bpo-45292: [PEP-654] add except* (GH-29581)

14 files changed, 1675 insertions, 34 deletions

diff --git a/Lib/ast.py b/Lib/ast.py
index 400d7c4..625738a 100644
--- a/Lib/ast.py
+++ b/Lib/ast.py
@@ -683,6 +683,7 @@ class _Unparser(NodeVisitor):
         self._type_ignores = {}
         self._indent = 0
         self._avoid_backslashes = _avoid_backslashes
+        self._in_try_star = False
 
     def interleave(self, inter, f, seq):
         """Call f on each item in seq, calling inter() in between."""
@@ -953,7 +954,7 @@ class _Unparser(NodeVisitor):
             self.write(" from ")
             self.traverse(node.cause)
 
-    def visit_Try(self, node):
+    def do_visit_try(self, node):
         self.fill("try")
         with self.block():
             self.traverse(node.body)
@@ -968,8 +969,24 @@ class _Unparser(NodeVisitor):
             with self.block():
                 self.traverse(node.finalbody)
 
+    def visit_Try(self, node):
+        prev_in_try_star = self._in_try_star
+        try:
+            self._in_try_star = False
+            self.do_visit_try(node)
+        finally:
+            self._in_try_star = prev_in_try_star
+
+    def visit_TryStar(self, node):
+        prev_in_try_star = self._in_try_star
+        try:
+            self._in_try_star = True
+            self.do_visit_try(node)
+        finally:
+            self._in_try_star = prev_in_try_star
+
     def visit_ExceptHandler(self, node):
-        self.fill("except")
+        self.fill("except*" if self._in_try_star else "except")
         if node.type:
             self.write(" ")
             self.traverse(node.type)
diff --git a/Lib/importlib/_bootstrap_external.py b/Lib/importlib/_bootstrap_external.py
index 6970e9f..6e7ea7b 100644
--- a/Lib/importlib/_bootstrap_external.py
+++ b/Lib/importlib/_bootstrap_external.py
@@ -371,6 +371,7 @@ _code_type = type(_write_atomic.__code__)
 #     Python 3.11a3 3464 (bpo-45636: Merge numeric BINARY_*/INPLACE_* into
 #                         BINARY_OP)
 #     Python 3.11a3 3465 (Add COPY_FREE_VARS opcode)
+#     Python 3.11a3 3466 (bpo-45292: PEP-654 except*)
 
 #
 # MAGIC must change whenever the bytecode emitted by the compiler may no
@@ -380,7 +381,7 @@ _code_type = type(_write_atomic.__code__)
 # Whenever MAGIC_NUMBER is changed, the ranges in the magic_values array
 # in PC/launcher.c must also be updated.
 
-MAGIC_NUMBER = (3465).to_bytes(2, 'little') + b'\r\n'
+MAGIC_NUMBER = (3466).to_bytes(2, 'little') + b'\r\n'
 _RAW_MAGIC_NUMBER = int.from_bytes(MAGIC_NUMBER, 'little')  # For import.c
 
 _PYCACHE = '__pycache__'
diff --git a/Lib/opcode.py b/Lib/opcode.py
index e5889bc..299216d 100644
--- a/Lib/opcode.py
+++ b/Lib/opcode.py
@@ -103,6 +103,7 @@ def_op('IMPORT_STAR', 84)
 def_op('SETUP_ANNOTATIONS', 85)
 def_op('YIELD_VALUE', 86)
 
+def_op('PREP_RERAISE_STAR', 88)
 def_op('POP_EXCEPT', 89)
 
 HAVE_ARGUMENT = 90              # Opcodes from here have an argument:
@@ -150,6 +151,8 @@ haslocal.append(125)
 def_op('DELETE_FAST', 126)      # Local variable number
 haslocal.append(126)
 
+jabs_op('JUMP_IF_NOT_EG_MATCH', 127)
+
 def_op('GEN_START', 129)        # Kind of generator/coroutine
 def_op('RAISE_VARARGS', 130)    # Number of raise arguments (1, 2, or 3)
 def_op('CALL_FUNCTION', 131)    # #args
diff --git a/Lib/test/test_ast.py b/Lib/test/test_ast.py
index e630677..314b360 100644
--- a/Lib/test/test_ast.py
+++ b/Lib/test/test_ast.py
@@ -86,6 +86,8 @@ exec_tests = [
     "try:\n  pass\nexcept Exception:\n  pass",
     # TryFinally
     "try:\n  pass\nfinally:\n  pass",
+    # TryStarExcept
+    "try:\n  pass\nexcept* Exception:\n  pass",
     # Assert
     "assert v",
     # Import
@@ -1310,6 +1312,26 @@ class ASTValidatorTests(unittest.TestCase):
         t = ast.Try([p], e, [p], [ast.Expr(ast.Name("x", ast.Store()))])
         self.stmt(t, "must have Load context")
 
+    def test_try_star(self):
+        p = ast.Pass()
+        t = ast.TryStar([], [], [], [p])
+        self.stmt(t, "empty body on TryStar")
+        t = ast.TryStar([ast.Expr(ast.Name("x", ast.Store()))], [], [], [p])
+        self.stmt(t, "must have Load context")
+        t = ast.TryStar([p], [], [], [])
+        self.stmt(t, "TryStar has neither except handlers nor finalbody")
+        t = ast.TryStar([p], [], [p], [p])
+        self.stmt(t, "TryStar has orelse but no except handlers")
+        t = ast.TryStar([p], [ast.ExceptHandler(None, "x", [])], [], [])
+        self.stmt(t, "empty body on ExceptHandler")
+        e = [ast.ExceptHandler(ast.Name("x", ast.Store()), "y", [p])]
+        self.stmt(ast.TryStar([p], e, [], []), "must have Load context")
+        e = [ast.ExceptHandler(None, "x", [p])]
+        t = ast.TryStar([p], e, [ast.Expr(ast.Name("x", ast.Store()))], [p])
+        self.stmt(t, "must have Load context")
+        t = ast.TryStar([p], e, [p], [ast.Expr(ast.Name("x", ast.Store()))])
+        self.stmt(t, "must have Load context")
+
     def test_assert(self):
         self.stmt(ast.Assert(ast.Name("x", ast.Store()), None),
                   "must have Load context")
@@ -2316,6 +2338,7 @@ exec_results = [
 ('Module', [('Raise', (1, 0, 1, 25), ('Call', (1, 6, 1, 25), ('Name', (1, 6, 1, 15), 'Exception', ('Load',)), [('Constant', (1, 16, 1, 24), 'string', None)], []), None)], []),
 ('Module', [('Try', (1, 0, 4, 6), [('Pass', (2, 2, 2, 6))], [('ExceptHandler', (3, 0, 4, 6), ('Name', (3, 7, 3, 16), 'Exception', ('Load',)), None, [('Pass', (4, 2, 4, 6))])], [], [])], []),
 ('Module', [('Try', (1, 0, 4, 6), [('Pass', (2, 2, 2, 6))], [], [], [('Pass', (4, 2, 4, 6))])], []),
+('Module', [('TryStar', (1, 0, 4, 6), [('Pass', (2, 2, 2, 6))], [('ExceptHandler', (3, 0, 4, 6), ('Name', (3, 8, 3, 17), 'Exception', ('Load',)), None, [('Pass', (4, 2, 4, 6))])], [], [])], []),
 ('Module', [('Assert', (1, 0, 1, 8), ('Name', (1, 7, 1, 8), 'v', ('Load',)), None)], []),
 ('Module', [('Import', (1, 0, 1, 10), [('alias', (1, 7, 1, 10), 'sys', None)])], []),
 ('Module', [('ImportFrom', (1, 0, 1, 17), 'sys', [('alias', (1, 16, 1, 17), 'v', None)], 0)], []),
diff --git a/Lib/test/test_compile.py b/Lib/test/test_compile.py
index f4ed6c7..5bd7b06 100644
--- a/Lib/test/test_compile.py
+++ b/Lib/test/test_compile.py
@@ -1263,6 +1263,39 @@ class TestStackSizeStability(unittest.TestCase):
             """
         self.check_stack_size(snippet)
 
