Re-teach Expr::isNullPointerConstant() about ImplicitCastExpr:-)
Re-teach Expr::isNullPointerConstant() about ImplicitCastExpr:-)

This fixes the following bug submitted by Neil...

const char *f (void) { return 0; }

...which would incorrectly warn with -pedantic enabled.


git-svn-id: ffe668792ed300d6c2daa1f6eba2e0aa28d7ec6c@41559 91177308-0d34-0410-b5e6-96231b3b80d8

apple/swift-clang,llvm-mirror/clang,llvm-mirror/clang,llvm-mirror/clang,llvm-mirror/clang,llvm-mirror/clang,apple/swift-clang,llvm-mirror/clang,llvm-mirror/clang,apple/swift-clang,apple/swift-clang,llvm-mirror/clang,apple/swift-clang,apple/swift-clang,llvm-mirror/clang,apple/swift-clang,apple/swift-clang,apple/swift-clang,apple/swift-clang,llvm-mirror/clang