Apologies for the non-minimality of the test-case, but this is a smidge weird.

The changes made in b2d25e "Compiler: Improved soundness of the op-assign optimizer" seem to have broken this:

//Should print ({ }) to stdout and return 0, because the array should end up empty. //This is what happens in 7.8 on Windows. //In the latest 8.0, the first removal fails, so it shows ({ "a" }) and returns 1. array(string) arr=({"a","b","c"});

int main() { add_constant("G",this); compile_string("void x() {string z="a"; G->arr-=({z});}")()->x(); compile_string("void x() {string z="b"; G->arr=G->arr-({z});}")()->x(); compile_string("void x() {G->arr-=({"c"});}")()->x(); write("%O\n",arr); return sizeof(arr); }

In theory, the three forms of element removal ought to be equivalent, but the first one doesn't seem to be functional. I'm afraid the details are a bit beyond me - the optimizer isn't something I'm familiar with. All I know is, bisection points to that commit, and reverting it on top of 8.0 makes the above script work correctly. Sorry for the vagueness.

ChrisA