+    def test_try_except_star_qualified(self):
+        snippet = """
+            try:
+                a
+            except* ImportError:
+                b
+            else:
+                c
+            """
+        self.check_stack_size(snippet)
+
+    def test_try_except_star_as(self):
+        snippet = """
+            try:
+                a
+            except* ImportError as e:
+                b
+            else:
+                c
+            """
+        self.check_stack_size(snippet)
+
+    def test_try_except_star_finally(self):
+        snippet = """
+                try:
+                    a
+                except* A:
+                    b
+                finally:
+                    c
+            """
+        self.check_stack_size(snippet)
+
     def test_try_finally(self):
         snippet = """
                 try:
diff --git a/Lib/test/test_dis.py b/Lib/test/test_dis.py
index dd328f0..e821e00 100644
--- a/Lib/test/test_dis.py
+++ b/Lib/test/test_dis.py
@@ -1119,7 +1119,7 @@ expected_opinfo_jumpy = [
   Instruction(opname='CALL_FUNCTION', opcode=131, arg=1, argval=1, argrepr='', offset=132, starts_line=None, is_jump_target=False, positions=None),
   Instruction(opname='POP_TOP', opcode=1, arg=None, argval=None, argrepr='', offset=134, starts_line=None, is_jump_target=False, positions=None),
   Instruction(opname='POP_EXCEPT', opcode=89, arg=None, argval=None, argrepr='', offset=136, starts_line=None, is_jump_target=False, positions=None),
-  Instruction(opname='JUMP_FORWARD', opcode=110, arg=33, argval=206, argrepr='to 206', offset=138, starts_line=None, is_jump_target=False, positions=None),
+  Instruction(opname='JUMP_FORWARD', opcode=110, arg=32, argval=204, argrepr='to 204', offset=138, starts_line=None, is_jump_target=False, positions=None),
   Instruction(opname='RERAISE', opcode=119, arg=0, argval=0, argrepr='', offset=140, starts_line=22, is_jump_target=True, positions=None),
   Instruction(opname='POP_EXCEPT_AND_RERAISE', opcode=37, arg=None, argval=None, argrepr='', offset=142, starts_line=None, is_jump_target=False, positions=None),
   Instruction(opname='LOAD_FAST', opcode=124, arg=0, argval='i', argrepr='i', offset=144, starts_line=25, is_jump_target=True, positions=None),
@@ -1134,7 +1134,7 @@ expected_opinfo_jumpy = [
   Instruction(opname='DUP_TOP', opcode=4, arg=None, argval=None, argrepr='', offset=162, starts_line=None, is_jump_target=False, positions=None),
   Instruction(opname='CALL_FUNCTION', opcode=131, arg=3, argval=3, argrepr='', offset=164, starts_line=None, is_jump_target=False, positions=None),
   Instruction(opname='POP_TOP', opcode=1, arg=None, argval=None, argrepr='', offset=166, starts_line=None, is_jump_target=False, positions=None),
-  Instruction(opname='JUMP_FORWARD', opcode=110, arg=25, argval=220, argrepr='to 220', offset=168, starts_line=None, is_jump_target=False, positions=None),
+  Instruction(opname='JUMP_FORWARD', opcode=110, arg=11, argval=192, argrepr='to 192', offset=168, starts_line=None, is_jump_target=False, positions=None),
   Instruction(opname='PUSH_EXC_INFO', opcode=35, arg=None, argval=None, argrepr='', offset=170, starts_line=None, is_jump_target=False, positions=None),
   Instruction(opname='WITH_EXCEPT_START', opcode=49, arg=None, argval=None, argrepr='', offset=172, starts_line=None, is_jump_target=False, positions=None),
   Instruction(opname='POP_JUMP_IF_TRUE', opcode=115, arg=90, argval=180, argrepr='to 180', offset=174, starts_line=None, is_jump_target=False, positions=None),
@@ -1146,34 +1146,26 @@ expected_opinfo_jumpy = [
   Instruction(opname='POP_EXCEPT', opcode=89, arg=None, argval=None, argrepr='', offset=186, starts_line=None, is_jump_target=False, positions=None),
   Instruction(opname='POP_TOP', opcode=1, arg=None, argval=None, argrepr='', offset=188, starts_line=None, is_jump_target=False, positions=None),
   Instruction(opname='POP_TOP', opcode=1, arg=None, argval=None, argrepr='', offset=190, starts_line=None, is_jump_target=False, positions=None),
-  Instruction(opname='NOP', opcode=9, arg=None, argval=None, argrepr='', offset=192, starts_line=None, is_jump_target=False, positions=None),
-  Instruction(opname='LOAD_GLOBAL', opcode=116, arg=1, argval='print', argrepr='print', offset=194, starts_line=28, is_jump_target=False, positions=None),
-  Instruction(opname='LOAD_CONST', opcode=100, arg=10, argval="OK, now we're done", argrepr='"OK, now we\'re done"', offset=196, starts_line=None, is_jump_target=False, positions=None),
-  Instruction(opname='CALL_FUNCTION', opcode=131, arg=1, argval=1, argrepr='', offset=198, starts_line=None, is_jump_target=False, positions=None),
-  Instruction(opname='POP_TOP', opcode=1, arg=None, argval=None, argrepr='', offset=200, starts_line=None, is_jump_target=False, positions=None),
-  Instruction(opname='LOAD_CONST', opcode=100, arg=0, argval=None, argrepr='None', offset=202, starts_line=None, is_jump_target=False, positions=None),
-  Instruction(opname='RETURN_VALUE', opcode=83, arg=None, argval=None, argrepr='', offset=204, starts_line=None, is_jump_target=False, positions=None),
-  Instruction(opname='NOP', opcode=9, arg=None, argval=None, argrepr='', offset=206, starts_line=23, is_jump_target=True, positions=None),
-  Instruction(opname='LOAD_GLOBAL', opcode=116, arg=1, argval='print', argrepr='print', offset=208, starts_line=28, is_jump_target=False, positions=None),
-  Instruction(opname='LOAD_CONST', opcode=100, arg=10, argval="OK, now we're done", argrepr='"OK, now we\'re done"', offset=210, starts_line=None, is_jump_target=False, positions=None),
-  Instruction(opname='CALL_FUNCTION', opcode=131, arg=1, argval=1, argrepr='', offset=212, starts_line=None, is_jump_target=False, positions=None),
-  Instruction(opname='POP_TOP', opcode=1, arg=None, argval=None, argrepr='', offset=214, starts_line=None, is_jump_target=False, positions=None),
-  Instruction(opname='LOAD_CONST', opcode=100, arg=0, argval=None, argrepr='None', offset=216, starts_line=None, is_jump_target=False, positions=None),
-  Instruction(opname='RETURN_VALUE', opcode=83, arg=None, argval=None, argrepr='', offset=218, starts_line=None, is_jump_target=False, positions=None),
-  Instruction(opname='NOP', opcode=9, arg=None, argval=None, argrepr='', offset=220, starts_line=25, is_jump_target=True, positions=None),
-  Instruction(opname='LOAD_GLOBAL', opcode=116, arg=1, argval='print', argrepr='print', offset=222, starts_line=28, is_jump_target=False, positions=None),
-  Instruction(opname='LOAD_CONST', opcode=100, arg=10, argval="OK, now we're done", argrepr='"OK, now we\'re done"', offset=224, starts_line=None, is_jump_target=False, positions=None),
-  Instruction(opname='CALL_FUNCTION', opcode=131, arg=1, argval=1, argrepr='', offset=226, starts_line=None, is_jump_target=False, positions=None),
-  Instruction(opname='POP_TOP', opcode=1, arg=None, argval=None, argrepr='', offset=228, starts_line=None, is_jump_target=False, positions=None),
-  Instruction(opname='LOAD_CONST', opcode=100, arg=0, argval=None, argrepr='None', offset=230, starts_line=None, is_jump_target=False, positions=None),
-  Instruction(opname='RETURN_VALUE', opcode=83, arg=None, argval=None, argrepr='', offset=232, starts_line=None, is_jump_target=False, positions=None),
-  Instruction(opname='PUSH_EXC_INFO', opcode=35, arg=None, argval=None, argrepr='', offset=234, starts_line=None, is_jump_target=False, positions=None),
-  Instruction(opname='LOAD_GLOBAL', opcode=116, arg=1, argval='print', argrepr='print', offset=236, starts_line=None, is_jump_target=False, positions=None),
-  Instruction(opname='LOAD_CONST', opcode=100, arg=10, argval="OK, now we're done", argrepr='"OK, now we\'re done"', offset=238, starts_line=None, is_jump_target=False, positions=None),
-  Instruction(opname='CALL_FUNCTION', opcode=131, arg=1, argval=1, argrepr='', offset=240, starts_line=None, is_jump_target=False, positions=None),
-  Instruction(opname='POP_TOP', opcode=1, arg=None, argval=None, argrepr='', offset=242, starts_line=None, is_jump_target=False, positions=None),
-  Instruction(opname='RERAISE', opcode=119, arg=0, argval=0, argrepr='', offset=244, starts_line=None, is_jump_target=False, positions=None),
-  Instruction(opname='POP_EXCEPT_AND_RERAISE', opcode=37, arg=None, argval=None, argrepr='', offset=246, starts_line=None, is_jump_target=False, positions=None),
+  Instruction(opname='LOAD_GLOBAL', opcode=116, arg=1, argval='print', argrepr='print', offset=192, starts_line=28, is_jump_target=True, positions=None),
+  Instruction(opname='LOAD_CONST', opcode=100, arg=10, argval="OK, now we're done", argrepr='"OK, now we\'re done"', offset=194, starts_line=None, is_jump_target=False, positions=None),
+  Instruction(opname='CALL_FUNCTION', opcode=131, arg=1, argval=1, argrepr='', offset=196, starts_line=None, is_jump_target=False, positions=None),
+  Instruction(opname='POP_TOP', opcode=1, arg=None, argval=None, argrepr='', offset=198, starts_line=None, is_jump_target=False, positions=None),
+  Instruction(opname='LOAD_CONST', opcode=100, arg=0, argval=None, argrepr='None', offset=200, starts_line=None, is_jump_target=False, positions=None),
+  Instruction(opname='RETURN_VALUE', opcode=83, arg=None, argval=None, argrepr='', offset=202, starts_line=None, is_jump_target=False, positions=None),
+  Instruction(opname='NOP', opcode=9, arg=None, argval=None, argrepr='', offset=204, starts_line=23, is_jump_target=True, positions=None),
+  Instruction(opname='LOAD_GLOBAL', opcode=116, arg=1, argval='print', argrepr='print', offset=206, starts_line=28, is_jump_target=False, positions=None),
+  Instruction(opname='LOAD_CONST', opcode=100, arg=10, argval="OK, now we're done", argrepr='"OK, now we\'re done"', offset=208, starts_line=None, is_jump_target=False, positions=None),
+  Instruction(opname='CALL_FUNCTION', opcode=131, arg=1, argval=1, argrepr='', offset=210, starts_line=None, is_jump_target=False, positions=None),
+  Instruction(opname='POP_TOP', opcode=1, arg=None, argval=None, argrepr='', offset=212, starts_line=None, is_jump_target=False, positions=None),
+  Instruction(opname='LOAD_CONST', opcode=100, arg=0, argval=None, argrepr='None', offset=214, starts_line=None, is_jump_target=False, positions=None),
+  Instruction(opname='RETURN_VALUE', opcode=83, arg=None, argval=None, argrepr='', offset=216, starts_line=None, is_jump_target=False, positions=None),
+  Instruction(opname='PUSH_EXC_INFO', opcode=35, arg=None, argval=None, argrepr='', offset=218, starts_line=None, is_jump_target=False, positions=None),
+  Instruction(opname='LOAD_GLOBAL', opcode=116, arg=1, argval='print', argrepr='print', offset=220, starts_line=None, is_jump_target=False, positions=None),
+  Instruction(opname='LOAD_CONST', opcode=100, arg=10, argval="OK, now we're done", argrepr='"OK, now we\'re done"', offset=222, starts_line=None, is_jump_target=False, positions=None),
+  Instruction(opname='CALL_FUNCTION', opcode=131, arg=1, argval=1, argrepr='', offset=224, starts_line=None, is_jump_target=False, positions=None),
+  Instruction(opname='POP_TOP', opcode=1, arg=None, argval=None, argrepr='', offset=226, starts_line=None, is_jump_target=False, positions=None),
+  Instruction(opname='RERAISE', opcode=119, arg=0, argval=0, argrepr='', offset=228, starts_line=None, is_jump_target=False, positions=None),
+  Instruction(opname='POP_EXCEPT_AND_RERAISE', opcode=37, arg=None, argval=None, argrepr='', offset=230, starts_line=None, is_jump_target=False, positions=None),
 ]
 
