==================================================== Extra Clang Tools |release| |ReleaseNotesTitle|

.. contents:: :local: :depth: 3

Written by the LLVM Team

.. only:: PreRelease

.. warning:: These are in-progress notes for the upcoming Extra Clang Tools |version| 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 |release|. 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 <https://llvm.org/releases/>_.

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.

What's New in Extra Clang Tools |release|?

Some of the major new features and improvements to Extra Clang Tools are listed here. Generic improvements to Extra Clang Tools as a whole or to its underlying infrastructure are described first, followed by tool-specific sections.

Major New Features

...

Improvements to clangd

• Introduced exmperimental support for C++20 Modules. The experimental support can be enabled by -experimental-modules-support option. It is in an early development stage and may not perform efficiently in real-world scenarios.

Inlay hints ^^^^^^^^^^^

Diagnostics ^^^^^^^^^^^

Semantic Highlighting ^^^^^^^^^^^^^^^^^^^^^

• Improved semantic token coverage in some edge cases, e.g. IndirectFieldDecl

Compile flags ^^^^^^^^^^^^^

Hover ^^^^^

Code completion ^^^^^^^^^^^^^^^

• --function-arg-placeholders=0 is now respected for variable template argument lists as well
• Macro proposals now use the completion item kind Constant (for object-like macros) or Function (for function-style macros) even for proposals coming from the index

Code actions ^^^^^^^^^^^^

• The "extract variable" tweak is no longer offered for the initializer expression of a declaration
• The tweak for turning unscoped into scoped enums now removes redundant prefixes from the enum values.
• Support "move function body out-of-line" in non-header files as well

Signature help ^^^^^^^^^^^^^^

• Signature help now shows function argument names for calls through pointers to functions in struct fields

Cross-references ^^^^^^^^^^^^^^^^

• Improve go-to-definition for some concept references

Document outline ^^^^^^^^^^^^^^^^

• Improved precision of document outline information for symbols whose definitions involve macro expansions

Clang-tidy integration ^^^^^^^^^^^^^^^^^^^^^^

• The quick fix for clang-tidy's readability-identifier-naming diagnostic is now hooked to invoke textDocument/rename, renaming the identifier across the whole project rather than just the translation unit of the diagnostic
• misc-const-correctness can now be enabled with FastCheckFilter: None (previously clangd would force it off unconditionally due to its run time)

Objective-C ^^^^^^^^^^^

• Added support for renaming Objective-C methods

Miscellaneous ^^^^^^^^^^^^^

• Worked around a clang-format bug that caused memory exhaustion when opening some large .h files due to the formatter's language guessing heuristic (#GH85703)
• Various other stability improvements, e.g. crash fixes
• Added a boolean option AnalyzeAngledIncludes to Includes config section, which allows to enable unused includes detection for all angled ("system") headers. At this moment umbrella headers are not supported, so enabling this option may result in false-positives.

Improvements to clang-doc

Improvements to clang-query

• Added the file command to dynamically load a list of commands and matchers from an external file, allowing the cost of reading the compilation database and building the AST to be imposed just once for faster prototyping.

• Removed support for enable output srcloc. Fixes #GH82591

Improvements to clang-rename

The improvements are...

Improvements to clang-tidy

• Improved :program:run-clang-tidy.py script. Added argument -source-filter to filter source files from the compilation database, via a RegEx. In a similar fashion to what -header-filter does for header files. Added progress indicator with a number of processed files and the runtime of each invocation after completion.

• Improved :program:check_clang_tidy.py script. Added argument -export-fixes to aid in clang-tidy and test development.

• Fixed bug where big values for unsigned check options overflowed into negative values when being printed with --dump-config.

• Fixed --verify-config option not properly parsing checks when using the literal operator in the .clang-tidy config.

• Added argument --exclude-header-filter and config option ExcludeHeaderFilterRegex to exclude headers from analysis via a RegEx.

• Added argument --allow-no-checks to suppress "no checks enabled" error when disabling all of the checks by --checks='-*'.

New checks ^^^^^^^^^^

• New :doc:boost-use-ranges <clang-tidy/checks/boost/use-ranges> check.

  Detects calls to standard library iterator algorithms that could be replaced with a Boost ranges version instead.

