[PATCH] D44241: Add a check for constructing non-trivial types without assigning to a variable

[Paul Fultz II via Phabricator via cfe-commits]

pfultz2 created this revision.
pfultz2 added reviewers: clang-tools-extra, aaron.ballman.
pfultz2 added a project: clang-tools-extra.
Herald added a subscriber: mgorny.

Diagnoses when a non-trivial type is not assigned to a variable. This is useful to check for problems like unnamed lock guards.

For example, if you had code written like this:

  int g_i = 0;
  std::mutex g_i_mutex;  // protects g_i
   
  void safe_increment()
  {
    std::lock_guard<std::mutex>{g_i_mutex};
    // The lock is locked and then unlocked before reaching here
    ++g_i;
  }

This will warn that a variable should be created instead:

  int g_i = 0;
  std::mutex g_i_mutex;  // protects g_i
   
  void safe_increment()
  {
    std::lock_guard<std::mutex> lock{g_i_mutex};
    // The lock is locked and then will be unlocked when exiting scope
    ++g_i;
  }


Repository:
  rCTE Clang Tools Extra

https://reviews.llvm.org/D44241

Files:
  clang-tidy/misc/CMakeLists.txt
  clang-tidy/misc/MiscTidyModule.cpp
  clang-tidy/misc/OwnerlessResourceCheck.cpp
  clang-tidy/misc/OwnerlessResourceCheck.h
  docs/ReleaseNotes.rst
  docs/clang-tidy/checks/list.rst
  docs/clang-tidy/checks/misc-ownerless-resource.rst
  test/clang-tidy/misc-ownerless-resource.cpp

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