Make "deprecated" Note a standard Error, disabled by default

docs/source/command_line.rst

@@ -537,12 +537,6 @@ potentially problematic or redundant in some way.
 
         This limitation will be removed in future releases of mypy.
 
-.. option:: --report-deprecated-as-error
-
-    By default, mypy emits notes if your code imports or uses deprecated
-    features.    This flag converts such notes to errors, causing mypy to
-    eventually finish with a non-zero exit code.  Features are considered
-    deprecated when decorated with ``warnings.deprecated``.
 
 .. _miscellaneous-strictness-flags:
 

docs/source/error_code_list2.rst

@@ -236,13 +236,12 @@ incorrect control flow or conditional checks that are accidentally always true o
 Check that imported or used feature is deprecated [deprecated]
 --------------------------------------------------------------
 
-By default, mypy generates a note if your code imports a deprecated feature explicitly with a
+If you use :option:`--enable-error-code deprecated <mypy --enable-error-code>`,
+mypy generates an error if your code imports a deprecated feature explicitly with a
 ``from mod import depr`` statement or uses a deprecated feature imported otherwise or defined
 locally.  Features are considered deprecated when decorated with ``warnings.deprecated``, as
-specified in `PEP 702 <https://peps.python.org/pep-0702>`_.  You can silence single notes via
+specified in `PEP 702 <https://peps.python.org/pep-0702>`_.  You can silence single errors via
 ``# type: ignore[deprecated]`` or turn off this check completely via ``--disable-error-code=deprecated``.
-Use the :option:`--report-deprecated-as-error <mypy --report-deprecated-as-error>` option for
-more strictness, which turns all such notes into errors.
 
 .. note::
 

mypy/checker.py

@@ -7696,8 +7696,7 @@ def warn_deprecated(self, node: SymbolNode | None, context: Context) -> None:
             and ((deprecated := node.deprecated) is not None)
             and not self.is_typeshed_stub
         ):
-            warn = self.msg.fail if self.options.report_deprecated_as_error else self.msg.note
-            warn(deprecated, context, code=codes.DEPRECATED)
+            self.msg.fail(deprecated, context, code=codes.DEPRECATED)
 
 
 class CollectArgTypeVarTypes(TypeTraverserVisitor):

mypy/errorcodes.py

@@ -308,6 +308,7 @@ def __hash__(self) -> int:
     "deprecated",
     "Warn when importing or using deprecated (overloaded) functions, methods or classes",
     "General",
+    default_enabled=False,
 )
 
 # This copy will not include any error codes defined later in the plugins.

mypy/errors.py

@@ -20,7 +20,7 @@
 
 # Show error codes for some note-level messages (these usually appear alone
 # and not as a comment for a previous error-level message).
-SHOW_NOTE_CODES: Final = {codes.ANNOTATION_UNCHECKED, codes.DEPRECATED}
+SHOW_NOTE_CODES: Final = {codes.ANNOTATION_UNCHECKED}
 
 # Do not add notes with links to error code docs to errors with these codes.
 # We can tweak this set as we get more experience about what is helpful and what is not.

mypy/main.py

@@ -804,13 +804,6 @@ def add_invertible_flag(
         help="Warn about statements or expressions inferred to be unreachable",
         group=lint_group,
     )
-    add_invertible_flag(
-        "--report-deprecated-as-error",
-        default=False,
-        strict_flag=False,
-        help="Report importing or using deprecated features as errors instead of notes",
-        group=lint_group,
-    )
 
     # Note: this group is intentionally added here even though we don't add
     # --strict to this group near the end.

mypy/options.py

@@ -173,9 +173,6 @@ def __init__(self) -> None:
         # declared with a precise type
         self.warn_return_any = False
 
-        # Report importing or using deprecated features as errors instead of notes.
-        self.report_deprecated_as_error = False
-
         # Warn about unused '# type: ignore' comments
         self.warn_unused_ignores = False
 

mypy/typeanal.py

@@ -790,8 +790,7 @@ def check_and_warn_deprecated(self, info: TypeInfo, ctx: Context) -> None:
                 if isinstance(imp, ImportFrom) and any(info.name == n[0] for n in imp.names):
                     break
             else:
-                warn = self.fail if self.options.report_deprecated_as_error else self.note
-                warn(deprecated, ctx, code=codes.DEPRECATED)
+                self.fail(deprecated, ctx, code=codes.DEPRECATED)
 
     def analyze_type_with_type_info(
         self, info: TypeInfo, args: Sequence[Type], ctx: Context, empty_tuple_index: bool