ReleaseNotes.rst

Extra Clang Tools |release| |ReleaseNotesTitle|

• Introduction
• What's New in Extra Clang Tools |release|?
  • Major New Features
  • Improvements to clangd
    • Inlay hints
    • Diagnostics
    • Semantic Highlighting
    • Compile flags
    • Hover
    • Code completion
    • Signature help
    • Cross-references
    • Objective-C
    • Miscellaneous
  • Improvements to clang-doc
  • Improvements to clang-query
  • Improvements to clang-rename
  • Improvements to clang-tidy
    • New checks
    • New check aliases
    • Changes in existing checks
    • Removed checks
  • Improvements to include-fixer
  • Improvements to clang-include-fixer
  • Improvements to modularize
  • Improvements to pp-trace
  • Clang-tidy Visual Studio plugin

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 <https://releases.llvm.org/download.html>`_.

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.

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

Inlay hints

• This feature provides texutal hints interleaved with the code, like parameter names, deduced types and designated initializers.
• The clangd/inlayHints LSP extension is now documented, and both position and range.
• Inlay hints are now on-by-default in clangd, if the client supports and exposes them. (vscode-clangd does so). The -inlay-hints flag has been removed.
• Inlay hints can be disabled or configured in the config file.

Diagnostics

• Unused #include diagnostics are available. These are off by default, and can be turned on through the Diagnostics.UnusedIncludes config option.
• Deprecated and Unnecessary tags from LSP 3.15 are set on -Wdeprecated and -Wunused diagnostics. Clients may display these in a specialized way.
• clangd suggests inserting includes to fix problems in more cases:
  • calling unknown functions in C, even when an implicit declaration is inferred.
  • incomplete types (some additional cases).
  • various diagnostics that specify "include <foo.h>" in their text.
• The "populate switch" action is more reliably offered as a fix for -Wswitch warnings, and works with C enums.
• Warnings specified by ExtraArgs: -W... flags in .clang-tidy config files are now produced.

Semantic Highlighting

• virtual modifier for method names
• usedAsMutableReference modifier for function parameters
• Lambda captures now marked as local variables.

Compile flags

• Compile flags like -xc++-header that must precede input file names are now added correctly by the CompileFlags.Add config option.
• If multiple architectures are specified (e.g. when targeting Apple M1+Intel), clangd will now use the host architecture instead of failing to parse.
• Added CompileFlags.Compiler option to override executable name in compile flags.
• Copying compile_commands.json entries from one file to another (and simply adjusting file) should now work correctly.

Hover

• Hovering on many attributes (e.g. [[nodiscard]]) will show documentation.
• Hovering on include directives shows the resolved header path.
• Hovering on character literals shows their numeric value.
• Code snippets are marked with the appropriate language instead of always C++. This may improve clients' syntax highlighting.
• Include desugared types in hover, like in diagnostics. Off by default, controlled with Hover.ShowAKA config option.

Code completion

• Completion of attributes (e.g. [[gsl::Owner(Foo)]])
• Completion of /*ParameterName=*/ comments.
• Documentation of items with annotate attributes now includes the annotation.
• Improved handling of results with 1-3 character names.
• Completion of members in constructor init lists (Foo() : member_() {}) is much more reliable.
• C++ Standard library completions should be less noisy: parameter names are deuglified (vector<_Tp> is now vector<Tp>) and many __implementation_details are hidden altogether.

Signature help

• Signatures for template argument lists
• Signatures for braced constructor calls
• Signatures for aggregate initializers
• Signatures for members in constructor init lists are much more reliable.
• Variadic functions correctly show signature help when typing the variadic arguments.
• Signature help is retriggered on closing brackets ), }, >. This means signature help should be correct after nested function calls.

Cross-references

• Support for textDocument/typeDefinition LSP request.
• Improved handling of symbols introduced via using declarations.
• Searching for references to an overriding method also returns references to the base class method. (Typically calls that may invoke the override).
• All references from the current file are always returned, even if there are enough to exceed our usual limit.

Objective-C

• #pragma mark directives now form groups in the document outline.
• id and instancetype are treated as keywords rather than typedefs

Miscellaneous

• Include request context on crashes when possible.
• Many stability, performance and correctness improvements.
• -use-dirty-headers command line flag to use dirty buffer contents when parsing headers, rather than the saved on-disk contents.
• clangd --check=/path/to/file.cpp now reads config files in ancestor directories, in addition to user config file.
• Improved compile flags handling in clangd-indexer.
• The index file format changed in this release, indexes need to be rebuilt. This should happen transparently in standard cases (the background index).

Improvements to clang-doc

The improvements are...

Improvements to clang-query

The improvements are...

Improvements to clang-rename

The improvements are...

Improvements to clang-tidy

• Ignore warnings from macros defined in system headers, if not using the -system-headers flag.
• Added support for globbing in NOLINT* expressions, to simplify suppressing multiple warnings in the same line.
• Added support for NOLINTBEGIN ... NOLINTEND comments to suppress Clang-Tidy warnings over multiple lines.
• Added support for external plugin checks with -load.

New checks

• New :doc:`abseil-cleanup-ctad <clang-tidy/checks/abseil-cleanup-ctad>` check.

  Suggests switching the initialization pattern of absl::Cleanup instances from the factory function to class template argument deduction (CTAD), in C++17 and higher.

