• via Digitalmars-d-bugs (32/32) Aug 11 2017 https://issues.dlang.org/show_bug.cgi?id=17744

via Digitalmars-d-bugs <digitalmars-d-bugs puremagic.com> writes:

https://issues.dlang.org/show_bug.cgi?id=17744

          Issue ID: 17744
           Summary: Type system hole: returning inout delegates
           Product: D
           Version: D2
          Hardware: All
                OS: All
            Status: NEW
          Severity: critical
          Priority: P1
         Component: dmd
          Assignee: nobody puremagic.com
          Reporter: timon.gehr gmx.ch

DMD v2.075.0:

 safe:
int a;
immutable(int) b=2;

inout(int)* delegate(inout(int)*) safe delegate() safe foo(inout(int)* y){
    inout(int)* bar(inout(int)* p){
        return y;
    }
    return ()=>&bar;
}
void main(){
    int* y=foo(&b)()(&a);
    *y=3;
    assert(&b is y); // passes. ouch.
    assert(b is *&b); // fails!
}

If &bar is returned directly instead of ()=>&bar, DMD applies a strange
work-around (it replaces `inout` in the returned delegate by `const`).

--