DList cleanup

[monarchdodra]

This is a preliminary edit to cleanup DList. It contains only mostly trivial edits I want to get out of the way.

Changes include:

• Relaxing certain template restrictions thanks to smarter compiler overload resolution. Also, un-template certain functions (this linearRemove(Take!Range r)), because we can now overload templates and non-templates
• Templatize and constraint opEquals, for types that aren't actually comparable. I ignored the issue of mutable comparison.
• Make front/back inout.
• Add more checks in Range for invalidated ranges.
• A lot of "opConcat" re-write. Not sure it is worth looking at the diff on that one. Speaking of which, I question being able to concat a DList we have ranges and the slice operator.

Lastly, I moved around some functions, and marked sections, to have a clearer idea of the class layout: Concat, Insertion, Removal. Because of this, there is some noise in the diff, but I can guarantee NO CHANGES were made to code that was moved.

PS: I'll squash when the pull is approved.

[monarchdodra]

concat section now looks like this:

/**
Returns a new $(D DList) that's the concatenation of $(D this) and its
argument $(D rhs).
     */
    DList opBinary(string op, Stuff)(Stuff rhs)
    if (op == "~" && is(typeof(insertBack(rhs))))
    {
        auto ret = this.dup;
        ret.insertBack(rhs);
        return ret;
    }
    /// ditto
    DList opBinary(string op)(DList rhs)
    if (op == "~")
    {
        return ret ~ rhs[];
    }

/**
Returns a new $(D DList) that's the concatenation of the argument $(D lhs)
and $(D this).
     */
    DList opBinaryRight(string op, Stuff)(Stuff lhs)
    if (op == "~" && is(typeof(insertFront(lhs))))
    {
        auto ret = this.dup;
        ret.insertFront(lhs);
        return ret;
    }

/**
Appends the contents of the argument $(D rhs) into $(D this).
     */
    DList opOpAssign(string op, Stuff)(Stuff rhs)
    if (op == "~" && is(typeof(insertBack(rhs))))
    {
        insertBack(rhs);
        return this;
    }

/// ditto
    DList opOpAssign(string op)(DList rhs)
    if (op == "~")
    {
        return this ~= rhs[];
    }

[DmitryOlshansky]

I think you'd better squash 'em anyway - the latter 2 commits are minor edits of the first one.

[monarchdodra]

I think you'd better squash 'em anyway - the latter 2 commits are minor edits of the first one.

Oops. Yeah, I meant to do that, but forgot. Done.

[DmitryOlshansky]

Maybe some kind of a4[].equal([0, 1])tests are warranted.

[monarchdodra]

Done.

[DmitryOlshansky]

Otherwise LGTM

[monarchdodra]

Thanks :)
Now, time to do some real changes.

[9rnsr]

This change introduces regression https://issues.dlang.org/show_bug.cgi?id=13279

But, I think it seems expected change by this PR.
@monarchdodra Could you please see the bugzilla issue?

[monarchdodra]

@monarchdodra Could you please see the bugzilla issue?

Thanks for the heads up. Replied there.