• New :doc:bugprone-crtp-constructor-accessibility <clang-tidy/checks/bugprone/crtp-constructor-accessibility> check.

  Detects error-prone Curiously Recurring Template Pattern usage, when the CRTP can be constructed outside itself and the derived class.

• New :doc:bugprone-pointer-arithmetic-on-polymorphic-object <clang-tidy/checks/bugprone/pointer-arithmetic-on-polymorphic-object> check.

  Finds pointer arithmetic performed on classes that contain a virtual function.

• New :doc:bugprone-return-const-ref-from-parameter <clang-tidy/checks/bugprone/return-const-ref-from-parameter> check.

  Detects return statements that return a constant reference parameter as constant reference. This may cause use-after-free errors if the caller uses xvalues as arguments.

• New :doc:bugprone-suspicious-stringview-data-usage <clang-tidy/checks/bugprone/suspicious-stringview-data-usage> check.

  Identifies suspicious usages of std::string_view::data() that could lead to reading out-of-bounds data due to inadequate or incorrect string null termination.

• New :doc:misc-use-internal-linkage <clang-tidy/checks/misc/use-internal-linkage> check.

  Detects variables and functions that can be marked as static or moved into an anonymous namespace to enforce internal linkage.

• New :doc:modernize-min-max-use-initializer-list <clang-tidy/checks/modernize/min-max-use-initializer-list> check.

  Replaces nested std::min and std::max calls with an initializer list where applicable.

• New :doc:modernize-use-designated-initializers <clang-tidy/checks/modernize/use-designated-initializers> check.

  Finds initializer lists for aggregate types that could be written as designated initializers instead.

• New :doc:modernize-use-ranges <clang-tidy/checks/modernize/use-ranges> check.

  Detects calls to standard library iterator algorithms that could be replaced with a ranges version instead.

• New :doc:modernize-use-std-format <clang-tidy/checks/modernize/use-std-format> check.

  Converts calls to absl::StrFormat, or other functions via configuration options, to C++20's std::format, or another function via a configuration option, modifying the format string appropriately and removing now-unnecessary calls to std::string::c_str() and std::string::data().

• New :doc:readability-enum-initial-value <clang-tidy/checks/readability/enum-initial-value> check.

  Enforces consistent style for enumerators' initialization, covering three styles: none, first only, or all initialized explicitly.

• New :doc:readability-math-missing-parentheses <clang-tidy/checks/readability/math-missing-parentheses> check.

  Check for missing parentheses in mathematical expressions that involve operators of different priorities.

• New :doc:readability-use-std-min-max <clang-tidy/checks/readability/use-std-min-max> check.

  Replaces certain conditional statements with equivalent calls to std::min or std::max.

New check aliases ^^^^^^^^^^^^^^^^^

• New alias :doc:cert-ctr56-cpp <clang-tidy/checks/cert/ctr56-cpp> to :doc:bugprone-pointer-arithmetic-on-polymorphic-object <clang-tidy/checks/bugprone/pointer-arithmetic-on-polymorphic-object> was added.

• New alias :doc:cert-int09-c <clang-tidy/checks/cert/int09-c> to :doc:readability-enum-initial-value <clang-tidy/checks/readability/enum-initial-value> was added.

Changes in existing checks ^^^^^^^^^^^^^^^^^^^^^^^^^^

• Improved :doc:bugprone-assert-side-effect <clang-tidy/checks/bugprone/assert-side-effect> check by detecting side effect from calling a method with non-const reference parameters.

• Improved :doc:bugprone-assignment-in-if-condition <clang-tidy/checks/bugprone/assignment-in-if-condition> check by ignoring assignments in the C++20 requires clause.

• Improved :doc:bugprone-casting-through-void <clang-tidy/checks/bugprone/casting-through-void> check by ignoring casts where source is already a void``` pointer, making middle void`` pointer casts bug-free.

• Improved :doc:bugprone-exception-escape <clang-tidy/checks/bugprone/exception-escape> check to correctly detect exception handler of type CV void * as catching all CV compatible pointer types.

• Improved :doc:bugprone-forwarding-reference-overload <clang-tidy/checks/bugprone/forwarding-reference-overload> check to ignore deleted constructors which won't hide other overloads.

