Add a secondary context for this error message

Add another context to this message reporting. This means that we'll now check both contexts when looking at what errors to ignore.

mypy/checker.py

@@ -2082,6 +2082,7 @@ def erase_override(t: Type) -> Type:
  arg_type_in_super,
  supertype,
  context,
+ secondary_context=node,
  )
  emitted_msg = True
 

mypy/errors.py

@@ -4,7 +4,7 @@
 import sys
 import traceback
 from collections import defaultdict
-from typing import Callable, NoReturn, Optional, TextIO, Tuple, TypeVar
+from typing import Callable, NoReturn, Optional, TextIO, Tuple, TypeVar, Iterable
 from typing_extensions import Final, Literal, TypeAlias as _TypeAlias
 
 from mypy import errorcodes as codes
@@ -78,7 +78,7 @@ class ErrorInfo:
 
  # Actual origin of the error message as tuple (path, line number, end line number)
  # If end line number is unknown, use line number.
- origin: tuple[str, int, int]
+ origin: tuple[str, Iterable[int]]
 
  # Fine-grained incremental target where this was reported
  target: str | None = None
@@ -104,7 +104,7 @@ def __init__(
  blocker: bool,
  only_once: bool,
  allow_dups: bool,
- origin: tuple[str, int, int] | None = None,
+ origin: tuple[str, Iterable[int]] | None = None,
  target: str | None = None,
  ) -> None:
  self.import_ctx = import_ctx
@@ -122,7 +122,7 @@ def __init__(
  self.blocker = blocker
  self.only_once = only_once
  self.allow_dups = allow_dups
- self.origin = origin or (file, line, line)
+ self.origin = origin or (file, [line])
  self.target = target
 
 
@@ -367,7 +367,7 @@ def report(
  file: str | None = None,
  only_once: bool = False,
  allow_dups: bool = False,
- origin_span: tuple[int, int] | None = None,
+ origin_span: Iterable[int] | None = None,
  offset: int = 0,
  end_line: int | None = None,
  end_column: int | None = None,
@@ -411,7 +411,7 @@ def report(
  message = " " * offset + message
 
  if origin_span is None:
- origin_span = (line, line)
+ origin_span = [line]
 
  if end_line is None:
  end_line = line
@@ -434,7 +434,7 @@ def report(
  blocker,
  only_once,
  allow_dups,
- origin=(self.file, *origin_span),
+ origin=(self.file, origin_span),
  target=self.current_target(),
  )
  self.add_error_info(info)
@@ -467,7 +467,7 @@ def _filter_error(self, file: str, info: ErrorInfo) -> bool:
  return False
 
  def add_error_info(self, info: ErrorInfo) -> None:
- file, line, end_line = info.origin
+ file, lines = info.origin
  # process the stack of ErrorWatchers before modifying any internal state
  # in case we need to filter out the error entirely
  # NB: we need to do this both here and in _add_error_info, otherwise we
@@ -478,7 +478,7 @@ def add_error_info(self, info: ErrorInfo) -> None:
  if file in self.ignored_lines:
  # Check each line in this context for "type: ignore" comments.
  # line == end_line for most nodes, so we only loop once.
- for scope_line in range(line, end_line + 1):
+ for scope_line in lines:
  if self.is_ignored_error(scope_line, info, self.ignored_lines[file]):
  # Annotation requests us to ignore all errors on this line.
  self.used_ignored_lines[file][scope_line].append(

mypy/messages.py

@@ -12,6 +12,7 @@
 from __future__ import annotations
 
 import difflib
+import itertools
 import re
 from contextlib import contextmanager
 from textwrap import dedent
@@ -136,6 +137,7 @@
 }
 
 
+
 class MessageBuilder:
  """Helper class for reporting type checker error messages with parameters.
 
@@ -210,34 +212,40 @@ def report(
  origin: Context | None = None,
  offset: int = 0,
  allow_dups: bool = False,
+ secondary_context: Context | None = None,
  ) -> None:
  """Report an error or note (unless disabled).
 
  Note that context controls where error is reported, while origin controls
  where # type: ignore comments have effect.
  """
 
- def span_from_context(ctx: Context) -> tuple[int, int]:
+ def span_from_context(ctx: Context) -> Iterable[int]:
  """This determines where a type: ignore for a given context has effect.
 
  Current logic is a bit tricky, to keep as much backwards compatibility as
  possible. We may reconsider this to always be a single line (or otherwise
  simplify it) when we drop Python 3.7.
  """
  if isinstance(ctx, (ClassDef, FuncDef)):
- return ctx.deco_line or ctx.line, ctx.line
+ return range(ctx.deco_line or ctx.line, ctx.line + 1)
  elif not isinstance(ctx, Expression):
- return ctx.line, ctx.line
+ return [ctx.line]
  else:
- return ctx.line, ctx.end_line or ctx.line
+ return range(ctx.line, (ctx.end_line or ctx.line) + 1)
 
