Code like this is fixed now:
```
fn foo(p: [u8, ..4]) {
match p {
[a, b, c, d] => {}
};
}
```
Invalid constructors are not reported as errors yet:
```
fn foo(p: [u8, ..4]) {
match p {
[_, _, _] => {} // this should be error
[_, _, _, _, _, .._] => {} // and this
_ => {}
}
}
```
Issue #8311 is partially fixed by this commit. Fixed-length arrays in
let statement are not yet allowed:
```
let [a, b, c] = [1, 2, 3]; // still fails
```
fail!() used to require owned strings but can handle static strings
now. Also, it can pass its arguments to fmt!() on its own, no need for
the caller to call fmt!() itself.
