Add more ast.parse() mode overrides (#6522)

eval -> Expression
func_type -> FunctionType
single -> Interactive

We need (simplified) to cover all cases in Python >= 3.8

- 1 case: parse(filename: str = ...)
- 4 cases: parse(filename: str, mode: Literal[...])
- 4 cases: parse(*, mode: Literal[...])

Author: lancelote

stdlib/ast.pyi

@@ -167,18 +167,66 @@ if sys.version_info >= (3, 8):
     @overload
     def parse(
         source: str | bytes,
-        filename: str | bytes = ...,
-        mode: str = ...,
+        filename: str | bytes,
+        mode: Literal["eval"],
+        *,
+        type_comments: bool = ...,
+        feature_version: None | int | _typing.Tuple[int, int] = ...,
+    ) -> Expression: ...
+    @overload
+    def parse(
+        source: str | bytes,
+        filename: str | bytes,
+        mode: Literal["func_type"],
+        *,
+        type_comments: bool = ...,
+        feature_version: None | int | _typing.Tuple[int, int] = ...,
+    ) -> FunctionType: ...
+    @overload
+    def parse(
+        source: str | bytes,
+        filename: str | bytes,
+        mode: Literal["single"],
+        *,
+        type_comments: bool = ...,
+        feature_version: None | int | _typing.Tuple[int, int] = ...,
+    ) -> Interactive: ...
+    @overload
+    def parse(
+        source: str | bytes,
         *,
+        mode: Literal["eval"],
         type_comments: bool = ...,
         feature_version: None | int | _typing.Tuple[int, int] = ...,
-    ) -> AST: ...
+    ) -> Expression: ...
+    @overload
+    def parse(
+        source: str | bytes,
+        *,
+        mode: Literal["func_type"],
+        type_comments: bool = ...,
+        feature_version: None | int | _typing.Tuple[int, int] = ...,
+    ) -> FunctionType: ...
+    @overload
+    def parse(
+        source: str | bytes,
+        *,
+        mode: Literal["single"],
+        type_comments: bool = ...,
+        feature_version: None | int | _typing.Tuple[int, int] = ...,
+    ) -> Interactive: ...
 
 else:
     @overload
     def parse(source: str | bytes, filename: str | bytes = ..., mode: Literal["exec"] = ...) -> Module: ...
     @overload
-    def parse(source: str | bytes, filename: str | bytes = ..., mode: str = ...) -> AST: ...
+    def parse(source: str | bytes, filename: str | bytes, mode: Literal["eval"]) -> Expression: ...
+    @overload
+    def parse(source: str | bytes, filename: str | bytes, mode: Literal["single"]) -> Interactive: ...
+    @overload
+    def parse(source: str | bytes, *, mode: Literal["eval"]) -> Expression: ...
+    @overload
+    def parse(source: str | bytes, *, mode: Literal["single"]) -> Interactive: ...
 
 if sys.version_info >= (3, 9):
     def unparse(ast_obj: AST) -> str: ...