This adds a `Substs` field to `ty_unboxed_closure` and plumbs basic
handling of it throughout the compiler. trans now correctly
monomorphizes captured free variables and llvm function defs. This
fixes uses of unboxed closures which reference a free type or region
parameter from their environment in either their signature or free
variables. Closes#16791
- Unify the representations of `cat_upvar` and `cat_copied_upvar`
- In `link_reborrowed_region`, account for the ability of upvars to
change their mutability due to later processing. A map of recursive
region links we may want to establish in the future is maintained,
with the links being established when the kind of the borrow is
adjusted.
- When categorizing upvars, add an explicit deref that represents the
closure environment pointer for closures that do not take the
environment by value. The region for the implicit pointer is an
anonymous free region type introduced for this purpose. This
creates the necessary constraint to prevent unsound reborrows from
the environment.
- Add a note to categorizations to make it easier to tell when extra
dereferences have been inserted by an upvar without having to
perform deep pattern matching.
- Adjust borrowck to deal with the changes. Where `cat_upvar` and
`cat_copied_upvar` were previously treated differently, they are
now both treated roughly like local variables within the closure
body, as the explicit derefs now ensure proper behavior. However,
error diagnostics had to be changed to explicitly look through the
extra dereferences to avoid producing confusing messages about
references not present in the source code.
Closes issue #17403. Remaining work:
- The error diagnostics that result from failed region inference are
pretty inscrutible and should be improved.
Code like the following is now rejected:
let mut x = 0u;
let f = || &mut x;
let y = f();
let z = f(); // multiple mutable references to the same location
This also breaks code that uses a similar construction even if it does
not go on to violate aliasability semantics. Such code will need to
be reworked in some way, such as by using a capture-by-value closure
type.
[breaking-change]
The implementation essentially desugars during type collection and AST
type conversion time into the parameter scheme we have now. Only fully
qualified names--e.g. `<T as Foo>::Bar`--are supported.
lifetime bounds. This doesn't really cause any difficulties, because
we already had to accommodate the fact that multiple implicit bounds
could accumulate. Object types still require precisely one lifetime
bound. This is a pre-step towards generalized where clauses (once you
have lifetime bounds in where clauses, it is harder to restrict them
to exactly one).
[breaking-change]
1. The internal layout for traits has changed from (vtable, data) to (data, vtable). If you were relying on this in unsafe transmutes, you might get some very weird and apparently unrelated errors. You should not be doing this! Prefer not to do this at all, but if you must, you should use raw::TraitObject rather than hardcoding rustc's internal representation into your code.
2. The minimal type of reference-to-vec-literals (e.g., `&[1, 2, 3]`) is now a fixed size vec (e.g., `&[int, ..3]`) where it used to be an unsized vec (e.g., `&[int]`). If you want the unszied type, you must explicitly give the type (e.g., `let x: &[_] = &[1, 2, 3]`). Note in particular where multiple blocks must have the same type (e.g., if and else clauses, vec elements), the compiler will not coerce to the unsized type without a hint. E.g., `[&[1], &[1, 2]]` used to be a valid expression of type '[&[int]]'. It no longer type checks since the first element now has type `&[int, ..1]` and the second has type &[int, ..2]` which are incompatible.
3. The type of blocks (including functions) must be coercible to the expected type (used to be a subtype). Mostly this makes things more flexible and not less (in particular, in the case of coercing function bodies to the return type). However, in some rare cases, this is less flexible. TBH, I'm not exactly sure of the exact effects. I think the change causes us to resolve inferred type variables slightly earlier which might make us slightly more restrictive. Possibly it only affects blocks with unreachable code. E.g., `if ... { fail!(); "Hello" }` used to type check, it no longer does. The fix is to add a semicolon after the string.
This patch primarily does two things: (1) it prevents lifetimes from
leaking out of unboxed closures; (2) it allows unboxed closure type
notation, call notation, and construction notation to construct closures
matching any of the three traits.
This breaks code that looked like:
let mut f;
{
let x = &5i;
f = |&mut:| *x + 10;
}
Change this code to avoid having a reference escape. For example:
{
let x = &5i;
let mut f; // <-- move here to avoid dangling reference
f = |&mut:| *x + 10;
}
I believe this is enough to consider unboxed closures essentially
implemented. Further issues (for example, higher-rank lifetimes) should
be filed as followups.
Closes#14449.
[breaking-change]
This leaves the `Share` trait at `std::kinds` via a `#[deprecated]` `pub use`
statement, but the `NoShare` struct is no longer part of `std::kinds::marker`
due to #12660 (the build cannot bootstrap otherwise).
All code referencing the `Share` trait should now reference the `Sync` trait,
and all code referencing the `NoShare` type should now reference the `NoSync`
type. The functionality and meaning of this trait have not changed, only the
naming.
Closes#16281
[breaking-change]
except where trait objects are involved.
Part of issue #15349, though I'm leaving it open for trait objects.
Cross borrowing for trait objects remains because it is needed until we
have DST.
