[PATCH] D13368: [clang-tidy] add check cppcoreguidelines-pro-type-static-cast-downcast

[Matthias Gehre via cfe-commits]

mgehre marked an inline comment as done.
mgehre added a comment.

I cannot think of any way to improve the usefulness of the diagnostic in the non-polymorphic case.
For now, this patch has a link to the CppCoreGuidelines document in the docs/**/*.rst file.

Also, this check is not enabled by default. One has to explicitly enable it, and may at that
point reason about the usefulness of the CppCoreGuidelines and this check.


================
Comment at: test/clang-tidy/cppcoreguidelines-pro-type-static-cast-downcast.cpp:39
@@ +38,3 @@
+  auto PP0 = static_cast<PolymorphicDerived*>(new PolymorphicBase());
+  // CHECK-MESSAGES: :[[@LINE-1]]:14: warning: do not use static_cast to downcast from a base to a derived class; use dynamic_cast instead [cppcoreguidelines-pro-type-static-cast-downcast]
+  // CHECK-FIXES: auto PP0 = dynamic_cast<PolymorphicDerived*>(new PolymorphicBase());
----------------
aaron.ballman wrote:
> No need to have the [cppcoreguidelines-pro-type-static-cast-downcast] part of the message on anything but the first diagnostic in the file. (This reduces clutter, but we test it one time just to make sure it's there).
I can remove it on the remaining messages that end in "use dynamic_cast instead". I need to keep it in the non-polymorphic case
to make sure that they are not followed by "use dynamic_cast instead".


http://reviews.llvm.org/D13368