Fix an issue where class methods would not be defined yet when accessing

opshin/type_inference.py

@@ -638,7 +638,7 @@ def type_from_annotation(self, ann: expr):
 
     def visit_sequence(self, node_seq: typing.List[stmt]) -> plt.AST:
         additional_functions = []
-        for n in node_seq:
+        for i, n in enumerate(node_seq):
             if not isinstance(n, ast.ClassDef):
                 continue
             non_method_attributes = []
@@ -675,12 +675,11 @@ def visit_sequence(self, node_seq: typing.List[stmt]) -> plt.AST:
                 custom_fix_missing_locations(ann, attribute.args.args[0])
                 ann.orig_id = attribute.args.args[0].orig_arg
                 func.args.args[0].annotation = ann
-                additional_functions.append(func)
+                additional_functions.append((i, func))
             n.body = non_method_attributes
         if additional_functions:
-            last = node_seq.pop()
-            node_seq.extend(additional_functions)
-            node_seq.append(last)
+            for i, f in reversed(additional_functions):
+                node_seq.insert(i + 1, f)
 
         stmts = []
         prevtyps = {}

tests/test_class_methods.py

@@ -568,3 +568,27 @@ def validator(a: int, b: int, c:int) -> bool:
 """
         ret = eval_uplc_value(source_code, 1, 2, 3)
         self.assertEqual(ret, True)
+
+    @given(x=st.integers(), y=st.integers())
+    @example(x=0, y=0)
+    def test_method_back_ref(self, x: int, y: int):
+        source_code = """
+from typing import Self
+from opshin.prelude import *
+@dataclass()
+class Foo(PlutusData):
+    a: int
+
+    def __ge__(self, other: Self) -> bool:
+        return self.a >= other.a
+
+def compare_foos(foo1: Foo, foo2: Foo) -> bool:
+    return foo1 >= foo2
+
+def validator(a: int, b: int) -> bool:
+    foo1 = Foo(a)
+    foo2 = Foo(b)
+    return compare_foos(foo1, foo2)
+"""
+        ret = eval_uplc_value(source_code, x, y)
+        self.assertEqual(ret, x >= y)