Make TryStar not crash (#13991)

Author: hauntsaninja

Diff for: mypy/fastparse.py

@@ -212,6 +212,10 @@ def ast3_parse(
         MatchAs = Any
         MatchOr = Any
         AstNode = Union[ast3.expr, ast3.stmt, ast3.ExceptHandler]
+    if sys.version_info >= (3, 11):
+        TryStar = ast3.TryStar
+    else:
+        TryStar = Any
 except ImportError:
     try:
         from typed_ast import ast35  # type: ignore[attr-defined]  # noqa: F401
@@ -1249,6 +1253,24 @@ def visit_Try(self, n: ast3.Try) -> TryStmt:
         )
         return self.set_line(node, n)
 
+    def visit_TryStar(self, n: TryStar) -> TryStmt:
+        # TODO: we treat TryStar exactly like Try, which makes mypy not crash. See #12840
+        vs = [
+            self.set_line(NameExpr(h.name), h) if h.name is not None else None for h in n.handlers
+        ]
+        types = [self.visit(h.type) for h in n.handlers]
+        handlers = [self.as_required_block(h.body, h.lineno) for h in n.handlers]
+
+        node = TryStmt(
+            self.as_required_block(n.body, n.lineno),
+            vs,
+            types,
+            handlers,
+            self.as_block(n.orelse, n.lineno),
+            self.as_block(n.finalbody, n.lineno),
+        )
+        return self.set_line(node, n)
+
     # Assert(expr test, expr? msg)
     def visit_Assert(self, n: ast3.Assert) -> AssertStmt:
         node = AssertStmt(self.visit(n.test), self.visit(n.msg))

Diff for: mypy/test/helpers.py

@@ -282,8 +282,14 @@ def num_skipped_suffix_lines(a1: list[str], a2: list[str]) -> int:
 
 
 def testfile_pyversion(path: str) -> tuple[int, int]:
-    if path.endswith("python310.test"):
+    if path.endswith("python311.test"):
+        return 3, 11
+    elif path.endswith("python310.test"):
         return 3, 10
+    elif path.endswith("python39.test"):
+        return 3, 9
+    elif path.endswith("python38.test"):
+        return 3, 8
     else:
         return defaults.PYTHON3_VERSION
 

Diff for: mypy/test/testcheck.py

@@ -44,6 +44,8 @@
     typecheck_files.remove("check-python39.test")
 if sys.version_info < (3, 10):
     typecheck_files.remove("check-python310.test")
+if sys.version_info < (3, 11):
+    typecheck_files.remove("check-python311.test")
 
 # Special tests for platforms with case-insensitive filesystems.
 if sys.platform not in ("darwin", "win32"):

Diff for: test-data/unit/check-python311.test

@@ -0,0 +1,6 @@
+[case testTryStarDoesNotCrash]
+try:
+    pass
+except* Exception as e:
+    reveal_type(e)  # N: Revealed type is "builtins.Exception"
+[builtins fixtures/exception.pyi]