• New :doc:`bugprone-stringview-nullptr <clang-tidy/checks/bugprone-stringview-nullptr>` check.

  Checks for various ways that the const CharT* constructor of std::basic_string_view can be passed a null argument.

• New :doc:`bugprone-suspicious-memory-comparison <clang-tidy/checks/bugprone-suspicious-memory-comparison>` check.

  Finds potentially incorrect calls to memcmp() based on properties of the arguments.

• New :doc:`cppcoreguidelines-virtual-class-destructor <clang-tidy/checks/cppcoreguidelines-virtual-class-destructor>` check.

  Finds virtual classes whose destructor is neither public and virtual nor protected and non-virtual.

• New :doc:`misc-misleading-bidirectional <clang-tidy/checks/misc-misleading-bidirectional>` check.

  Inspects string literal and comments for unterminated bidirectional Unicode characters.

• New :doc:`misc-misleading-identifier <clang-tidy/checks/misc-misleading-identifier>` check.

  Reports identifier with unicode right-to-left characters.

• New :doc:`readability-container-contains <clang-tidy/checks/readability-container-contains>` check.

  Finds usages of container.count() and container.find() == container.end() which should be replaced by a call to the container.contains() method introduced in C++20.

• New :doc:`readability-container-data-pointer <clang-tidy/checks/readability-container-data-pointer>` check.

  Finds cases where code could use data() rather than the address of the element at index 0 in a container.

• New :doc:`readability-duplicate-include <clang-tidy/checks/readability-duplicate-include>` check.

  Looks for duplicate includes and removes them.

• New :doc:`readability-identifier-length <clang-tidy/checks/readability-identifier-length>` check.

  Reports identifiers whose names are too short. Currently checks local variables and function parameters only.

New check aliases

• New alias :doc:`cert-err33-c <clang-tidy/checks/cert-err33-c>` to :doc:`bugprone-unused-return-value <clang-tidy/checks/bugprone-unused-return-value>` was added.
• New alias :doc:`cert-exp42-c <clang-tidy/checks/cert-exp42-c>` to :doc:`bugprone-suspicious-memory-comparison <clang-tidy/checks/bugprone-suspicious-memory-comparison>` was added.
• New alias :doc:`cert-flp37-c <clang-tidy/checks/cert-flp37-c>` to :doc:`bugprone-suspicious-memory-comparison <clang-tidy/checks/bugprone-suspicious-memory-comparison>` was added.

Changes in existing checks

• :doc:`bugprone-assert-side-effect <clang-tidy/checks/bugprone-assert-side-effect>` check now supports an IgnoredFunctions option to explicitly consider the specified semicolon-separated functions list as not having any side-effects. Regular expressions for the list items are also accepted.

• Fixed a false positive in :doc:`bugprone-throw-keyword-missing <clang-tidy/checks/bugprone-throw-keyword-missing>` when creating an exception object using placement new.

• Removed default setting cppcoreguidelines-explicit-virtual-functions.IgnoreDestructors = "true", from :doc:`cppcoreguidelines-explicit-virtual-functions <clang-tidy/checks/cppcoreguidelines-explicit-virtual-functions>` to match the current state of the C++ Core Guidelines.

• Eliminated false positives for :doc:`cppcoreguidelines-macro-usage <clang-tidy/checks/cppcoreguidelines-macro-usage>` by restricting the warning about using constants to only macros that expand to literals.

• :doc:`cppcoreguidelines-narrowing-conversions <clang-tidy/checks/cppcoreguidelines-narrowing-conversions>` check now supports a WarnOnIntegerToFloatingPointNarrowingConversion option to control whether to warn on narrowing integer to floating-point conversions.

• Make the :doc:`cppcoreguidelines-pro-bounds-array-to-pointer-decay <clang-tidy/checks/cppcoreguidelines-pro-bounds-array-to-pointer-decay>` check accept string literal to pointer decay in conditional operator even if operands are of the same length.

• Removed suggestion use gsl::at from warning message in the :doc:`cppcoreguidelines-pro-bounds-constant-array-index <clang-tidy/checks/cppcoreguidelines-pro-bounds-constant-array-index>` check, since that is not a requirement from the C++ Core Guidelines. This allows people to choose their own safe indexing strategy. The fix-it is kept for those who want to use the GSL library.

• Fixed a false positive in :doc:`fuchsia-trailing-return <clang-tidy/checks/fuchsia-trailing-return>` for C++17 deduction guides.

• Updated :doc:`google-readability-casting <clang-tidy/checks/google-readability-casting>` to diagnose and fix functional casts, to achieve feature parity with the corresponding cpplint.py check.

• Generalized the :doc:`modernize-use-default-member-init <clang-tidy/checks/modernize-use-default-member-init>` check to handle non-default constructors.

• Improved :doc:`performance-move-const-arg <clang-tidy/checks/performance-move-const-arg>` check.

  Removed a wrong FixIt for trivially copyable objects wrapped by std::move() and passed to an rvalue reference parameter. Removal of std::move() would break the code.

• :doc:`readability-simplify-boolean-expr <clang-tidy/checks/readability-simplify-boolean-expr>` now simplifies return statements associated with case, default and labeled statements.

• Fixed a crash in :doc:`readability-suspicious-call-argument <clang-tidy/checks/readability-suspicious-call-argument>` related to passing arguments that refer to program elements without a trivial identifier.

Removed checks

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

The improvements are...

Clang-tidy Visual Studio plugin