My merges for #5143 missed a couple other copies. This patch corrects this, and gets stage0 to compile libsyntax with `#[deny(vecs_implicitly_copyable)]`. stage1 still fails though.
Before:
````
test.rs:3:21: 3:30 error: expected constant integer for repeat count but found variable
test.rs:3 let a = ~[0, ..n]; //~ ERROR expected constant integer for repeat count but found variable
^~~~~~~~~
````
After:
````
test.rs:3:27: 3:28 error: expected constant integer for repeat count but found variable
test.rs:3 let a = ~[0, ..n]; //~ ERROR expected constant integer for repeat count but found variable
^
````
Good morning,
It's taken a long time, but I finally am almost done freeing libsyntax of `vecs_implicitly_copyable` in this pull request, but I'm running into some issues. I've confirmed that all but the last commit (which only disables `vecs_implicitly_copyable` pass the `check` tests. The last commit errors with this message, which makes no sense to me:
```
/Users/erickt/rust/rust/src/libcore/num/f32.rs:35:37: 35:43 error: expected `,` but found `=`
/Users/erickt/rust/rust/src/libcore/num/f32.rs:35 pub pure fn $name($( $arg : $arg_ty ),*) -> $rv {
^~~~~~
```
and this stack trace:
```
#1 0x00000001000b059b in sys::begin_unwind_::_a923ca4ae164c::_06 ()
#2 0x00000001000b0542 in sys::begin_unwind::anon::anon::expr_fn_13876 ()
#3 0x00000001000048a1 in sys::begin_unwind::_8ec273289fc0adc0::_06 ()
#4 0x00000001005df999 in diagnostic::__extensions__::meth_7941::span_fatal::_efdf2d14612d79ec::_06 ()
#5 0x0000000100682d48 in parse::parser::__extensions__::meth_16938::fatal::_8aa3239426747a3::_06 ()
#6 0x00000001006850b8 in parse::common::__extensions__::meth_17005::expect::_d3604ec6c7698d5f::_06 ()
#7 0x00000001006b59f1 in parse::common::__extensions__::parse_seq_to_before_end_17860::_48c79835f9eb1011::_06 ()
#8 0x00000001006a50f7 in parse::parser::__extensions__::meth_17606::parse_fn_decl::_14f3785fe78967d::_06 ()
#9 0x00000001006b6f59 in parse::parser::__extensions__::meth_17987::parse_item_fn::_8a6be529cf7b2ca5::_06 ()
#10 0x00000001006ac839 in parse::parser::__extensions__::meth_17761::parse_item_or_view_item::_bfead947d6dd7d25::_06 ()
#11 0x00000001006c8b8f in parse::parser::__extensions__::meth_18364::parse_item::_96b54e33f65abe76::_06 ()
#12 0x000000010076179f in ext::tt::macro_rules::add_new_extension::generic_extension::anon::anon::expr_fn_23365 ()
#13 0x000000010072e793 in ext::expand::expand_item_mac::_a4f486c4465cfb1b::_06 ()
#14 0x00000001007b5ad3 in __morestack ()
```
There also a bunch of new warnings that I haven't cleaned up yet: https://gist.github.com/erickt/5048251.
@nikomatsakis thought there might be some scary bug in the parser caused by moving a vector in the parser instead of copying it, which is why I'm filing this pull request before it's ready. Thanks for any help!
This allows `TreeMap`/`TreeSet` to fully express their requirements and reduces the comparisons from ~1.5 per level to 1 which really helps for string keys.
I also added `ReverseIter` to the prelude exports because I forgot when I originally added it.
The fix is straight-forward, but there are several changes
while fixing the issue.
1) disallow `mut` keyword when making a new struct
In code base, there are following code,
```rust
struct Foo { mut a: int };
let a = Foo { mut a: 1 };
```
This is because of structural record, which is
deprecated corrently (see issue #3089) In structural
record, `mut` keyword should be allowd to control
mutability. But without structural record, we don't
need to allow `mut` keyword while constructing struct.
2) disallow structural records in parser level
This is related to 1). With structural records, there
is an ambiguity between empty block and empty struct
To solve the problem, I change parser to stop parsing
structural records. I think this is not a problem,
because structural records are not compiled already.
Misc. issues
There is an ambiguity between empty struct vs. empty match stmt.
with following code,
```rust
match x{} {}
```
Two interpretation is possible, which is listed blow
```rust
match (x{}) {} // matching with newly-constructed empty struct
(match x{}) {} // matching with empty enum(or struct) x
// and then empty block
```
It seems that there is no such code in rust code base, but
there is one test which uses empty match statement:
https://github.com/mozilla/rust/blob/incoming/src/test/run-pass/issue-3037.rs
All other cases could be distinguished with look-ahead,
but this can't be. One possible solution is wrapping with
parentheses when matching with an uninhabited type.
```rust
enum what { }
fn match_with_empty(x: what) -> ~str {
match (x) { //use parentheses to remove the ambiguity
}
}
```
