Revert "TypeForm: Enable by default (#21262)"

This reverts commit dd851f5.

Author: JukkaL

docs/source/command_line.rst

@@ -1211,7 +1211,7 @@ format into the specified directory.
 Enabling incomplete/experimental features
 *****************************************
 
-.. option:: --enable-incomplete-feature {PreciseTupleTypes,InlineTypedDict}
+.. option:: --enable-incomplete-feature {PreciseTupleTypes,InlineTypedDict,TypeForm}
 
     Some features may require several mypy releases to implement, for example
     due to their complexity, potential for backwards incompatibility, or
@@ -1266,6 +1266,8 @@ List of currently incomplete/experimental features:
      def test_values() -> {"width": int, "description": str}:
          return {"width": 42, "description": "test"}
 
+* ``TypeForm``: this feature enables ``TypeForm``, as described in
+  `PEP 747 – Annotating Type Forms <https://peps.python.org/pep-0747/>_`.
 
 
 Miscellaneous

mypy/options.py

@@ -94,8 +94,8 @@ class BuildType:
 NEW_GENERIC_SYNTAX: Final = "NewGenericSyntax"
 INLINE_TYPEDDICT: Final = "InlineTypedDict"
 TYPE_FORM: Final = "TypeForm"
-INCOMPLETE_FEATURES: Final = frozenset((PRECISE_TUPLE_TYPES, INLINE_TYPEDDICT))
-COMPLETE_FEATURES: Final = frozenset((TYPE_VAR_TUPLE, UNPACK, NEW_GENERIC_SYNTAX, TYPE_FORM))
+INCOMPLETE_FEATURES: Final = frozenset((PRECISE_TUPLE_TYPES, INLINE_TYPEDDICT, TYPE_FORM))
+COMPLETE_FEATURES: Final = frozenset((TYPE_VAR_TUPLE, UNPACK, NEW_GENERIC_SYNTAX))
 
 
 class Options:

mypy/semanal.py

@@ -195,7 +195,7 @@
     type_aliases_source_versions,
     typing_extensions_aliases,
 )
-from mypy.options import Options
+from mypy.options import TYPE_FORM, Options
 from mypy.patterns import (
     AsPattern,
     ClassPattern,
@@ -3701,7 +3701,8 @@ def analyze_lvalues(self, s: AssignmentStmt) -> None:
             )
 
     def analyze_rvalue_as_type_form(self, s: AssignmentStmt) -> None:
-        self.try_parse_as_type_expression(s.rvalue)
+        if TYPE_FORM in self.options.enable_incomplete_feature:
+            self.try_parse_as_type_expression(s.rvalue)
 
     def apply_dynamic_class_hook(self, s: AssignmentStmt) -> None:
         if not isinstance(s.rvalue, CallExpr):
@@ -5451,7 +5452,8 @@ def visit_return_stmt(self, s: ReturnStmt) -> None:
             self.fail('"return" not allowed in except* block', s, serious=True)
         if s.expr:
             s.expr.accept(self)
-            self.try_parse_as_type_expression(s.expr)
+            if TYPE_FORM in self.options.enable_incomplete_feature:
+                self.try_parse_as_type_expression(s.expr)
         self.statement = old
 
     def visit_raise_stmt(self, s: RaiseStmt) -> None:
@@ -6054,9 +6056,11 @@ def visit_call_expr(self, expr: CallExpr) -> None:
             expr.analyzed.accept(self)
         else:
             # Normal call expression.
+            calculate_type_forms = TYPE_FORM in self.options.enable_incomplete_feature
             for a in expr.args:
                 a.accept(self)
-                self.try_parse_as_type_expression(a)
+                if calculate_type_forms:
+                    self.try_parse_as_type_expression(a)
 
             if (
                 isinstance(expr.callee, MemberExpr)

mypy/typeanal.py

@@ -49,7 +49,7 @@
     check_arg_kinds,
     check_param_names,
 )
-from mypy.options import INLINE_TYPEDDICT, Options
+from mypy.options import INLINE_TYPEDDICT, TYPE_FORM, Options
 from mypy.plugin import AnalyzeTypeContext, Plugin, TypeAnalyzerPluginInterface
 from mypy.semanal_shared import (
     SemanticAnalyzerCoreInterface,
@@ -674,6 +674,12 @@ def try_analyze_special_unbound_type(self, t: UnboundType, fullname: str) -> Typ
                 item = AnyType(TypeOfAny.from_error)
             return TypeType.make_normalized(item, line=t.line, column=t.column)
         elif fullname in ("typing_extensions.TypeForm", "typing.TypeForm"):
+            if TYPE_FORM not in self.options.enable_incomplete_feature:
+                self.fail(
+                    "TypeForm is experimental,"
+                    " must be enabled with --enable-incomplete-feature=TypeForm",
+                    t,
+                )
             if len(t.args) == 0:
                 any_type = self.get_omitted_any(t)
                 return TypeType(any_type, line=t.line, column=t.column, is_type_form=True)

test-data/unit/check-fastparse.test

@@ -337,7 +337,7 @@ def call() -> str: pass
 [builtins fixtures/module.pyi]
 
 [case testInvalidEscapeSequenceWarningsSuppressed]
-# flags: --python-version 3.15
+# flags: --python-version 3.14 --enable-incomplete-feature=TypeForm
 # Test that SyntaxWarnings for invalid escape sequences are suppressed
 # when parsing potential type expressions containing regex patterns or
 # similar strings. Callable arguments are always potential type expressions.