 # One last piece of inspect fodder to check the default line number handling
diff --git a/Lib/test/test_except_star.py b/Lib/test/test_except_star.py
new file mode 100644
index 0000000..b03de9c
--- /dev/null
+++ b/Lib/test/test_except_star.py
@@ -0,0 +1,976 @@
+import sys
+import unittest
+import textwrap
+
+class TestInvalidExceptStar(unittest.TestCase):
+    def test_mixed_except_and_except_star_is_syntax_error(self):
+        errors = [
+            "try: pass\nexcept ValueError: pass\nexcept* TypeError: pass\n",
+            "try: pass\nexcept* ValueError: pass\nexcept TypeError: pass\n",
+            "try: pass\nexcept ValueError as e: pass\nexcept* TypeError: pass\n",
+            "try: pass\nexcept* ValueError as e: pass\nexcept TypeError: pass\n",
+            "try: pass\nexcept ValueError: pass\nexcept* TypeError as e: pass\n",
+            "try: pass\nexcept* ValueError: pass\nexcept TypeError as e: pass\n",
+            "try: pass\nexcept ValueError: pass\nexcept*: pass\n",
+            "try: pass\nexcept* ValueError: pass\nexcept: pass\n",
+        ]
+
+        for err in errors:
+            with self.assertRaises(SyntaxError):
+                compile(err, "<string>", "exec")
+
+    def test_except_star_ExceptionGroup_is_runtime_error_single(self):
+        with self.assertRaises(TypeError):
+            try:
+                raise OSError("blah")
+            except* ExceptionGroup as e:
+                pass
+
+    def test_except_star_ExceptionGroup_is_runtime_error_tuple(self):
+        with self.assertRaises(TypeError):
+            try:
+                raise ExceptionGroup("eg", [ValueError(42)])
+            except* (TypeError, ExceptionGroup):
+                pass
+
+    def test_except_star_invalid_exception_type(self):
+        with self.assertRaises(TypeError):
+            try:
+                raise ValueError
+            except* 42:
+                pass
+
+        with self.assertRaises(TypeError):
+            try:
+                raise ValueError
+            except* (ValueError, 42):
+                pass
+
+
+class TestBreakContinueReturnInExceptStarBlock(unittest.TestCase):
+    MSG = (r"'break', 'continue' and 'return'"
+           r" cannot appear in an except\* block")
+
+    def check_invalid(self, src):
+        with self.assertRaisesRegex(SyntaxError, self.MSG):
+            compile(textwrap.dedent(src), "<string>", "exec")
+
+    def test_break_in_except_star(self):
+        self.check_invalid(
+            """
+            try:
+                raise ValueError
+            except* Exception as e:
+                break
+            """)
+
+        self.check_invalid(
+            """
+            for i in range(5):
+                try:
+                    pass
+                except* Exception as e:
+                    if i == 2:
+                        break
+            """)
+
+        self.check_invalid(
+            """
+            for i in range(5):
+                try:
+                    pass
+                except* Exception as e:
+                    if i == 2:
+                        break
+                finally:
+                    return 0
+            """)
+
+
+    def test_continue_in_except_star_block_invalid(self):
+        self.check_invalid(
+            """
+            for i in range(5):
+                try:
+                    raise ValueError
+                except* Exception as e:
+                    continue
+            """)
+
+        self.check_invalid(
+            """
+            for i in range(5):
+                try:
+                    pass
+                except* Exception as e:
+                    if i == 2:
+                        continue
+            """)
+
+        self.check_invalid(
+            """
+            for i in range(5):
+                try:
+                    pass
+                except* Exception as e:
+                    if i == 2:
+                        continue
+                finally:
+                    return 0
+            """)
+
+    def test_return_in_except_star_block_invalid(self):
+        self.check_invalid(
+            """
+            def f():
+                try:
+                    raise ValueError
+                except* Exception as e:
+                    return 42
+            """)
+
+        self.check_invalid(
+            """
+            def f():
+                try:
+                    pass
+                except* Exception as e:
+                    return 42
+                finally:
+                    finished = True
+            """)
+
+    def test_break_continue_in_except_star_block_valid(self):
+        try:
+            raise ValueError(42)
+        except* Exception as e:
+            count = 0
+            for i in range(5):
+                if i == 0:
+                    continue
+                if i == 4:
+                    break
+                count += 1
+
+            self.assertEqual(count, 3)
+            self.assertEqual(i, 4)
+            exc = e
+        self.assertIsInstance(exc, ExceptionGroup)
+
+    def test_return_in_except_star_block_valid(self):
+        try:
+            raise ValueError(42)
+        except* Exception as e:
+            def f(x):
+                return 2*x
+            r = f(3)
+            exc = e
+        self.assertEqual(r, 6)
+        self.assertIsInstance(exc, ExceptionGroup)
+
+
+class ExceptStarTest(unittest.TestCase):
+    def assertExceptionIsLike(self, exc, template):
+        if exc is None and template is None:
+            return
+
+        if template is None:
+            self.fail(f"unexpected exception: {exc}")
+
+        if exc is None:
+            self.fail(f"expected an exception like {template!r}, got None")
+
+        if not isinstance(exc, ExceptionGroup):
+            self.assertEqual(exc.__class__, template.__class__)
+            self.assertEqual(exc.args[0], template.args[0])
+        else:
+            self.assertEqual(exc.message, template.message)
+            self.assertEqual(len(exc.exceptions), len(template.exceptions))
+            for e, t in zip(exc.exceptions, template.exceptions):
+                self.assertExceptionIsLike(e, t)
+
+    def assertMetadataEqual(self, e1, e2):
+        if e1 is None or e2 is None:
+            self.assertTrue(e1 is None and e2 is None)
+        else:
+            self.assertEqual(e1.__context__, e2.__context__)
+            self.assertEqual(e1.__cause__, e2.__cause__)
+            self.assertEqual(e1.__traceback__, e2.__traceback__)
+
+    def assertMetadataNotEqual(self, e1, e2):
+        if e1 is None or e2 is None:
+            self.assertNotEqual(e1, e2)
+        else:
+            return not (e1.__context__ == e2.__context__
+                        and e1.__cause__ == e2.__cause__
+                        and e1.__traceback__ == e2.__traceback__)
+
+
+class TestExceptStarSplitSemantics(ExceptStarTest):
+    def doSplitTestNamed(self, exc, T, match_template, rest_template):
+        initial_exc_info = sys.exc_info()
+        exc_info = match = rest = None
+        try:
+            try:
+                raise exc
+            except* T as e:
+                exc_info = sys.exc_info()
+                match = e
+        except BaseException as e:
+            rest = e
+
+        if match_template:
+            self.assertEqual(exc_info[1], match)
+        else:
+            self.assertIsNone(exc_info)
+        self.assertExceptionIsLike(match, match_template)
+        self.assertExceptionIsLike(rest, rest_template)
+        self.assertEqual(sys.exc_info(), initial_exc_info)
+
+    def doSplitTestUnnamed(self, exc, T, match_template, rest_template):
+        initial_exc_info = sys.exc_info()
+        exc_info = match = rest = None
+        try:
+            try:
+                raise exc
+            except* T:
+                exc_info = sys.exc_info()
+                match = sys.exc_info()[1]
+            else:
+                if rest_template:
+                    self.fail("Exception not raised")
+        except BaseException as e:
+            rest = e
+        self.assertExceptionIsLike(match, match_template)
+        if match_template:
+            self.assertEqual(exc_info[0], type(match_template))
+        self.assertExceptionIsLike(rest, rest_template)
+        self.assertEqual(sys.exc_info(), initial_exc_info)
+
+    def doSplitTestInExceptHandler(self, exc, T, match_template, rest_template):
+        try:
+            raise ExceptionGroup('eg', [TypeError(1), ValueError(2)])
+        except Exception:
+            self.doSplitTestNamed(exc, T, match_template, rest_template)
+            self.doSplitTestUnnamed(exc, T, match_template, rest_template)
+
+    def doSplitTestInExceptStarHandler(self, exc, T, match_template, rest_template):
+        try:
+            raise ExceptionGroup('eg', [TypeError(1), ValueError(2)])
+        except* Exception:
+            self.doSplitTestNamed(exc, T, match_template, rest_template)
+            self.doSplitTestUnnamed(exc, T, match_template, rest_template)
+
+    def doSplitTest(self, exc, T, match_template, rest_template):
+        self.doSplitTestNamed(exc, T, match_template, rest_template)
+        self.doSplitTestUnnamed(exc, T, match_template, rest_template)
+        self.doSplitTestInExceptHandler(exc, T, match_template, rest_template)
+        self.doSplitTestInExceptStarHandler(exc, T, match_template, rest_template)
+
+    def test_no_match_single_type(self):
+        self.doSplitTest(
+            ExceptionGroup("test1", [ValueError("V"), TypeError("T")]),
+            SyntaxError,
+            None,
+            ExceptionGroup("test1", [ValueError("V"), TypeError("T")]))
+
+    def test_match_single_type(self):
+        self.doSplitTest(
+            ExceptionGroup("test2", [ValueError("V1"), ValueError("V2")]),
+            ValueError,
+            ExceptionGroup("test2", [ValueError("V1"), ValueError("V2")]),
+            None)
+
+    def test_match_single_type_partial_match(self):
+        self.doSplitTest(
+            ExceptionGroup(
+                "test3",
+                [ValueError("V1"), OSError("OS"), ValueError("V2")]),
+            ValueError,
+            ExceptionGroup("test3", [ValueError("V1"), ValueError("V2")]),
+            ExceptionGroup("test3", [OSError("OS")]))
+
+    def test_match_single_type_nested(self):
+        self.doSplitTest(
+            ExceptionGroup(
+                "g1", [
+                ValueError("V1"),
+                OSError("OS1"),
+                ExceptionGroup(
+                    "g2", [
+                    OSError("OS2"),
+                    ValueError("V2"),
+                    TypeError("T")])]),
+            ValueError,
+            ExceptionGroup(
+                "g1", [
+                ValueError("V1"),
+                ExceptionGroup("g2", [ValueError("V2")])]),
+            ExceptionGroup("g1", [
+                OSError("OS1"),
+                ExceptionGroup("g2", [
+                    OSError("OS2"), TypeError("T")])]))
+
+    def test_match_type_tuple_nested(self):
+        self.doSplitTest(
+            ExceptionGroup(
+                "h1", [
+                ValueError("V1"),
+                OSError("OS1"),
+                ExceptionGroup(
+                    "h2", [OSError("OS2"), ValueError("V2"), TypeError("T")])]),
+            (ValueError, TypeError),
+            ExceptionGroup(
+                "h1", [
+                ValueError("V1"),
+                ExceptionGroup("h2", [ValueError("V2"), TypeError("T")])]),
+            ExceptionGroup(
+                "h1", [
+                OSError("OS1"),
+                ExceptionGroup("h2", [OSError("OS2")])]))
+
+    def test_empty_groups_removed(self):
+        self.doSplitTest(
+            ExceptionGroup(
+                "eg", [
+                ExceptionGroup("i1", [ValueError("V1")]),
+                ExceptionGroup("i2", [ValueError("V2"), TypeError("T1")]),
+                ExceptionGroup("i3", [TypeError("T2")])]),
+            TypeError,
+            ExceptionGroup("eg", [
+                ExceptionGroup("i2", [TypeError("T1")]),
+                ExceptionGroup("i3", [TypeError("T2")])]),
+            ExceptionGroup("eg", [
+                    ExceptionGroup("i1", [ValueError("V1")]),
+                    ExceptionGroup("i2", [ValueError("V2")])]))
+
+    def test_singleton_groups_are_kept(self):
+        self.doSplitTest(
+            ExceptionGroup("j1", [
+                ExceptionGroup("j2", [
+                    ExceptionGroup("j3", [ValueError("V1")]),
+                    ExceptionGroup("j4", [TypeError("T")])])]),
+            TypeError,
+            ExceptionGroup(
+                "j1",
+                [ExceptionGroup("j2", [ExceptionGroup("j4", [TypeError("T")])])]),
+            ExceptionGroup(
+                "j1",
+                [ExceptionGroup("j2", [ExceptionGroup("j3", [ValueError("V1")])])]))
+
+    def test_naked_exception_matched_wrapped1(self):
+        self.doSplitTest(
+            ValueError("V"),
+            ValueError,
+            ExceptionGroup("", [ValueError("V")]),
+            None)
+
+    def test_naked_exception_matched_wrapped2(self):
+        self.doSplitTest(
+            ValueError("V"),
+            Exception,
+            ExceptionGroup("", [ValueError("V")]),
+            None)
+
+    def test_exception_group_except_star_Exception_not_wrapped(self):
+        self.doSplitTest(
+            ExceptionGroup("eg", [ValueError("V")]),
+            Exception,
+            ExceptionGroup("eg", [ValueError("V")]),
+            None)
+
+    def test_plain_exception_not_matched(self):
+        self.doSplitTest(
+            ValueError("V"),
+            TypeError,
+            None,
+            ValueError("V"))
+
+    def test_match__supertype(self):
+        self.doSplitTest(
+            ExceptionGroup("st", [BlockingIOError("io"), TypeError("T")]),
+            OSError,
+            ExceptionGroup("st", [BlockingIOError("io")]),
+            ExceptionGroup("st", [TypeError("T")]))
+
+    def test_multiple_matches_named(self):
+        try:
+            raise ExceptionGroup("mmn", [OSError("os"), BlockingIOError("io")])
+        except* BlockingIOError as e:
+            self.assertExceptionIsLike(e,
+                ExceptionGroup("mmn", [BlockingIOError("io")]))
+        except* OSError as e:
+            self.assertExceptionIsLike(e,
+                ExceptionGroup("mmn", [OSError("os")]))
+        else:
+            self.fail("Exception not raised")
+
+    def test_multiple_matches_unnamed(self):
+        try:
+            raise ExceptionGroup("mmu", [OSError("os"), BlockingIOError("io")])
+        except* BlockingIOError:
+            e = sys.exc_info()[1]
+            self.assertExceptionIsLike(e,
+                ExceptionGroup("mmu", [BlockingIOError("io")]))
+        except* OSError:
+            e = sys.exc_info()[1]
+            self.assertExceptionIsLike(e,
+                ExceptionGroup("mmu", [OSError("os")]))
+        else:
+            self.fail("Exception not raised")
+
+    def test_first_match_wins_named(self):
+        try:
+            raise ExceptionGroup("fst", [BlockingIOError("io")])
+        except* OSError as e:
+            self.assertExceptionIsLike(e,
+                ExceptionGroup("fst", [BlockingIOError("io")]))
+        except* BlockingIOError:
+            self.fail("Should have been matched as OSError")
+        else:
+            self.fail("Exception not raised")
+
+    def test_first_match_wins_unnamed(self):
+        try:
+            raise ExceptionGroup("fstu", [BlockingIOError("io")])
+        except* OSError:
+            e = sys.exc_info()[1]
+            self.assertExceptionIsLike(e,
+                ExceptionGroup("fstu", [BlockingIOError("io")]))
+        except* BlockingIOError:
+            pass
+        else:
+            self.fail("Exception not raised")
+
+    def test_nested_except_stars(self):
+        try:
+            raise ExceptionGroup("n", [BlockingIOError("io")])
+        except* BlockingIOError:
+            try:
+                raise ExceptionGroup("n", [ValueError("io")])
+            except* ValueError:
+                pass
+            else:
+                self.fail("Exception not raised")
+            e = sys.exc_info()[1]
+            self.assertExceptionIsLike(e,
+                 ExceptionGroup("n", [BlockingIOError("io")]))
+        else:
+            self.fail("Exception not raised")
+
+    def test_nested_in_loop(self):
+        for _ in range(2):
+            try:
+                raise ExceptionGroup("nl", [BlockingIOError("io")])
+            except* BlockingIOError:
+                pass
+            else:
+                self.fail("Exception not raised")
+
+
+class TestExceptStarReraise(ExceptStarTest):
+    def test_reraise_all_named(self):
+        try:
+            try:
+                raise ExceptionGroup(
+                    "eg", [TypeError(1), ValueError(2), OSError(3)])
+            except* TypeError as e:
+                raise
+            except* ValueError as e:
+                raise
+            # OSError not handled
+        except ExceptionGroup as e:
+            exc = e
+
+        self.assertExceptionIsLike(
+            exc,
+            ExceptionGroup("eg", [TypeError(1), ValueError(2), OSError(3)]))
+
+    def test_reraise_all_unnamed(self):
+        try:
+            try:
+                raise ExceptionGroup(
