diff --git a/src/protocol/eval/value.rs b/src/protocol/eval/value.rs
index 9d9d1736c3a51487dd77f3215782dd1149e0671b..d8bf773b7bc74426a37fa54ad573c4c0d6d8bd00 100644
--- a/src/protocol/eval/value.rs
+++ b/src/protocol/eval/value.rs
@@ -65,39 +65,26 @@ pub enum Value {
     Struct(HeapPos),
 }
 
-macro_rules! impl_union_unpack_as_value {
-    ($func_name:ident, $variant_name:path, $return_type:ty) => {
-        impl Value {
-            pub(crate) fn $func_name(&self) -> $return_type {
-                match self {
-                    $variant_name(v) => *v,
-                    _ => panic!(concat!("called ", stringify!($func_name()), " on {:?}"), self),
-                }
-            }
-        }
-    }
-}
-
-impl_union_unpack_as_value!(as_stack_boundary, Value::PrevStackBoundary, isize);
-impl_union_unpack_as_value!(as_ref,     Value::Ref,     ValueId);
-impl_union_unpack_as_value!(as_input,   Value::Input,   PortId);
-impl_union_unpack_as_value!(as_output,  Value::Output,  PortId);
-impl_union_unpack_as_value!(as_message, Value::Message, HeapPos);
-impl_union_unpack_as_value!(as_bool,    Value::Bool,    bool);
-impl_union_unpack_as_value!(as_char,    Value::Char,    char);
-impl_union_unpack_as_value!(as_string,  Value::String,  HeapPos);
-impl_union_unpack_as_value!(as_uint8,   Value::UInt8,   u8);
-impl_union_unpack_as_value!(as_uint16,  Value::UInt16,  u16);
-impl_union_unpack_as_value!(as_uint32,  Value::UInt32,  u32);
-impl_union_unpack_as_value!(as_uint64,  Value::UInt64,  u64);
-impl_union_unpack_as_value!(as_sint8,   Value::SInt8,   i8);
-impl_union_unpack_as_value!(as_sint16,  Value::SInt16,  i16);
-impl_union_unpack_as_value!(as_sint32,  Value::SInt32,  i32);
-impl_union_unpack_as_value!(as_sint64,  Value::SInt64,  i64);
-impl_union_unpack_as_value!(as_array,   Value::Array,   HeapPos);
-impl_union_unpack_as_value!(as_tuple,   Value::Tuple,   HeapPos);
-impl_union_unpack_as_value!(as_enum,    Value::Enum,    i64);
-impl_union_unpack_as_value!(as_struct,  Value::Struct,  HeapPos);
+union_cast_to_value_method_impl!(as_stack_boundary, isize, Value::PrevStackBoundary);
+union_cast_to_value_method_impl!(as_ref, ValueId, Value::Ref);
+union_cast_to_value_method_impl!(as_input, PortId, Value::Input);
+union_cast_to_value_method_impl!(as_output, PortId, Value::Output);
+union_cast_to_value_method_impl!(as_message, HeapPos, Value::Message);
+union_cast_to_value_method_impl!(as_bool, bool, Value::Bool);
+union_cast_to_value_method_impl!(as_char, char, Value::Char);
+union_cast_to_value_method_impl!(as_string, HeapPos, Value::String);
+union_cast_to_value_method_impl!(as_uint8, u8, Value::UInt8);
+union_cast_to_value_method_impl!(as_uint16, u16, Value::UInt16);
+union_cast_to_value_method_impl!(as_uint32, u32, Value::UInt32);
+union_cast_to_value_method_impl!(as_uint64, u64, Value::UInt64);
+union_cast_to_value_method_impl!(as_sint8, i8, Value::SInt8);
+union_cast_to_value_method_impl!(as_sint16, i16, Value::SInt16);
+union_cast_to_value_method_impl!(as_sint32, i32, Value::SInt32);
+union_cast_to_value_method_impl!(as_sint64, i64, Value::SInt64);
+union_cast_to_value_method_impl!(as_array, HeapPos, Value::Array);
+union_cast_to_value_method_impl!(as_tuple, HeapPos, Value::Tuple);
+union_cast_to_value_method_impl!(as_enum, i64, Value::Enum);
+union_cast_to_value_method_impl!(as_struct, HeapPos, Value::Struct);
 
 impl Value {
     pub(crate) fn as_union(&self) -> (i64, HeapPos) {
@@ -107,6 +94,14 @@ impl Value {
         }
     }
 
+    pub(crate) fn as_port_id(&self) -> PortId {
+        match self {
+            Value::Input(v) => *v,
+            Value::Output(v) => *v,
+            _ => unreachable!(),
+        }
+    }
+
     pub(crate) fn is_integer(&self) -> bool {
         match self {
             Value::UInt8(_) | Value::UInt16(_) | Value::UInt32(_) | Value::UInt64(_) |