The below code compiles, but shouldn't: array operations can't be used as initializers according to the spec, they need a slice as the lvalue. void main() { auto x = [2,3,4]; auto y = [1,1,1]; auto z = x[] - y[]; assert (z == [1,2,3]); } The assertion fails: z becomes a dynamic array with length 0 and an invalid pointer. A similarly incorrect array results with most other operators. Using +, however, gives the following strange diagnostic: foo.d(5): Error: Array operation x[] + y[] not implemented This makes no sense, since x[] + y[] itself is perfectly fine as well as implemented. Replacing 'auto z' with 'int[3] z' makes all cases succeed, but that contradicts the spec. IMHO there's no reason why using array operations as initializers should be invalid but that's what the spec currently says; added the 'spec' keyword to this in the hopes that this is legalized.
I have recently discovered some bugs that are related to this --- import std.stdio; int main() { int[] a = [1, 2, 3][]; int[] b = a[] + 4; writeln("-> ", b); // -> 1 2 3 0 1935766371 1768515939 1764585331 int[] c; c[] = a[] + 4; writeln("-> ", c); // -> c = [1, 1, 1][]; c[] = a[] + 4; writeln("-> ", c); // -> 5 6 7 c = [0][]; c[] = a[] + 4; writeln("-> ", c); // -> 5 c = a[] + 4; writeln("-> ", c); // -> 1 2 3 0 1935766371 1768515939 1764585331 int[3] d = a[] + 4; // this is ok writeln("-> ", d); // -> 5 6 7 int[3] e = [1, 2, 3]; int[3] f = [5, 6, 7]; //writeln( "-> ", e[] + f[] ); // Compile Error -- Error: Array operation e[] + f[] not implemented // yet, this works: writeln( "-> ", e.dup[] += f[] ); // -> 6 8 10 return 0; }
Also see http://d.puremagic.com/issues/show_bug.cgi?id=2549
*** Issue 3815 has been marked as a duplicate of this issue. ***
The patch for bug 3522 fixes this.
Changeset 460
Fixed DMD2.044