Merge remote-tracking branch 'upstream/master' into bugfix/gh-19312-setter-of-nothing

Author: sterliakov

docs/source/generics.rst

@@ -630,7 +630,7 @@ Let us illustrate this by few simple examples:
 
      my_circles: list[Circle] = []
      add_one(my_circles)     # This may appear safe, but...
-     my_circles[-1].rotate()  # ...this will fail, since my_circles[0] is now a Shape, not a Circle
+     my_circles[0].rotate()  # ...this will fail, since my_circles[0] is now a Shape, not a Circle
 
   Another example of invariant type is ``dict``. Most mutable containers
   are invariant.

misc/perf_compare.py

@@ -35,11 +35,13 @@ def heading(s: str) -> None:
     print()
 
 
-def build_mypy(target_dir: str) -> None:
+def build_mypy(target_dir: str, multi_file: bool) -> None:
     env = os.environ.copy()
     env["CC"] = "clang"
     env["MYPYC_OPT_LEVEL"] = "2"
     env["PYTHONHASHSEED"] = "1"
+    if multi_file:
+        env["MYPYC_MULTI_FILE"] = "1"
     cmd = [sys.executable, "setup.py", "--use-mypyc", "build_ext", "--inplace"]
     subprocess.run(cmd, env=env, check=True, cwd=target_dir)
 
@@ -110,6 +112,12 @@ def main() -> None:
         action="store_true",
         help="measure incremental run (fully cached)",
     )
+    parser.add_argument(
+        "--multi-file",
+        default=False,
+        action="store_true",
+        help="compile each mypy module to a separate C file (reduces RAM use)",
+    )
     parser.add_argument(
         "--dont-setup",
         default=False,
@@ -127,9 +135,9 @@ def main() -> None:
     parser.add_argument(
         "-j",
         metavar="N",
-        default=8,
+        default=4,
         type=int,
-        help="set maximum number of parallel builds (default=8)",
+        help="set maximum number of parallel builds (default=4) -- high numbers require a lot of RAM!",
     )
     parser.add_argument(
         "-r",
@@ -155,6 +163,7 @@ def main() -> None:
     args = parser.parse_args()
     incremental: bool = args.incremental
     dont_setup: bool = args.dont_setup
+    multi_file: bool = args.multi_file
     commits = args.commit
     num_runs: int = args.num_runs + 1
     max_workers: int = args.j
@@ -185,7 +194,9 @@ def main() -> None:
         print("(This will take a while...)")
 
         with ThreadPoolExecutor(max_workers=max_workers) as executor:
-            futures = [executor.submit(build_mypy, target_dir) for target_dir in target_dirs]
+            futures = [
+                executor.submit(build_mypy, target_dir, multi_file) for target_dir in target_dirs
+            ]
             for future in as_completed(futures):
                 future.result()
 

mypy/checker.py

@@ -318,6 +318,8 @@ class ExpressionChecker(ExpressionVisitor[Type], ExpressionCheckerSharedApi):
     strfrm_checker: StringFormatterChecker
     plugin: Plugin
 
+    _arg_infer_context_cache: ArgumentInferContext | None
+
     def __init__(
         self,
         chk: mypy.checker.TypeChecker,
@@ -352,6 +354,8 @@ def __init__(
         self.is_callee = False
         type_state.infer_polymorphic = not self.chk.options.old_type_inference
 
+        self._arg_infer_context_cache = None
+
     def reset(self) -> None:
         self.resolved_type = {}
 
@@ -2277,9 +2281,11 @@ def infer_function_type_arguments_pass2(
         return callee_type, inferred_args
 
     def argument_infer_context(self) -> ArgumentInferContext:
-        return ArgumentInferContext(
-            self.chk.named_type("typing.Mapping"), self.chk.named_type("typing.Iterable")
-        )
+        if self._arg_infer_context_cache is None:
+            self._arg_infer_context_cache = ArgumentInferContext(
+                self.chk.named_type("typing.Mapping"), self.chk.named_type("typing.Iterable")
+            )
+        return self._arg_infer_context_cache
 
