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digitalmars.D.bugs - [Issue 1603] New: Overload sets bug

reply d-bugmail puremagic.com writes:
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.


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Oct 20 2007
next sibling parent d-bugmail puremagic.com writes:
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





If it's ambiguous, it should error.  This kind of hijacking is exactly why
overload sets are defined the way they are.


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Oct 21 2007
prev sibling next sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=1603


andrei metalanguage.com changed:

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





Literal strings should not bind to const char *. The overload sets
corresponding to the two functions are disjoint.


--
Oct 21 2007
prev sibling next sibling parent d-bugmail puremagic.com writes:
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







 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.


--
Oct 21 2007
prev sibling next sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=1603


andrei metalanguage.com changed:

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









 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.)


--
Oct 21 2007
prev sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=1603


bugzilla digitalmars.com changed:

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





Fixed dmd 2.026


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Mar 11 2009