diff --git a/crates/hir-def/src/body.rs b/crates/hir-def/src/body.rs
index 26fd58c0a40..c0baf6011f7 100644
--- a/crates/hir-def/src/body.rs
+++ b/crates/hir-def/src/body.rs
@@ -166,9 +166,10 @@ pub(crate) fn body_with_source_map_query(
         };
         let module = def.module(db);
         let expander = Expander::new(db, file_id, module);
-        let (mut body, source_map) =
+        let (mut body, mut source_map) =
             Body::new(db, def, expander, params, body, module.krate, is_async_fn);
         body.shrink_to_fit();
+        source_map.shrink_to_fit();
 
         (Arc::new(body), Arc::new(source_map))
     }
@@ -390,4 +391,29 @@ pub fn macro_expansion_expr(&self, node: InFile<&ast::MacroExpr>) -> Option<Expr
     pub fn diagnostics(&self) -> &[BodyDiagnostic] {
         &self.diagnostics
     }
+
+    fn shrink_to_fit(&mut self) {
+        let Self {
+            expr_map,
+            expr_map_back,
+            pat_map,
+            pat_map_back,
+            label_map,
+            label_map_back,
+            field_map_back,
+            pat_field_map_back,
+            expansions,
+            diagnostics,
+        } = self;
+        expr_map.shrink_to_fit();
+        expr_map_back.shrink_to_fit();
+        pat_map.shrink_to_fit();
+        pat_map_back.shrink_to_fit();
+        label_map.shrink_to_fit();
+        label_map_back.shrink_to_fit();
+        field_map_back.shrink_to_fit();
+        pat_field_map_back.shrink_to_fit();
+        expansions.shrink_to_fit();
+        diagnostics.shrink_to_fit();
+    }
 }
diff --git a/crates/hir-def/src/import_map.rs b/crates/hir-def/src/import_map.rs
index c961d7d86d8..721da29ce81 100644
--- a/crates/hir-def/src/import_map.rs
+++ b/crates/hir-def/src/import_map.rs
@@ -175,7 +175,7 @@ fn collect_import_map(db: &dyn DefDatabase, krate: CrateId) -> FxIndexMap<ItemIn
             }
         }
     }
-
+    map.shrink_to_fit();
     map
 }