diff --git a/src/tint/BUILD.gn b/src/tint/BUILD.gn
index cb735b86ed..d74eaac120 100644
--- a/src/tint/BUILD.gn
+++ b/src/tint/BUILD.gn
@@ -367,6 +367,7 @@ libtint_source_set("libtint_core_all_src") {
     "clone_context.cc",
     "clone_context.h",
     "constant/constant.h",
+    "constant/node.h",
     "debug.cc",
     "debug.h",
     "demangler.cc",
@@ -760,6 +761,8 @@ libtint_source_set("libtint_constant_src") {
   sources = [
     "constant/constant.cc",
     "constant/constant.h",
+    "constant/node.cc",
+    "constant/node.h",
   ]
   public_deps = [ ":libtint_core_all_src" ]
 }
diff --git a/src/tint/CMakeLists.txt b/src/tint/CMakeLists.txt
index 3148070991..d32da21856 100644
--- a/src/tint/CMakeLists.txt
+++ b/src/tint/CMakeLists.txt
@@ -256,6 +256,8 @@ list(APPEND TINT_LIB_SRCS
   clone_context.h
   constant/constant.cc
   constant/constant.h
+  constant/node.cc
+  constant/node.h
   demangler.cc
   demangler.h
   inspector/entry_point.cc
diff --git a/src/tint/constant/constant.cc b/src/tint/constant/constant.cc
index 4dba6ab830..a5b0caf16a 100644
--- a/src/tint/constant/constant.cc
+++ b/src/tint/constant/constant.cc
@@ -14,6 +14,8 @@
 
 #include "src/tint/constant/constant.h"
 
+TINT_INSTANTIATE_TYPEINFO(tint::constant::Constant);
+
 namespace tint::constant {
 
 Constant::Constant() = default;
diff --git a/src/tint/constant/constant.h b/src/tint/constant/constant.h
index 62cc3c6cca..bd60f49a01 100644
--- a/src/tint/constant/constant.h
+++ b/src/tint/constant/constant.h
@@ -17,19 +17,21 @@
 
 #include <variant>
 
+#include "src/tint/castable.h"
+#include "src/tint/constant/node.h"
 #include "src/tint/number.h"
 #include "src/tint/type/type.h"
 
 namespace tint::constant {
 
 /// Constant is the interface to a compile-time evaluated expression value.
-class Constant {
+class Constant : public Castable<Constant, Node> {
   public:
     /// Constructor
     Constant();
 
     /// Destructor
-    virtual ~Constant();
+    ~Constant() override;
 
     /// @returns the type of the constant
     virtual const type::Type* Type() const = 0;
diff --git a/src/tint/constant/node.cc b/src/tint/constant/node.cc
new file mode 100644
index 0000000000..8f18ba6195
--- /dev/null
+++ b/src/tint/constant/node.cc
@@ -0,0 +1,27 @@
+// Copyright 2022 The Tint Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "src/tint/constant/node.h"
+
+TINT_INSTANTIATE_TYPEINFO(tint::constant::Node);
+
+namespace tint::constant {
+
+Node::Node() = default;
+
+Node::Node(const Node&) = default;
+
+Node::~Node() = default;
+
+}  // namespace tint::constant
diff --git a/src/tint/constant/node.h b/src/tint/constant/node.h
new file mode 100644
index 0000000000..41d00e09e7
--- /dev/null
+++ b/src/tint/constant/node.h
@@ -0,0 +1,37 @@
+// Copyright 2022 The Tint Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef SRC_TINT_CONSTANT_NODE_H_
+#define SRC_TINT_CONSTANT_NODE_H_
+
+#include "src/tint/castable.h"
+
+namespace tint::constant {
+
+/// Node is the base class for all constant nodes
+class Node : public Castable<Node> {
+  public:
+    /// Constructor
+    Node();
+
+    /// Copy constructor
+    Node(const Node&);
+
+    /// Destructor
+    ~Node() override;
+};
+
+}  // namespace tint::constant
+
+#endif  // SRC_TINT_CONSTANT_NODE_H_
diff --git a/src/tint/resolver/const_eval.cc b/src/tint/resolver/const_eval.cc
index 558564388b..115082c2f5 100644
--- a/src/tint/resolver/const_eval.cc
+++ b/src/tint/resolver/const_eval.cc
@@ -23,6 +23,7 @@
 #include <utility>
 
