Do not call convert.name_to_value() directly in typing overlays.

Calling pytd.ToType first ensures we handle cases like type aliases.

PiperOrigin-RevId: 446583723

Author: martindemello

pytype/overlays/typing_overlay.py

@@ -81,6 +81,18 @@ def __init__(self, module_name, aliases, ctx):
     super().__init__(ctx, module_name, member_map, ast)
 
 
+def _build(name):
+  def resolve(ctx):
+    ast = ctx.loader.typing
+    pytd_type = pytd.ToType(ast.Lookup(name), True, True, True)
+    return ctx.convert.constant_to_value(pytd_type)
+  return resolve
+
+
+def _build_not_supported_yet(name, ast):
+  return lambda ctx: not_supported_yet(name, ctx, ast=ast)
+
+
 class Union(abstract.AnnotationClass):
   """Implementation of typing.Union[...]."""
 
@@ -433,14 +445,6 @@ def _build_value(self, node, inner, ellipses):
     return self.ctx.convert.merge_values(values)
 
 
-def _build(name):
-  return lambda ctx: ctx.convert.name_to_value(name)
-
-
-def _build_not_supported_yet(name, ast):
-  return lambda ctx: not_supported_yet(name, ctx, ast=ast)
-
-
 def not_supported_yet(name, ctx, *, ast=None, details=None):
   ast = ast or ctx.loader.typing
   full_name = f"{ast.name}.{name}"

pytype/tests/test_collections_abc.py

@@ -14,6 +14,13 @@ class Foo(collections.abc.Mapping):
         pass
     """)
 
+  def test_bytestring(self):
+    """Check that we handle type aliases."""
+    self.Check("""
+      import collections
+      x: collections.abc.ByteString
+    """)
+
   def test_callable(self):
     ty = self.Infer("""
       from collections.abc import Callable