Your snippet doesn't prove that, but -MO=Concise does.

Damn it! You stole my proof of proof :) I have exactly that on my terminal all ready to c&p.

But the list operator doesn't return a list in scalar context.

I never said it did?

No reduction occurs, default or otherwise.

If I code:

sub x{ wantarray ? 'fred' : @_[ 0 .. $#_ ]; }

print x( 1, 2, 3 );;
fred

print scalar( x( 1, 2, 3 ) );;
3
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The list I supplied to x() and attempted to return, appears reduced,; is less (different) than it was; is no longer that same list. That's all I meant by "default reduction".

Ie. the thing that happens when a construct that would, in a list context, produce a 'list', appears in a scalar context.

Now, if you can find a better term for that than "list in a scalar context", enlighten away!

Actually, I think that thing, that I tried to avoid controversy by terming "reduction", can actually be seen happening:

    if (GIMME != G_ARRAY) {
        if (++MARK <= SP)
            *MARK = *SP;
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I'd read that (with licence) as: if we're not in an G_ARRAY context, if there are more than one items on the stack, then throw away all but the last item.

It's the builtin or operator that makes the choice, not the context.

The builtin or operator? Where? I don't see no or operators?