• Improved :doc:bugprone-implicit-widening-of-multiplication-result <clang-tidy/checks/bugprone/implicit-widening-of-multiplication-result> check by adding an option to ignore constant expressions of signed integer types that fit in the source expression type.

• Improved :doc:bugprone-inc-dec-in-conditions <clang-tidy/checks/bugprone/inc-dec-in-conditions> check to ignore code within unevaluated contexts, such as decltype.

• Improved :doc:bugprone-lambda-function-name<clang-tidy/checks/bugprone/lambda-function-name> check by ignoring __func__ macro in lambda captures, initializers of default parameters and nested function declarations.

• Improved :doc:bugprone-multi-level-implicit-pointer-conversion <clang-tidy/checks/bugprone/multi-level-implicit-pointer-conversion> check by ignoring implicit pointer conversions that are part of a cast expression.

• Improved :doc:bugprone-non-zero-enum-to-bool-conversion <clang-tidy/checks/bugprone/non-zero-enum-to-bool-conversion> check by eliminating false positives resulting from direct usage of bitwise operators within parentheses.

• Improved :doc:bugprone-optional-value-conversion <clang-tidy/checks/bugprone/optional-value-conversion> check by eliminating false positives resulting from use of optionals in unevaluated context.

• Improved :doc:bugprone-sizeof-expression <clang-tidy/checks/bugprone/sizeof-expression> check by clarifying the diagnostics, eliminating some false positives and adding a new (off-by-default) option WarnOnSizeOfPointer that reports all sizeof(pointer) expressions (except for a few that are idiomatic).

• Improved :doc:bugprone-suspicious-include <clang-tidy/checks/bugprone/suspicious-include> check by replacing the local options HeaderFileExtensions and ImplementationFileExtensions by the global options of the same name.

• Improved :doc:bugprone-too-small-loop-variable <clang-tidy/checks/bugprone/too-small-loop-variable> check by incorporating better support for const loop boundaries.

• Improved :doc:bugprone-unused-local-non-trivial-variable <clang-tidy/checks/bugprone/unused-local-non-trivial-variable> check by ignoring local variable with [maybe_unused] attribute.

• Improved :doc:bugprone-unused-return-value <clang-tidy/checks/bugprone/unused-return-value> check by updating the parameter CheckedFunctions to support regexp, avoiding false positive for function with the same prefix as the default argument, e.g. std::unique_ptr and std::unique, avoiding false positive for assignment operator overloading.

• Improved :doc:bugprone-use-after-move <clang-tidy/checks/bugprone/use-after-move> check to also handle calls to std::forward. Fixed sequencing of designated initializers. Fixed sequencing of callees: In C++17 and later, the callee of a function is guaranteed to be sequenced before the arguments, so don't warn if the use happens in the callee and the move happens in one of the arguments.

• Improved :doc:cppcoreguidelines-avoid-non-const-global-variables <clang-tidy/checks/cppcoreguidelines/avoid-non-const-global-variables> check with a new option AllowInternalLinkage to disable the warning for variables with internal linkage.

• Improved :doc:cppcoreguidelines-macro-usage <clang-tidy/checks/cppcoreguidelines/macro-usage> check by ignoring macro with hash preprocessing token.

• Improved :doc:cppcoreguidelines-missing-std-forward <clang-tidy/checks/cppcoreguidelines/missing-std-forward> check by no longer giving false positives for deleted functions, by fixing false negatives when only a few parameters are forwarded and by ignoring parameters without a name (unused arguments).

• Improved :doc:cppcoreguidelines-owning-memory <clang-tidy/checks/cppcoreguidelines/owning-memory> check to properly handle return type in lambdas and in nested functions.

• Improved :doc:cppcoreguidelines-prefer-member-initializer <clang-tidy/checks/cppcoreguidelines/prefer-member-initializer> check by removing enforcement of rule C.48 <https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#c48-prefer-in-class-initializers-to-member-initializers-in-constructors-for-constant-initializers>_, which was deprecated since :program:clang-tidy 17. This rule is now covered by :doc:cppcoreguidelines-use-default-member-init <clang-tidy/checks/cppcoreguidelines/use-default-member-init>. Fixed incorrect hints when using list-initialization.

