diff --git a/test/bytecode_3.0_run/05_block_fallback.pyc b/test/bytecode_3.0_run/05_block_fallback.pyc
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diff --git a/test/bytecode_3.5_run/05_block_fallback.pyc b/test/bytecode_3.5_run/05_block_fallback.pyc
new file mode 100644
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diff --git a/test/bytecode_3.7_run/05_block_fallback.pyc b/test/bytecode_3.7_run/05_block_fallback.pyc
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diff --git a/test/simple_source/bug30/05_block_fallback.py b/test/simple_source/bug30/05_block_fallback.py
new file mode 100644
index 00000000..ed1c979c
--- /dev/null
+++ b/test/simple_source/bug30/05_block_fallback.py
@@ -0,0 +1,32 @@
+# Adapted from 3.7.6 test_contains
+# The bug was in reconstructing something equivalent to
+# "while False: yelid None" which is *needed* in __iter__().
+# Sheeh!
+
+# RUNNABLE!
+def test_block_fallback():
+    # blocking fallback with __contains__ = None
+    class ByContains(object):
+        def __contains__(self, other):
+            return False
+    c = ByContains()
+    class BlockContains(ByContains):
+        """Is not a container
+
+        This class is a perfectly good iterable (as tested by
+        list(bc)), as well as inheriting from a perfectly good
+        container, but __contains__ = None prevents the usual
+        fallback to iteration in the container protocol. That
+        is, normally, 0 in bc would fall back to the equivalent
+        of any(x==0 for x in bc), but here it's blocked from
+        doing so.
+        """
+        def __iter__(self):
+            while False:
+                yield None
+        __contains__ = None
+    bc = BlockContains()
+    assert not (0 in c)
+    assert not (0 in list(bc))
+
+test_block_fallback()
diff --git a/test/stdlib/3.7-exclude.sh b/test/stdlib/3.7-exclude.sh
index 52bff135..2b1f0c19 100644
--- a/test/stdlib/3.7-exclude.sh
+++ b/test/stdlib/3.7-exclude.sh
@@ -30,7 +30,7 @@ SKIP_TESTS=(
     [test_compileall.py]=1 # fails on its own
     [test_compile.py]=1  # Code introspects on co_consts in a non-decompilable way
     [test_concurrent_futures.py]=1 # too long
-    [test_coroutines.py]=1 # test
+    [test_coroutines.py]=1 # parse error
     [test_codecs.py]=1 # test assert failures; encoding/decoding stuff
     [test_ctypes.py]=1 # it fails on its own
     [test_curses.py]=1 # probably byte string not handled properly
diff --git a/uncompyle6/semantics/make_function3.py b/uncompyle6/semantics/make_function3.py
index 66bc6fa3..fd61e9a7 100644
--- a/uncompyle6/semantics/make_function3.py
+++ b/uncompyle6/semantics/make_function3.py
@@ -677,7 +677,7 @@ def make_function3(self, node, is_lambda, nested=1, code_node=None):
     # add in "yield" just so that the compiler will mark
     # the GENERATOR bit of the function. See for example
     # Python 3.x's test_generator.py test program.
-    if code.co_flags & CO_GENERATOR:
+    if not is_lambda code.co_flags & CO_GENERATOR:
         need_bogus_yield = True
         for token in scanner_code._tokens:
             if token in ("YIELD_VALUE", "YIELD_FROM"):
diff --git a/uncompyle6/semantics/make_function36.py b/uncompyle6/semantics/make_function36.py
index f273f265..c696a508 100644
--- a/uncompyle6/semantics/make_function36.py
+++ b/uncompyle6/semantics/make_function36.py
@@ -356,7 +356,7 @@ def make_function36(self, node, is_lambda, nested=1, code_node=None):
     # add in "yield" just so that the compiler will mark
     # the GENERATOR bit of the function. See for example
     # Python 3.x's test_connection.py and test_contexlib_async test programs.
-    if code.co_flags & (CO_GENERATOR | CO_ASYNC_GENERATOR):
+    if not is_lambda and code.co_flags & (CO_GENERATOR | CO_ASYNC_GENERATOR):
         need_bogus_yield = True
         for token in scanner_code._tokens:
             if token == "YIELD_VALUE":