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digitalmars.D.bugs - [Issue 9149] New: 'const' is broken


           Summary: 'const' is broken
           Product: D
           Version: D2
          Platform: All
        OS/Version: All
            Status: NEW
          Severity: normal
          Priority: P2
         Component: DMD
        AssignedTo: nobody puremagic.com
        ReportedBy: timon.gehr gmx.ch

Delegates cannot implicitly convert to const without breaking const guarantees.
Reading a mutable delegate out of a const reference therefore must be a compile
error. (for the same reason a mutable member function cannot be called on a
const receiver.)

import std.stdio;

class T{
    int x;
    int delegate()pure b;
    this(){ b = ()pure=>x++; }
void main(){
    auto s=new T();
    const c = s.b; // ok, should fail
    const t=s;
    writeln(c(), c(), c(), c());
    writeln(t.b(), t.b(), t.b(), t.b()); // ok, should fail

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Dec 13 2012