+                    "eg", [TypeError(1), ValueError(2), OSError(3)])
+            except* TypeError:
+                raise
+            except* ValueError:
+                raise
+            # OSError not handled
+        except ExceptionGroup as e:
+            exc = e
+
+        self.assertExceptionIsLike(
+            exc,
+            ExceptionGroup("eg", [TypeError(1), ValueError(2), OSError(3)]))
+
+    def test_reraise_some_handle_all_named(self):
+        try:
+            try:
+                raise ExceptionGroup(
+                    "eg", [TypeError(1), ValueError(2), OSError(3)])
+            except* TypeError as e:
+                raise
+            except* ValueError as e:
+                pass
+            # OSError not handled
+        except ExceptionGroup as e:
+            exc = e
+
+        self.assertExceptionIsLike(
+            exc, ExceptionGroup("eg", [TypeError(1), OSError(3)]))
+
+    def test_reraise_partial_handle_all_unnamed(self):
+        try:
+            try:
+                raise ExceptionGroup(
+                    "eg", [TypeError(1), ValueError(2)])
+            except* TypeError:
+                raise
+            except* ValueError:
+                pass
+        except ExceptionGroup as e:
+            exc = e
+
+        self.assertExceptionIsLike(
+            exc, ExceptionGroup("eg", [TypeError(1)]))
+
+    def test_reraise_partial_handle_some_named(self):
+        try:
+            try:
+                raise ExceptionGroup(
+                    "eg", [TypeError(1), ValueError(2), OSError(3)])
+            except* TypeError as e:
+                raise
+            except* ValueError as e:
+                pass
+            # OSError not handled
+        except ExceptionGroup as e:
+            exc = e
+
+        self.assertExceptionIsLike(
+            exc, ExceptionGroup("eg", [TypeError(1), OSError(3)]))
+
+    def test_reraise_partial_handle_some_unnamed(self):
+        try:
+            try:
+                raise ExceptionGroup(
+                    "eg", [TypeError(1), ValueError(2), OSError(3)])
+            except* TypeError:
+                raise
+            except* ValueError:
+                pass
+        except ExceptionGroup as e:
+            exc = e
+
+        self.assertExceptionIsLike(
+            exc, ExceptionGroup("eg", [TypeError(1), OSError(3)]))
+
+    def test_reraise_plain_exception_named(self):
+        try:
+            try:
+                raise ValueError(42)
+            except* ValueError as e:
+                raise
+        except ExceptionGroup as e:
+            exc = e
+
+        self.assertExceptionIsLike(
+            exc, ExceptionGroup("", [ValueError(42)]))
+
+    def test_reraise_plain_exception_unnamed(self):
+        try:
+            try:
+                raise ValueError(42)
+            except* ValueError:
+                raise
+        except ExceptionGroup as e:
+            exc = e
+
+        self.assertExceptionIsLike(
+            exc, ExceptionGroup("", [ValueError(42)]))
+
+
+class TestExceptStarRaise(ExceptStarTest):
+    def test_raise_named(self):
+        orig = ExceptionGroup("eg", [ValueError(1), OSError(2)])
+        try:
+            try:
+                raise orig
+            except* OSError as e:
+                raise TypeError(3)
+        except ExceptionGroup as e:
+            exc = e
+
+        self.assertExceptionIsLike(
+            exc,
+            ExceptionGroup(
+                "", [TypeError(3), ExceptionGroup("eg", [ValueError(1)])]))
+
+        self.assertExceptionIsLike(
+            exc.exceptions[0].__context__,
+            ExceptionGroup("eg", [OSError(2)]))
+
+        self.assertMetadataNotEqual(orig, exc)
+        self.assertMetadataEqual(orig, exc.exceptions[0].__context__)
+
+    def test_raise_unnamed(self):
+        orig = ExceptionGroup("eg", [ValueError(1), OSError(2)])
+        try:
+            try:
+                raise orig
+            except* OSError:
+                raise TypeError(3)
+        except ExceptionGroup as e:
+            exc = e
+
+        self.assertExceptionIsLike(
+            exc,
+            ExceptionGroup(
+                "", [TypeError(3), ExceptionGroup("eg", [ValueError(1)])]))
+
+        self.assertExceptionIsLike(
+            exc.exceptions[0].__context__,
+            ExceptionGroup("eg", [OSError(2)]))
+
+        self.assertMetadataNotEqual(orig, exc)
+        self.assertMetadataEqual(orig, exc.exceptions[0].__context__)
+
+    def test_raise_handle_all_raise_one_named(self):
+        orig = ExceptionGroup("eg", [TypeError(1), ValueError(2)])
+        try:
+            try:
+                raise orig
+            except* (TypeError, ValueError) as e:
+                raise SyntaxError(3)
+        except BaseException as e:
+            exc = e
+
+        self.assertExceptionIsLike(
+            exc, ExceptionGroup("", [SyntaxError(3)]))
+
+        self.assertExceptionIsLike(
+            exc.exceptions[0].__context__,
+            ExceptionGroup("eg", [TypeError(1), ValueError(2)]))
+
+        self.assertMetadataNotEqual(orig, exc)
+        self.assertMetadataEqual(orig, exc.exceptions[0].__context__)
+
+    def test_raise_handle_all_raise_one_unnamed(self):
+        orig = ExceptionGroup("eg", [TypeError(1), ValueError(2)])
+        try:
+            try:
+                raise orig
+            except* (TypeError, ValueError) as e:
+                raise SyntaxError(3)
+        except ExceptionGroup as e:
+            exc = e
+
+        self.assertExceptionIsLike(
+            exc, ExceptionGroup("", [SyntaxError(3)]))
+
+        self.assertExceptionIsLike(
+            exc.exceptions[0].__context__,
+            ExceptionGroup("eg", [TypeError(1), ValueError(2)]))
+
+        self.assertMetadataNotEqual(orig, exc)
+        self.assertMetadataEqual(orig, exc.exceptions[0].__context__)
+
+    def test_raise_handle_all_raise_two_named(self):
+        orig = ExceptionGroup("eg", [TypeError(1), ValueError(2)])
+        try:
+            try:
+                raise orig
+            except* TypeError as e:
+                raise SyntaxError(3)
+            except* ValueError as e:
+                raise SyntaxError(4)
+        except ExceptionGroup as e:
+            exc = e
+
+        self.assertExceptionIsLike(
+            exc, ExceptionGroup("", [SyntaxError(3), SyntaxError(4)]))
+
+        self.assertExceptionIsLike(
+            exc.exceptions[0].__context__,
+            ExceptionGroup("eg", [TypeError(1)]))
+
+        self.assertExceptionIsLike(
+            exc.exceptions[1].__context__,
+            ExceptionGroup("eg", [ValueError(2)]))
+
+        self.assertMetadataNotEqual(orig, exc)
+        self.assertMetadataEqual(orig, exc.exceptions[0].__context__)
+        self.assertMetadataEqual(orig, exc.exceptions[1].__context__)
+
+    def test_raise_handle_all_raise_two_unnamed(self):
+        orig = ExceptionGroup("eg", [TypeError(1), ValueError(2)])
+        try:
+            try:
+                raise orig
+            except* TypeError:
+                raise SyntaxError(3)
+            except* ValueError:
+                raise SyntaxError(4)
+        except ExceptionGroup as e:
+            exc = e
+
+        self.assertExceptionIsLike(
+            exc, ExceptionGroup("", [SyntaxError(3), SyntaxError(4)]))
+
+        self.assertExceptionIsLike(
+            exc.exceptions[0].__context__,
+            ExceptionGroup("eg", [TypeError(1)]))
+
+        self.assertExceptionIsLike(
+            exc.exceptions[1].__context__,
+            ExceptionGroup("eg", [ValueError(2)]))
+
+        self.assertMetadataNotEqual(orig, exc)
+        self.assertMetadataEqual(orig, exc.exceptions[0].__context__)
+        self.assertMetadataEqual(orig, exc.exceptions[1].__context__)
+
+
+class TestExceptStarRaiseFrom(ExceptStarTest):
+    def test_raise_named(self):
+        orig = ExceptionGroup("eg", [ValueError(1), OSError(2)])
+        try:
+            try:
+                raise orig
+            except* OSError as e:
+                raise TypeError(3) from e
+        except ExceptionGroup as e:
+            exc = e
+
+        self.assertExceptionIsLike(
+            exc,
+            ExceptionGroup(
+                "", [TypeError(3), ExceptionGroup("eg", [ValueError(1)])]))
+
+        self.assertExceptionIsLike(
+            exc.exceptions[0].__context__,
+            ExceptionGroup("eg", [OSError(2)]))
+
+        self.assertExceptionIsLike(
+            exc.exceptions[0].__cause__,
+            ExceptionGroup("eg", [OSError(2)]))
+
+        self.assertMetadataNotEqual(orig, exc)
+        self.assertMetadataEqual(orig, exc.exceptions[0].__context__)
+        self.assertMetadataEqual(orig, exc.exceptions[0].__cause__)
+        self.assertMetadataNotEqual(orig, exc.exceptions[1].__context__)
+        self.assertMetadataNotEqual(orig, exc.exceptions[1].__cause__)
+
+    def test_raise_unnamed(self):
+        orig = ExceptionGroup("eg", [ValueError(1), OSError(2)])
+        try:
+            try:
+                raise orig
+            except* OSError:
+                e = sys.exc_info()[1]
+                raise TypeError(3) from e
+        except ExceptionGroup as e:
+            exc = e
+
+        self.assertExceptionIsLike(
+            exc,
+            ExceptionGroup(
+                "", [TypeError(3), ExceptionGroup("eg", [ValueError(1)])]))
+
+        self.assertExceptionIsLike(
+            exc.exceptions[0].__context__,
+            ExceptionGroup("eg", [OSError(2)]))
+
+        self.assertExceptionIsLike(
+            exc.exceptions[0].__cause__,
+            ExceptionGroup("eg", [OSError(2)]))
+
+        self.assertMetadataNotEqual(orig, exc)
+        self.assertMetadataEqual(orig, exc.exceptions[0].__context__)
+        self.assertMetadataEqual(orig, exc.exceptions[0].__cause__)
+        self.assertMetadataNotEqual(orig, exc.exceptions[1].__context__)
+        self.assertMetadataNotEqual(orig, exc.exceptions[1].__cause__)
+
+    def test_raise_handle_all_raise_one_named(self):
+        orig = ExceptionGroup("eg", [TypeError(1), ValueError(2)])
+        try:
+            try:
+                raise orig
+            except* (TypeError, ValueError) as e:
+                raise SyntaxError(3) from e
+        except BaseException as e:
+            exc = e
+
+        self.assertExceptionIsLike(
+            exc, ExceptionGroup("", [SyntaxError(3)]))
+
+        self.assertExceptionIsLike(
+            exc.exceptions[0].__context__,
+            ExceptionGroup("eg", [TypeError(1), ValueError(2)]))
+
+        self.assertExceptionIsLike(
+            exc.exceptions[0].__cause__,
+            ExceptionGroup("eg", [TypeError(1), ValueError(2)]))
+
+        self.assertMetadataNotEqual(orig, exc)
+        self.assertMetadataEqual(orig, exc.exceptions[0].__context__)
+        self.assertMetadataEqual(orig, exc.exceptions[0].__cause__)
+
+    def test_raise_handle_all_raise_one_unnamed(self):
+        orig = ExceptionGroup("eg", [TypeError(1), ValueError(2)])
+        try:
+            try:
+                raise orig
+            except* (TypeError, ValueError) as e:
+                e = sys.exc_info()[1]
+                raise SyntaxError(3) from e
+        except ExceptionGroup as e:
+            exc = e
+
+        self.assertExceptionIsLike(
+            exc, ExceptionGroup("", [SyntaxError(3)]))
+
+        self.assertExceptionIsLike(
+            exc.exceptions[0].__context__,
+            ExceptionGroup("eg", [TypeError(1), ValueError(2)]))
+
+        self.assertExceptionIsLike(
+            exc.exceptions[0].__cause__,
+            ExceptionGroup("eg", [TypeError(1), ValueError(2)]))
+
+        self.assertMetadataNotEqual(orig, exc)
+        self.assertMetadataEqual(orig, exc.exceptions[0].__context__)
+        self.assertMetadataEqual(orig, exc.exceptions[0].__cause__)
+
+    def test_raise_handle_all_raise_two_named(self):
+        orig = ExceptionGroup("eg", [TypeError(1), ValueError(2)])
+        try:
+            try:
+                raise orig
+            except* TypeError as e:
+                raise SyntaxError(3) from e
+            except* ValueError as e:
+                raise SyntaxError(4) from e
+        except ExceptionGroup as e:
+            exc = e
+
+        self.assertExceptionIsLike(
+            exc, ExceptionGroup("", [SyntaxError(3), SyntaxError(4)]))
+
+        self.assertExceptionIsLike(
+            exc.exceptions[0].__context__,
+            ExceptionGroup("eg", [TypeError(1)]))
+
+        self.assertExceptionIsLike(
+            exc.exceptions[0].__cause__,
+            ExceptionGroup("eg", [TypeError(1)]))
+
+        self.assertExceptionIsLike(
+            exc.exceptions[1].__context__,
+            ExceptionGroup("eg", [ValueError(2)]))
+
+        self.assertExceptionIsLike(
+            exc.exceptions[1].__cause__,
+            ExceptionGroup("eg", [ValueError(2)]))
+
+        self.assertMetadataNotEqual(orig, exc)
+        self.assertMetadataEqual(orig, exc.exceptions[0].__context__)
+        self.assertMetadataEqual(orig, exc.exceptions[0].__cause__)
+
+    def test_raise_handle_all_raise_two_unnamed(self):
+        orig = ExceptionGroup("eg", [TypeError(1), ValueError(2)])
+        try:
+            try:
+                raise orig
+            except* TypeError:
+                e = sys.exc_info()[1]
+                raise SyntaxError(3) from e
+            except* ValueError:
+                e = sys.exc_info()[1]
+                raise SyntaxError(4) from e
+        except ExceptionGroup as e:
+            exc = e
+
+        self.assertExceptionIsLike(
+            exc, ExceptionGroup("", [SyntaxError(3), SyntaxError(4)]))
+
+        self.assertExceptionIsLike(
+            exc.exceptions[0].__context__,
+            ExceptionGroup("eg", [TypeError(1)]))
+
+        self.assertExceptionIsLike(
+            exc.exceptions[0].__cause__,
+            ExceptionGroup("eg", [TypeError(1)]))
+
+        self.assertExceptionIsLike(
+            exc.exceptions[1].__context__,
+            ExceptionGroup("eg", [ValueError(2)]))
+
+        self.assertExceptionIsLike(
+            exc.exceptions[1].__cause__,
+            ExceptionGroup("eg", [ValueError(2)]))
+
+        self.assertMetadataNotEqual(orig, exc)
+        self.assertMetadataEqual(orig, exc.exceptions[0].__context__)
+        self.assertMetadataEqual(orig, exc.exceptions[0].__cause__)
+        self.assertMetadataEqual(orig, exc.exceptions[1].__context__)
+        self.assertMetadataEqual(orig, exc.exceptions[1].__cause__)
+
+
+class TestExceptStarExceptionGroupSubclass(ExceptStarTest):
+    def test_except_star_EG_subclass(self):
+        class EG(ExceptionGroup):
+            def __new__(cls, message, excs, code):
+                obj = super().__new__(cls, message, excs)
+                obj.code = code
+                return obj
+
+            def derive(self, excs):
+                return EG(self.message, excs, self.code)
+
+        try:
+            try:
+                try:
+                    try:
+                        raise TypeError(2)
+                    except TypeError as te:
+                        raise EG("nested", [te], 101) from None
+                except EG as nested:
+                    try:
+                        raise ValueError(1)
+                    except ValueError as ve:
+                        raise EG("eg", [ve, nested], 42)
+            except* ValueError as eg:
+                veg = eg
+        except EG as eg:
+            teg = eg
+
+        self.assertIsInstance(veg, EG)
+        self.assertIsInstance(teg, EG)
+        self.assertIsInstance(teg.exceptions[0], EG)
+        self.assertMetadataEqual(veg, teg)
+        self.assertEqual(veg.code, 42)
+        self.assertEqual(teg.code, 42)
+        self.assertEqual(teg.exceptions[0].code, 101)
+
+
+class TestExceptStarCleanup(ExceptStarTest):
+    def test_exc_info_restored(self):
+        try:
+            try:
+                raise ValueError(42)
+            except:
+                try:
+                    raise TypeError(int)
+                except* Exception:
+                    pass
+                1/0
+        except Exception as e:
+            exc = e
+
+        self.assertExceptionIsLike(exc, ZeroDivisionError('division by zero'))
+        self.assertExceptionIsLike(exc.__context__, ValueError(42))
+        self.assertEqual(sys.exc_info(), (None, None, None))
+
+
+if __name__ == '__main__':
+    unittest.main()
diff --git a/Lib/test/test_exception_group.py b/Lib/test/test_exception_group.py
index 62ec1ee..c793c45 100644
--- a/Lib/test/test_exception_group.py
+++ b/Lib/test/test_exception_group.py
@@ -211,7 +211,8 @@ class ExceptionGroupSubgroupTests(ExceptionGroupTestBase):
     def test_basics_subgroup_split__bad_arg_type(self):
         bad_args = ["bad arg",
                     OSError('instance not type'),
-                    [OSError('instance not type')],]
+                    [OSError, TypeError],
+                    (OSError, 42)]
         for arg in bad_args:
             with self.assertRaises(TypeError):
                 self.eg.subgroup(arg)
diff --git a/Lib/test/test_exception_variations.py b/Lib/test/test_exception_variations.py
index d874b0e..aabac6d 100644
--- a/Lib/test/test_exception_variations.py
+++ b/Lib/test/test_exception_variations.py
@@ -172,5 +172,283 @@ class ExceptionTestCase(unittest.TestCase):
         self.assertTrue(hit_finally)
         self.assertTrue(hit_except)
 
