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

[Aaron Ballman via cfe-commits]

aaron.ballman added inline comments.

================
Comment at: clang-tidy/cppcoreguidelines/ProTypeStaticCastDowncastCheck.cpp:33
@@ +32,3 @@
+
+  SubExpr = SubExpr->IgnoreParens();
+  QualType SourceType = SubExpr->getType();
----------------
Will the type dependence check also look through parens, or should this move up a few lines?

================
Comment at: clang-tidy/cppcoreguidelines/ProTypeStaticCastDowncastCheck.cpp:42
@@ +41,3 @@
+  const CXXRecordDecl* SourceDecl;
+  if (SourceType->isPointerType())
+    SourceDecl = SourceType->getPointeeCXXRecordDecl();
----------------
No need for this or the check above -- getPointeeCXXRecordDecl() already does the right thing for references. You should be able to do:

```
if (auto *DestDecl = DestType->getPointeeCXXRecordDecl()) {
  // etc
}
```
Also note  that auto DestDecl isn't a good idea as it hides the fact that DestDecl is a pointer from anyone reading the code.

================
Comment at: clang-tidy/cppcoreguidelines/ProTypeStaticCastDowncastCheck.cpp:51
@@ +50,3 @@
+  if (DestDecl->isDerivedFrom(SourceDecl)) {
+    diag(MatchedCast->getOperatorLoc(), "do not use static_cast to cast from base to derived. Use "
+                                      "dynamic_cast instead. (C++ Core "
----------------
Formatting looks off on this; also, I don't think you need the parenthetical as that information is part of the checker name itself.


http://reviews.llvm.org/D13368