     def get_arg_infer_passes(
         self,
@@ -2338,10 +2344,10 @@ def apply_inferred_arguments(
         # Report error if some of the variables could not be solved. In that
         # case assume that all variables have type Any to avoid extra
         # bogus error messages.
-        for i, inferred_type in enumerate(inferred_args):
+        for inferred_type, tv in zip(inferred_args, callee_type.variables):
             if not inferred_type or has_erased_component(inferred_type):
                 # Could not infer a non-trivial type for a type variable.
-                self.msg.could_not_infer_type_arguments(callee_type, i + 1, context)
+                self.msg.could_not_infer_type_arguments(callee_type, tv, context)
                 inferred_args = [AnyType(TypeOfAny.from_error)] * len(inferred_args)
         # Apply the inferred types to the function type. In this case the
         # return type must be CallableType, since we give the right number of type

mypy/checkexpr.py

@@ -45,7 +45,6 @@
     freeze_all_type_vars,
     function_type,
     get_all_type_vars,
-    get_type_vars,
     make_simplified_union,
     supported_self_type,
     tuple_fallback,
@@ -371,8 +370,6 @@ def analyze_instance_member_access(
                     signature, mx.self_type, method.is_class, mx.context, name, mx.msg
                 )
                 signature = bind_self(signature, mx.self_type, is_classmethod=method.is_class)
-        # TODO: should we skip these steps for static methods as well?
-        # Since generic static methods should not be allowed.
         typ = map_instance_to_supertype(typ, method.info)
         member_type = expand_type_by_instance(signature, typ)
         freeze_all_type_vars(member_type)
@@ -1198,34 +1195,42 @@ def analyze_class_attribute_access(
 
         if isinstance(node.node, Var):
             assert isuper is not None
+            object_type = get_proper_type(mx.self_type)
             # Check if original variable type has type variables. For example:
             #     class C(Generic[T]):
             #         x: T
             #     C.x  # Error, ambiguous access
             #     C[int].x  # Also an error, since C[int] is same as C at runtime
             # Exception is Self type wrapped in ClassVar, that is safe.
+            prohibit_self = not node.node.is_classvar
             def_vars = set(node.node.info.defn.type_vars)
-            if not node.node.is_classvar and node.node.info.self_type:
+            if prohibit_self and node.node.info.self_type:
                 def_vars.add(node.node.info.self_type)
-            # TODO: should we include ParamSpec etc. here (i.e. use get_all_type_vars)?
-            typ_vars = set(get_type_vars(t))
-            if def_vars & typ_vars:
-                # Exception: access on Type[...], including first argument of class methods is OK.
-                if not isinstance(get_proper_type(mx.original_type), TypeType) or node.implicit:
-                    if node.node.is_classvar:
-                        message = message_registry.GENERIC_CLASS_VAR_ACCESS
-                    else:
-                        message = message_registry.GENERIC_INSTANCE_VAR_CLASS_ACCESS
-                    mx.fail(message)
+            # Exception: access on Type[...], including first argument of class methods is OK.
+            prohibit_generic = not isinstance(object_type, TypeType) or node.implicit
+            if prohibit_generic and def_vars & set(get_all_type_vars(t)):
+                if node.node.is_classvar:
+                    message = message_registry.GENERIC_CLASS_VAR_ACCESS
+                else:
+                    message = message_registry.GENERIC_INSTANCE_VAR_CLASS_ACCESS
+                mx.fail(message)
             t = expand_self_type_if_needed(t, mx, node.node, itype, is_class=True)
+            t = expand_type_by_instance(t, isuper)
             # Erase non-mapped variables, but keep mapped ones, even if there is an error.
             # In the above example this means that we infer following types:
             #     C.x -> Any
             #     C[int].x -> int
-            t = erase_typevars(expand_type_by_instance(t, isuper), {tv.id for tv in def_vars})
-
-        is_classmethod = (is_decorated and cast(Decorator, node.node).func.is_class) or (
-            isinstance(node.node, SYMBOL_FUNCBASE_TYPES) and node.node.is_class
+            if prohibit_generic:
+                erase_vars = set(itype.type.defn.type_vars)
+                if prohibit_self and itype.type.self_type:
+                    erase_vars.add(itype.type.self_type)
+                t = erase_typevars(t, {tv.id for tv in erase_vars})
+
+        is_classmethod = (
+            (is_decorated and cast(Decorator, node.node).func.is_class)
+            or (isinstance(node.node, SYMBOL_FUNCBASE_TYPES) and node.node.is_class)
+            or isinstance(node.node, Var)
+            and node.node.is_classmethod
         )
         is_staticmethod = (is_decorated and cast(Decorator, node.node).func.is_static) or (
             isinstance(node.node, SYMBOL_FUNCBASE_TYPES) and node.node.is_static
@@ -1237,7 +1242,12 @@ def analyze_class_attribute_access(
             is_trivial_self = node.node.func.is_trivial_self and not node.node.decorators
         elif isinstance(node.node, (FuncDef, OverloadedFuncDef)):
             is_trivial_self = node.node.is_trivial_self
-        if isinstance(t, FunctionLike) and is_classmethod and not is_trivial_self:
+        if (
+            isinstance(t, FunctionLike)
+            and is_classmethod
+            and not is_trivial_self
+            and not t.bound()
+        ):
             t = check_self_arg(t, mx.self_type, False, mx.context, name, mx.msg)
         t = add_class_tvars(
             t,
@@ -1406,7 +1416,7 @@ class B(A[str]): pass
         tvars = original_vars if original_vars is not None else []
         if not mx.preserve_type_var_ids:
             t = freshen_all_functions_type_vars(t)
-        if is_classmethod:
+        if is_classmethod and not t.is_bound:
             if is_trivial_self:
                 t = bind_self_fast(t, mx.self_type)
             else:

