[clang-tidy] add new check cppcoreguidelines-pro-type-cstyle-cast

Summary:
This check flags all use of c-style casts that perform a static_cast
downcast, const_cast, or reinterpret_cast.

Use of these casts can violate type safety and cause the program to
access a
variable that is actually of type X to be accessed as if it were of an
unrelated type Z. Note that a C-style (T)expression cast means to
perform
the first of the following that is possible: a const_cast, a
static_cast, a
static_cast followed by a const_cast, a reinterpret_cast, or a
reinterpret_cast followed by a const_cast. This rule bans (T)expression
only when used to perform an unsafe cast.

This rule is part of the "Type safety" profile of the C++ Core
Guidelines, see
https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md#-type4-dont-use-c-style-texpression-casts-that-would-perform-a-static_cast-downcast-const_cast-or-reinterpret_cast.

Reviewers: alexfh, sbenza, bkramer, aaron.ballman

Subscribers: cfe-commits

Differential Revision: http://reviews.llvm.org/D14096

llvm-svn: 252425

clang-tools-extra/clang-tidy/cppcoreguidelines/CppCoreGuidelinesTidyModule.cpp

@@ -14,6 +14,7 @@
 #include "ProBoundsArrayToPointerDecayCheck.h"
 #include "ProBoundsPointerArithmeticCheck.h"
 #include "ProTypeConstCastCheck.h"
+#include "ProTypeCstyleCastCheck.h"
 #include "ProTypeReinterpretCastCheck.h"
 #include "ProTypeStaticCastDowncastCheck.h"
 #include "ProTypeUnionAccessCheck.h"
@@ -33,6 +34,8 @@ public:
         "cppcoreguidelines-pro-bounds-pointer-arithmetic");
     CheckFactories.registerCheck<ProTypeConstCastCheck>(
         "cppcoreguidelines-pro-type-const-cast");
+    CheckFactories.registerCheck<ProTypeCstyleCastCheck>(
+        "cppcoreguidelines-pro-type-cstyle-cast");
     CheckFactories.registerCheck<ProTypeReinterpretCastCheck>(
         "cppcoreguidelines-pro-type-reinterpret-cast");
     CheckFactories.registerCheck<ProTypeStaticCastDowncastCheck>(