diff --git a/src/ast/mod.rs b/src/ast/mod.rs
index 4d8847c..c9a94eb 100644
--- a/src/ast/mod.rs
+++ b/src/ast/mod.rs
@@ -926,6 +926,10 @@ impl ModuleDef {
     pub fn set_out_expr(&mut self, expr: Expression) {
         self.out_expr = Some(Box::new(expr));
     }
+
+    pub fn derive_shape(&mut self, expr: Expression) {
+        todo!()
+    }
 }
 
 /// RangeDef defines a range with optional step.
diff --git a/src/ast/typecheck/mod.rs b/src/ast/typecheck/mod.rs
index 13555dc..11ecbb6 100644
--- a/src/ast/typecheck/mod.rs
+++ b/src/ast/typecheck/mod.rs
@@ -245,7 +245,7 @@ impl DeriveShape for Expression {
             Expression::Func(def) => def.derive_shape(symbol_table),
             Expression::Select(def) => def.derive_shape(symbol_table),
             Expression::FuncOp(_) => todo!(),
-            Expression::Module(_) => todo!(),
+            Expression::Module(def) => def.derive_shape(symbol_table),
             Expression::Fail(_) => todo!(),
             Expression::Debug(_) => todo!(),
         }