OpenE2K/rust
2
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

integrate the edition code.

Browse Source 
As a driveby change, I made `#![feature(nll)]` *always* take
precedence over `-Z borrowck`.  The main effect this had is that it
means tests with `#![feature(nll)]` will ignore uses of `-Z
borrowck=compare`. This affected only one test as far as I can tell,
and I think that test used `-Z borrowck=compare` only as a historical
accident.
This commit is contained in:
Felix S. Klock II 2018-07-26 13:17:33 +02:00
parent 1a59dafe11
commit 4b2e553dac
3 changed files with 50 additions and 52 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

66
src/librustc/ty/context.rs
View File

@ -74,6 +74,7 @@ use rustc_target::spec::abi;
use syntax::ast::{self, NodeId};
use syntax::attr;
use syntax::codemap::MultiSpan;
use syntax::edition::Edition;
use syntax::feature_gate;
use syntax::symbol::{Symbol, keywords, InternedString};
use syntax_pos::Span;
@ -1403,34 +1404,51 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
/// What mode(s) of borrowck should we run? AST? MIR? both?
/// (Also considers the `#![feature(nll)]` setting.)
pub fn borrowck_mode(&self) -> BorrowckMode {
// Here are the main constraints we need to deal with:
//
// 1. An opts.borrowck_mode of `BorrowckMode::Ast` is
// synonymous with no `-Z borrowck=...` flag at all.
// (This is arguably a historical accident.)
//
// 2. `BorrowckMode::Migrate` is the limited migration to
// NLL that we are deploying with the 2018 edition.
//
// 3. We want to allow developers on the Nightly channel
// to opt back into the "hard error" mode for NLL,
// (which they can do via specifying `#![feature(nll)]`
// explicitly in their crate).
//
// So, this precedence list is how pnkfelix chose to work with
// the above constraints:
//
// * `#![feature(nll)]` *always* means use NLL with hard
// errors. (To simplify the code here, it now even overrides
// a user's attempt to specify `-Z borrowck=compare`, which
// we arguably do not need anymore and should remove.)
//
// * Otherwise, if no `-Z borrowck=...` flag was given (or
// if `borrowck=ast` was specified), then use the default
// as required by the edition.
//
// * Otherwise, use the behavior requested via `-Z borrowck=...`
if self.features().nll { return BorrowckMode::Mir; }
match self.sess.opts.borrowck_mode {
mode @ BorrowckMode::Mir |
mode @ BorrowckMode::Compare => mode,
mode @ BorrowckMode::Compare |
mode @ BorrowckMode::Migrate => mode,
// `BorrowckMode::Ast` is synonymous with no `-Z
// borrowck=...` flag at all. Therefore, we definitely
// want `#![feature(nll)]` to override it.
mode @ BorrowckMode::Ast => {
if self.features().nll {
BorrowckMode::Mir
} else {
mode
}
}
BorrowckMode::Ast => match self.sess.edition() {
Edition::Edition2015 => BorrowckMode::Ast,
Edition::Edition2018 => BorrowckMode::Migrate,
// `BorrowckMode::Migrate` is modelling the behavior one
// will eventually specify via `--edition 2018`. We want
// to allow developers on the Nightly channel to opt back
// into the "hard error" mode for NLL, which they can do
// via specifying `#![feature(nll)]` explicitly in their
// crate.
mode @ BorrowckMode::Migrate => {
if self.features().nll {
BorrowckMode::Mir
} else {
mode
}
}
// For now, future editions mean Migrate. (But it
// would make a lot of sense for it to be changed to
// `BorrowckMode::Mir`, depending on how we plan to
// time the forcing of full migration to NLL.)
_ => BorrowckMode::Migrate,
},
}
}

8
src/test/ui/generator/generator-with-nll.rs
View File

@ -8,17 +8,15 @@
// option. This file may not be copied, modified, or distributed
// except according to those terms.
// compile-flags: -Z borrowck=compare
#![feature(generators)]
#![feature(nll)]
fn main() {
|| {
// The reference in `_a` is a Legal with NLL since it ends before the yield
let _a = &mut true; //~ ERROR borrow may still be in use when generator yields (Ast)
let b = &mut true; //~ ERROR borrow may still be in use when generator yields (Ast)
//~^ borrow may still be in use when generator yields (Mir)
let _a = &mut true;
let b = &mut true;
//~^ borrow may still be in use when generator yields
yield ();
println!("{}", b);
};

28
src/test/ui/generator/generator-with-nll.stderr
View File

@ -1,30 +1,12 @@
error[E0626]: borrow may still be in use when generator yields (Ast)
--> $DIR/generator-with-nll.rs:19:23
error[E0626]: borrow may still be in use when generator yields
--> $DIR/generator-with-nll.rs:18:17
|
LL | let _a = &mut true; //~ ERROR borrow may still be in use when generator yields (Ast)
| ^^^^
...
LL | yield ();
| -------- possible yield occurs here
error[E0626]: borrow may still be in use when generator yields (Ast)
--> $DIR/generator-with-nll.rs:20:22
|
LL | let b = &mut true; //~ ERROR borrow may still be in use when generator yields (Ast)
| ^^^^
LL | //~^ borrow may still be in use when generator yields (Mir)
LL | yield ();
| -------- possible yield occurs here
error[E0626]: borrow may still be in use when generator yields (Mir)
--> $DIR/generator-with-nll.rs:20:17
|
LL | let b = &mut true; //~ ERROR borrow may still be in use when generator yields (Ast)
LL | let b = &mut true;
| ^^^^^^^^^
LL | //~^ borrow may still be in use when generator yields (Mir)
LL | //~^ borrow may still be in use when generator yields
LL | yield ();
| -------- possible yield occurs here
error: aborting due to 3 previous errors
error: aborting due to previous error
For more information about this error, try `rustc --explain E0626`.