+
+class ExceptStarTestCases(unittest.TestCase):
+    def test_try_except_else_finally(self):
+        hit_except = False
+        hit_else = False
+        hit_finally = False
+
+        try:
+            raise Exception('nyaa!')
+        except* BaseException:
+            hit_except = True
+        else:
+            hit_else = True
+        finally:
+            hit_finally = True
+
+        self.assertTrue(hit_except)
+        self.assertTrue(hit_finally)
+        self.assertFalse(hit_else)
+
+    def test_try_except_else_finally_no_exception(self):
+        hit_except = False
+        hit_else = False
+        hit_finally = False
+
+        try:
+            pass
+        except* BaseException:
+            hit_except = True
+        else:
+            hit_else = True
+        finally:
+            hit_finally = True
+
+        self.assertFalse(hit_except)
+        self.assertTrue(hit_finally)
+        self.assertTrue(hit_else)
+
+    def test_try_except_finally(self):
+        hit_except = False
+        hit_finally = False
+
+        try:
+            raise Exception('yarr!')
+        except* BaseException:
+            hit_except = True
+        finally:
+            hit_finally = True
+
+        self.assertTrue(hit_except)
+        self.assertTrue(hit_finally)
+
+    def test_try_except_finally_no_exception(self):
+        hit_except = False
+        hit_finally = False
+
+        try:
+            pass
+        except* BaseException:
+            hit_except = True
+        finally:
+            hit_finally = True
+
+        self.assertFalse(hit_except)
+        self.assertTrue(hit_finally)
+
+    def test_try_except(self):
+        hit_except = False
+
+        try:
+            raise Exception('ahoy!')
+        except* BaseException:
+            hit_except = True
+
+        self.assertTrue(hit_except)
+
+    def test_try_except_no_exception(self):
+        hit_except = False
+
+        try:
+            pass
+        except* BaseException:
+            hit_except = True
+
+        self.assertFalse(hit_except)
+
+    def test_try_except_else(self):
+        hit_except = False
+        hit_else = False
+
+        try:
+            raise Exception('foo!')
+        except* BaseException:
+            hit_except = True
+        else:
+            hit_else = True
+
+        self.assertFalse(hit_else)
+        self.assertTrue(hit_except)
+
+    def test_try_except_else_no_exception(self):
+        hit_except = False
+        hit_else = False
+
+        try:
+            pass
+        except* BaseException:
+            hit_except = True
+        else:
+            hit_else = True
+
+        self.assertFalse(hit_except)
+        self.assertTrue(hit_else)
+
+    def test_try_finally_no_exception(self):
+        hit_finally = False
+
+        try:
+            pass
+        finally:
+            hit_finally = True
+
+        self.assertTrue(hit_finally)
+
+    def test_nested(self):
+        hit_finally = False
+        hit_inner_except = False
+        hit_inner_finally = False
+
+        try:
+            try:
+                raise Exception('inner exception')
+            except* BaseException:
+                hit_inner_except = True
+            finally:
+                hit_inner_finally = True
+        finally:
+            hit_finally = True
+
+        self.assertTrue(hit_inner_except)
+        self.assertTrue(hit_inner_finally)
+        self.assertTrue(hit_finally)
+
+    def test_nested_else(self):
+        hit_else = False
+        hit_finally = False
+        hit_except = False
+        hit_inner_except = False
+        hit_inner_else = False
+
+        try:
+            try:
+                pass
+            except* BaseException:
+                hit_inner_except = True
+            else:
+                hit_inner_else = True
+
+            raise Exception('outer exception')
+        except* BaseException:
+            hit_except = True
+        else:
+            hit_else = True
+        finally:
+            hit_finally = True
+
+        self.assertFalse(hit_inner_except)
+        self.assertTrue(hit_inner_else)
+        self.assertFalse(hit_else)
+        self.assertTrue(hit_finally)
+        self.assertTrue(hit_except)
+
+    def test_nested_mixed1(self):
+        hit_except = False
+        hit_finally = False
+        hit_inner_except = False
+        hit_inner_finally = False
+
+        try:
+            try:
+                raise Exception('inner exception')
+            except* BaseException:
+                hit_inner_except = True
+            finally:
+                hit_inner_finally = True
+        except:
+            hit_except = True
+        finally:
+            hit_finally = True
+
+        self.assertTrue(hit_inner_except)
+        self.assertTrue(hit_inner_finally)
+        self.assertFalse(hit_except)
+        self.assertTrue(hit_finally)
+
+    def test_nested_mixed2(self):
+        hit_except = False
+        hit_finally = False
+        hit_inner_except = False
+        hit_inner_finally = False
+
+        try:
+            try:
+                raise Exception('inner exception')
+            except:
+                hit_inner_except = True
+            finally:
+                hit_inner_finally = True
+        except* BaseException:
+            hit_except = True
+        finally:
+            hit_finally = True
+
+        self.assertTrue(hit_inner_except)
+        self.assertTrue(hit_inner_finally)
+        self.assertFalse(hit_except)
+        self.assertTrue(hit_finally)
+
+
+    def test_nested_else_mixed1(self):
+        hit_else = False
+        hit_finally = False
+        hit_except = False
+        hit_inner_except = False
+        hit_inner_else = False
+
+        try:
+            try:
+                pass
+            except* BaseException:
+                hit_inner_except = True
+            else:
+                hit_inner_else = True
+
+            raise Exception('outer exception')
+        except:
+            hit_except = True
+        else:
+            hit_else = True
+        finally:
+            hit_finally = True
+
+        self.assertFalse(hit_inner_except)
+        self.assertTrue(hit_inner_else)
+        self.assertFalse(hit_else)
+        self.assertTrue(hit_finally)
+        self.assertTrue(hit_except)
+
+    def test_nested_else_mixed2(self):
+        hit_else = False
+        hit_finally = False
+        hit_except = False
+        hit_inner_except = False
+        hit_inner_else = False
+
+        try:
+            try:
+                pass
+            except:
+                hit_inner_except = True
+            else:
+                hit_inner_else = True
+
+            raise Exception('outer exception')
+        except* BaseException:
+            hit_except = True
+        else:
+            hit_else = True
+        finally:
+            hit_finally = True
+
+        self.assertFalse(hit_inner_except)
+        self.assertTrue(hit_inner_else)
+        self.assertFalse(hit_else)
+        self.assertTrue(hit_finally)
+        self.assertTrue(hit_except)
+
+
 if __name__ == '__main__':
     unittest.main()
diff --git a/Lib/test/test_exceptions.py b/Lib/test/test_exceptions.py
index ffcb5e1..3e7808c 100644
--- a/Lib/test/test_exceptions.py
+++ b/Lib/test/test_exceptions.py
@@ -241,6 +241,8 @@ class ExceptionTests(unittest.TestCase):
         check('def f():\n  continue', 2, 3)
         check('def f():\n  break', 2, 3)
         check('try:\n  pass\nexcept:\n  pass\nexcept ValueError:\n  pass', 3, 1)
+        check('try:\n  pass\nexcept*:\n  pass', 3, 8)
+        check('try:\n  pass\nexcept*:\n  pass\nexcept* ValueError:\n  pass', 3, 8)
 
