diff --git a/crates/aiken-lang/src/tipo.rs b/crates/aiken-lang/src/tipo.rs
index fc3e2e0c..f8b1e6f7 100644
--- a/crates/aiken-lang/src/tipo.rs
+++ b/crates/aiken-lang/src/tipo.rs
@@ -719,7 +719,14 @@ pub fn get_arg_type_name(tipo: &Type) -> String {
             let inner_args = elems.iter().map(|arg| get_arg_type_name(arg)).collect_vec();
             inner_args.join("_")
         }
-        _ => unreachable!(),
+        Type::Pair { fst, snd, .. } => {
+            let inner_args = [fst, snd]
+                .iter()
+                .map(|arg| get_arg_type_name(arg))
+                .collect_vec();
+            inner_args.join("_")
+        }
+        _ => unreachable!("WTF {:#?}", tipo),
     }
 }
 
diff --git a/examples/acceptance_tests/119/aiken.toml b/examples/acceptance_tests/119/aiken.toml
new file mode 100644
index 00000000..ccab61e4
--- /dev/null
+++ b/examples/acceptance_tests/119/aiken.toml
@@ -0,0 +1,19 @@
+name = "aiken-lang/104"
+version = "0.0.0"
+license = "Apache-2.0"
+description = "Aiken contracts for project 'aiken-lang/104'"
+
+[repository]
+user = "aiken-lang"
+project = "104"
+platform = "github"
+
+[[dependencies]]
+name = "aiken-lang/stdlib"
+version = "main"
+source = "github"
+
+[[dependencies]]
+name = "aiken-lang/fuzz"
+version = "main"
+source = "github"
diff --git a/examples/acceptance_tests/119/validators/tests.ak b/examples/acceptance_tests/119/validators/tests.ak
new file mode 100644
index 00000000..b19ddee9
--- /dev/null
+++ b/examples/acceptance_tests/119/validators/tests.ak
@@ -0,0 +1,12 @@
+pub type Thing =
+  Option<Pairs<ByteArray, Pairs<ByteArray, Int>>>
+
+validator foo_3 {
+  mint(redeemer: Thing, _policy_, _tx) {
+    redeemer == redeemer
+  }
+
+  else(_) {
+    fail
+  }
+}