diff --git a/relay/include/relay/evaluator.h b/relay/include/relay/evaluator.h
index 734bfadc36f6f..3a7a2f340337e 100644
--- a/relay/include/relay/evaluator.h
+++ b/relay/include/relay/evaluator.h
@@ -24,22 +24,22 @@ class Evaluator : public ExprFunctor<Value(const Expr& n)> {
   Evaluator();
   Evaluator(Environment env) : env(env) {}
   Value Eval(const Expr& expr);
-  Value VisitExpr_(const LocalIdNode* op);
-  Value VisitExpr_(const GlobalIdNode* op);
-  Value VisitExpr_(const IntrinsicIdNode* op);
-  Value VisitExpr_(const FloatLitNode* op);
-  Value VisitExpr_(const BoolLitNode* op);
-  Value VisitExpr_(const IntLitNode* op);
-  Value VisitExpr_(const TensorLitNode* op);
-  Value VisitExpr_(const ProductLitNode* op);
-  Value VisitExpr_(const CastNode* op);
-  Value VisitExpr_(const ParamNode* op);
-  Value VisitExpr_(const FunctionNode* op);
-  Value VisitExpr_(const CallNode* op);
-  Value VisitExpr_(const DebugNode* op);
-  Value VisitExpr_(const UnaryOpNode* op);
-  Value VisitExpr_(const BinaryOpNode* op);
-  Value VisitExpr_(const AssignmentNode* op);
+  Value VisitExpr_(const LocalIdNode* op) override;
+  Value VisitExpr_(const GlobalIdNode* op) override;
+  Value VisitExpr_(const IntrinsicIdNode* op) override;
+  Value VisitExpr_(const FloatLitNode* op) override;
+  Value VisitExpr_(const BoolLitNode* op) override;
+  Value VisitExpr_(const IntLitNode* op) override;
+  Value VisitExpr_(const TensorLitNode* op) override;
+  Value VisitExpr_(const ProductLitNode* op) override;
+  Value VisitExpr_(const CastNode* op) override;
+  Value VisitExpr_(const ParamNode* op) override;
+  Value VisitExpr_(const FunctionNode* op) override;
+  Value VisitExpr_(const CallNode* op) override;
+  Value VisitExpr_(const DebugNode* op) override;
+  Value VisitExpr_(const UnaryOpNode* op) override;
+  Value VisitExpr_(const BinaryOpNode* op) override;
+  Value VisitExpr_(const AssignmentNode* op) override;
 };
 
 }  // namespace relay
diff --git a/relay/include/relay/typechecker.h b/relay/include/relay/typechecker.h
index e422e40b4d1eb..66354a7c50f90 100644
--- a/relay/include/relay/typechecker.h
+++ b/relay/include/relay/typechecker.h
@@ -20,22 +20,22 @@ class Typechecker : public ExprFunctor<Type(const Expr & n)>  {
   Typechecker();
   Typechecker(Environment env) : env(env) {}
   Type Check(const Expr & expr);
-  Type VisitExpr_(const LocalIdNode* op);
-  Type VisitExpr_(const GlobalIdNode* op);
-  Type VisitExpr_(const IntrinsicIdNode* op);
-  Type VisitExpr_(const FloatLitNode* op);
-  Type VisitExpr_(const BoolLitNode* op);
-  Type VisitExpr_(const IntLitNode* op);
-  Type VisitExpr_(const TensorLitNode* op);
-  Type VisitExpr_(const ProductLitNode* op);
-  Type VisitExpr_(const CastNode* op);
-  Type VisitExpr_(const ParamNode* op);
-  Type VisitExpr_(const FunctionNode* op);
-  Type VisitExpr_(const CallNode* op);
-  Type VisitExpr_(const DebugNode* op);
-  Type VisitExpr_(const UnaryOpNode* op);
-  Type VisitExpr_(const BinaryOpNode* op);
-  Type VisitExpr_(const AssignmentNode* op);
+  Type VisitExpr_(const LocalIdNode* op) override;
+  Type VisitExpr_(const GlobalIdNode* op) override;
+  Type VisitExpr_(const IntrinsicIdNode* op) override;
+  Type VisitExpr_(const FloatLitNode* op) override;
+  Type VisitExpr_(const BoolLitNode* op) override;
+  Type VisitExpr_(const IntLitNode* op) override;
+  Type VisitExpr_(const TensorLitNode* op) override;
+  Type VisitExpr_(const ProductLitNode* op) override;
+  Type VisitExpr_(const CastNode* op) override;
+  Type VisitExpr_(const ParamNode* op) override;
+  Type VisitExpr_(const FunctionNode* op) override;
+  Type VisitExpr_(const CallNode* op) override;
+  Type VisitExpr_(const DebugNode* op) override;
+  Type VisitExpr_(const UnaryOpNode* op) override;
+  Type VisitExpr_(const BinaryOpNode* op) override;
+  Type VisitExpr_(const AssignmentNode* op) override;
 };
 