         # Errors thrown by tokenizer.c
         check('(0x+1)', 1, 3)
diff --git a/Lib/test/test_grammar.py b/Lib/test/test_grammar.py
index b6c4574..a2460ad 100644
--- a/Lib/test/test_grammar.py
+++ b/Lib/test/test_grammar.py
@@ -1419,6 +1419,30 @@ class GrammarTests(unittest.TestCase):
             compile("try:\n    pass\nexcept Exception as a.b:\n    pass", "?", "exec")
             compile("try:\n    pass\nexcept Exception as a[b]:\n    pass", "?", "exec")
 
+    def test_try_star(self):
+        ### try_stmt: 'try': suite (except_star_clause : suite) + ['else' ':' suite]
+        ### except_star_clause: 'except*' expr ['as' NAME]
+        try:
+            1/0
+        except* ZeroDivisionError:
+            pass
+        else:
+            pass
+        try: 1/0
+        except* EOFError: pass
+        except* ZeroDivisionError as msg: pass
+        else: pass
+        try: 1/0
+        except* (EOFError, TypeError, ZeroDivisionError): pass
+        try: 1/0
+        except* (EOFError, TypeError, ZeroDivisionError) as msg: pass
+        try: pass
+        finally: pass
+        with self.assertRaises(SyntaxError):
+            compile("try:\n    pass\nexcept* Exception as a.b:\n    pass", "?", "exec")
+            compile("try:\n    pass\nexcept* Exception as a[b]:\n    pass", "?", "exec")
+            compile("try:\n    pass\nexcept*:\n    pass", "?", "exec")
+
     def test_suite(self):
         # simple_stmt | NEWLINE INDENT NEWLINE* (stmt NEWLINE*)+ DEDENT
         if 1: pass
diff --git a/Lib/test/test_syntax.py b/Lib/test/test_syntax.py
index fc3c629..6286529 100644
--- a/Lib/test/test_syntax.py
+++ b/Lib/test/test_syntax.py
@@ -955,6 +955,48 @@ Custom error messages for try blocks that are not followed by except/finally
    Traceback (most recent call last):
    SyntaxError: expected 'except' or 'finally' block
 
