_ast: fix version availability for py39, fix up some visit_ methods (#4008)

stdlib/3/_ast.pyi

@@ -46,9 +46,6 @@ class Interactive(mod):
 class Expression(mod):
     body: expr
 
-class Suite(mod):
-    body: typing.List[stmt]
-
 
 class stmt(AST): ...
 
@@ -166,24 +163,6 @@ class Pass(stmt): ...
 class Break(stmt): ...
 class Continue(stmt): ...
 
-
-class slice(AST):
-    ...
-
-_slice = slice  # this lets us type the variable named 'slice' below
-
-class Slice(slice):
-    lower: Optional[expr]
-    upper: Optional[expr]
-    step: Optional[expr]
-
-class ExtSlice(slice):
-    dims: typing.List[slice]
-
-class Index(slice):
-    value: expr
-
-
 class expr(AST): ...
 
 class BoolOp(expr):
@@ -296,7 +275,21 @@ class Attribute(expr):
 if sys.version_info >= (3, 9):
     _SliceT = expr
 else:
-    _SliceT = _slice
+    class slice(AST):
+        ...
+    _SliceT = slice
+
+class Slice(_SliceT):
+    lower: Optional[expr]
+    upper: Optional[expr]
+    step: Optional[expr]
+
+if sys.version_info < (3, 9):
+    class ExtSlice(slice):
+        dims: typing.List[slice]
+
+    class Index(slice):
+        value: expr
 
 class Subscript(expr):
     value: expr
@@ -323,11 +316,15 @@ class Tuple(expr):
 class expr_context(AST):
     ...
 
-class AugLoad(expr_context): ...
-class AugStore(expr_context): ...
+if sys.version_info < (3, 9):
+    class AugLoad(expr_context): ...
+    class AugStore(expr_context): ...
+    class Param(expr_context): ...
+    class Suite(mod):
+        body: typing.List[stmt]
+
 class Del(expr_context): ...
 class Load(expr_context): ...
-class Param(expr_context): ...
 class Store(expr_context): ...
 
 

stdlib/3/ast.pyi

@@ -16,13 +16,28 @@ if sys.version_info >= (3, 8):
 else:
     from typing_extensions import Literal
 
+
+if sys.version_info >= (3, 8):
+    class Num(Constant): ...
+    class Str(Constant): ...
+    class Bytes(Constant): ...
+    class NameConstant(Constant): ...
+    class Ellipsis(Constant): ...
+if sys.version_info >= (3, 9):
+    class slice(AST): ...
+    class ExtSlice(slice): ...
+    class Index(slice): ...
+    class Suite(mod): ...
+    class AugLoad(expr_context): ...
+    class AugStore(expr_context): ...
+    class Param(expr_context): ...
+
 class NodeVisitor:
     def visit(self, node: AST) -> Any: ...
     def generic_visit(self, node: AST) -> Any: ...
     def visit_Module(self, node: Module) -> Any: ...
     def visit_Interactive(self, node: Interactive) -> Any: ...
     def visit_Expression(self, node: Expression) -> Any: ...
-    def visit_Suite(self, node: Suite) -> Any: ...
     def visit_FunctionDef(self, node: FunctionDef) -> Any: ...
     def visit_AsyncFunctionDef(self, node: AsyncFunctionDef) -> Any: ...
     def visit_ClassDef(self, node: ClassDef) -> Any: ...
@@ -50,8 +65,6 @@ class NodeVisitor:
     def visit_Break(self, node: Break) -> Any: ...
     def visit_Continue(self, node: Continue) -> Any: ...
     def visit_Slice(self, node: Slice) -> Any: ...
-    def visit_ExtSlice(self, node: ExtSlice) -> Any: ...
-    def visit_Index(self, node: Index) -> Any: ...
     def visit_BoolOp(self, node: BoolOp) -> Any: ...
     def visit_BinOp(self, node: BinOp) -> Any: ...
     def visit_UnaryOp(self, node: UnaryOp) -> Any: ...
@@ -71,18 +84,6 @@ class NodeVisitor:
     if sys.version_info >= (3, 6):
         def visit_FormattedValue(self, node: FormattedValue) -> Any: ...
         def visit_JoinedStr(self, node: JoinedStr) -> Any: ...
-    if sys.version_info < (3, 8):
-        def visit_Num(self, node: Num) -> Any: ...
-        def visit_Str(self, node: Str) -> Any: ...
-        def visit_Bytes(self, node: Bytes) -> Any: ...
-        def visit_NameConstant(self, node: NameConstant) -> Any: ...
-        def visit_Ellipsis(self, node: Ellipsis) -> Any: ...
-    else:
-        def visit_Num(self, node: Constant) -> Any: ...
-        def visit_Str(self, node: Constant) -> Any: ...
-        def visit_Bytes(self, node: Constant) -> Any: ...
-        def visit_NameConstant(self, node: Constant) -> Any: ...
-        def visit_Ellipsis(self, node: Constant) -> Any: ...
     if sys.version_info >= (3, 6):
         def visit_Constant(self, node: Constant) -> Any: ...
     if sys.version_info >= (3, 8):
@@ -93,11 +94,8 @@ class NodeVisitor:
     def visit_Name(self, node: Name) -> Any: ...
     def visit_List(self, node: List) -> Any: ...
     def visit_Tuple(self, node: Tuple) -> Any: ...
-    def visit_AugLoad(self, node: AugLoad) -> Any: ...
-    def visit_AugStore(self, node: AugStore) -> Any: ...
     def visit_Del(self, node: Del) -> Any: ...
     def visit_Load(self, node: Load) -> Any: ...
-    def visit_Param(self, node: Param) -> Any: ...
     def visit_Store(self, node: Store) -> Any: ...
     def visit_And(self, node: And) -> Any: ...
     def visit_Or(self, node: Or) -> Any: ...
@@ -135,6 +133,18 @@ class NodeVisitor:
     def visit_keyword(self, node: keyword) -> Any: ...
     def visit_alias(self, node: alias) -> Any: ...
     def visit_withitem(self, node: withitem) -> Any: ...
+    # visit methods for deprecated nodes
+    def visit_ExtSlice(self, node: ExtSlice) -> Any: ...
+    def visit_Index(self, node: Index) -> Any: ...
+    def visit_Suite(self, node: Suite) -> Any: ...
+    def visit_AugLoad(self, node: AugLoad) -> Any: ...
+    def visit_AugStore(self, node: AugStore) -> Any: ...
+    def visit_Param(self, node: Param) -> Any: ...
+    def visit_Num(self, node: Num) -> Any: ...
+    def visit_Str(self, node: Str) -> Any: ...
+    def visit_Bytes(self, node: Bytes) -> Any: ...
+    def visit_NameConstant(self, node: NameConstant) -> Any: ...
+    def visit_Ellipsis(self, node: Ellipsis) -> Any: ...
 
 class NodeTransformer(NodeVisitor):
     def generic_visit(self, node: AST) -> Optional[AST]: ...
@@ -184,10 +194,3 @@ def literal_eval(node_or_string: Union[str, AST]) -> Any: ...
 if sys.version_info >= (3, 8):
     def get_source_segment(source: str, node: AST, *, padded: bool = ...) -> Optional[str]: ...
 def walk(node: AST) -> Iterator[AST]: ...
-
-if sys.version_info >= (3, 8):
-    class Num(Constant): ...
-    class Str(Constant): ...
-    class Bytes(Constant): ...
-    class NameConstant(Constant): ...
-    class Ellipsis(Constant): ...