Rename Red Knot (#17820)

crates/ty_python_semantic/resources/mdtest/exception/basic.md

@@ -0,0 +1,179 @@
+# Exception Handling
+
+## Single Exception
+
+```py
+import re
+
+try:
+    help()
+except NameError as e:
+    reveal_type(e)  # revealed: NameError
+except re.error as f:
+    reveal_type(f)  # revealed: error
+```
+
+## Unknown type in except handler does not cause spurious diagnostic
+
+```py
+from nonexistent_module import foo  # error: [unresolved-import]
+
+try:
+    help()
+except foo as e:
+    reveal_type(foo)  # revealed: Unknown
+    reveal_type(e)  # revealed: Unknown
+```
+
+## Multiple Exceptions in a Tuple
+
+```py
+EXCEPTIONS = (AttributeError, TypeError)
+
+try:
+    help()
+except (RuntimeError, OSError) as e:
+    reveal_type(e)  # revealed: RuntimeError | OSError
+except EXCEPTIONS as f:
+    reveal_type(f)  # revealed: AttributeError | TypeError
+```
+
+## Dynamic exception types
+
+```py
+def foo(
+    x: type[AttributeError],
+    y: tuple[type[OSError], type[RuntimeError]],
+    z: tuple[type[BaseException], ...],
+):
+    try:
+        help()
+    except x as e:
+        reveal_type(e)  # revealed: AttributeError
+    except y as f:
+        reveal_type(f)  # revealed: OSError | RuntimeError
+    except z as g:
+        # TODO: should be `BaseException`
+        reveal_type(g)  # revealed: @Todo(full tuple[...] support)
+```
+
+## Invalid exception handlers
+
+```py
+try:
+    pass
+# error: [invalid-exception-caught] "Cannot catch object of type `Literal[3]` in an exception handler (must be a `BaseException` subclass or a tuple of `BaseException` subclasses)"
+except 3 as e:
+    reveal_type(e)  # revealed: Unknown
+
+try:
+    pass
+# error: [invalid-exception-caught] "Cannot catch object of type `Literal["foo"]` in an exception handler (must be a `BaseException` subclass or a tuple of `BaseException` subclasses)"
+# error: [invalid-exception-caught] "Cannot catch object of type `Literal[b"bar"]` in an exception handler (must be a `BaseException` subclass or a tuple of `BaseException` subclasses)"
+except (ValueError, OSError, "foo", b"bar") as e:
+    reveal_type(e)  # revealed: ValueError | OSError | Unknown
+
+def foo(
+    x: type[str],
+    y: tuple[type[OSError], type[RuntimeError], int],
+    z: tuple[type[str], ...],
+):
+    try:
+        help()
+    # error: [invalid-exception-caught]
+    except x as e:
+        reveal_type(e)  # revealed: Unknown
+    # error: [invalid-exception-caught]
+    except y as f:
+        reveal_type(f)  # revealed: OSError | RuntimeError | Unknown
+    except z as g:
+        # TODO: should emit a diagnostic here:
+        reveal_type(g)  # revealed: @Todo(full tuple[...] support)
+```
+
+## Object raised is not an exception
+
+```py
+try:
+    raise AttributeError()  # fine
+except:
+    ...
+
+try:
+    raise FloatingPointError  # fine
+except:
+    ...
+
+try:
+    raise 1  # error: [invalid-raise]
+except:
+    ...
+
+try:
+    raise int  # error: [invalid-raise]
+except:
+    ...
+
+def _(e: Exception | type[Exception]):
+    raise e  # fine
+
+def _(e: Exception | type[Exception] | None):
+    raise e  # error: [invalid-raise]
+```
+
+## Exception cause is not an exception
+
+```py
+def _():
+    try:
+        raise EOFError() from GeneratorExit  # fine
+    except:
+        ...
+
+def _():
+    try:
+        raise StopIteration from MemoryError()  # fine
+    except:
+        ...
+
+def _():
+    try:
+        raise BufferError() from None  # fine
+    except:
+        ...
+
+def _():
+    try:
+        raise ZeroDivisionError from False  # error: [invalid-raise]
+    except:
+        ...
+
+def _():
+    try:
+        raise SystemExit from bool()  # error: [invalid-raise]
+    except:
+        ...
+
+def _():
+    try:
+        raise
+    except KeyboardInterrupt as e:  # fine
+        reveal_type(e)  # revealed: KeyboardInterrupt
+        raise LookupError from e  # fine
+
+def _():
+    try:
+        raise
+    except int as e:  # error: [invalid-exception-caught]
+        reveal_type(e)  # revealed: Unknown
+        raise KeyError from e
+
+def _(e: Exception | type[Exception]):
+    raise ModuleNotFoundError from e  # fine
+
+def _(e: Exception | type[Exception] | None):
+    raise IndexError from e  # fine
+
+def _(e: int | None):
+    raise IndexError from e  # error: [invalid-raise]
+```