https://issues.dlang.org/show_bug.cgi?id=23240

--- Comment #1 from Alexey <animuspexus@protonmail.com> ---
also, the following modification to the code compiles ok and resulting program segfaults on run

```
import std.stdio;

interface ClassInterface
{
    ClassInterface setValue(string val);
}

class ClassPrototype : ClassInterface
{
    string value;

    void setValue(string val)
    {
        value = val;
    }

    abstract void doSomething();
}

class Class : ClassPrototype
{
    override void doSomething()
    {
        writeln("321");
    }
}

void main()
{
    auto inst = new Class();
    inst.setValue("123");
    ClassInterface zzz = cast(ClassInterface) inst;
    assert(zzz);
    auto xxx = zzz.setValue("333");
}
```

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https://issues.dlang.org/show_bug.cgi?id=23240

Alexey <animuspexus@protonmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |accepts-invalid

--

https://issues.dlang.org/show_bug.cgi?id=23240

kinke <kinke@gmx.net> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |kinke@gmx.net
           Hardware|x86_64                      |All
                 OS|Linux                       |All
           Severity|normal                      |regression

--- Comment #2 from kinke <kinke@gmx.net> ---
This is a regression. According to run.dlang.io:

2.060-2.063:
onlineapp.d(12): Error: function onlineapp.ClassPrototype.setValue of type
void(string val) overrides but is not covariant with
onlineapp.ClassInterface.setValue of type ClassInterface(string val)

2.064-2.092:
onlineapp.d(20): Error: class `onlineapp.Class` interface function
`ClassInterface setValue(string val)` is not implemented

Wrongly compiles since v2.093.

--

https://issues.dlang.org/show_bug.cgi?id=23240

--- Comment #3 from Alexey <animuspexus@protonmail.com> ---
looks like this bug is related to those bugs

https://issues.dlang.org/show_bug.cgi?id=21321 https://issues.dlang.org/show_bug.cgi?id=21184

basically, I've simply searched by 'abstract word' and there are looks like more related  bugs.

--

https://issues.dlang.org/show_bug.cgi?id=23240

--- Comment #4 from dlangBugzillaToGithub <robert.schadek@posteo.de> ---
THIS ISSUE HAS BEEN MOVED TO GITHUB

https://github.com/dlang/dmd/issues/18117

DO NOT COMMENT HERE ANYMORE, NOBODY WILL SEE IT, THIS ISSUE HAS BEEN MOVED TO GITHUB

--