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digitalmars.D.bugs - [Issue 2252] New: Sequence of super interfaces matters

reply d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=2252

           Summary: Sequence of super interfaces matters
           Product: D
           Version: 1.033
          Platform: PC
        OS/Version: Linux
            Status: NEW
          Severity: normal
          Priority: P2
         Component: DMD
        AssignedTo: bugzilla digitalmars.com
        ReportedBy: benoit tionex.de


import std.stdio;

version=PROBLEM;
interface I1 {
    void foo();
}
interface IConsts {
}
version(PROBLEM){
    interface I2 : IConsts, I1 {
        void bar();
    }
}
else{
    interface I2 : I1, IConsts {
        void bar();
    }
}
class C1 : I1 {
    void foo() { writefln("foo"); }
}
class C2 : C1, I2 {
    void bar() { writefln("bar"); } 
    void bar2() { writefln("bar"); } 
}
void main() { 
        C2 c2 = new C2(); 
        c2.foo(); 
        c2.bar(); 
} 

//-------------------------------------
If version=PROBLEM is set, the error given is:
class t.C2 interface function I1.foo is not implemented


--
Jul 29 2008
next sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=2252






The following example has no workaround:

import std.stdio;

interface I1 {
    void foo1();
}

interface I2 {
    void foo2();
}

interface I3 : I1, I2 {
    void bar();
}

class C1 : I1, I2 {
    void foo1() { writefln("foo1"); }
    void foo2() { writefln("foo2"); }
}

class C2 : C1, I3 {
    void bar() { writefln("bar"); }
}

void main() {
        C2 c2 = new C2();
        c2.foo1();
        c2.foo2();
        c2.bar();
}


--
Jul 29 2008
prev sibling next sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=2252






Just to make it more clear:
last example produces the following error message:
test.d(20): class test.C2 interface function I2.foo2 is not implemented

because of this line:
interface I3 : I1, I2 { /* ... */ }

I1 somehow shadows I2 and its implementation is not found in C2.

exchanging an interface declaration order:
interface I3 : I2, I1 { /* ... */ }

unhides I2 implementation but hides I1's one:
test.d(20): class test.C2 interface function I1.foo1 is not implemented.


--
Jul 29 2008
prev sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=2252


smjg iname.com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |smjg iname.com
           Keywords|                            |accepts-invalid





ISTM the bug is actually that the original code compiles without
version=PROBLEM, rather than that it fails with.

http://www.digitalmars.com/d/1.0/interface.html
"A reimplemented interface must implement all the interface functions, it does
not inherit them from a super class"

C2 reimplements I1, albeit indirectly.  So the code should be

class C2 : C1, I2 {
    void foo() { super.foo(); }
    void bar() { writefln("bar"); } 
    void bar2() { writefln("bar"); } 
}

You could argue that indirect reimplementation should be exempt from this
requirement, but that would be an enhancement request.


--
Nov 24 2008