[clang-tidy/google-readability-casting] Disable check for Objective-C++

Summary:
Previously, `google-readability-casting` was disabled for Objective-C.

The Google Objective-C++ style allows both Objective-C and
C++ style in the same file. Since clang-tidy doesn't have a good
way to allow multiple styles per file, this disables the
check for Objective-C++.

Test Plan: New tests added. Ran tests with:
  % make -j16 check-clang-tools
  Before diff, confirmed tests failed:
  https://reviews.llvm.org/P8081
  After diff, confirrmed tests passed.

Reviewers: alexfh, Wizard, hokein, stephanemoore

Reviewed By: alexfh, Wizard, stephanemoore

Subscribers: stephanemoore, cfe-commits, bkramer, klimek

Differential Revision: https://reviews.llvm.org/D46659

llvm-svn: 332516

1 files changed, 2 insertions, 1 deletions

diff --git a/clang-tools-extra/clang-tidy/google/AvoidCStyleCastsCheck.cpp b/clang-tools-extra/clang-tidy/google/AvoidCStyleCastsCheck.cpp
index 80cc475b07a..4c7c164b906 100644
--- a/clang-tools-extra/clang-tidy/google/AvoidCStyleCastsCheck.cpp
+++ b/clang-tools-extra/clang-tidy/google/AvoidCStyleCastsCheck.cpp
@@ -100,7 +100,8 @@ void AvoidCStyleCastsCheck::check(const MatchFinder::MatchResult &Result) {
   }
 
   // The rest of this check is only relevant to C++.
-  if (!getLangOpts().CPlusPlus)
+  // We also disable it for Objective-C++.
+  if (!getLangOpts().CPlusPlus || getLangOpts().ObjC1 || getLangOpts().ObjC2)
     return;
   // Ignore code inside extern "C" {} blocks.
   if (!match(expr(hasAncestor(linkageSpecDecl())), *CastExpr, *Result.Context)