 }  // namespace relay
diff --git a/relay/include/relay/visitor.h b/relay/include/relay/visitor.h
index 034db9b0ce416..c05f433ae881c 100644
--- a/relay/include/relay/visitor.h
+++ b/relay/include/relay/visitor.h
@@ -45,7 +45,7 @@ class FunctorNode
 
   void VisitAttrs(tvm::AttrVisitor* v) final {}
 
-  NodeRef VisitExpr_(const LocalIdNode* local, tvm::Array<NodeRef> args) {
+  NodeRef VisitExpr_(const LocalIdNode* local, tvm::Array<NodeRef> args) override {
     if (visit_local_id != nullptr) {
       return visit_local_id(local->name, args);
     } else {
@@ -53,7 +53,7 @@ class FunctorNode
     }
   }
 
-  NodeRef VisitExpr_(const GlobalIdNode* global, tvm::Array<NodeRef> args) {
+  NodeRef VisitExpr_(const GlobalIdNode* global, tvm::Array<NodeRef> args) override {
     if (visit_global_id != nullptr) {
       return visit_global_id(global->name, args);
     } else {
@@ -62,7 +62,7 @@ class FunctorNode
   }
 
   NodeRef VisitExpr_(const IntrinsicIdNode* intrinsic,
-                     tvm::Array<NodeRef> args) {
+                     tvm::Array<NodeRef> args) override {
     if (visit_intrinsic_id != nullptr) {
       return visit_intrinsic_id(intrinsic->name, args);
     } else {
@@ -70,7 +70,7 @@ class FunctorNode
     }
   }
 
-  NodeRef VisitExpr_(const FloatLitNode* float_lit, tvm::Array<NodeRef> args) {
+  NodeRef VisitExpr_(const FloatLitNode* float_lit, tvm::Array<NodeRef> args) override {
     if (visit_float_lit != nullptr) {
       return visit_float_lit(float_lit->value, args);
     } else {
@@ -78,7 +78,7 @@ class FunctorNode
     }
   }
 
-  NodeRef VisitExpr_(const BoolLitNode* bool_lit, tvm::Array<NodeRef> args) {
+  NodeRef VisitExpr_(const BoolLitNode* bool_lit, tvm::Array<NodeRef> args) override {
     if (visit_bool_lit != nullptr) {
       return visit_bool_lit(bool_lit->value, args);
     } else {
@@ -86,7 +86,7 @@ class FunctorNode
     }
   }
 
-  NodeRef VisitExpr_(const IntLitNode* int_lit, tvm::Array<NodeRef> args) {
+  NodeRef VisitExpr_(const IntLitNode* int_lit, tvm::Array<NodeRef> args) override {
     if (visit_int_lit != nullptr) {
       return visit_int_lit(int_lit->value, args);
     } else {
@@ -95,7 +95,7 @@ class FunctorNode
   }
 
   NodeRef VisitExpr_(const TensorLitNode* tensor_lit,
-                     tvm::Array<NodeRef> args) {
+                     tvm::Array<NodeRef> args) override {
     if (visit_tensor_lit != nullptr) {
       return visit_tensor_lit(tensor_lit->data, args);
     } else {
@@ -104,7 +104,7 @@ class FunctorNode
   }
 
   NodeRef VisitExpr_(const ProductLitNode* product_lit,
-                     tvm::Array<NodeRef> args) {
+                     tvm::Array<NodeRef> args) override {
     if (visit_product_lit != nullptr) {
       return visit_product_lit(product_lit->fields, args);
     } else {
@@ -112,7 +112,7 @@ class FunctorNode
     }
   }
 
