3 files changed, 59 insertions, 7 deletions

diff --git a/crates/hir_def/src/body/lower.rs b/crates/hir_def/src/body/lower.rs
index c0b0b7841..c11da30d2 100644
--- a/crates/hir_def/src/body/lower.rs
+++ b/crates/hir_def/src/body/lower.rs
@@ -1,10 +1,11 @@
 //! Transforms `ast::Expr` into an equivalent `hir_def::expr::Expr`
 //! representation.
 
-use std::mem;
+use std::{mem, sync::Arc};
 
 use either::Either;
 use hir_expand::{
+    ast_id_map::{AstIdMap, FileAstId},
     hygiene::Hygiene,
     name::{name, AsName, Name},
     ExpandError, HirFileId,
@@ -39,20 +40,39 @@ use crate::{
 
 use super::{diagnostics::BodyDiagnostic, ExprSource, PatSource};
 
-pub(crate) struct LowerCtx {
+pub struct LowerCtx {
     hygiene: Hygiene,
+    file_id: Option<HirFileId>,
+    source_ast_id_map: Option<Arc<AstIdMap>>,
 }
 
 impl LowerCtx {
-    pub(crate) fn new(db: &dyn DefDatabase, file_id: HirFileId) -> Self {
-        LowerCtx { hygiene: Hygiene::new(db.upcast(), file_id) }
+    pub fn new(db: &dyn DefDatabase, file_id: HirFileId) -> Self {
+        LowerCtx {
+            hygiene: Hygiene::new(db.upcast(), file_id),
+            file_id: Some(file_id),
+            source_ast_id_map: Some(db.ast_id_map(file_id)),
+        }
+    }
+
+    pub fn with_hygiene(hygiene: &Hygiene) -> Self {
+        LowerCtx { hygiene: hygiene.clone(), file_id: None, source_ast_id_map: None }
+    }
+
+    pub(crate) fn hygiene(&self) -> &Hygiene {
+        &self.hygiene
     }
-    pub(crate) fn with_hygiene(hygiene: &Hygiene) -> Self {
-        LowerCtx { hygiene: hygiene.clone() }
+
+    pub(crate) fn file_id(&self) -> HirFileId {
+        self.file_id.unwrap()
     }
 
     pub(crate) fn lower_path(&self, ast: ast::Path) -> Option<Path> {
-        Path::from_src(ast, &self.hygiene)
+        Path::from_src(ast, self)
+    }
+
+    pub(crate) fn ast_id<N: AstNode>(&self, item: &N) -> Option<FileAstId<N>> {
+        self.source_ast_id_map.as_ref().map(|ast_id_map| ast_id_map.ast_id(item))
     }
 }
 
diff --git a/crates/hir_def/src/body/tests.rs b/crates/hir_def/src/body/tests.rs
index 63f5fe88d..3e8f16306 100644
--- a/crates/hir_def/src/body/tests.rs
+++ b/crates/hir_def/src/body/tests.rs
@@ -40,6 +40,14 @@ fn block_def_map_at(ra_fixture: &str) -> String {
     module.def_map(&db).dump(&db)
 }
 
+fn check_block_scopes_at(ra_fixture: &str, expect: Expect) {
+    let (db, position) = crate::test_db::TestDB::with_position(ra_fixture);
+
+    let module = db.module_at_position(position);
+    let actual = module.def_map(&db).dump_block_scopes(&db);
+    expect.assert_eq(&actual);
+}
+
 fn check_at(ra_fixture: &str, expect: Expect) {
     let actual = block_def_map_at(ra_fixture);
     expect.assert_eq(&actual);
diff --git a/crates/hir_def/src/body/tests/block.rs b/crates/hir_def/src/body/tests/block.rs
index 3b6ba4cde..bc3d0f138 100644
--- a/crates/hir_def/src/body/tests/block.rs
+++ b/crates/hir_def/src/body/tests/block.rs
@@ -134,6 +134,30 @@ struct Struct {}
 }
 
 #[test]
+fn nested_module_scoping() {
+    check_block_scopes_at(
+        r#"
+fn f() {
+    mod module {
+        struct Struct {}
+        fn f() {
+            use self::Struct;
+            $0
+        }
+    }
+}
+    "#,
+        expect![[r#"
+            BlockId(1) in ModuleId { krate: CrateId(0), block: Some(BlockId(0)), local_id: Idx::<ModuleData>(0) }
+            BlockId(0) in ModuleId { krate: CrateId(0), block: None, local_id: Idx::<ModuleData>(0) }
+            crate scope
+        "#]],
+    );
+    // FIXME: The module nesting here is wrong!
+    // The first block map should be located in module #1 (`mod module`), not #0 (BlockId(0) root module)
+}
+
+#[test]
 fn legacy_macro_items() {
     // Checks that legacy-scoped `macro_rules!` from parent namespaces are resolved and expanded
     // correctly.