www.digitalmars.com         C & C++   DMDScript  

digitalmars.D.bugs - [Issue 7206] New: Constructor from mixin does not conflict with other constructors

reply d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=7206

           Summary: Constructor from mixin does not conflict with other
                    constructors
           Product: D
           Version: D2
          Platform: Other
        OS/Version: All
            Status: NEW
          Severity: normal
          Priority: P2
         Component: DMD
        AssignedTo: nobody puremagic.com
        ReportedBy: robert octarineparrot.com


--- Comment #0 from Robert Clipsham <robert octarineparrot.com> 2012-01-02
22:10:55 GMT ---
----
import std.stdio;

mixin template foo() {
    this() {
        writefln("a");
    }
}

class A {
    mixin foo!();
    this() {
        writefln("b");
    }
version(ErrorsAsExpected) {
    this() {
        writefln("c");
    }
}
}

void main() {
    A a = new A;
}
----
When the above is compiled, no error is given, however when
-version=ErrorsAsExpected is given an error occurs. Tested with dmd 2.057.

-- 
Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
Jan 02 2012
next sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=7206



--- Comment #1 from Robert Clipsham <robert octarineparrot.com> 2012-01-02
22:13:34 GMT ---
I forgot to mention, when ErrorsAsExpected is not defined, this prints b, the
constructor from the mixin is disregarded.

-- 
Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
Jan 02 2012
prev sibling next sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=7206


timon.gehr gmx.ch changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |timon.gehr gmx.ch


--- Comment #2 from timon.gehr gmx.ch 2012-01-02 14:24:56 PST ---
This is by design:

Spec: Mixin Scope
The declarations in a mixin are 'imported' into the surrounding scope. If the
name of a declaration in a mixin is the same as a declaration in the
surrounding scope, the surrounding declaration overrides the mixin one.

-- 
Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
Jan 02 2012
prev sibling next sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=7206


Trass3r <mrmocool gmx.de> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |diagnostic
                 CC|                            |mrmocool gmx.de


--- Comment #3 from Trass3r <mrmocool gmx.de> 2012-01-02 14:42:28 PST ---
Imho it isn't right though to silently accept this.
There should at least be a warning that the code doesn't work as the general
programmer would expect and maybe give a hint that you can achieve overload
resolution with an additional alias.

Otherwise it heavily depends on your code if you are lucky and get an error
message like in http://d.puremagic.com/issues/show_bug.cgi?id=3332 or
unexpected behavior.

This is not limited to constructors. Overload resolution in general isn't
easily possible.
I have to resort to ugly string mixins just because of this.

-- 
Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
Jan 02 2012
prev sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=7206


SomeDude <lovelydear mailmetrash.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |lovelydear mailmetrash.com


--- Comment #4 from SomeDude <lovelydear mailmetrash.com> 2012-04-19 12:38:06
PDT ---
PS E:\DigitalMars\dmd2\samples> rdmd bug.d
b
PS E:\DigitalMars\dmd2\samples> rdmd -version=ErrorsAsExpected bug.d
bug.d(22): Error: constructor bug.A.this called with argument types:
        (())
matches both:
        bug.A.this()
and:
        bug.A.this()
PS E:\DigitalMars\dmd2\samples>

-- 
Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
Apr 19 2012