diff --git a/src/validation/code.rs b/src/validation/code.rs
index 03a1ff75..5dc0efe8 100644
--- a/src/validation/code.rs
+++ b/src/validation/code.rs
@@ -351,3 +351,24 @@ where
     }
     Ok(())
 }
+
+/// Type signature of a block
+pub enum BlockType {
+    Empty,
+    Primitive(ValType),
+    TyIndex(usize),
+}
+
+///
+pub enum ValidationStackEntry {
+    ValType(ValType),
+    Block(BlockType),
+    Loop(BlockType),
+    If(BlockType),
+}
+
+impl From<ValType> for ValidationStackEntry {
+    fn from(val_ty: ValType) -> Self {
+        Self::ValType(val_ty)
+    }
+}