Include What You Use Versions Save

Compatible with Clang 18.

Major changes:

• [iwyu] Improve type analysis for typedefs, aliases and templates
• [iwyu] Improve analysis of macros expanding macros
• [iwyu] Improve IWYU driver for better validation and job handling
• [iwyu] Reject IWYU invocations with precompiled headers (see FAQ)
• [iwyu_tool] Better preserve failure exit codes
• [mappings] Add mappings for libstdc++ <debug/...> headers
• [mappings] Make mappings for POSIX and standard C headers stricter (more portable)
• [doc] Add separate FAQ page for longer descriptions
• [ci] IWYU now runs on itself in CI (finally!)

... and many smaller improvements

Compatible with Clang 17.

Major changes:

• [iwyu] Improve analysis of type aliases (typedef and using)
• [iwyu] Improve analysis of namespace aliases (namespace xyz = foobar)
• [iwyu] Improve support for elaborated forward declarations (typedef struct Foo Bar;)
• [iwyu] Improve handling of "autocast" and function return types, particularly with complex template types.
• [iwyu] Add new IWYU pragma: always_keep, which lets a header announce that it should always be kept wherever included
• [iwyu] Automatically use builtin libc++ mappings if libc++ is the active standard library
• [mappings] Improve mappings for libc++ and posix headers

... and many smaller improvements

• [iwyu] Support IWYU pragma: export for forward-declarations
• [iwyu] Silently break cycles in mappings instead of crashing
• [iwyu] Require full type inside typeid()
• [iwyu] Improve template reporting and resugaring
• [iwyu] Improve reporting of explicit template instantiations
• [iwyu] Fix a few crashers
• [iwyu] Improve logging (many small fixes)
• Abandon python2 for scripts in favor of python3

Compatible with Clang 15.

• [iwyu] New --comment_style option to control verbosity of 'why' comments
• [iwyu] New --regex option to select regex dialect
• [iwyu] Add support for regex replacement in mappings
• [iwyu] Add begin_keep/end_keep pragmas for protecting ranges of includes or forward-declares
• [iwyu] Fix several crasher bugs for unusual inputs
• [iwyu] More exhaustive handling of type aliases and enums
• [iwyu] Recognize IWYU pragmas in CRLF source files
• [iwyu] Respect configured toolchain on macOS (and overrides via -nostdinc++ + -isystem)
• [fix_includes] Recognize namespace alias declarations
• [mappings] Improve mappings for POSIX and libc headers
• [cmake] Build now requires a C++17 compiler (as does LLVM)
• [cmake] Support LLVM external project build (see README)

... and many other changes

• [iwyu] Fix crash on C++20 consteval expressions
• [iwyu] Use more conventional exit codes (breaking change!)
• [iwyu_tool] Fix deprecation warning for python3
• [iwyu] Fix crash on va_list on AArch64
• [iwyu] Improved support for using declarations based on new Clang design

Note the breaking change for exit codes; IWYU now always returns zero by default. See the README or help text for more information about compatibility overrides.

• [iwyu] Improve support for various C++ features (builtins, CTAD, specializations, type aliases)
• [iwyu] Fix crash on invalid code
• [iwyu] Remove hard dependency on x86 LLVM target
• [mappings] Improve mappings for GNU libc
• [iwyu_tool] More concise output for clang output format

• [iwyu_tool] Accept --load/-l argument for load limiting
• [iwyu_tool] Signal success/failure with exit code
• [mappings] Harmonize mapping generators
• [mappings] Add mapping generator for CPython
• [mappings] Improve mappings for libstdc++ and Boost
• [cmake] Add explicit C++14 compiler flag
• ... and many internal improvements

• [iwyu] Fix crash due to undefined behavior in AST traversal
• [iwyu] Improve handling of operator new including C++17 features
• [iwyu] Improve handling of templates
• [iwyu_tool] Remove known compiler wrappers from the command list
• [mappings] Improve Qt mapping generator
• [mappings] Improve boost mappings
• [mappings] Improve built-in mappings for <time.h>
• [mappings] Add built-in mappings for max_align_t, ptrdiff_t, and wchar_t
• [cmake] Support shared LLVM/Clang libraries and other improvements

• [iwyu] Report non-builtin enum base types
• [iwyu] Disable forward-declares for decls in inline namespaces
• [iwyu] Make C structs forward-declarable again
• [iwyu] Always keep Qt .moc includes
• [iwyu] Include binary type traits in analysis (e.g. __is_convertible_to)
• [iwyu_tool] Fail fast if include-what-you-use is not found
• [iwyu_tool] Print all diagnostic ouptut to stderr
• [fix_includes] Improve file extension detection
• Add man page for include-what-you-use

• [iwyu] Improved handling of relative includes in mappings and pragmas
• [iwyu] Path normalization now collapses ..
• [iwyu] Improve --no_fwd_decls not to remove required forward declarations
• [iwyu] Improved handling of builtin templates
• [iwyu] Don't mark forward declarations final
• [iwyu] Tolerate using declarations in precompiled header
• [mappings] Add script to generate Qt mappings, and new mappings for Qt 5.11
• [iwyu_tool] Use directory from compilation database if available
• Numerous documentation and build improvements