fix type inference for C true division

Cython/Compiler/ExprNodes.py

@@ -9780,11 +9780,20 @@ class DivNode(NumBinopNode):
         except Exception, e:
             self.compile_time_value_error(e)
 
-    def analyse_operation(self, env):
+    def _check_truedivision(self, env):
         if self.cdivision or env.directives['cdivision']:
             self.ctruedivision = False
         else:
             self.ctruedivision = self.truedivision
+
+    def infer_type(self, env):
+        self._check_truedivision(env)
+        return self.result_type(
+            self.operand1.infer_type(env),
+            self.operand2.infer_type(env))
+
+    def analyse_operation(self, env):
+        self._check_truedivision(env)
         NumBinopNode.analyse_operation(self, env)
         if self.is_cpp_operation():
             self.cdivision = True

tests/run/future_division.pyx

 from __future__ import division
 
+cimport cython
+
 def doit(x,y):
     """
     >>> doit(1,2)
@@ -81,3 +83,15 @@ def float_mix_rev(float a):
     (0.25, 0.0, 1.25, 1.0, 1.25, 1.0)
     """
     return 1/a, 1//a, 5.0/a, 5.0//a, 5/a, 5//a
+
+
+def infer_division_type():
+    """
+    >>> v = infer_division_type()
+    double
+    >>> v
+    8333333.25
+    """
+    v = (10000**2 - 1) / 12
+    print(cython.typeof(v))
+    return v