[Issue 19211] New: [REG 2.072] cant get the type of a non-const delegate in a const function

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=19211

          Issue ID: 19211
           Summary: [REG 2.072] cant get the type of a non-const delegate
                    in a const function
           Product: D
           Version: D2
          Hardware: All
                OS: All
            Status: NEW
          Keywords: diagnostic, rejects-valid
          Severity: regression
          Priority: P1
         Component: dmd
          Assignee: nobody at puremagic.com
          Reporter: b2.temp at gmx.com

This used to be possible:


struct Foo
{
    void func1(){}
    void func2() const 
    {alias Fun = typeof(&func1);}  
}

until FE 2.072 but now produces the following error message:

> Error: mutable method `Foo.func1` is not callable using a `const` `this`

What's sure:

- this should work always inside `typeof()` since the intention is not to use
the delegate.
- the error message is wrong for the same reason.

What's less sure:

- should `&func1` always working as long as not called ?

For now the following workaround has to be used:

    alias Fun = typeof(&(cast()this).func1);

--