1 files changed, 141 insertions, 0 deletions
diff --git a/pylint/test/functional/iterable_context.py b/pylint/test/functional/iterable_context.py
new file mode 100644
index 0000000..8dfcbbe
--- /dev/null
+++ b/pylint/test/functional/iterable_context.py
@@ -0,0 +1,141 @@
+"""
+Checks that primitive values are not used in an
+iterating/mapping context.
+"""
+# pylint: disable=missing-docstring,invalid-name,too-few-public-methods,no-init,no-self-use,import-error,unused-argument,bad-mcs-method-argument
+from __future__ import print_function
+
+# primitives
+numbers = [1, 2, 3]
+
+for i in numbers:
+    pass
+
+for i in iter(numbers):
+    pass
+
+for i in "123":
+    pass
+
+for i in u"123":
+    pass
+
+for i in b"123":
+    pass
+
+for i in bytearray(b"123"):
+    pass
+
+for i in set(numbers):
+    pass
+
+for i in frozenset(numbers):
+    pass
+
+for i in dict(a=1, b=2):
+    pass
+
+# comprehensions
+for i in [x for x in range(10)]:
+    pass
+
+for i in {x for x in range(1, 100, 2)}:
+    pass
+
+for i in {x: 10 - x for x in range(10)}:
+    pass
+
+# generators
+def powers_of_two():
+    k = 0
+    while k < 10:
+        yield 2 ** k
+        k += 1
+
+for i in powers_of_two():
+    pass
+
+for i in powers_of_two:  # [not-an-iterable]
+    pass
+
+# check for custom iterators
+class A(object):
+    pass
+
+class B(object):
+    def __iter__(self):
+        return self
+
+    def __next__(self):
+        return 1
+
+    def next(self):
+        return 1
+
+class C(object):
+    "old-style iterator"
+    def __getitem__(self, k):
+        if k > 10:
+            raise IndexError
+        return k + 1
+
+    def __len__(self):
+        return 10
+
+for i in C():
+    print(i)
+
+
+def test(*args):
+    print(args)
+
+
+test(*A())  # [not-an-iterable]
+test(*B())
+test(*B)  # [not-an-iterable]
+for i in A():  # [not-an-iterable]
+    pass
+for i in B():
+    pass
+for i in B:  # [not-an-iterable]
+    pass
+
+for i in range:  # [not-an-iterable]
+    pass
+
+# check that primitive non-iterable types are catched
+for i in True:  # [not-an-iterable]
+    pass
+
+for i in None:  # [not-an-iterable]
+    pass
+
+for i in 8.5:  # [not-an-iterable]
+    pass
+
+for i in 10:  # [not-an-iterable]
+    pass
+
+
+# skip uninferable instances
+from some_missing_module import Iterable
+
+class MyClass(Iterable):
+    pass
+
+m = MyClass()
+for i in m:
+    print(i)
+
+# skip checks if statement is inside mixin class
+class ManagedAccessViewMixin(object):
+    access_requirements = None
+
+    def get_access_requirements(self):
+        return self.access_requirements
+
+    def dispatch(self, *_args, **_kwargs):
+        klasses = self.get_access_requirements()
+
+        for requirement in klasses:
+            print(requirement)