diff --git a/mypy/fastparse.py b/mypy/fastparse.py
index 15122012a0dc..413af5a8c08f 100644
--- a/mypy/fastparse.py
+++ b/mypy/fastparse.py
@@ -928,7 +928,11 @@ def visit_Call(self, n: Call) -> CallExpr:
 
     # Num(object n) -- a number as a PyObject.
     def visit_Num(self, n: ast3.Num) -> Union[IntExpr, FloatExpr, ComplexExpr]:
-        val = n.n
+        # The n field has the type complex, but complex isn't *really*
+        # a parent of int and float, and this causes isinstance below
+        # to think that the complex branch is always picked. Avoid
+        # this by throwing away the type.
+        val = n.n  # type: object
         if isinstance(val, int):
             e = IntExpr(val)  # type: Union[IntExpr, FloatExpr, ComplexExpr]
         elif isinstance(val, float):
diff --git a/mypy/fastparse2.py b/mypy/fastparse2.py
index 876864796ebe..8100c316ea30 100644
--- a/mypy/fastparse2.py
+++ b/mypy/fastparse2.py
@@ -902,7 +902,11 @@ def visit_Call(self, n: Call) -> CallExpr:
 
     # Num(object n) -- a number as a PyObject.
     def visit_Num(self, n: ast27.Num) -> Expression:
-        value = n.n
+        # The n field has the type complex, but complex isn't *really*
+        # a parent of int and float, and this causes isinstance below
+        # to think that the complex branch is always picked. Avoid
+        # this by throwing away the type.
+        value = n.n  # type: object
         is_inverse = False
         if str(n.n).startswith('-'):  # Hackish because of complex.
             value = -n.n