3 files changed, 21 insertions, 10 deletions

diff --git a/crates/hir/Cargo.toml b/crates/hir/Cargo.toml
index d4ea7327e..55e9c3f0c 100644
--- a/crates/hir/Cargo.toml
+++ b/crates/hir/Cargo.toml
@@ -15,6 +15,7 @@ rustc-hash = "1.1.0"
 either = "1.5.3"
 arrayvec = "0.5.1"
 itertools = "0.10.0"
+smallvec = "1.4.0"
 
 stdx = { path = "../stdx", version = "0.0.0" }
 syntax = { path = "../syntax", version = "0.0.0" }
diff --git a/crates/hir/src/semantics.rs b/crates/hir/src/semantics.rs
index 945638cc5..519339c0c 100644
--- a/crates/hir/src/semantics.rs
+++ b/crates/hir/src/semantics.rs
@@ -259,6 +259,10 @@ impl<'db, DB: HirDatabase> Semantics<'db, DB> {
     }
 
     pub fn to_module_def(&self, file: FileId) -> Option<Module> {
+        self.imp.to_module_def(file).next()
+    }
+
+    pub fn to_module_defs(&self, file: FileId) -> impl Iterator<Item = Module> {
         self.imp.to_module_def(file)
     }
 
@@ -537,8 +541,8 @@ impl<'db> SemanticsImpl<'db> {
         f(&mut ctx)
     }
 
-    fn to_module_def(&self, file: FileId) -> Option<Module> {
-        self.with_ctx(|ctx| ctx.file_to_def(file)).map(Module::from)
+    fn to_module_def(&self, file: FileId) -> impl Iterator<Item = Module> {
+        self.with_ctx(|ctx| ctx.file_to_def(file)).into_iter().map(Module::from)
     }
 
     fn scope(&self, node: &SyntaxNode) -> SemanticsScope<'db> {
diff --git a/crates/hir/src/semantics/source_to_def.rs b/crates/hir/src/semantics/source_to_def.rs
index 6c612ee86..e9d820140 100644
--- a/crates/hir/src/semantics/source_to_def.rs
+++ b/crates/hir/src/semantics/source_to_def.rs
@@ -12,6 +12,7 @@ use hir_def::{
 };
 use hir_expand::{name::AsName, AstId, MacroDefKind};
 use rustc_hash::FxHashMap;
+use smallvec::SmallVec;
 use stdx::impl_from;
 use syntax::{
     ast::{self, NameOwner},
@@ -28,14 +29,19 @@ pub(super) struct SourceToDefCtx<'a, 'b> {
 }
 
 impl SourceToDefCtx<'_, '_> {
-    pub(super) fn file_to_def(&mut self, file: FileId) -> Option<ModuleId> {
+    pub(super) fn file_to_def(&mut self, file: FileId) -> SmallVec<[ModuleId; 1]> {
         let _p = profile::span("SourceBinder::to_module_def");
-        self.db.relevant_crates(file).iter().find_map(|&crate_id| {
+        let mut mods = SmallVec::new();
+        for &crate_id in self.db.relevant_crates(file).iter() {
             // 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_def_map.module_id(local_id))
-        })
+            mods.extend(
+                crate_def_map
+                    .modules_for_file(file)
+                    .map(|local_id| crate_def_map.module_id(local_id)),
+            )
+        }
+        mods
     }
 
     pub(super) fn module_to_def(&mut self, src: InFile<ast::Module>) -> Option<ModuleId> {
@@ -55,7 +61,7 @@ impl SourceToDefCtx<'_, '_> {
             Some(parent_declaration) => self.module_to_def(parent_declaration),
             None => {
                 let file_id = src.file_id.original_file(self.db.upcast());
-                self.file_to_def(file_id)
+                self.file_to_def(file_id).get(0).copied()
             }
         }?;
 
@@ -185,7 +191,7 @@ 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).get(0).copied()?.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 })
@@ -245,7 +251,7 @@ impl SourceToDefCtx<'_, '_> {
             return Some(res);
         }
 
-        let def = self.file_to_def(src.file_id.original_file(self.db.upcast()))?;
+        let def = self.file_to_def(src.file_id.original_file(self.db.upcast())).get(0).copied()?;
         Some(def.into())
     }