stubgen: Replace obsolete typing aliases with builtin containers (pyt…

…hon#16780)

Addresses part of python#16737

This only replaces typing symbols that have equivalents in the
`builtins` module. Replacing other symbols, like those from the
`collections.abc` module, are a bit more complicated so I suggest we
handle them separately.

I also changed the default `TypedDict` module from `typing_extensions`
to `typing` as typeshed dropped support for Python 3.7.

mypy/stubgen.py

@@ -47,7 +47,7 @@
 import os.path
 import sys
 import traceback
-from typing import Final, Iterable
+from typing import Final, Iterable, Iterator
 
 import mypy.build
 import mypy.mixedtraverser
@@ -114,6 +114,7 @@
 from mypy.stubdoc import ArgSig, FunctionSig
 from mypy.stubgenc import InspectionStubGenerator, generate_stub_for_c_module
 from mypy.stubutil import (
+    TYPING_BUILTIN_REPLACEMENTS,
     BaseStubGenerator,
     CantImport,
     ClassInfo,
@@ -289,20 +290,19 @@ def visit_call_expr(self, node: CallExpr) -> str:
                 raise ValueError(f"Unknown argument kind {kind} in call")
         return f"{callee}({', '.join(args)})"
 
+    def _visit_ref_expr(self, node: NameExpr | MemberExpr) -> str:
+        fullname = self.stubgen.get_fullname(node)
+        if fullname in TYPING_BUILTIN_REPLACEMENTS:
+            return self.stubgen.add_name(TYPING_BUILTIN_REPLACEMENTS[fullname], require=False)
+        qualname = get_qualified_name(node)
+        self.stubgen.import_tracker.require_name(qualname)
+        return qualname
+
     def visit_name_expr(self, node: NameExpr) -> str:
-        self.stubgen.import_tracker.require_name(node.name)
-        return node.name
+        return self._visit_ref_expr(node)
 
     def visit_member_expr(self, o: MemberExpr) -> str:
-        node: Expression = o
-        trailer = ""
-        while isinstance(node, MemberExpr):
-            trailer = "." + node.name + trailer
-            node = node.expr
-        if not isinstance(node, NameExpr):
-            return ERROR_MARKER
-        self.stubgen.import_tracker.require_name(node.name)
-        return node.name + trailer
+        return self._visit_ref_expr(o)
 
     def visit_str_expr(self, node: StrExpr) -> str:
         return repr(node.value)
@@ -351,11 +351,17 @@ def find_defined_names(file: MypyFile) -> set[str]:
     return finder.names
 
 
+def get_assigned_names(lvalues: Iterable[Expression]) -> Iterator[str]:
+    for lvalue in lvalues:
+        if isinstance(lvalue, NameExpr):
+            yield lvalue.name
+        elif isinstance(lvalue, TupleExpr):
+            yield from get_assigned_names(lvalue.items)
+
+
 class DefinitionFinder(mypy.traverser.TraverserVisitor):
     """Find names of things defined at the top level of a module."""
 
-    # TODO: Assignment statements etc.
-
     def __init__(self) -> None:
         # Short names of things defined at the top level.
         self.names: set[str] = set()
@@ -368,6 +374,10 @@ def visit_func_def(self, o: FuncDef) -> None:
         # Don't recurse, as we only keep track of top-level definitions.
         self.names.add(o.name)
 
+    def visit_assignment_stmt(self, o: AssignmentStmt) -> None:
+        for name in get_assigned_names(o.lvalues):
+            self.names.add(name)
+
 
 def find_referenced_names(file: MypyFile) -> set[str]:
     finder = ReferenceFinder()
@@ -1023,10 +1033,15 @@ def is_alias_expression(self, expr: Expression, top_level: bool = True) -> bool:
                 and isinstance(expr.node, (FuncDef, Decorator, MypyFile))
                 or isinstance(expr.node, TypeInfo)
             ) and not self.is_private_member(expr.node.fullname)
-        elif (
-            isinstance(expr, IndexExpr)
-            and isinstance(expr.base, NameExpr)
-            and not self.is_private_name(expr.base.name)
+        elif isinstance(expr, IndexExpr) and (
+            (isinstance(expr.base, NameExpr) and not self.is_private_name(expr.base.name))
+            or (  # Also some known aliases that could be member expression
+                isinstance(expr.base, MemberExpr)
+                and not self.is_private_member(get_qualified_name(expr.base))
+                and self.get_fullname(expr.base).startswith(
+                    ("builtins.", "typing.", "typing_extensions.", "collections.abc.")
+                )
+            )
         ):
             if isinstance(expr.index, TupleExpr):
                 indices = expr.index.items

mypy/stubutil.py

@@ -22,6 +22,26 @@
 # Modules that may fail when imported, or that may have side effects (fully qualified).
 NOT_IMPORTABLE_MODULES = ()
 
