Avoid various NamedTuples

Jukka mentioned these are slow to construct, so might as well get rid of
them

Author: hauntsaninja

mypy/binder.py

@@ -3,7 +3,7 @@
 from collections import defaultdict
 from collections.abc import Iterator
 from contextlib import contextmanager
-from typing import Literal, NamedTuple, TypeAlias as _TypeAlias
+from typing import Final, Literal, TypeAlias as _TypeAlias
 
 from mypy.erasetype import remove_instance_last_known_values
 from mypy.literals import Key, extract_var_from_literal_hash, literal, literal_hash, subkeys
@@ -42,9 +42,10 @@
 BindableExpression: _TypeAlias = IndexExpr | MemberExpr | NameExpr
 
 
-class CurrentType(NamedTuple):
-    type: Type
-    from_assignment: bool
+class CurrentType:
+    def __init__(self, type: Type, from_assignment: bool) -> None:
+        self.type: Final = type
+        self.from_assignment: Final = from_assignment
 
 
 class Frame:

mypy/build_worker/worker.py

@@ -23,7 +23,7 @@
 import platform
 import sys
 import time
-from typing import NamedTuple
+from typing import Final
 
 from librt.internal import ReadBuffer, read_tag
 
@@ -65,12 +65,20 @@
 CONNECTION_NAME = "build_worker"
 
 
-class ServerContext(NamedTuple):
-    options: Options
-    disable_error_code: list[str]
-    enable_error_code: list[str]
-    errors: Errors
-    fscache: FileSystemCache
+class ServerContext:
+    def __init__(
+        self,
+        options: Options,
+        disable_error_code: list[str],
+        enable_error_code: list[str],
+        errors: Errors,
+        fscache: FileSystemCache,
+    ) -> None:
+        self.options: Final = options
+        self.disable_error_code: Final = disable_error_code
+        self.enable_error_code: Final = enable_error_code
+        self.errors: Final = errors
+        self.fscache: Final = fscache
 
 
 def main(argv: list[str]) -> None:

mypy/checker.py

@@ -353,10 +353,11 @@ class FineGrainedDeferredNode(NamedTuple):
 # Keeps track of partial types in a single scope. In fine-grained incremental
 # mode partial types initially defined at the top level cannot be completed in
 # a function, and we use the 'is_function' attribute to enforce this.
-class PartialTypeScope(NamedTuple):
-    map: dict[Var, Context]
-    is_function: bool
-    is_local: bool
+class PartialTypeScope:
+    def __init__(self, map: dict[Var, Context], is_function: bool, is_local: bool) -> None:
+        self.map: Final = map
+        self.is_function: Final = is_function
+        self.is_local: Final = is_local
 
 
 class LocalTypeMap:
@@ -1604,14 +1605,14 @@ def check_func_def(
                             else:
                                 msg = message_registry.MISSING_RETURN_STATEMENT
                             if body_is_trivial:
-                                msg = msg._replace(code=codes.EMPTY_BODY)
+                                msg = ErrorMessage(msg.value, code=codes.EMPTY_BODY)
                             self.fail(msg, defn)
                             if may_be_abstract:
                                 self.note(message_registry.EMPTY_BODY_ABSTRACT, defn)
                     else:
                         msg = message_registry.INCOMPATIBLE_RETURN_VALUE_TYPE
                         if body_is_trivial:
-                            msg = msg._replace(code=codes.EMPTY_BODY)
+                            msg = ErrorMessage(msg.value, code=codes.EMPTY_BODY)
                         # similar to code in check_return_stmt
                         if (
                             not self.check_subtype(
@@ -7857,7 +7858,7 @@ def enter_partial_types(
             self.options.check_untyped_defs and self.dynamic_funcs and self.dynamic_funcs[-1]
         )
 
-        partial_types, _, _ = self.partial_types.pop()
+        partial_types = self.partial_types.pop().map
         if not self.current_node_deferred:
             for var, context in partial_types.items():
                 if isinstance(var.type, PartialType) and var.type.type is None and not permissive:

mypy/checker_shared.py

@@ -5,7 +5,7 @@
 from abc import abstractmethod
 from collections.abc import Iterator, Sequence, Set as AbstractSet
 from contextlib import contextmanager
-from typing import NamedTuple, overload
+from typing import Final, overload
 
 from mypy_extensions import trait
 
@@ -42,9 +42,10 @@
 
 # An object that represents either a precise type or a type with an upper bound;
 # it is important for correct type inference with isinstance.
-class TypeRange(NamedTuple):
-    item: Type
-    is_upper_bound: bool  # False => precise type
+class TypeRange:
+    def __init__(self, item: Type, is_upper_bound: bool) -> None:
+        self.item: Final = item
+        self.is_upper_bound: Final = is_upper_bound  # False => precise type
 
 
 @trait

mypy/infer.py

@@ -3,7 +3,7 @@
 from __future__ import annotations
 
 from collections.abc import Sequence
-from typing import NamedTuple
+from typing import Final
 
 from mypy.constraints import (
     SUBTYPE_OF,
@@ -16,7 +16,7 @@
 from mypy.types import CallableType, Instance, Type, TypeVarLikeType
 
 
-class ArgumentInferContext(NamedTuple):
+class ArgumentInferContext:
     """Type argument inference context.
 
     We need this because we pass around ``Mapping`` and ``Iterable`` types.
@@ -26,8 +26,9 @@ class ArgumentInferContext(NamedTuple):
     https://github.com/python/mypy/issues/11144
     """
 
-    mapping_type: Instance
-    iterable_type: Instance
+    def __init__(self, mapping_type: Instance, iterable_type: Instance) -> None:
+        self.mapping_type: Final = mapping_type
+        self.iterable_type: Final = iterable_type
 
 
 def infer_function_type_arguments(

mypy/message_registry.py

@@ -8,15 +8,16 @@
 
 from __future__ import annotations
 
-from typing import Final, NamedTuple
+from typing import Final
 
 from mypy import errorcodes as codes
 from mypy.errorcodes import ErrorCode
 
 
-class ErrorMessage(NamedTuple):
-    value: str
-    code: ErrorCode | None = None
+class ErrorMessage:
+    def __init__(self, value: str, code: ErrorCode | None = None) -> None:
+        self.value: Final = value
+        self.code: Final = code
 
     def format(self, *args: object, **kwargs: object) -> ErrorMessage:
         return ErrorMessage(self.value.format(*args, **kwargs), code=self.code)

mypy/plugins/functools.py

@@ -2,7 +2,7 @@
 
 from __future__ import annotations
 
-from typing import Final, NamedTuple
+from typing import Final
 
 import mypy.checker
 import mypy.plugin
@@ -43,9 +43,10 @@
 PARTIAL: Final = "functools.partial"
 
 
-class _MethodInfo(NamedTuple):
-    is_static: bool
-    type: CallableType
+class _MethodInfo:
+    def __init__(self, is_static: bool, type: CallableType) -> None:
+        self.is_static: Final = is_static
+        self.type: Final = type
 
 
 def functools_total_ordering_maker_callback(