• Improved :doc:cppcoreguidelines-special-member-functions <clang-tidy/checks/cppcoreguidelines/special-member-functions> check with a new option AllowImplicitlyDeletedCopyOrMove, which removes the requirement for explicit copy or move special member functions when they are already implicitly deleted.

• Improved :doc:google-build-namespaces <clang-tidy/checks/google/build-namespaces> check by replacing the local option HeaderFileExtensions by the global option of the same name.

• Improved :doc:google-explicit-constructor <clang-tidy/checks/google/explicit-constructor> check to better handle C++20 explicit(bool).

• Improved :doc:google-global-names-in-headers <clang-tidy/checks/google/global-names-in-headers> check by replacing the local option HeaderFileExtensions by the global option of the same name.

• Improved :doc:google-runtime-int <clang-tidy/checks/google/runtime-int> check performance through optimizations.

• Improved :doc:hicpp-signed-bitwise <clang-tidy/checks/hicpp/signed-bitwise> check by ignoring false positives involving positive integer literals behind implicit casts when IgnorePositiveIntegerLiterals is enabled.

• Improved :doc:hicpp-ignored-remove-result <clang-tidy/checks/hicpp/ignored-remove-result> check by ignoring other functions with same prefixes as the target specific functions.

• Improved :doc:linuxkernel-must-check-errs <clang-tidy/checks/linuxkernel/must-check-errs> check documentation to consistently use the check's proper name.

• Improved :doc:llvm-header-guard <clang-tidy/checks/llvm/header-guard> check by replacing the local option HeaderFileExtensions by the global option of the same name.

• Improved :doc:misc-const-correctness <clang-tidy/checks/misc/const-correctness> check by avoiding infinite recursion for recursive functions with forwarding reference parameters and reference variables which refer to themselves. Also adapted the check to work with function-try-blocks.

• Improved :doc:misc-definitions-in-headers <clang-tidy/checks/misc/definitions-in-headers> check by replacing the local option HeaderFileExtensions by the global option of the same name. Additionally, the option UseHeaderFileExtensions is removed, so that the check uses the HeaderFileExtensions option unconditionally.

• Improved :doc:misc-header-include-cycle <clang-tidy/checks/misc/header-include-cycle> check by avoiding crash for self include cycles.

• Improved :doc:misc-unused-using-decls <clang-tidy/checks/misc/unused-using-decls> check by replacing the local option HeaderFileExtensions by the global option of the same name.

• Improved :doc:misc-use-anonymous-namespace <clang-tidy/checks/misc/use-anonymous-namespace> check by replacing the local option HeaderFileExtensions by the global option of the same name.

• Improved :doc:modernize-avoid-c-arrays <clang-tidy/checks/modernize/avoid-c-arrays> check by introducing the new AllowStringArrays option, enabling the exclusion of array types with deduced length initialized from string literals.

• Improved :doc:modernize-loop-convert <clang-tidy/checks/modernize/loop-convert> check by ensuring that fix-its don't remove parentheses used in sizeof calls when they have array index accesses as arguments.

• Improved :doc:modernize-use-constraints <clang-tidy/checks/modernize/use-constraints> check by fixing a crash that occurred in some scenarios and excluding system headers from analysis.

• Improved :doc:modernize-use-nullptr <clang-tidy/checks/modernize/use-nullptr> check to include support for C23, which also has introduced the nullptr keyword.

• Improved :doc:modernize-use-override <clang-tidy/checks/modernize/use-override> check to also remove any trailing whitespace when deleting the virtual keyword.

• Improved :doc:modernize-use-starts-ends-with <clang-tidy/checks/modernize/use-starts-ends-with> check to also handle calls to compare method.

• Improved :doc:modernize-use-std-print <clang-tidy/checks/modernize/use-std-print> check to not crash if the format string parameter of the function to be replaced is not of the expected type.

• Improved :doc:modernize-use-using <clang-tidy/checks/modernize/use-using> check by adding support for detection of typedefs declared on function level.

• Improved :doc:performance-inefficient-vector-operation <clang-tidy/checks/performance/inefficient-vector-operation> fixing false negatives caused by different variable definition type and variable initial value type in loop initialization expression.

• Improved :doc:performance-move-const-arg <clang-tidy/checks/performance/move-const-arg> check by ignoring std::move() calls when their target is used as an rvalue.

