Disable renaming of type parameters

It's not practical to rename type parameters safely until we can properly model annotation namespaces.

src/python_minifier/__init__.py

@@ -166,6 +166,14 @@ def minify(
         rename_globals = False
         rename_locals = False
 
+    if preserve_locals is None:
+        preserve_locals = []
+    if preserve_globals is None:
+        preserve_globals = []
+
+    preserve_locals.extend(module.preserved)
+    preserve_globals.extend(module.preserved)
+
     allow_rename_locals(module, rename_locals, preserve_locals)
     allow_rename_globals(module, rename_globals, preserve_globals)
 

src/python_minifier/rename/bind_names.py

@@ -15,6 +15,7 @@ class NameBinder(NodeVisitor):
     def __call__(self, module):
         assert isinstance(module, ast.Module)
         module.tainted = False
+        module.preserved = set()
         return self.visit(module)
 
     def get_binding(self, name, namespace):
@@ -165,14 +166,20 @@ def visit_TypeVar(self, node):
         if node.name not in node.namespace.nonlocal_names:
             self.get_binding(node.name, node.namespace).add_reference(node)
 
+        get_global_namespace(node.namespace).preserved.add(node.name)
+
     def visit_TypeVarTuple(self, node):
         if node.name not in node.namespace.nonlocal_names:
             self.get_binding(node.name, node.namespace).add_reference(node)
 
+        get_global_namespace(node.namespace).preserved.add(node.name)
+
     def visit_ParamSpec(self, node):
         if node.name not in node.namespace.nonlocal_names:
             self.get_binding(node.name, node.namespace).add_reference(node)
 
+        get_global_namespace(node.namespace).preserved.add(node.name)
+
 def bind_names(module):
     """
     Bind names to their local namespace