``assignment-from-no-return`` is not emitted for coroutines.

The reason for that is that the function calls actually are returning
something, a future object that needs to be consumed through the event loop,
so emitting this check for coroutines is wrong.

Close #1715

5 files changed, 35 insertions, 1 deletions

diff --git a/ChangeLog b/ChangeLog
index 26f534b69..2010ca015 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -7,6 +7,9 @@ What's New in Pylint 2.2?
 
 Release date: TBA
 
+   * ``assignment-from-no-return`` is not emitted for coroutines.
+
+     Close #1715
 
    * Report format string type mismatches.
 
diff --git a/pylint/checkers/typecheck.py b/pylint/checkers/typecheck.py
index 2bb224d2f..fff87753b 100644
--- a/pylint/checkers/typecheck.py
+++ b/pylint/checkers/typecheck.py
@@ -830,7 +830,8 @@ accessed. Python regular expressions are accepted.'}
                 and not function_node.decorators):
             return
         if (function_node.is_generator()
-                or function_node.is_abstract(pass_is_abstract=False)):
+                or function_node.is_abstract(pass_is_abstract=False)
+                or isinstance(function_node, astroid.AsyncFunctionDef)):
             return
         returns = list(function_node.nodes_of_class(astroid.Return,
                                                     skip_klass=astroid.FunctionDef))
diff --git a/pylint/test/functional/assignment_from_no_return_py3.py b/pylint/test/functional/assignment_from_no_return_py3.py
new file mode 100644
index 000000000..2339706ce
--- /dev/null
+++ b/pylint/test/functional/assignment_from_no_return_py3.py
@@ -0,0 +1,28 @@
+# pylint: disable=missing-docstring
+
+import asyncio
+
+
+async def bla1():
+    await asyncio.sleep(1)
+
+
+async def bla2():
+    await asyncio.sleep(2)
+
+
+async def combining_coroutine1():
+    await bla1()
+    await bla2()
+
+
+async def combining_coroutine2():
+    future1 = bla1()
+    future2 = bla2()
+    await asyncio.gather(future1, future2)
+
+
+def do_stuff():
+    loop = asyncio.get_event_loop()
+    loop.run_until_complete(combining_coroutine1())
+    loop.run_until_complete(combining_coroutine2())
diff --git a/pylint/test/functional/assignment_from_no_return_py3.rc b/pylint/test/functional/assignment_from_no_return_py3.rc
new file mode 100644
index 000000000..1450ccc64
--- /dev/null
+++ b/pylint/test/functional/assignment_from_no_return_py3.rc
@@ -0,0 +1,2 @@
+[testoptions]
+min_pyver=3.6
\ No newline at end of file
diff --git a/pylint/test/functional/assignment_from_no_return_py3.txt b/pylint/test/functional/assignment_from_no_return_py3.txt
new file mode 100644
index 000000000..e69de29bb
--- /dev/null
+++ b/pylint/test/functional/assignment_from_no_return_py3.txt