diff --git a/mlir/include/mlir/IR/Attributes.h b/mlir/include/mlir/IR/Attributes.h
index ac5dd49f0ba39..f433363e5dede 100644
--- a/mlir/include/mlir/IR/Attributes.h
+++ b/mlir/include/mlir/IR/Attributes.h
@@ -409,7 +409,6 @@ struct CastInfo<To, From,
     /// Return a constant true instead of a dynamic true when casting to self or
     /// up the hierarchy.
     if constexpr (std::is_base_of_v<To, From>) {
-      (void)ty;
       return true;
     } else {
       return To::classof(ty);
diff --git a/mlir/include/mlir/IR/Types.h b/mlir/include/mlir/IR/Types.h
index 832794928a441..46bb733101c12 100644
--- a/mlir/include/mlir/IR/Types.h
+++ b/mlir/include/mlir/IR/Types.h
@@ -406,7 +406,6 @@ struct CastInfo<
     /// Return a constant true instead of a dynamic true when casting to self or
     /// up the hierarchy.
     if constexpr (std::is_base_of_v<To, From>) {
-      (void)ty;
       return true;
     } else {
       return To::classof(ty);
diff --git a/mlir/include/mlir/IR/Value.h b/mlir/include/mlir/IR/Value.h
index 4e550fe3e3a60..dbcc10d4f4df8 100644
--- a/mlir/include/mlir/IR/Value.h
+++ b/mlir/include/mlir/IR/Value.h
@@ -605,7 +605,6 @@ struct CastInfo<
     /// Return a constant true instead of a dynamic true when casting to self or
     /// up the hierarchy.
     if constexpr (std::is_base_of_v<To, From>) {
-      (void)ty;
       return true;
     } else {
       return To::classof(ty);