+Custom error message for try block mixing except and except*
+
+   >>> try:
+   ...    pass
+   ... except TypeError:
+   ...    pass
+   ... except* ValueError:
+   ...    pass
+   Traceback (most recent call last):
+   SyntaxError: cannot have both 'except' and 'except*' on the same 'try'
+
+   >>> try:
+   ...    pass
+   ... except* TypeError:
+   ...    pass
+   ... except ValueError:
+   ...    pass
+   Traceback (most recent call last):
+   SyntaxError: cannot have both 'except' and 'except*' on the same 'try'
+
+   >>> try:
+   ...    pass
+   ... except TypeError:
+   ...    pass
+   ... except TypeError:
+   ...    pass
+   ... except* ValueError:
+   ...    pass
+   Traceback (most recent call last):
+   SyntaxError: cannot have both 'except' and 'except*' on the same 'try'
+
+   >>> try:
+   ...    pass
+   ... except* TypeError:
+   ...    pass
+   ... except* TypeError:
+   ...    pass
+   ... except ValueError:
+   ...    pass
+   Traceback (most recent call last):
+   SyntaxError: cannot have both 'except' and 'except*' on the same 'try'
+
 Ensure that early = are not matched by the parser as invalid comparisons
    >>> f(2, 4, x=34); 1 $ 2
    Traceback (most recent call last):
@@ -1070,6 +1112,13 @@ Specialized indentation errors:
 