• Improved :doc:performance-unnecessary-copy-initialization <clang-tidy/checks/performance/unnecessary-copy-initialization> check by detecting more cases of constant access. In particular, pointers can be analyzed, so the check now handles the common patterns const auto e = (*vector_ptr)[i] and const auto e = vector_ptr->at(i);. Calls to mutable function where there exists a const overload are also handled. Fix crash in the case of a non-member operator call.

• Improved :doc:performance-unnecessary-value-param <clang-tidy/checks/performance/unnecessary-value-param> check detecting more cases for template functions including lambdas with auto. E.g., std::sort(a.begin(), a.end(), [](auto x, auto y) { return a > b; }); will be detected for expensive to copy types. Fixed false positives for dependent call expressions.

• Improved :doc:readability-avoid-return-with-void-value <clang-tidy/checks/readability/avoid-return-with-void-value> check by adding fix-its.

• Improved :doc:readability-const-return-type <clang-tidy/checks/readability/const-return-type> check to eliminate false positives when returning types with const not at the top level.

• Improved :doc:readability-container-size-empty <clang-tidy/checks/readability/container-size-empty> check to prevent false positives when utilizing size or length methods that accept parameter. Fixed crash when facing template user defined literals.

• Improved :doc:readability-duplicate-include <clang-tidy/checks/readability/duplicate-include> check by excluding include directives that form the filename using macro.

• Improved :doc:readability-else-after-return <clang-tidy/checks/readability/else-after-return> check to ignore if consteval statements, for which the else branch must not be removed.

• Improved :doc:readability-identifier-naming <clang-tidy/checks/readability/identifier-naming> check in GetConfigPerFile mode by resolving symbolic links to header files. Fixed handling of Hungarian Prefix when configured to LowerCase. Added support for renaming designated initializers. Added support for renaming macro arguments. Fixed renaming conflicts arising from out-of-line member function template definitions.

• Improved :doc:readability-implicit-bool-conversion <clang-tidy/checks/readability/implicit-bool-conversion> check to provide valid fix suggestions for static_cast without a preceding space and fixed problem with duplicate parentheses in double implicit casts. Corrected the fix suggestions for C23 and later by using C-style casts instead of static_cast. Fixed false positives in C++20 spaceship operator by ignoring casts in implicit and defaulted functions.

• Improved :doc:readability-non-const-parameter <clang-tidy/checks/readability/non-const-parameter> check to not crash when redeclaration have fewer parameters than expected.

• Improved :doc:readability-redundant-inline-specifier <clang-tidy/checks/readability/redundant-inline-specifier> check to properly emit warnings for static data member with an in-class initializer.

• Improved :doc:readability-redundant-member-init <clang-tidy/checks/readability/redundant-member-init> check to avoid false-positives when type of the member does not match the type of the initializer.

• Improved :doc:readability-static-accessed-through-instance <clang-tidy/checks/readability/static-accessed-through-instance> check to support calls to overloaded operators as base expression and provide fixes to expressions with side-effects.

• Improved :doc:readability-simplify-boolean-expr <clang-tidy/checks/readability/simplify-boolean-expr> check to avoid to emit warning for macro when IgnoreMacro option is enabled and improve messages when auto-fix does not work.

• Improved :doc:readability-static-definition-in-anonymous-namespace <clang-tidy/checks/readability/static-definition-in-anonymous-namespace> check by resolving fix-it overlaps in template code by disregarding implicit instances.

• Improved :doc:readability-string-compare <clang-tidy/checks/readability/string-compare> check to also detect usages of std::string_view::compare. Added a StringLikeClasses option to detect usages of compare method in custom string-like classes.

Removed checks ^^^^^^^^^^^^^^

• Removed cert-dcl21-cpp, which was deprecated since :program:clang-tidy 17, since the rule DCL21-CPP has been removed from the CERT guidelines.

Miscellaneous ^^^^^^^^^^^^^

• Fixed incorrect formatting in :program:clang-apply-replacements when no --format option is specified. Now :program:clang-apply-replacements applies formatting only with the option.

Improvements to include-fixer

The improvements are...

Improvements to clang-include-fixer

The improvements are...

Improvements to modularize

The improvements are...

Improvements to pp-trace

Clang-tidy Visual Studio plugin