Checker callbacks not invoked for DeclRefExpr, MemberExpr, CXXThisExpr

I’m trying to write a checker for C++ code.

Registering for PreStmt gives no result, whereas registering for PreStmt at least gives me a callback on ImplicitCast(DeclRefExpr). Likewise for MemberExpr.

I haven’t found a way to consistently get a callback for CXXThisExpr.

On the other hand, CXXNewExpr, CXXDeleteStmt, etc, callback all function as expected.

Is this a known issue or am I (likely) doing things wrong?

Thanks,
Aemon

p.s. My clang tree is synced at git 7b47adcbea945e31db3e96567e8
A few months old now.