New semantic analyzer: Fix import prios (#6424)

Old semantic analyzer first pass is setting whether an import is a top level one or not. New semantic analyzer reachability pass didn't do this. As a result, this screwed up import priorities, and in turn, ordering of modules within SCCs. This caused many `Cannot determine type of 'foo'` errors since we don't defer module top levels.

Author: ilevkivskyi

mypy/newsemanal/semanal_pass1.py

@@ -1,7 +1,8 @@
 """Block/import reachability analysis."""
 
 from mypy.nodes import (
-    MypyFile, AssertStmt, IfStmt, Block, AssignmentStmt, ExpressionStmt, ReturnStmt, ForStmt
+    MypyFile, AssertStmt, IfStmt, Block, AssignmentStmt, ExpressionStmt, ReturnStmt, ForStmt,
+    Import, ImportAll, ImportFrom, ClassDef, FuncDef
 )
 from mypy.traverser import TraverserVisitor
 from mypy.options import Options
@@ -40,16 +41,32 @@ def visit_file(self, file: MypyFile, fnam: str, mod_id: str, options: Options) -
         self.cur_mod_id = mod_id
         self.cur_mod_node = file
         self.options = options
+        self.is_global_scope = True
 
         for i, defn in enumerate(file.defs):
+            if isinstance(defn, (ClassDef, FuncDef)):
+                self.is_global_scope = False
             defn.accept(self)
+            self.is_global_scope = True
             if isinstance(defn, AssertStmt) and assert_will_always_fail(defn, options):
                 # We've encountered an assert that's always false,
                 # e.g. assert sys.platform == 'lol'.  Truncate the
                 # list of statements.  This mutates file.defs too.
                 del file.defs[i + 1:]
                 break
 
+    def visit_import_from(self, node: ImportFrom) -> None:
+        node.is_top_level = self.is_global_scope
+        super().visit_import_from(node)
+
+    def visit_import_all(self, node: ImportAll) -> None:
+        node.is_top_level = self.is_global_scope
+        super().visit_import_all(node)
+
+    def visit_import(self, node: Import) -> None:
+        node.is_top_level = self.is_global_scope
+        super().visit_import(node)
+
     def visit_if_stmt(self, s: IfStmt) -> None:
         infer_reachability_of_if_statement(s, self.options)
         for node in s.body:

test-data/unit/check-newsemanal.test

@@ -1399,3 +1399,21 @@ a = A()
 reveal_type(a.x)  # E: Revealed type is '__main__.B'
 a.y = 1  # E: Incompatible types in assignment (expression has type "int", variable has type "B")
 [builtins fixtures/property.pyi]
+
+[case testNewAnalyzerImportPriosB]
+import b
+[file a.py]
+from b import x
+reveal_type(x)  # E: Revealed type is 'Tuple[builtins.int, builtins.int]'
+[file b.py]
+import a
+x = (1, 2)
+
+[case testNewAnalyzerImportPriosA]
+import a
+[file a.py]
+from b import x
+reveal_type(x)  # E: Revealed type is 'Tuple[builtins.int, builtins.int]'
+[file b.py]
+import a
+x = (1, 2)

test-data/unit/pythoneval.test

@@ -1369,6 +1369,6 @@ reveal_type(x['test'][0])
 -- fully analyze typeshed
 typing.pyi:251: error: Class typing.Sequence has abstract attributes "__len__"
 typing.pyi:251: note: If it is meant to be abstract, add 'abc.ABCMeta' as an explicit metaclass
-codecs.pyi:49: error: Cannot overwrite NamedTuple attribute "__init__"
 ast.pyi:31: error: Name 'PyCF_ONLY_AST' already defined (possibly by an import)
+codecs.pyi:49: error: Cannot overwrite NamedTuple attribute "__init__"
 _testNewAnalyzerBasicTypeshed_newsemanal.py:4: error: Revealed type is 'builtins.int*'