http://d.puremagic.com/issues/show_bug.cgi?id=1603

           Summary: Overload sets bug
           Product: D
           Version: 2.007
          Platform: PC
        OS/Version: All
            Status: NEW
          Severity: normal
          Priority: P2
         Component: DMD
        AssignedTo: bugzilla@digitalmars.com
        ReportedBy: andrei@metalanguage.com


The following code does not compile:

module A;
extern(C) void foo(in char*) {}
// end of module

module B;
void foo(string) {}
// end of module

import A, B;

main()
{
  foo("string");
}

The call is ambiguous although it should make it to B.foo.


-- 

http://d.puremagic.com/issues/show_bug.cgi?id=1603


smjg@iname.com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |smjg@iname.com
             Status|NEW                         |RESOLVED
         Resolution|                            |INVALID




------- Comment #1 from smjg@iname.com  2007-10-21 08:09 -------
If it's ambiguous, it should error.  This kind of hijacking is exactly why overload sets are defined the way they are.


-- 

http://d.puremagic.com/issues/show_bug.cgi?id=1603


andrei@metalanguage.com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |REOPENED
         Resolution|INVALID                     |




------- Comment #2 from andrei@metalanguage.com  2007-10-21 11:20 -------
Literal strings should not bind to const char *. The overload sets corresponding to the two functions are disjoint.


-- 

http://d.puremagic.com/issues/show_bug.cgi?id=1603


smjg@iname.com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |spec
            Summary|Overload sets bug           |String literals bind to
                   |                            |pointer types




------- Comment #3 from smjg@iname.com  2007-10-21 12:28 -------
(In reply to comment #2)
> Literal strings should not bind to const char *.

By my experiments, string literals are simultaneously of all of these types:

invariant(char)*
invariant(wchar)*
invariant(dchar)*
invariant(char)[]
invariant(wchar)[]
invariant(dchar)[]

and therefore to the const versions of these types.  But there doesn't seem to be any documentation to the fact that they bind to the pointer types (unless I haven't found it).

So the issue has nothing to do with overload sets.  Try this and see.

----------
extern(C) void foo(in char*) {}

void main() {
        foo("string");
}

invariant(char)*   cp = "string";
invariant(wchar)*  wp = "string";
invariant(dchar)*  dp = "string";
invariant(char)[]  ca = "string";
invariant(wchar)[] wa = "string";
invariant(dchar)[] da = "string";
----------

And why is this issue set to version 2.007?  That version isn't even out yet.


-- 

http://d.puremagic.com/issues/show_bug.cgi?id=1603


andrei@metalanguage.com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Version|2.007                       |unspecified




------- Comment #4 from andrei@metalanguage.com  2007-10-21 12:33 -------
(In reply to comment #3)
> (In reply to comment #2)
> > Literal strings should not bind to const char *.
> 
> By my experiments, string literals are simultaneously of all of these types:
> 
> invariant(char)*
> invariant(wchar)*
> invariant(dchar)*
> invariant(char)[]
> invariant(wchar)[]
> invariant(dchar)[]
> 
> and therefore to the const versions of these types.  But there doesn't seem to be any documentation to the fact that they bind to the pointer types (unless I haven't found it).
> 
> So the issue has nothing to do with overload sets.

You are right. I suggest we leave this bug opened with the new title until a formal resolution is found. Although accepting conversion of string literals to invariant char* is sound, in my opinion that's a bit too friendly towards C functions, and it creates unnecessary ambiguity. It's not too hard to add a .ptr when calling a C function.

(I've set the version to unspecified.)


-- 

http://d.puremagic.com/issues/show_bug.cgi?id=1603


bugzilla@digitalmars.com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|REOPENED                    |RESOLVED
         Resolution|                            |FIXED




------- Comment #5 from bugzilla@digitalmars.com  2009-03-11 14:56 -------
Fixed dmd 2.026


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