    >>> try:
    ...     something()
+   ... except* A:
+   ... pass
+   Traceback (most recent call last):
+   IndentationError: expected an indented block after 'except*' statement on line 3
+
+   >>> try:
+   ...     something()
    ... except A:
    ...     pass
    ... finally:
@@ -1077,6 +1126,15 @@ Specialized indentation errors:
    Traceback (most recent call last):
    IndentationError: expected an indented block after 'finally' statement on line 5
 
+   >>> try:
+   ...     something()
+   ... except* A:
+   ...     pass
+   ... finally:
+   ... pass
+   Traceback (most recent call last):
+   IndentationError: expected an indented block after 'finally' statement on line 5
+
    >>> with A:
    ... pass
    Traceback (most recent call last):
@@ -1180,6 +1238,48 @@ raise a custom exception
    SyntaxError: multiple exception types must be parenthesized
 
 
+   >>> try:
+   ...   pass
+   ... except* A, B:
+   ...   pass
+   Traceback (most recent call last):
+   SyntaxError: multiple exception types must be parenthesized
+
+   >>> try:
+   ...   pass
+   ... except* A, B, C:
+   ...   pass
+   Traceback (most recent call last):
+   SyntaxError: multiple exception types must be parenthesized
+
+   >>> try:
+   ...   pass
+   ... except* A, B, C as blech:
+   ...   pass
+   Traceback (most recent call last):
+   SyntaxError: multiple exception types must be parenthesized
+
+   >>> try:
+   ...   pass
+   ... except* A, B, C as blech:
+   ...   pass
+   ... finally:
+   ...   pass
+   Traceback (most recent call last):
+   SyntaxError: multiple exception types must be parenthesized
+
+Custom exception for 'except*' without an exception type
+
+   >>> try:
+   ...   pass
+   ... except* A as a:
+   ...   pass
+   ... except*:
+   ...   pass
+   Traceback (most recent call last):
+   SyntaxError: expected one or more exception types
+
+
 >>> f(a=23, a=234)
 Traceback (most recent call last):
    ...
diff --git a/Lib/test/test_sys_settrace.py b/Lib/test/test_sys_settrace.py
index 15c33a2..dc2aef1 100644
--- a/Lib/test/test_sys_settrace.py
+++ b/Lib/test/test_sys_settrace.py
@@ -1213,6 +1213,181 @@ class TraceTestCase(unittest.TestCase):
              (5, 'line'),
              (5, 'return')])
 
+    def test_try_except_star_no_exception(self):
+
+        def func():
+            try:
+                2
+            except* Exception:
+                4
+            else:
+                6
+            finally:
+                8
+
+        self.run_and_compare(func,
+            [(0, 'call'),
+             (1, 'line'),
+             (2, 'line'),
+             (6, 'line'),
+             (8, 'line'),
+             (8, 'return')])
+
+    def test_try_except_star_named_no_exception(self):
+
+        def func():
+            try:
+                2
+            except* Exception as e:
+                4
+            else:
+                6
+            finally:
+                8
+
+        self.run_and_compare(func,
+            [(0, 'call'),
+             (1, 'line'),
+             (2, 'line'),
+             (6, 'line'),
+             (8, 'line'),
+             (8, 'return')])
+
+    def test_try_except_star_exception_caught(self):
+
+        def func():
+            try:
+                raise ValueError(2)
+            except* ValueError:
+                4
+            else:
+                6
+            finally:
+                8
+
+        self.run_and_compare(func,
+            [(0, 'call'),
+             (1, 'line'),
+             (2, 'line'),
+             (2, 'exception'),
+             (3, 'line'),
+             (4, 'line'),
+             (8, 'line'),
+             (8, 'return')])
+
+    def test_try_except_star_named_exception_caught(self):
+
+        def func():
+            try:
+                raise ValueError(2)
+            except* ValueError as e:
+                4
+            else:
+                6
+            finally:
+                8
+
+        self.run_and_compare(func,
+            [(0, 'call'),
+             (1, 'line'),
+             (2, 'line'),
+             (2, 'exception'),
+             (3, 'line'),
+             (4, 'line'),
+             (8, 'line'),
+             (8, 'return')])
+
+    def test_try_except_star_exception_not_caught(self):
+
+        def func():
+            try:
+                try:
+                    raise ValueError(3)
+                except* TypeError:
+                    5
+            except ValueError:
+                7
+
+        self.run_and_compare(func,
+            [(0, 'call'),
+             (1, 'line'),
+             (2, 'line'),
+             (3, 'line'),
+             (3, 'exception'),
+             (4, 'line'),
+             (6, 'line'),
+             (7, 'line'),
+             (7, 'return')])
+
+    def test_try_except_star_named_exception_not_caught(self):
+
+        def func():
+            try:
+                try:
+                    raise ValueError(3)
+                except* TypeError as e:
+                    5
+            except ValueError:
+                7
+
+        self.run_and_compare(func,
+            [(0, 'call'),
+             (1, 'line'),
+             (2, 'line'),
+             (3, 'line'),
+             (3, 'exception'),
+             (4, 'line'),
+             (6, 'line'),
+             (7, 'line'),
+             (7, 'return')])
+
+    def test_try_except_star_nested(self):
+
+        def func():
+            try:
+                try:
+                    raise ExceptionGroup(
+                        'eg',
+                        [ValueError(5), TypeError('bad type')])
+                except* TypeError as e:
+                    7
+                except* OSError:
+                    9
+                except* ValueError:
+                    raise
+            except* ValueError:
+                try:
+                    raise TypeError(14)
+                except* OSError:
+                    16
+                except* TypeError as e:
+                    18
+            return 0
+
+        self.run_and_compare(func,
+            [(0, 'call'),
+             (1, 'line'),
+             (2, 'line'),
+             (3, 'line'),
+             (4, 'line'),
+             (5, 'line'),
+             (3, 'line'),
+             (3, 'exception'),
+             (6, 'line'),
+             (7, 'line'),
+             (8, 'line'),
+             (10, 'line'),
+             (11, 'line'),
+             (12, 'line'),
+             (13, 'line'),
+             (14, 'line'),
+             (14, 'exception'),
+             (15, 'line'),
+             (17, 'line'),
+             (18, 'line'),
+             (19, 'line'),
+             (19, 'return')])
+
 
 class SkipLineEventsTraceTestCase(TraceTestCase):
     """Repeat the trace tests, but with per-line events skipped"""
diff --git a/Lib/test/test_unparse.py b/Lib/test/test_unparse.py
index d8ba487..f5be13a 100644
--- a/Lib/test/test_unparse.py
+++ b/Lib/test/test_unparse.py
@@ -93,6 +93,19 @@ finally:
     suite5
 """
 
+try_except_star_finally = """\
+try:
+    suite1
+except* ex1:
+    suite2
+except* ex2:
+    suite3
+else:
+    suite4
+finally:
+    suite5
+"""
+
 with_simple = """\
 with f():
     suite1
@@ -304,6 +317,9 @@ class UnparseTestCase(ASTTestCase):
     def test_try_except_finally(self):
         self.check_ast_roundtrip(try_except_finally)
 
+    def test_try_except_star_finally(self):
+        self.check_ast_roundtrip(try_except_star_finally)
+
     def test_starred_assignment(self):
         self.check_ast_roundtrip("a, *b, c = seq")
         self.check_ast_roundtrip("a, (*b, c) = seq")