Source code to scan:
template <typename T>
class HB {
T m;
public:
void HBfunc1();
};
template <typename T>
void HB<T>::HBfunc1() {
class HC {
public:
void HCfunc2() { };
};
HC().HCfunc2();
}
void TestTemplate() { HB<int>().HBfunc1(); };
The above code works fine in VS2019, when use Clang LibTooling to scan the AST:
virtual bool VisitCallExpr(CallExpr *call) {
std::cout << "VisitCallExpr: ";
if (call->getDirectCallee()) {
std::cout << " "<<call->getDirectCallee()->getQualifiedNameAsString();
}
else {
Decl *callee = call->getCalleeDecl();
if (!callee) {
std::cout << "\nNow dump call:\n";
call->dump();
}
}
std::cout<<"\n";
return true;
}
When visiting the CallExpr for this line in the scaned source:
HC().HCfunc2();
The callee is null and the dump of the CallExpr are:
VisitCallExpr:
Now dump call:
CallExpr 0x1c2ef83b3a0 '<dependent type>'
`-CXXDependentScopeMemberExpr 0x1c2ef83b348 '<dependent type>' lvalue .HCfunc2
`-CXXUnresolvedConstructExpr 0x1c2ef83b320 'class HC' 'class HC'
Clang doesn't report error in the scanning process (Since the code works fine).
In LLVM source code there is:
// This represents the type of an expression whose type is
// totally unknown, e.g. 'T::foo'. It is permitted for this to
// appear in situations where the structure of the type is
// theoretically deducible.
BUILTIN_TYPE(Dependent, DependentTy)
Why the type HC is considered unknown? Will any type be unknown while scanning the AST without issueing any warning/erroe? How to visit invocation like this and extract information about its callee? Does the scaned code have problems?