mypy/checkmember.py

@@ -1335,6 +1335,11 @@ def visit_tuple_type(self, template: TupleType) -> list[Constraint]:
                     res.extend(
                         infer_constraints(template_items[i], actual_items[i], self.direction)
                     )
+            res.extend(
+                infer_constraints(
+                    template.partial_fallback, actual.partial_fallback, self.direction
+                )
+            )
             return res
         elif isinstance(actual, AnyType):
             return self.infer_against_any(template.items, actual)

mypy/constraints.py

@@ -4,13 +4,15 @@
 import sys
 import traceback
 from collections import defaultdict
-from collections.abc import Iterable
+from collections.abc import Iterable, Iterator
+from itertools import chain
 from typing import Callable, Final, NoReturn, Optional, TextIO, TypeVar
 from typing_extensions import Literal, Self, TypeAlias as _TypeAlias
 
 from mypy import errorcodes as codes
 from mypy.error_formatter import ErrorFormatter
 from mypy.errorcodes import IMPORT, IMPORT_NOT_FOUND, IMPORT_UNTYPED, ErrorCode, mypy_error_codes
+from mypy.nodes import Context
 from mypy.options import Options
 from mypy.scope import Scope
 from mypy.util import DEFAULT_SOURCE_OFFSET, is_typeshed_file
@@ -219,23 +221,43 @@ def filtered_errors(self) -> list[ErrorInfo]:
         return self._filtered
 
 
-class LoopErrorWatcher(ErrorWatcher):
-    """Error watcher that filters and separately collects `unreachable` errors,
-    `redundant-expr` and `redundant-casts` errors, and revealed types when analysing
-    loops iteratively to help avoid making too-hasty reports."""
+class IterationDependentErrors:
+    """An `IterationDependentErrors` instance serves to collect the `unreachable`,
+    `redundant-expr`, and `redundant-casts` errors, as well as the revealed types,
+    handled by the individual `IterationErrorWatcher` instances sequentially applied to
+    the same code section."""
 
-    # Meaning of the tuple items: ErrorCode, message, line, column, end_line, end_column:
-    uselessness_errors: set[tuple[ErrorCode, str, int, int, int, int]]
+    # One set of `unreachable`, `redundant-expr`, and `redundant-casts` errors per
+    # iteration step.  Meaning of the tuple items: ErrorCode, message, line, column,
+    # end_line, end_column.
+    uselessness_errors: list[set[tuple[ErrorCode, str, int, int, int, int]]]
 
-    # Meaning of the tuple items: function_or_member, line, column, end_line, end_column:
+    # One set of unreachable line numbers per iteration step.  Not only the lines where
+    # the error report occurs but really all unreachable lines.
+    unreachable_lines: list[set[int]]
+
+    # One set of revealed types for each `reveal_type` statement.  Each created set can
+    # grow during the iteration.  Meaning of the tuple items: function_or_member, line,
+    # column, end_line, end_column:
     revealed_types: dict[tuple[str | None, int, int, int, int], set[str]]
 