+# Typing constructs to be replaced by their builtin equivalents.
+TYPING_BUILTIN_REPLACEMENTS: Final = {
+    # From typing
+    "typing.Text": "builtins.str",
+    "typing.Tuple": "builtins.tuple",
+    "typing.List": "builtins.list",
+    "typing.Dict": "builtins.dict",
+    "typing.Set": "builtins.set",
+    "typing.FrozenSet": "builtins.frozenset",
+    "typing.Type": "builtins.type",
+    # From typing_extensions
+    "typing_extensions.Text": "builtins.str",
+    "typing_extensions.Tuple": "builtins.tuple",
+    "typing_extensions.List": "builtins.list",
+    "typing_extensions.Dict": "builtins.dict",
+    "typing_extensions.Set": "builtins.set",
+    "typing_extensions.FrozenSet": "builtins.frozenset",
+    "typing_extensions.Type": "builtins.type",
+}
+
 
 class CantImport(Exception):
     def __init__(self, module: str, message: str) -> None:
@@ -229,6 +249,8 @@ def visit_unbound_type(self, t: UnboundType) -> str:
             return " | ".join([item.accept(self) for item in t.args])
         if fullname == "typing.Optional":
             return f"{t.args[0].accept(self)} | None"
+        if fullname in TYPING_BUILTIN_REPLACEMENTS:
+            s = self.stubgen.add_name(TYPING_BUILTIN_REPLACEMENTS[fullname], require=True)
         if self.known_modules is not None and "." in s:
             # see if this object is from any of the modules that we're currently processing.
             # reverse sort so that subpackages come before parents: e.g. "foo.bar" before "foo".
@@ -476,7 +498,7 @@ def reexport(self, name: str) -> None:
     def import_lines(self) -> list[str]:
         """The list of required import lines (as strings with python code).
 
-        In order for a module be included in this output, an indentifier must be both
+        In order for a module be included in this output, an identifier must be both
         'required' via require_name() and 'imported' via add_import_from()
         or add_import()
         """
@@ -585,9 +607,9 @@ def __init__(
         # a corresponding import statement.
         self.known_imports = {
             "_typeshed": ["Incomplete"],
-            "typing": ["Any", "TypeVar", "NamedTuple"],
+            "typing": ["Any", "TypeVar", "NamedTuple", "TypedDict"],
             "collections.abc": ["Generator"],
-            "typing_extensions": ["TypedDict", "ParamSpec", "TypeVarTuple"],
+            "typing_extensions": ["ParamSpec", "TypeVarTuple"],
         }
 
     def get_sig_generators(self) -> list[SignatureGenerator]:
@@ -613,7 +635,10 @@ def add_name(self, fullname: str, require: bool = True) -> str:
         """
         module, name = fullname.rsplit(".", 1)
         alias = "_" + name if name in self.defined_names else None
-        self.import_tracker.add_import_from(module, [(name, alias)], require=require)
+        while alias in self.defined_names:
+            alias = "_" + alias
+        if module != "builtins" or alias:  # don't import from builtins unless needed
+            self.import_tracker.add_import_from(module, [(name, alias)], require=require)
         return alias or name
 
     def add_import_line(self, line: str) -> None:

test-data/pybind11_fixtures/expected_stubs_no_docs/pybind11_fixtures/__init__.pyi

@@ -1,6 +1,6 @@
 import os
 from . import demo as demo
-from typing import List, Tuple, overload
+from typing import overload
 
 class StaticMethods:
     def __init__(self, *args, **kwargs) -> None: ...
@@ -22,6 +22,6 @@ class TestStruct:
 
 def func_incomplete_signature(*args, **kwargs): ...
 def func_returning_optional() -> int | None: ...
-def func_returning_pair() -> Tuple[int, float]: ...
+def func_returning_pair() -> tuple[int, float]: ...
 def func_returning_path() -> os.PathLike: ...
-def func_returning_vector() -> List[float]: ...
+def func_returning_vector() -> list[float]: ...

test-data/pybind11_fixtures/expected_stubs_no_docs/pybind11_fixtures/demo.pyi

@@ -1,4 +1,4 @@
-from typing import ClassVar, List, overload
+from typing import ClassVar, overload
 
 PI: float
 __version__: str
@@ -47,7 +47,7 @@ class Point:
     def __init__(self) -> None: ...
     @overload
     def __init__(self, x: float, y: float) -> None: ...
-    def as_list(self) -> List[float]: ...
+    def as_list(self) -> list[float]: ...
     @overload
     def distance_to(self, x: float, y: float) -> float: ...
     @overload

test-data/pybind11_fixtures/expected_stubs_with_docs/pybind11_fixtures/__init__.pyi

@@ -1,6 +1,6 @@
 import os
 from . import demo as demo
-from typing import List, Tuple, overload
+from typing import overload
 
 class StaticMethods:
     def __init__(self, *args, **kwargs) -> None:
@@ -44,9 +44,9 @@ def func_incomplete_signature(*args, **kwargs):
     """func_incomplete_signature() -> dummy_sub_namespace::HasNoBinding"""
 def func_returning_optional() -> int | None:
     """func_returning_optional() -> Optional[int]"""
-def func_returning_pair() -> Tuple[int, float]:
+def func_returning_pair() -> tuple[int, float]:
     """func_returning_pair() -> Tuple[int, float]"""
 def func_returning_path() -> os.PathLike:
     """func_returning_path() -> os.PathLike"""
-def func_returning_vector() -> List[float]:
+def func_returning_vector() -> list[float]:
     """func_returning_vector() -> List[float]"""

test-data/pybind11_fixtures/expected_stubs_with_docs/pybind11_fixtures/demo.pyi

@@ -1,4 +1,4 @@
-from typing import ClassVar, List, overload
+from typing import ClassVar, overload
 
 PI: float
 __version__: str
@@ -73,7 +73,7 @@ class Point:
 
         2. __init__(self: pybind11_fixtures.demo.Point, x: float, y: float) -> None
         """
-    def as_list(self) -> List[float]:
+    def as_list(self) -> list[float]:
         """as_list(self: pybind11_fixtures.demo.Point) -> List[float]"""
     @overload
     def distance_to(self, x: float, y: float) -> float: