source_root = db.source_root(source_root_id);
+                res.extend(source_root.iter().map(|id| (id, None)));
+            }
+            return SearchScope::new(res);
+        }
+
         let module = match self.module(db) {
             Some(it) => it,
             None => return SearchScope::empty(),