- origin_span: tuple[int, int] | None
+ origin_span: Iterable[int] | None
  if origin is not None:
  origin_span = span_from_context(origin)
  elif context is not None:
  origin_span = span_from_context(context)
  else:
  origin_span = None
+
+ if secondary_context is not None:
+ assert origin_span is not None
+ origin_span = itertools.chain(origin_span, span_from_context(secondary_context))
+
  self.errors.report(
  context.line if context else -1,
  context.column if context else -1,
@@ -260,9 +268,10 @@ def fail(
  code: ErrorCode | None = None,
  file: str | None = None,
  allow_dups: bool = False,
+ secondary_context: Context | None = None,
  ) -> None:
  """Report an error message (unless disabled)."""
- self.report(msg, context, "error", code=code, file=file, allow_dups=allow_dups)
+ self.report(msg, context, "error", code=code, file=file, allow_dups=allow_dups, secondary_context=secondary_context)
 
  def note(
  self,
@@ -274,6 +283,7 @@ def note(
  allow_dups: bool = False,
  *,
  code: ErrorCode | None = None,
+ secondary_context: Context | None = None,
  ) -> None:
  """Report a note (unless disabled)."""
  self.report(
@@ -285,6 +295,7 @@ def note(
  offset=offset,
  allow_dups=allow_dups,
  code=code,
+ secondary_context=secondary_context,
  )
 
  def note_multiline(
@@ -295,11 +306,13 @@ def note_multiline(
  offset: int = 0,
  allow_dups: bool = False,
  code: ErrorCode | None = None,
+ *,
+ secondary_context: Context | None = None,
  ) -> None:
  """Report as many notes as lines in the message (unless disabled)."""
  for msg in messages.splitlines():
  self.report(
- msg, context, "note", file=file, offset=offset, allow_dups=allow_dups, code=code
+ msg, context, "note", file=file, offset=offset, allow_dups=allow_dups, code=code, secondary_context=secondary_context,
  )
 
  #
@@ -1153,6 +1166,7 @@ def argument_incompatible_with_supertype(
  arg_type_in_supertype: Type,
  supertype: str,
  context: Context,
+ secondary_context: Context,
  ) -> None:
  target = self.override_target(name, name_in_supertype, supertype)
  arg_type_in_supertype_f = format_type_bare(arg_type_in_supertype)
@@ -1163,17 +1177,19 @@ def argument_incompatible_with_supertype(
  ),
  context,
  code=codes.OVERRIDE,
+ secondary_context=secondary_context,
  )
- self.note("This violates the Liskov substitution principle", context, code=codes.OVERRIDE)
+ self.note("This violates the Liskov substitution principle", context, code=codes.OVERRIDE, secondary_context=secondary_context)
  self.note(
  "See https://mypy.readthedocs.io/en/stable/common_issues.html#incompatible-overrides",
  context,
  code=codes.OVERRIDE,
+ secondary_context=secondary_context,
  )
 
  if name == "__eq__" and type_name:
  multiline_msg = self.comparison_method_example_msg(class_name=type_name)
- self.note_multiline(multiline_msg, context, code=codes.OVERRIDE)
+ self.note_multiline(multiline_msg, context, code=codes.OVERRIDE, secondary_context=secondary_context)
 
  def comparison_method_example_msg(self, class_name: str) -> str:
  return dedent(

test-data/unit/check-classes.test

@@ -331,6 +331,59 @@ main:7: note: This violates the Liskov substitution principle
 main:7: note: See https://mypy.readthedocs.io/en/stable/common_issues.html#incompatible-overrides
 main:9: error: Return type "object" of "h" incompatible with return type "A" in supertype "A"
 
+[case testMethodOverridingWithIncompatibleTypesOnMultipleLines]
+class A:
+ def f(self, x: int, y: str) -> None: pass
+class B(A):
+ def f(
+ self,
+ x: int,
+ y: bool,
+ ) -> None:
+ pass
+[out]
+main:7: error: Argument 2 of "f" is incompatible with supertype "A"; supertype defines the argument type as "str"
+main:7: note: This violates the Liskov substitution principle
+main:7: note: See https://mypy.readthedocs.io/en/stable/common_issues.html#incompatible-overrides
+
+[case testMultiLineMethodOverridingWithIncompatibleTypesIgnorableAtArgument]
+class A:
+ def f(self, x: int, y: str) -> None: pass
+
+class B(A):
+ def f(
+ self,
+ x: int,
+ y: bool, # type: ignore[override]
+ ) -> None:
+ pass
+
+[case testMultiLineMethodOverridingWithIncompatibleTypesIgnorableAtDefinition]
+class A:
+ def f(self, x: int, y: str) -> None: pass
+class B(A):
+ def f( # type: ignore[override]
+ self,
+ x: int,
+ y: bool,
+ ) -> None:
+ pass
+
+[case testMultiLineMethodOverridingWithIncompatibleTypesWrongIgnore]
+class A:
+ def f(self, x: int, y: str) -> None: pass
+class B(A):
+ def f( # type: ignore[return-type]
+ self,
+ x: int,
+ y: bool,
+ ) -> None:
+ pass
+[out]
+main:7: error: Argument 2 of "f" is incompatible with supertype "A"; supertype defines the argument type as "str"
+main:7: note: This violates the Liskov substitution principle
+main:7: note: See https://mypy.readthedocs.io/en/stable/common_issues.html#incompatible-overrides
+
 [case testEqMethodsOverridingWithNonObjects]
 class A:
  def __eq__(self, other: A) -> bool: pass # Fail