This will break code like:
fn foo(x: &int) { ... }
let a = box 3i;
foo(a);
Change this code to:
fn foo(x: &int) { ... }
let a = box 3i;
foo(&*a);
[breaking-change]
This basically meant changing the interface so that no borrowed `&Vec`
is exposed, by hiding `fn get_vec` and `fn get_mut_vec` and revising
`fn all_vecs`.
Instead, clients should use one of the other methods; `get_slice`,
`pop`, `truncate`, `replace`, `push_all`, or `is_empty_in`, which
should work for any case currently used in rustc.
The f128 type has very little support in the compiler and the feature is
basically unusable today. Supporting half-baked features in the compiler can be
detrimental to the long-term development of the compiler, and hence this feature
is being removed.
Use ty_rptr/ty_uniq(ty_trait) rather than TraitStore to represent trait types.
Also addresses (but doesn't close) #12470.
Part of the work towards DST (#12938).
[breaking-change] lifetime parameters in `&mut trait` are now invariant. They used to be contravariant.
parameters
This involves numerous substeps:
1. Treat Self same as any other parameter.
2. No longer compute offsets for method parameters.
3. Store all generic types (both trait/impl and method) with a method,
eliminating odd discrepancies.
4. Stop doing unspeakable things to static methods and instead just use
the natural types, now that we can easily add the type parameters from
trait into the method's polytype.
5. No doubt some more. It was hard to separate these into distinct commits.
Fixes#13564
* The select/plural methods from format strings are removed
* The # character no longer needs to be escaped
* The \-based escapes have been removed
* '{{' is now an escape for '{'
* '}}' is now an escape for '}'
Closes#14810
[breaking-change]
1. Wherever the `buf` field of a `Formatter` was used, the `Formatter` is used
instead.
2. The usage of `write_fmt` is minimized as much as possible, the `write!` macro
is preferred wherever possible.
3. Usage of `fmt::write` is minimized, favoring the `write!` macro instead.
Previously, the parser would not allow you to simultaneously implement a
function with a different abi as well as being unsafe at the same time. This
extends the parser to allow functions of the form:
unsafe extern fn foo() {
// ...
}
The closure type grammar was also changed to reflect this reversal, types
previously written as "extern unsafe fn()" must now be written as
"unsafe extern fn()". The parser currently has a hack which allows the old
style, but this will go away once a snapshot has landed.
Closes#10025
[breaking-change]
for `~str`/`~[]`.
Note that `~self` still remains, since I forgot to add support for
`Box<self>` before the snapshot.
How to update your code:
* Instead of `~EXPR`, you should write `box EXPR`.
* Instead of `~TYPE`, you should write `Box<Type>`.
* Instead of `~PATTERN`, you should write `box PATTERN`.
[breaking-change]
Previously, the parser would not allow you to simultaneously implement a
function with a different abi as well as being unsafe at the same time. This
extends the parser to allow functions of the form:
unsafe extern fn foo() {
// ...
}
The closure type grammar was also changed to reflect this reversal, types
previously written as "extern unsafe fn()" must now be written as
"unsafe extern fn()". The parser currently has a hack which allows the old
style, but this will go away once a snapshot has landed.
Closes#10025
[breaking-change]
Similar to my recent changes to ~[T]/&[T], these changes remove the vstore abstraction and represent str types as ~(str) and &(str). The Option<uint> in ty_str is the length of the string, None if the string is dynamically sized.
This currently requires linking against a library like libquadmath (or
libgcc), because compiler-rt barely has any support for this and most
hardware does not yet have 128-bit precision floating point. For this
reason, it's currently hidden behind a feature gate.
When compiler-rt is updated to trunk, some tests can be added for
constant evaluation since there will be support for the comparison
operators.
Closes#13381
Refactores all uses of ty_vec and associated things to remove the vstore abstraction (still used for strings, for now). Pointers to vectors are stored as ty_rptr or ty_uniq wrapped around a ty_vec. There are no user-facing changes. Existing behaviour is preserved by special-casing many instances of pointers containing vectors. Hopefully with DST most of these hacks will go away. For now it is useful to leave them hanging around rather than abstracting them into a method or something.
Closes#13554.
Cleans up some remnants of the old mutability system and only allows vector/trait mutability in `VstoreSlice` (`&mut [T]`) and `RegionTraitStore` (`&mut Trait`).
This change removes the AbiSet from the AST, converting all usage to have just
one Abi value. The current scheme selects a relevant ABI given a list of ABIs
based on the target architecture and how relevant each ABI is to that
architecture.
Instead of this mildly complicated scheme, only one ABI will be allowed in abi
strings, and pseudo-abis will be created for special cases as necessary. For
example the "system" abi exists for stdcall on win32 and C on win64.
Closes#10049
Summary:
So far, we've used the term POD "Plain Old Data" to refer to types that
can be safely copied. However, this term is not consistent with the
other built-in bounds that use verbs instead. This patch renames the Pod
kind into Copy.
RFC: 0003-opt-in-builtin-traits
Test Plan: make check
Reviewers: cmr
Differential Revision: http://phabricator.octayn.net/D3
