Adds Final types where they were missing (#11278)

I've noticed several missing Final types here and there.
I've looked though the whole project and added them where appropriate.

Author: sobolevn

mypy/build.py

@@ -69,7 +69,7 @@
 DEBUG_FINE_GRAINED: Final = False
 
 # These modules are special and should always come from typeshed.
-CORE_BUILTIN_MODULES = {
+CORE_BUILTIN_MODULES: Final = {
     'builtins',
     'typing',
     'types',

mypy/fastparse.py

@@ -132,7 +132,7 @@ def ast3_parse(source: Union[str, bytes], filename: str, mode: str,
 
 INVALID_SLICE_ERROR: Final = 'Slice usage in type annotation is invalid'
 
-TYPE_IGNORE_PATTERN = re.compile(r'[^#]*#\s*type:\s*ignore\s*(.*)')
+TYPE_IGNORE_PATTERN: Final = re.compile(r'[^#]*#\s*type:\s*ignore\s*(.*)')
 
 
 def parse(source: Union[str, bytes],

mypy/plugins/functools.py

@@ -1,17 +1,18 @@
 """Plugin for supporting the functools standard library module."""
 from typing import Dict, NamedTuple, Optional
+from typing_extensions import Final
 
 import mypy.plugin
 from mypy.nodes import ARG_POS, ARG_STAR2, Argument, FuncItem, Var
 from mypy.plugins.common import add_method_to_class
 from mypy.types import AnyType, CallableType, get_proper_type, Type, TypeOfAny, UnboundType
 
 
-functools_total_ordering_makers = {
+functools_total_ordering_makers: Final = {
     'functools.total_ordering',
 }
 
-_ORDERING_METHODS = {
+_ORDERING_METHODS: Final = {
     '__lt__',
     '__le__',
     '__gt__',

mypy/plugins/singledispatch.py

@@ -22,11 +22,11 @@
     ('singledispatch_obj', Instance),
 ])
 
-SINGLEDISPATCH_TYPE = 'functools._SingleDispatchCallable'
+SINGLEDISPATCH_TYPE: Final = 'functools._SingleDispatchCallable'
 
-SINGLEDISPATCH_REGISTER_METHOD = '{}.register'.format(SINGLEDISPATCH_TYPE)  # type: Final
+SINGLEDISPATCH_REGISTER_METHOD: Final = '{}.register'.format(SINGLEDISPATCH_TYPE)
 
-SINGLEDISPATCH_CALLABLE_CALL_METHOD = '{}.__call__'.format(SINGLEDISPATCH_TYPE)  # type: Final
+SINGLEDISPATCH_CALLABLE_CALL_METHOD: Final = '{}.__call__'.format(SINGLEDISPATCH_TYPE)
 
 
 def get_singledispatch_info(typ: Instance) -> Optional[SingledispatchTypeVars]:
@@ -45,11 +45,11 @@ def get_first_arg(args: List[List[T]]) -> Optional[T]:
     return None
 
 
-REGISTER_RETURN_CLASS = '_SingleDispatchRegisterCallable'
+REGISTER_RETURN_CLASS: Final = '_SingleDispatchRegisterCallable'
 
-REGISTER_CALLABLE_CALL_METHOD = 'functools.{}.__call__'.format(
+REGISTER_CALLABLE_CALL_METHOD: Final = 'functools.{}.__call__'.format(
     REGISTER_RETURN_CLASS
-)  # type: Final
+)
 
 
 def make_fake_register_class_instance(api: CheckerPluginInterface, type_args: Sequence[Type]

mypy/semanal_main.py

@@ -25,7 +25,7 @@
 """
 
 from typing import List, Tuple, Optional, Union, Callable
-from typing_extensions import TYPE_CHECKING
+from typing_extensions import TYPE_CHECKING, Final
 
 from mypy.backports import nullcontext
 from mypy.nodes import (
@@ -55,12 +55,12 @@
 
 
 # If we perform this many iterations, raise an exception since we are likely stuck.
-MAX_ITERATIONS = 20
+MAX_ITERATIONS: Final = 20
 
 
 # Number of passes over core modules before going on to the rest of the builtin SCC.
-CORE_WARMUP = 2
-core_modules = ['typing', 'builtins', 'abc', 'collections']
+CORE_WARMUP: Final = 2
+core_modules: Final = ['typing', 'builtins', 'abc', 'collections']
 
 
 def semantic_analysis_for_scc(graph: 'Graph', scc: List[str], errors: Errors) -> None:

mypy/stubgenc.py

@@ -10,6 +10,7 @@
 import re
 from typing import List, Dict, Tuple, Optional, Mapping, Any, Set
 from types import ModuleType
+from typing_extensions import Final
 
 from mypy.moduleinspect import is_c_module
 from mypy.stubdoc import (
@@ -19,7 +20,7 @@
 )
 
 # Members of the typing module to consider for importing by default.
-_DEFAULT_TYPING_IMPORTS = (
+_DEFAULT_TYPING_IMPORTS: Final = (
     'Any',
     'Callable',
     'ClassVar',

mypy/util.py

@@ -30,14 +30,14 @@
 
 # At least this number of columns will be shown on each side of
 # error location when printing source code snippet.
-MINIMUM_WIDTH = 20
+MINIMUM_WIDTH: Final = 20
 
 # VT100 color code processing was added in Windows 10, but only the second major update,
 # Threshold 2. Fortunately, everyone (even on LTSB, Long Term Support Branch) should
 # have a version of Windows 10 newer than this. Note that Windows 8 and below are not
 # supported, but are either going out of support, or make up only a few % of the market.
-MINIMUM_WINDOWS_MAJOR_VT100 = 10
-MINIMUM_WINDOWS_BUILD_VT100 = 10586
+MINIMUM_WINDOWS_MAJOR_VT100: Final = 10
+MINIMUM_WINDOWS_BUILD_VT100: Final = 10586
 
 default_python2_interpreter: Final = [
     "python2",