Extra Clang Tools 24.0.0git (In-Progress) Release Notes¶

Written by the LLVM Team

Warning

These are in-progress notes for the upcoming Extra Clang Tools 24 release. Release notes for previous releases can be found on the Download Page.

Introduction ¶

This document contains the release notes for the Extra Clang Tools, part of the Clang release 24.0.0git. Here we describe the status of the Extra Clang Tools in some detail, including major improvements from the previous release and new feature work. All LLVM releases may be downloaded from the LLVM releases web site.

For more information about Clang or LLVM, including information about the latest release, please see the Clang Web Site or the LLVM Web Site.

Note that if you are reading this file from a Git checkout or the main Clang web page, this document applies to the next release, not the current one. To see the release notes for a specific release, please see the releases page.

The deprecated zircon clang-tidy module has been removed. Users of zircon-temporary-objects should migrate to fuchsia-temporary-objects.
In 22nd release, The clang-tidy/ClangTidyModuleRegistry.h header was deprecated. All of the symbols it used to define were moved into clang-tidy/ClangTidyModule.h. The deprecated header has been removed in this release.

clangd now applies clang-tidy fix-it post-processing before exposing fixes.

Improved check_clang_tidy.py by adding support of -std=cXX-or-earlier values, mirroring the existing -std=cXX-or-later. New construct expands to the given standard and every earlier one.
On Windows, clang-tidy will now better match mixes of forwards and backwards slashes when using the --line-filter option. This also improves piping from git to clang-tidy-diff.py, where slashes will now be automatically normalized.

New checks ¶

New llvm-invalid-regex-pattern check.

Detects malformed regex patterns defined in a single string literal.
New modernize-use-to-underlying check.

Finds casts from a scoped enumeration (enum class) to an integer type and replaces them with a call to std::to_underlying (introduced in C++23).
New performance-expensive-value-or check.

Finds calls to value_or (and alternative spellings valueOr, ValueOr) on optional types where the return type is expensive to copy.
New portability-avoid-pragma-comment check.

Finds uses of #pragma comment and, for lib or linker comments, suggests using the build system for improved portability.
New readability-redundant-zero-initializer check.

Finds explicit zero initializers of arrays that can be replaced with empty braces.

New check aliases ¶

Changes in existing checks ¶

Improved bugprone-implicit-widening-of-multiplication-result check by suggesting a wider type of the same signedness as the original operands, instead of forcing a signed type, when a multiplication of two unsigned operands narrower than int is only signed due to integer promotion.
Improved bugprone-macro-parentheses by fixing invalid fixes for macro arguments used as names in alias declarations.
Fixed a crash in bugprone-misplaced-operator-in-strlen-in-alloc when checking an array new expression without a size expression.
Fixed a crash in bugprone-pointer-arithmetic-on-polymorphic-object when the pointer points to an incomplete (forward-declared) type.
Fixed a crash in bugprone-std-namespace-modification when checking lambda closure types used as template arguments.
Improved cppcoreguidelines-missing-std-forward check by diagnosing unforwarded auto&& parameters in C++20 abbreviated function templates.
Improved cppcoreguidelines-pro-type-member-init check by treating std::array the same as built-in arrays when IgnoreArrays option is enabled.
Improved cppcoreguidelines-use-enum-class check by omitting unnamed enums from the enum class requirement, as previously the check suggested users an ill-formed fix.
Improved misc-const-correctness check:
- Fixed false positives when the pointee is written through a pointer that is incremented, decremented or adjusted with += or -=, such as *p++ = 0.
- Fixed false positives when the pointee is written through a pointer assignment, such as *(p = q) = 0.
Improved misc-redundant-expression by fixing false positives in nested expressions involving different macros or a mix of macro and non-macro operands.
Fixed a crash in modernize-raw-string-literal on synthetic string literals created for raw user-defined literal operators, such as 12_w.
Improved modernize-return-braced-init-list check to no longer rewrite the return value when the constructed type has a std::initializer_list constructor, as the braced form could select a different constructor.
Fixed a crash in modernize-use-noexcept when analyzing malformed template code with an unparsed exception specification.
Improved performance-inefficient-algorithm check to no longer produce a fix with the container or the searched-for value missing, such as .find(43) or s.find(), when either comes from a macro. The value is copied as written rather than with its parentheses stripped, and no fix is offered when an argument covers only part of a macro expansion, as it then has no source text of its own.
Improved readability-enum-initial-value check by adding the AllowReferencedInitialValues to support the INT09-C-EX1 exception, allowing enumerators initialized by referencing another enumerator in the same enum (e.g., last = first).
Improved readability-identifier-naming check:
- Fixed a crash when checking forward-declared classes with DefaultHungarianPrefix enabled.
- Fixed DefaultHungarianPrefix being incorrectly diagnosed as an invalid option.
- Fixed invalid fixes when renaming parameter packs used in sizeof... expressions.
- Added the TypedefInheritAnonTagConfig, which checks a typedef or type alias that provides the only name of an otherwise unnamed tag, such as typedef enum {} MyEnum;, against the style configured for that tag kind instead of the typedef or type alias style.
- Added support for naming lambda init-captures (e.g. [Captured = Var]) via the new LambdaCapture options. Simple, non-init captures continue to follow the naming style of the variable they capture.
- Added the AllowTrailingUnderscore, which permits a single trailing underscore on any identifier.
Improved readability-named-parameter check by ignoring standard tag types (e.g. std::in_place_t, std::allocator_arg_t, std::nothrow_t, iterator tags, lock tags, etc.) that are used exclusively for overload resolution. Added the IgnoredTypes option to allow customizing the set of ignored types.
Improved readability-trailing-comma check:
- Fixed false positives on designated initializers, where initializer lists synthesized for intermediate subobjects caused the trailing comma of the enclosing list to be incorrectly rewritten.
- Fixed a false positive on empty brace initializers of types with default member initializers.
Improved readability-use-std-min-max check by fixing spurious trailing semicolons and lost comments when the if body has no braces.

Removed checks ¶

Removed the deprecated zircon-temporary-objects check. Users should migrate to fuchsia-temporary-objects.

Extra Clang Tools 24.0.0git documentation