Change to resolve and update compiler and libs for uses.
[breaking-change]
Enum variants are now in both the value and type namespaces. This means that
if you have a variant with the same name as a type in scope in a module, you
will get a name clash and thus an error. The solution is to either rename the
type or the variant.
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.
Adjust the handling of `#[inline]` items so that they get translated into every
compilation unit that uses them. This is necessary to preserve the semantics
of `#[inline(always)]`.
Crate-local `#[inline]` functions and statics are blindly translated into every
compilation unit. Cross-crate inlined items and monomorphizations of
`#[inline]` functions are translated the first time a reference is seen in each
compilation unit. When using multiple compilation units, inlined items are
given `available_externally` linkage whenever possible to avoid duplicating
object code.
Use a shared lookup table of previously-translated monomorphizations/glue
functions to avoid translating those functions in every compilation unit where
they're used. Instead, the function will be translated in whichever
compilation unit uses it first, and the remaining compilation units will link
against that original definition.
Rotate between compilation units while translating. The "worker threads"
commit added support for multiple compilation units, but only translated into
one, leaving the rest empty. With this commit, `trans` rotates between various
compilation units while translating, using a simple stragtegy: upon entering a
module, switch to translating into whichever compilation unit currently
contains the fewest LLVM instructions.
Most of the actual changes here involve getting symbol linkage right, so that
items translated into different compilation units will link together properly
at the end.
[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.
methods.
This paves the way to associated items by introducing an extra level of
abstraction ("impl-or-trait item") between traits/implementations and
methods. This new abstraction is encoded in the metadata and used
throughout the compiler where appropriate.
There are no functional changes; this is purely a refactoring.
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]
Using the Show impl for Names created global symbols with names like
`"str\"str\"(1027)"`. This adjusts strings, binaries and vtables to
avoid using that impl.
Fixes#15799.
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 makes two changes to region inference: (1) it allows region
inference to relate early-bound regions; and (2) it allows regions to be
related before variance runs. The former is needed because there is no
relation between the two regions before region substitution happens,
while the latter is needed because type collection has to run before
variance. We assume that, before variance is inferred, that lifetimes
are invariant. This is a conservative overapproximation.
This relates to #13885. This does not remove `~self` from the language
yet, however.
[breaking-change]
Per @pnkfelix 's suggestion, using a trait to make these
field accesses more readable (and vastly more similar
to the original code.
oops fix new ast_map fix
This change propagates to many locations, but because of the
Macro Exterminator (or, more properly, the invariant that it
protects), macro invocations can't occur downstream of expansion.
This means that in librustc and librustdoc, extracting the
desired field can simply assume that it can't be a macro
invocation. Functions in ast_util abstract over this check.
formerly, the self identifier was being discarded during parsing, which
stymies hygiene. The best fix here seems to be to attach a self identifier
to ExplicitSelf_, a change that rippled through the rest of the compiler,
but without any obvious damage.
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
ty::substs struct. This is a holdover from the olden days of yore. This patch
removes the last vestiges of that practice. This is part of the work
I was doing on #5527.
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]
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
