From a395e857897a85ed2e0417746cad11acb145d68c Mon Sep 17 00:00:00 2001
From: Jukka Lehtosalo <jukka.lehtosalo@iki.fi>
Date: Wed, 23 Jan 2019 17:15:09 +0000
Subject: [PATCH 1/2] New semantic analyzer: Various small updates

These respond to some review feedback to
https://github.com/python/mypy/pull/6240.
---
 mypy/newsemanal/semanal.py           | 2 +-
 mypy/newsemanal/semanal_main.py      | 3 +++
 mypy/plugin.py                       | 7 ++++++-
 test-data/unit/check-newsemanal.test | 8 ++++++++
 4 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/mypy/newsemanal/semanal.py b/mypy/newsemanal/semanal.py
index 9c8bff7a335d0..6602d5dd3b93c 100644
--- a/mypy/newsemanal/semanal.py
+++ b/mypy/newsemanal/semanal.py
@@ -2640,7 +2640,7 @@ def analyze_types(self, items: List[Expression]) -> List[Type]:
                 if analyzed is not None:
                     result.append(analyzed)
                 else:
-                    # TODO: Is this the right thing to do?
+                    # TODO: Is this the right thing to do? Or maybe return Optional[List[Type]]?
                     result.append(AnyType(TypeOfAny.from_error))
             except TypeTranslationError:
                 self.fail('Type expected', node)
diff --git a/mypy/newsemanal/semanal_main.py b/mypy/newsemanal/semanal_main.py
index 00fed2fef97b5..21fcf463cba52 100644
--- a/mypy/newsemanal/semanal_main.py
+++ b/mypy/newsemanal/semanal_main.py
@@ -17,6 +17,9 @@
 
 def semantic_analysis_for_scc(graph: 'Graph', scc: List[str]) -> None:
     # Assume reachability analysis has already been performed.
+    #
+    # Note that functions can't define new module-level attributes,
+    # since module top levels are fully processed before functions.
     process_top_levels(graph, scc)
     process_functions(graph, scc)
 
diff --git a/mypy/plugin.py b/mypy/plugin.py
index fba43a29d2aac..23fe3c68b51a7 100644
--- a/mypy/plugin.py
+++ b/mypy/plugin.py
@@ -182,7 +182,12 @@ def anal_type(self, t: Type, *,
                   allow_unbound_tvars: bool = False,
                   report_invalid_types: bool = True,
                   third_pass: bool = False) -> Optional[Type]:
-        """Analyze an unbound type."""
+        """Analyze an unbound type.
+
+        Return None if the some part of the type is not ready yet (only
+        happens with the new semantic analyzer). In this case the current
+        target being analyzed will be deferred and analyzed again.
+        """
         raise NotImplementedError
 
     @abstractmethod
diff --git a/test-data/unit/check-newsemanal.test b/test-data/unit/check-newsemanal.test
index 25d3b667cf871..5e28a9fb94cca 100644
--- a/test-data/unit/check-newsemanal.test
+++ b/test-data/unit/check-newsemanal.test
@@ -80,6 +80,14 @@ from b import bad # E: Module 'b' has no attribute 'bad'
 [file b.py]
 from a import bad2 # E: Module 'a' has no attribute 'bad2'
 
+[case testNewAnalyzerTypeAnnotationCycle4]
+# flags: --new-semantic-analyzer
+import b
+[file a.py]
+from b import bad # E: Module 'b' has no attribute 'bad'
+[file b.py]
+from a import bad
+
 [case testNewAnalyzerSimpleFunction]
 # flags: --new-semantic-analyzer
 def f(x: int) -> str:

From 6333811dc25313aaf607eea6879fa6a7375f33f3 Mon Sep 17 00:00:00 2001
From: Jukka Lehtosalo <jukka.lehtosalo@iki.fi>
Date: Thu, 24 Jan 2019 14:38:02 +0000
Subject: [PATCH 2/2] Updated based on feedback

---
 mypy/newsemanal/semanal_main.py      | 11 +++++++----
 test-data/unit/check-newsemanal.test |  1 +
 2 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/mypy/newsemanal/semanal_main.py b/mypy/newsemanal/semanal_main.py
index 21fcf463cba52..a113da67927f0 100644
--- a/mypy/newsemanal/semanal_main.py
+++ b/mypy/newsemanal/semanal_main.py
@@ -16,10 +16,13 @@
 
 
 def semantic_analysis_for_scc(graph: 'Graph', scc: List[str]) -> None:
-    # Assume reachability analysis has already been performed.
-    #
-    # Note that functions can't define new module-level attributes,
-    # since module top levels are fully processed before functions.
+    """Perform semantic analysis for all modules in a SCC (import cycle).
+
+    Assume that reachability analysis has already been performed.
+    """
+    # Note that functions can't define new module-level attributes
+    # using 'global x', since module top levels are fully processed
+    # before functions. This limitation is unlikely to go away soon.
     process_top_levels(graph, scc)
     process_functions(graph, scc)
 
diff --git a/test-data/unit/check-newsemanal.test b/test-data/unit/check-newsemanal.test
index 5e28a9fb94cca..cb11e3e6ffabc 100644
--- a/test-data/unit/check-newsemanal.test
+++ b/test-data/unit/check-newsemanal.test
@@ -86,6 +86,7 @@ import b
 [file a.py]
 from b import bad # E: Module 'b' has no attribute 'bad'
 [file b.py]
+# TODO: Could we generate an error here as well?
 from a import bad
 
 [case testNewAnalyzerSimpleFunction]