-    # Not only the lines where the error report occurs but really all unreachable lines:
-    unreachable_lines: set[int]
+    def __init__(self) -> None:
+        self.uselessness_errors = []
+        self.unreachable_lines = []
+        self.revealed_types = defaultdict(set)
+
+
+class IterationErrorWatcher(ErrorWatcher):
+    """Error watcher that filters and separately collects `unreachable` errors,
+    `redundant-expr` and `redundant-casts` errors, and revealed types when analysing
+    code sections iteratively to help avoid making too-hasty reports."""
+
+    iteration_dependent_errors: IterationDependentErrors
 
     def __init__(
         self,
         errors: Errors,
+        iteration_dependent_errors: IterationDependentErrors,
         *,
         filter_errors: bool | Callable[[str, ErrorInfo], bool] = False,
         save_filtered_errors: bool = False,
@@ -247,31 +269,71 @@ def __init__(
             save_filtered_errors=save_filtered_errors,
             filter_deprecated=filter_deprecated,
         )
-        self.uselessness_errors = set()
-        self.unreachable_lines = set()
-        self.revealed_types = defaultdict(set)
+        self.iteration_dependent_errors = iteration_dependent_errors
+        iteration_dependent_errors.uselessness_errors.append(set())
+        iteration_dependent_errors.unreachable_lines.append(set())
 
     def on_error(self, file: str, info: ErrorInfo) -> bool:
+        """Filter out the "iteration-dependent" errors and notes and store their
+        information to handle them after iteration is completed."""
+
+        iter_errors = self.iteration_dependent_errors
 
         if info.code in (codes.UNREACHABLE, codes.REDUNDANT_EXPR, codes.REDUNDANT_CAST):
-            self.uselessness_errors.add(
+            iter_errors.uselessness_errors[-1].add(
                 (info.code, info.message, info.line, info.column, info.end_line, info.end_column)
             )
             if info.code == codes.UNREACHABLE:
-                self.unreachable_lines.update(range(info.line, info.end_line + 1))
+                iter_errors.unreachable_lines[-1].update(range(info.line, info.end_line + 1))
             return True
 
         if info.code == codes.MISC and info.message.startswith("Revealed type is "):
             key = info.function_or_member, info.line, info.column, info.end_line, info.end_column
             types = info.message.split('"')[1]
             if types.startswith("Union["):
-                self.revealed_types[key].update(types[6:-1].split(", "))
+                iter_errors.revealed_types[key].update(types[6:-1].split(", "))
             else:
-                self.revealed_types[key].add(types)
+                iter_errors.revealed_types[key].add(types)
             return True
 
         return super().on_error(file, info)
 
+    def yield_error_infos(self) -> Iterator[tuple[str, Context, ErrorCode]]:
+        """Report only those `unreachable`, `redundant-expr`, and `redundant-casts`
+        errors that could not be ruled out in any iteration step."""
+
+        persistent_uselessness_errors = set()
+        iter_errors = self.iteration_dependent_errors
+        for candidate in set(chain(*iter_errors.uselessness_errors)):
+            if all(
+                (candidate in errors) or (candidate[2] in lines)
+                for errors, lines in zip(
+                    iter_errors.uselessness_errors, iter_errors.unreachable_lines
+                )
+            ):
+                persistent_uselessness_errors.add(candidate)
+        for error_info in persistent_uselessness_errors:
+            context = Context(line=error_info[2], column=error_info[3])
+            context.end_line = error_info[4]
+            context.end_column = error_info[5]
+            yield error_info[1], context, error_info[0]
+
+    def yield_note_infos(self, options: Options) -> Iterator[tuple[str, Context]]:
+        """Yield all types revealed in at least one iteration step."""
+
+        for note_info, types in self.iteration_dependent_errors.revealed_types.items():
+            sorted_ = sorted(types, key=lambda typ: typ.lower())
+            if len(types) == 1:
+                revealed = sorted_[0]
+            elif options.use_or_syntax():
+                revealed = " | ".join(sorted_)
+            else:
+                revealed = f"Union[{', '.join(sorted_)}]"
+            context = Context(line=note_info[1], column=note_info[2])
+            context.end_line = note_info[3]
+            context.end_column = note_info[4]
+            yield f'Revealed type is "{revealed}"', context
+
 
 class Errors:
     """Container for compile errors.
@@ -786,6 +848,8 @@ def generate_unused_ignore_errors(self, file: str) -> None:
                 code=codes.UNUSED_IGNORE,
                 blocker=False,
                 only_once=False,
+                origin=(self.file, [line]),
+                target=self.target_module,
             )
             self._add_error_info(file, info)
 
@@ -837,6 +901,8 @@ def generate_ignore_without_code_errors(
                 code=codes.IGNORE_WITHOUT_CODE,
                 blocker=False,
                 only_once=False,
+                origin=(self.file, [line]),
+                target=self.target_module,
             )
             self._add_error_info(file, info)