[dcl.spec.auto.general] p13 What is a function whose return type is considered as undeduced?

[xmh0511]

Full name of submitter (unless configured in github; will be published with the issue): Jim X

Consider this example

struct A{
    auto f(){
        g();
    }
    auto g(){}
};

The compiler says

use of 'auto A::g()' before deduction of 'auto'

The justification might be [dcl.spec.auto.general] p13. However, it's unclear what function whose return type is considered as undeduced.

Suggestion Resolution:

A function whose return type contains placeholder type at point P is considered undeduced if its definition is not reachable.

[jensmaurer]

This is the "complete class context" question, and how exactly (in which order) class bodies and member function bodies are parsed.

[xmh0511]

This is the "complete class context" question, and how exactly (in which order) class bodies and member function bodies are parsed.

According to [class.mem.general] p8, the body of A::f is complete class context, and the name lookup finds the declaration from the class-specifier of A as per [class.member.lookup] p3. It is unclear whether the declaration found from the class-specifier is considered undeduced.

[frederick-vs-ja]

It seems that this should be handled together with CWG1890.