[Issue 10424] array operations accept rvalues on the lhs

[d-bugmail at puremagic.com]

http://d.puremagic.com/issues/show_bug.cgi?id=10424


Kenji Hara <k.hara.pg at gmail.com> changed:

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


--- Comment #2 from Kenji Hara <k.hara.pg at gmail.com> 2013-06-20 18:39:14 PDT ---
(In reply to comment #0)
> int f();
> int[] g();
> void main()
> {
>     //f() = 42; // as expected: Error: f() is not an lvalue
>     //g() = [42]; // as expected: Error: g() is not an lvalue
>     g()[] = [42]; // compiles, but shouldn't
> }

The line is correct D code. g() returns an rvalue int[] array, but the
assignment is element-wise, and elements of array are always lvalue.
Then, there's no meaningless rvalue modification.

void main()
{
    int[] a = [1];
    int[] arr = a;
    int[] g() { return arr; }

    g()[] = [42]; // element-wise assignment
    // essentially same as:
    // int[] x = [42]; arr[] = x[];

    assert(arr.ptr == a.ptr);
    assert(arr == [42]);
}

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