 #include "src/tint/constant/constant.h"
+#include "src/tint/number.h"
 #include "src/tint/program_builder.h"
 #include "src/tint/sem/member_accessor_expression.h"
 #include "src/tint/sem/type_initializer.h"
@@ -248,7 +249,11 @@ std::make_unsigned_t<T> CountTrailingBits(T e, T bit_value_to_count) {
 
 /// ImplConstant inherits from constant::Constant to add an private implementation method for
 /// conversion.
-struct ImplConstant : public constant::Constant {
+class ImplConstant : public Castable<ImplConstant, constant::Constant> {
+  public:
+    ImplConstant() = default;
+    ~ImplConstant() override = default;
+
     /// Convert attempts to convert the constant value to the given type. On error, Convert()
     /// creates a new diagnostic message and returns a Failure.
     virtual utils::Result<const ImplConstant*> Convert(ProgramBuilder& builder,
@@ -267,7 +272,8 @@ const ImplConstant* CreateComposite(ProgramBuilder& builder,
 /// Element holds a single scalar or abstract-numeric value.
 /// Element implements the Constant interface.
 template <typename T>
-struct Element : ImplConstant {
+class Element : public Castable<Element<T>, ImplConstant> {
+  public:
     static_assert(!std::is_same_v<UnwrapNumber<T>, T> || std::is_same_v<T, bool>,
                   "T must be a Number or bool");
 
@@ -355,7 +361,8 @@ struct Element : ImplConstant {
 /// Splat is used for zero-initializers, 'splat' initializers, or initializers where each element is
 /// identical. Splat may be of a vector, matrix or array type.
 /// Splat implements the Constant interface.
-struct Splat : ImplConstant {
+class Splat : public Castable<Splat, ImplConstant> {
+  public:
     Splat(const type::Type* t, const constant::Constant* e, size_t n) : type(t), el(e), count(n) {}
     ~Splat() override = default;
     const type::Type* Type() const override { return type; }
@@ -393,7 +400,8 @@ struct Splat : ImplConstant {
 /// If each element is the same type and value, then a Splat would be a more efficient constant
 /// implementation. Use CreateComposite() to create the appropriate Constant type.
 /// Composite implements the Constant interface.
-struct Composite : ImplConstant {
+class Composite : public Castable<Composite, ImplConstant> {
+  public:
     Composite(const type::Type* t,
               utils::VectorRef<const constant::Constant*> els,
               bool all_0,
@@ -460,6 +468,23 @@ struct Composite : ImplConstant {
     const size_t hash;
 };
 
+}  // namespace
+}  // namespace tint::resolver
+
+TINT_INSTANTIATE_TYPEINFO(tint::resolver::ImplConstant);
+TINT_INSTANTIATE_TYPEINFO(tint::resolver::Element<tint::AInt>);
+TINT_INSTANTIATE_TYPEINFO(tint::resolver::Element<tint::AFloat>);
+TINT_INSTANTIATE_TYPEINFO(tint::resolver::Element<tint::i32>);
+TINT_INSTANTIATE_TYPEINFO(tint::resolver::Element<tint::u32>);
+TINT_INSTANTIATE_TYPEINFO(tint::resolver::Element<tint::f16>);
+TINT_INSTANTIATE_TYPEINFO(tint::resolver::Element<tint::f32>);
+TINT_INSTANTIATE_TYPEINFO(tint::resolver::Element<bool>);
+TINT_INSTANTIATE_TYPEINFO(tint::resolver::Splat);
+TINT_INSTANTIATE_TYPEINFO(tint::resolver::Composite);
+
+namespace tint::resolver {
+namespace {
+
 /// CreateElement constructs and returns an Element<T>.
 template <typename T>
 ImplResult CreateElement(ProgramBuilder& builder, const Source& source, const type::Type* t, T v) {