https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101107
Bug ID: 101107
Summary: Misleading error message in aggregate initialization
in CRTP base class
Product: gcc
Version: 11.1.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: btzy1996 at gmail dot com
Target Milestone: ---
The following code gives a compile error:
```
template <typename Prev, typename Next>
struct Combiner;
template <typename T>
struct Base {
template <typename Next>
auto dostuff(Next next) {
return Combiner<T, Next>{Base<Combiner<T, Next>>{}, *this, next};
}
};
template <typename Prev, typename Next>
struct Combiner : public Base<Combiner<Prev, Next>> {
Prev prev;
Next next;
};
struct A : public Base<A> {
int stuff;
};
struct B : public Base<B> {
int stuff;
};
int main(){
A{{}, 1}.dostuff(B{{}, 2});
}
```
Error message:
```
<source>: In instantiation of 'auto Base<T>::dostuff(Next) [with Next = B; T =
A]':
<source>:27:21: required from here
<source>:8:68: error: cannot convert 'B' to 'int' in initialization
8 | return Combiner<T, Next>{Base<Combiner<T, Next>>{}, *this,
next};
| ^~~~
| |
| B
Compiler returned: 1
```
However, the error message is misleading - it seems clear that the programmer
forgot to cast `*this` to the derived type (i.e. change `*this` to
`static_cast<const T&>(*this)`), but the error message is about something
totally different.
