fixing more pair issues

crates/aiken-lang/src/ast.rs

@@ -342,6 +342,19 @@ impl TypedDataType {
         }
     }
 
+    pub fn pair(fst_tipo: Rc<Type>, snd_tipo: Rc<Type>) -> Self {
+        DataType {
+            constructors: vec![],
+            doc: None,
+            location: Span::empty(),
+            name: "Pair".to_string(),
+            opaque: false,
+            parameters: vec!["a".to_string(), "b".to_string()],
+            public: true,
+            typed_parameters: vec![fst_tipo, snd_tipo],
+        }
+    }
+
     pub fn bool() -> Self {
         DataType {
             constructors: vec![

crates/aiken-lang/src/builtins.rs

@@ -1328,6 +1328,17 @@ pub fn prelude_data_types(id_gen: &IdGenerator) -> IndexMap<DataTypeKey, TypedDa
         bool_data_type,
     );
 
+    let pair_data_type =
+        TypedDataType::pair(generic_var(id_gen.next()), generic_var(id_gen.next()));
+
+    data_types.insert(
+        DataTypeKey {
+            module_name: "".to_string(),
+            defined_type: "Pair".to_string(),
+        },
+        pair_data_type,
+    );
+
     // Option
     let option_data_type = TypedDataType::option(generic_var(id_gen.next()));
     data_types.insert(

crates/aiken-lang/src/gen_uplc.rs

@@ -649,6 +649,12 @@ impl<'a> CodeGenerator<'a> {
                 } => {
                     if check_replaceable_opaque_type(&record.tipo(), &self.data_types) {
                         self.build(record, module_build_name, &[])
+                    } else if record.tipo().is_pair() {
+                        AirTree::pair_index(
+                            usize::try_from(*index).unwrap(),
+                            tipo.clone(),
+                            self.build(record, module_build_name, &[]),
+                        )
                     } else {
                         let function_name = format!("__access_index_{}", *index);
 

crates/aiken-lang/src/tipo.rs

@@ -653,6 +653,15 @@ pub fn lookup_data_type_by_tipo(
                 None
             }
         }
+        Type::Pair { .. } => {
+            let data_type_key = DataTypeKey {
+                module_name: "".to_string(),
+                defined_type: "Pair".to_string(),
+            };
+
+            data_types.get(&data_type_key).cloned().cloned()
+        }
+
         _ => None,
     }
 }