Do not assert at this location. It is possible that the assertion triggers but pytype is indeed looking at a ParamSpec being passed in.

PiperOrigin-RevId: 754605988

Author: h-joo

pytype/matcher.py

@@ -1199,8 +1199,6 @@ def _match_subst_against_subst(
                 old_subst.copy(t=b1.AssignToNewVariable(self._node)),
             )
           else:
-            # If t isn't a TypeVar here it should be a ParamSpec
-            assert t in self._paramspecs
             new_var = self.ctx.program.NewVariable()
             new_var.PasteBindingWithNewData(
                 b2, self.ctx.convert.get_maybe_abstract_instance(b2.data)

pytype/tests/test_paramspec.py

@@ -611,6 +611,25 @@ def f(x: int, y) -> Any: ...
       """,
       )
 
+  def test_paramspec_in_callable_as_param_not_fail(self):
+    self.Check("""
+    from typing import ParamSpec, Callable
+
+    _P = ParamSpec("_P")
+    LogTextFn = Callable[_P, None]
+
+    class ModelHandlerInterface:
+      def __init__(self, log_text: LogTextFn, log_code: LogTextFn):
+        pass
+
+    class GeminiModelHandler(ModelHandlerInterface):
+      def __init__(self, log_text: LogTextFn, log_code: LogTextFn):
+        super().__init__(
+            log_text,
+            log_code,
+        )
+    """)
+
 
 class ContextlibTest(test_base.BaseTest):
   """Test some more complex uses of contextlib."""