remove dead left-over code in any()/all() optimisation that issued an "unreachable code" warning

CHANGES.rst

@@ -59,6 +59,9 @@ Bugs fixed
 * Iteration over ``dict(...).items()`` failed to get optimised when dict
   arguments included keyword arguments.
 
+* Optimised `all(genexpr)`/`any(genexpr)` calls could warn about unused code.
+  This fixes ticket 876.
+
 
 0.23.5 (2016-03-26)
 ===================

Cython/Compiler/Optimize.py

@@ -1526,13 +1526,9 @@ class EarlyReplaceBuiltinCalls(Visitor.EnvTransform):
         for L in LL:
             for x in L:
                 if not p(x):
-                    _result = False
-                    break
-            else:
-                continue
-            break
+                    return False
         else:
-            _result = True
+            return True
         """
         return self._transform_any_all(node, pos_args, False)
 
@@ -1546,13 +1542,9 @@ class EarlyReplaceBuiltinCalls(Visitor.EnvTransform):
         for L in LL:
             for x in L:
                 if p(x):
-                    _result = True
-                    break
-            else:
-                continue
-            break
+                    return True
         else:
-            _result = False
+            return False
         """
         return self._transform_any_all(node, pos_args, True)
 
@@ -1583,15 +1575,6 @@ class EarlyReplaceBuiltinCalls(Visitor.EnvTransform):
                         value=ExprNodes.BoolNode(yield_expression.pos, value=is_any, constant_result=is_any))
                 )]
         )
-        loop = loop_node
-        while isinstance(loop.body, Nodes.LoopNode):
-            next_loop = loop.body
-            loop.body = Nodes.StatListNode(loop.body.pos, stats=[
-                loop.body,
-                Nodes.BreakStatNode(yield_expression.pos)
-            ])
-            next_loop.else_clause = Nodes.ContinueStatNode(yield_expression.pos)
-            loop = next_loop
         loop_node.else_clause = Nodes.ReturnStatNode(
             node.pos,
             value=ExprNodes.BoolNode(yield_expression.pos, value=not is_any, constant_result=not is_any))

tests/run/all.pyx

+# mode: run
+# tag: all, builtins, werror
 
 cdef class VerboseGetItem(object):
     cdef object sequence
@@ -53,6 +55,7 @@ def all_item(x):
     """
     return all(x)
 
+
 @cython.test_assert_path_exists(
     "//ForInStatNode",
     "//InlinedGeneratorExpressionNode"
@@ -86,6 +89,7 @@ def all_in_simple_gen(seq):
     """
     return all(x for x in seq)
 
+
 @cython.test_assert_path_exists(
     "//ForInStatNode",
     "//InlinedGeneratorExpressionNode"
@@ -122,6 +126,7 @@ def all_in_simple_gen_scope(seq):
     assert x == 'abc'
     return result
 
+
 @cython.test_assert_path_exists(
     "//ForInStatNode",
     "//InlinedGeneratorExpressionNode"
@@ -158,10 +163,12 @@ def all_in_conditional_gen(seq):
     """
     return all(x%3 for x in seq if x%2 == 1)
 
+
 mixed_ustring = u'AbcDefGhIjKlmnoP'
 lower_ustring = mixed_ustring.lower()
 upper_ustring = mixed_ustring.upper()
 
+
 @cython.test_assert_path_exists(
     '//PythonCapiCallNode',
     '//ForFromStatNode'
@@ -181,6 +188,7 @@ def all_lower_case_characters(unicode ustring):
     """
     return all(uchar.islower() for uchar in ustring)
 
+
 @cython.test_assert_path_exists(
     "//ForInStatNode",
     "//InlinedGeneratorExpressionNode",
@@ -217,6 +225,7 @@ def all_in_typed_gen(seq):
     cdef int x
     return all(x for x in seq)
 
+
 @cython.test_assert_path_exists(
     "//ForInStatNode",
     "//InlinedGeneratorExpressionNode",
@@ -268,6 +277,14 @@ def all_in_double_gen(seq):
     1
     2
     False
+    >>> all_in_double_gen([VerboseGetItem([1,1,1]),VerboseGetItem([1,0,1]),VerboseGetItem([1,1])])
+    0
+    1
+    2
+    3
+    0
+    1
+    False
     """
     cdef int x
     return all(x for L in seq for x in L)

tests/run/control_flow_loop.pyx

+# mode: run
+# tag: forin, control-flow, werror
+
+def for_in_break(LL, p=bool):
+    """
+    >>> for_in_break([[1,2,3], [4,5,6]])
+    True
+    >>> for_in_break([[1,2,3], [4,5,0]])
+    False
+    >>> for_in_break([[1,2,3], [0,4,5]])
+    False
+    >>> for_in_break([[1,2,3], [0,4,5], [6,7,8]])
+    False
+
+    >>> def collect(x):
+    ...     v.append(x)
+    ...     return x
+
+    >>> v = []
+    >>> for_in_break([[1,2,3], [4,5,6]], p=collect)
+    True
+    >>> v
+    [1, 2, 3, 4, 5, 6]
+
+    >>> v = []
+    >>> for_in_break([[1,2,3], [4,5,0]], p=collect)
+    False
+    >>> v
+    [1, 2, 3, 4, 5, 0]
+
+    >>> v = []
+    >>> for_in_break([[1,2,3], [0,4,5]], p=collect)
+    False
+    >>> v
+    [1, 2, 3, 0]
+
+    >>> v = []
+    >>> for_in_break([[1,2,3], [0,4,5], [6,7,8]], p=collect)
+    False
+    >>> v
+    [1, 2, 3, 0]
+    """
+    result = 'NOK'
+    # implements the builtin all()
+    for L in LL:
+        for x in L:
+            if not p(x):
+                result = False
+                break
+        else:
+            continue
+        break
+    else:
+        result = True
+    return result