[clang] [clang][analyzer] Do not analyze opaque types in CXXDeleteChecker (PR #70638)

[Gábor Horváth via cfe-commits]

Xazax-hun wrote:

In case it is not too hard to synthesize a test case, could you add a regression test as well in a follow-up commit?

https://github.com/llvm/llvm-project/pull/70638