More tests.

Author: Guido van Rossum

test-data/unit/check-modules.test

@@ -860,12 +860,17 @@ class Base:
     pass
 def foo() -> int:
     import y
+    reveal_type(y.Sub.attr)
     return y.Sub.attr
 [file y.py]
 import x
 class Sub(x.Base):
     attr = 0
 [out]
+tmp/y.py:1: note: In module imported here,
+main:1: note: ... from here:
+tmp/x.py: note: In function "foo":
+tmp/x.py:5: error: Revealed type is 'builtins.int'
 
 -- This case has a symmetrical cycle, so it doesn't matter in what
 -- order the files are processed.  It depends on the lightweight type
@@ -927,3 +932,30 @@ class Sub(x.Base):
     sattr = ''
     uattr = u''
 [out]
+
+-- This case tests module-level variables.
+
+[case testImportCycleStability7]
+import x
+[file x.py]
+def foo() -> int:
+    import y
+    reveal_type(y.value)
+    return y.value
+[file y.py]
+import x
+value = 12
+[out]
+main:1: note: In module imported here:
+tmp/x.py: note: In function "foo":
+tmp/x.py:3: error: Revealed type is 'builtins.int'
+
+-- This is not really cycle-related but still about the lightweight
+-- type checker.
+
+[case testImportCycleStability8]
+x = 1  # type: str
+reveal_type(x)
+[out]
+main:1: error: Incompatible types in assignment (expression has type "int", variable has type "str")
+main:2: error: Revealed type is 'builtins.str'