diff --git a/src/basedtyping/__init__.py b/src/basedtyping/__init__.py
index 4c58362..069819e 100644
--- a/src/basedtyping/__init__.py
+++ b/src/basedtyping/__init__.py
@@ -624,8 +624,10 @@ def __init__(self, arg: str, *, is_argument=True, module: object=None, is_class=
         try:
             code = compile(arg_to_compile, "<string>", "eval")
         except SyntaxError:
+            if arg.startswith("def"):
+                arg = arg[3:].lstrip()
             code = compile(
-                ast.parse(arg.removeprefix("def").lstrip(), mode="func_type"),
+                ast.parse(arg, mode="func_type"),
                 "<string>",
                 "func_type",
                 ast.PyCF_ONLY_AST,
@@ -641,8 +643,10 @@ def __init__(self, arg: str, *, is_argument=True, module: object=None, is_class=
 
     def _evaluate(
         self,
-        globalns: dict[str, Any] | None,
-        localns: dict[str, Any] | None,
+        globalns: typing.Mapping[str, object] | None,
+        localns: typing.Mapping[str, object] | None,
+        type_params: object = None,
+        *,
         recursive_guard: frozenset[str] | None = None,
     ) -> Any:
         return transformer._eval_direct(self, globalns, localns)
diff --git a/src/basedtyping/transformer.py b/src/basedtyping/transformer.py
index 1abc859..62dea21 100644
--- a/src/basedtyping/transformer.py
+++ b/src/basedtyping/transformer.py
@@ -8,12 +8,10 @@
 import uuid
 from contextlib import contextmanager
 from enum import Enum
-from typing import Any
 
 import typing_extensions
 
 import basedtyping
-from basedtyping import ForwardRef
 
 class CringeTransformer(ast.NodeTransformer):
     """
@@ -61,7 +59,7 @@ def eval_type(
     ) -> object:
         if not isinstance(node, ast.Expression):
             node = ast.copy_location(ast.Expression(node), node)
-        ref = ForwardRef(ast.dump(node))
+        ref = typing.ForwardRef(ast.dump(node))
         if original_ref:
             for attr in ("is_argument", " is_class", "module"):
                 attr = f"__forward_{attr}__"
@@ -79,22 +77,22 @@ def eval_type(
         except TypeError as err:
             return None
 
-    def _typing(self, attr: str):
+    def _typing(self, attr: str) -> ast.Attribute:
         result = ast.Attribute(
             value=ast.Name(id=self.typing_name, ctx=ast.Load()), attr=attr, ctx=ast.Load()
         )
         return ast.fix_missing_locations(result)
 
-    def _basedtyping(self, attr: str):
+    def _basedtyping(self, attr: str) -> ast.Attribute:
         result = ast.Attribute(
             value=ast.Name(id=self.basedtyping_name, ctx=ast.Load()), attr=attr, ctx=ast.Load()
         )
         return ast.fix_missing_locations(result)
 
-    def _literal(self, value: ast.Constant | ast.Name | ast.Attribute):
+    def _literal(self, value: ast.Constant | ast.Name | ast.Attribute) -> ast.Subscript:
         return self.subscript(self._typing("Literal"), value)
 
-    def subscript(self, value, slice):
+    def subscript(self, value: ast.AST, slice: ast.AST) -> ast.Subscript:
         result = ast.Subscript(value=value, slice=ast.Index(slice), ctx=ast.Load())
         return ast.fix_missing_locations(result)
 
@@ -122,26 +120,27 @@ def visit_Subscript(self, node: ast.Subscript) -> ast.AST:
             node = self.subscript(self._typing("Callable"), node.slice)
         return node
 
-    def visit_Attribute(self, node) -> ast.Name:
+    def visit_Attribute(self, node: ast.Attribute) -> ast.AST:
         node = self.generic_visit(node)
+        assert isinstance(node, ast.expr)
         node_type = self.eval_type(node)
         if isinstance(node_type, Enum):
-            node = self._literal(node)
+            assert isinstance(node, (ast.Name, ast.Attribute))
+            return self._literal(node)
         return node
 
-    def visit_Name(self, node) -> ast.Name:
-        node = self.generic_visit(node)
+    def visit_Name(self, node: ast.Name) -> ast.AST:
         name_type = self.eval_type(node)
         if isinstance(name_type, Enum):
-            node = self._literal(node)
+            return self._literal(node)
         return node
 
     def visit_Constant(self, node: ast.Constant) -> ast.AST:
-        node = self.generic_visit(node)
-        if isinstance(node.value, int) or (
-            self.string_literals and isinstance(node.value, str)
+        value = typing.cast(object, node.value)
+        if isinstance(value, int) or (
+            self.string_literals and isinstance(value, str)
         ):
-            node = self._literal(node)
+            return self._literal(node)
         return node
 
     def visit_Tuple(self, node: ast.Tuple) -> ast.AST:
@@ -152,7 +151,8 @@ def visit_Tuple(self, node: ast.Tuple) -> ast.AST:
 
     def visit_Compare(self, node: ast.Compare) -> ast.AST:
         if len(node.ops) == 1 and isinstance(node.ops[0], ast.Is):
-            node = self.subscript(self._typing("TypeIs"), self.generic_visit(node.comparators[0]))
+            result = self.subscript(self._typing("TypeIs"), self.generic_visit(node.comparators[0]))
+            return self.generic_visit(result)
         return self.generic_visit(node)
 
     def visit_IfExp(self, node: ast.IfExp) -> ast.AST:
@@ -168,6 +168,7 @@ def visit_IfExp(self, node: ast.IfExp) -> ast.AST:
 
     def visit_FunctionType(self, node: ast.FunctionType) -> ast.AST:
         node = self.generic_visit(node)
+        assert  isinstance(node, ast.FunctionType)
         return self.subscript(
             self._typing("Callable"),
             ast.Tuple([ast.List(node.argtypes, ctx=ast.Load()), node.returns], ctx=ast.Load()),