Revert "fixing more pair issues"

This reverts commit b76cc7436294cd73e7bbaf656c76a8f8b0ad56a9.

crates/aiken-lang/src/ast.rs

@@ -342,19 +342,6 @@ 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

@@ -1328,17 +1328,6 @@ 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

@@ -649,12 +649,6 @@ 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

@@ -653,15 +653,6 @@ 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,
     }
 }