err: tidy up some uses of PyErr::occurred

src/types/floatob.rs

@@ -52,11 +52,13 @@ impl<'source> FromPyObject<'source> for f64 {
     fn extract(obj: &'source PyAny) -> PyResult<Self> {
         let v = unsafe { ffi::PyFloat_AsDouble(obj.as_ptr()) };
 
-        if v == -1.0 && PyErr::occurred(obj.py()) {
-            Err(PyErr::fetch(obj.py()))
-        } else {
-            Ok(v)
+        if v == -1.0 {
+            if let Some(err) = PyErr::take(obj.py()) {
+                return Err(err);
+            }
         }
+
+        Ok(v)
     }
 }
 

src/types/iterator.rs

@@ -58,13 +58,7 @@ impl<'p> Iterator for &'p PyIterator {
 
         match unsafe { py.from_owned_ptr_or_opt(ffi::PyIter_Next(self.0.as_ptr())) } {
             Some(obj) => Some(Ok(obj)),
-            None => {
-                if PyErr::occurred(py) {
-                    Some(Err(PyErr::fetch(py)))
-                } else {
-                    None
-                }
-            }
+            None => PyErr::take(py).map(Err),
         }
     }
 }

src/types/num.rs

@@ -10,18 +10,6 @@ use std::convert::TryFrom;
 use std::i64;
 use std::os::raw::c_long;
 
-fn err_if_invalid_value<T: PartialEq>(
-    py: Python,
-    invalid_value: T,
-    actual_value: T,
-) -> PyResult<T> {
-    if actual_value == invalid_value && PyErr::occurred(py) {
-        Err(PyErr::fetch(py))
-    } else {
-        Ok(actual_value)
-    }
-}
-
 macro_rules! int_fits_larger_int {
     ($rust_type:ty, $larger_type:ty) => {
         impl ToPyObject for $rust_type {
@@ -273,6 +261,20 @@ mod slow_128bit_int_conversion {
     int_convert_128!(u128, u64);
 }
 
+fn err_if_invalid_value<T: PartialEq>(
+    py: Python,
+    invalid_value: T,
+    actual_value: T,
+) -> PyResult<T> {
+    if actual_value == invalid_value {
+        if let Some(err) = PyErr::take(py) {
+            return Err(err);
+        }
+    }
+
+    Ok(actual_value)
+}
+
 #[cfg(test)]
 mod test_128bit_intergers {
     use super::*;