.clang-tidy

# Part of the Carbon Language project, under the Apache License v2.0 with LLVM
# Exceptions. See /LICENSE for license information.
# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception

---
# Get colors when outputting through `bazel build --config=clang-tidy`.
UseColor: true
# This is necessary for `--config=clang-tidy` to catch errors.
WarningsAsErrors: '*'

# - bugprone-exception-escape finds issues like out-of-memory in main(). We
#   don't use exceptions, so it's unlikely to find real issues.
# - bugprone-macro-parentheses has false positives in places such as using an
#   argument to declare a name, which cannot have parentheses. For our limited
#   use of macros, this is a common conflict.
# - bugprone-switch-missing-default-case has false positives for `enum_base.h`.
#   Clang's built-in switch warnings cover most of our risk of bugs here.
# - bugprone-unchecked-optional-access in clang-tidy 16 has false positives on
#   code like:
#     while (auto name_ref = insts().Get(inst_id).TryAs<SemIR::NameRef>()) {
#       inst_id = name_ref->value_id;
#                 ^ unchecked access to optional value
#     }
# - google-readability-function-size overlaps with readability-function-size.
# - modernize-use-designated-initializers is disabled because it fires on
#   creation of SemIR typed insts, for which we do not currently want to use
#   designated initialization.
# - modernize-use-nodiscard is disabled because it only fixes const methods,
#   not non-const, which yields distracting results on accessors.
# - performance-unnecessary-value-param is disabled because it duplicate
#   modernize-pass-by-value.
Checks:
  -*, bugprone-*, -bugprone-branch-clone, -bugprone-easily-swappable-parameters,
  -bugprone-exception-escape, -bugprone-macro-parentheses,
  -bugprone-narrowing-conversions, -bugprone-switch-missing-default-case,
  -bugprone-unchecked-optional-access, google-*,
  -google-readability-function-size, -google-readability-todo,
  misc-definitions-in-headers, misc-misplaced-const, misc-redundant-expression,
  misc-static-assert, misc-unconventional-assign-operator,
  misc-uniqueptr-reset-release, misc-unused-*, modernize-*,
  -modernize-avoid-c-arrays, -modernize-return-braced-init-list,
  -modernize-use-default-member-init, -modernize-use-designated-initializers,
  -modernize-use-emplace, -modernize-use-nodiscard, performance-*,
  -performance-unnecessary-value-param, readability-*,
  -readability-convert-member-functions-to-static,
  -readability-function-cognitive-complexity, -readability-else-after-return,
  -readability-identifier-length, -readability-implicit-bool-conversion,
  -readability-magic-numbers, -readability-make-member-function-const,
  -readability-static-definition-in-anonymous-namespace,
  -readability-suspicious-call-argument, -readability-use-anyofallof
CheckOptions:
  - { key: readability-identifier-naming.ClassCase, value: CamelCase }
  - { key: readability-identifier-naming.ClassConstantCase, value: CamelCase }
  - {
      key: readability-identifier-naming.ConstexprVariableCase,
      value: CamelCase,
    }
  - { key: readability-identifier-naming.NamespaceCase, value: CamelCase }
  - { key: readability-identifier-naming.StructCase, value: CamelCase }
  - {
      key: readability-identifier-naming.TemplateParameterCase,
      value: CamelCase,
    }
  - { key: readability-identifier-naming.TypeAliasCase, value: CamelCase }
  - { key: readability-identifier-naming.TypedefCase, value: CamelCase }
  - { key: readability-identifier-naming.UnionCase, value: CamelCase }
  - { key: readability-identifier-naming.VariableCase, value: lower_case }
  - { key: readability-identifier-naming.ParameterCase, value: lower_case }
  - { key: readability-identifier-naming.ClassMemberCase, value: lower_case }
  - {
      key: readability-identifier-naming.MethodIgnoredRegexp,
      value: '^classof$',
    }
  - {
      # This erroneously fires in C++20 mode with LLVM 16 clang-tidy, due to:
      # https://github.com/llvm/llvm-project/issues/46097
      key: readability-identifier-naming.TemplateParameterIgnoredRegexp,
      value: '^expr-type$',
    }