-  NodeRef VisitExpr_(const CastNode* cast, tvm::Array<NodeRef> args) {
+  NodeRef VisitExpr_(const CastNode* cast, tvm::Array<NodeRef> args) override {
     if (visit_cast != nullptr) {
       return visit_cast(cast->target, cast->node, args);
     } else {
@@ -120,7 +120,7 @@ class FunctorNode
     }
   }
 
-  NodeRef VisitExpr_(const ParamNode* param, tvm::Array<NodeRef> args) {
+  NodeRef VisitExpr_(const ParamNode* param, tvm::Array<NodeRef> args) override {
     if (visit_param != nullptr) {
       return visit_param(param->id, param->type, args);
     } else {
@@ -128,7 +128,7 @@ class FunctorNode
     }
   }
 
-  NodeRef VisitExpr_(const FunctionNode* fn, tvm::Array<NodeRef> args) {
+  NodeRef VisitExpr_(const FunctionNode* fn, tvm::Array<NodeRef> args) override {
     if (visit_function != nullptr) {
       return visit_function(fn->params, fn->body, args);
     } else {
@@ -136,7 +136,7 @@ class FunctorNode
     }
   }
 
-  NodeRef VisitExpr_(const CallNode* call, tvm::Array<NodeRef> args) {
+  NodeRef VisitExpr_(const CallNode* call, tvm::Array<NodeRef> args) override {
     if (visit_call != nullptr) {
       return visit_call(call->fn, call->args, args);
     } else {
@@ -144,7 +144,7 @@ class FunctorNode
     }
   }
 
-  NodeRef VisitExpr_(const DebugNode* debug, tvm::Array<NodeRef> args) {
+  NodeRef VisitExpr_(const DebugNode* debug, tvm::Array<NodeRef> args) override {
     if (visit_debug != nullptr) {
       return visit_debug(debug->node, args);
     } else {
@@ -152,7 +152,7 @@ class FunctorNode
     }
   }
 
-  NodeRef VisitExpr_(const UnaryOpNode* uop, tvm::Array<NodeRef> args) {
+  NodeRef VisitExpr_(const UnaryOpNode* uop, tvm::Array<NodeRef> args) override {
     if (visit_unary_op != nullptr) {
       return visit_unary_op(static_cast<int>(uop->op), uop->node, args);
     } else {
@@ -160,7 +160,7 @@ class FunctorNode
     }
   }
 
-  NodeRef VisitExpr_(const BinaryOpNode* bop, tvm::Array<NodeRef> args) {
+  NodeRef VisitExpr_(const BinaryOpNode* bop, tvm::Array<NodeRef> args) override {
     if (visit_binary_op != nullptr) {
       return visit_binary_op(static_cast<int>(bop->op), bop->left, bop->right,
                              args);
@@ -169,7 +169,7 @@ class FunctorNode
     }
   }
 
-  NodeRef VisitExpr_(const AssignmentNode* bop, tvm::Array<NodeRef> args) {
+  NodeRef VisitExpr_(const AssignmentNode* bop, tvm::Array<NodeRef> args) override {
     throw "foo";
     // if (visit_assignment != nullptr) {
     //   return visit_assignment(intrinsic->name, args);
@@ -178,7 +178,7 @@ class FunctorNode
     // }
   }
 
-  NodeRef VisitExpr_(const ReverseNode* rev, tvm::Array<NodeRef> args) {
+  NodeRef VisitExpr_(const ReverseNode* rev, tvm::Array<NodeRef> args) override {
     if (visit_reverse != nullptr) {
       return visit_reverse(rev->node, args);
     } else {
@@ -186,7 +186,7 @@ class FunctorNode
     }
   }
 
-  NodeRef VisitExpr_(const AccumulateNode* acc, tvm::Array<NodeRef> args) {
+  NodeRef VisitExpr_(const AccumulateNode* acc, tvm::Array<NodeRef> args) override {
     if (visit_accumulate != nullptr) {
       return visit_accumulate(acc->update_binders, acc->value, args);
     } else {
@@ -194,7 +194,7 @@ class FunctorNode
     }
   }
 
-  NodeRef VisitExpr_(const ZeroNode* zero, tvm::Array<NodeRef> args) {
+  NodeRef VisitExpr_(const ZeroNode* zero, tvm::Array<NodeRef> args) override {
     if (visit_zero != nullptr) {
       return visit_zero(zero->type, args);
     } else {