diff --git a/crates/red_knot_python_semantic/resources/mdtest/binary/integers.md b/crates/red_knot_python_semantic/resources/mdtest/binary/integers.md
index 9251e3e8d2..5c6296fb07 100644
--- a/crates/red_knot_python_semantic/resources/mdtest/binary/integers.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/binary/integers.md
@@ -21,12 +21,23 @@ reveal_type(f)  # revealed: Literal[2]
 ## Division by Zero
 
 ```py
+class MyInt(int):
+    def __truediv__(self, other):
+        return 100
+
+def returns_int() -> int:
+    return MyInt(3)
+
 # TODO: `a` should be `int` and `e` should be `float` once we support inference.
 a = 1 / 0  # error: "Cannot divide object of type `Literal[1]` by zero"
 b = 2 // 0  # error: "Cannot floor divide object of type `Literal[2]` by zero"
 c = 3 % 0  # error: "Cannot reduce object of type `Literal[3]` modulo zero"
-d = int() / 0  # error: "Cannot divide object of type `int` by zero"
-e = 1.0 / 0  # error: "Cannot divide object of type `float` by zero"
+# even `int` type could be a subclass of `int` with custom behavior; no error
+d = returns_int() / 0
+# this could be flagged as an error, if we had an ExactFloat or ExactInstance
+# type, but given only a `float` type we can't issue an error for the same
+# reason: could be a custom float subclass
+e = 1.0 / 0
 
 reveal_type(a)  # revealed: float
 reveal_type(b)  # revealed: int
diff --git a/crates/red_knot_python_semantic/src/types/infer.rs b/crates/red_knot_python_semantic/src/types/infer.rs
index e815dba0f6..02e91aa141 100644
--- a/crates/red_knot_python_semantic/src/types/infer.rs
+++ b/crates/red_knot_python_semantic/src/types/infer.rs
@@ -540,9 +540,6 @@ impl<'db> TypeInferenceBuilder<'db> {
     fn check_division_by_zero(&mut self, expr: &ast::ExprBinOp, left: Type<'db>) {
         match left {
             Type::IntLiteral(_) => {}
-            Type::Instance(cls)
-                if cls.is_known(self.db, KnownClass::Float)
-                    || cls.is_known(self.db, KnownClass::Int) => {}
             _ => return,
         };