This is accomplished by rewriting static expressions into equivalent patterns.
This way, patterns referencing static variables can both participate
in exhaustiveness analysis as well as be compiled down into the appropriate
branch of the decision trees that match expressions are codegened to.
Fixes#6533.
Fixes#13626.
Fixes#13731.
Fixes#14576.
Fixes#15393.
Part of the original discussions around the `--crate-name` flag brought up that
mass confusion can arise when the flag specifies a different name than is
contained in the crate.
The current primary use case of the `--crate-name` flag is through cargo and
not requiring a `#[crate_name]` attribute, but if the `#[crate_name]` attribute
is specified it will likely go awry when the two names deviate from one another.
This commit requires that if both are provided they both match to prevent this
confusion.
Importing from types was disallowed in #6462. Flag was set for paths whether it is a module or a type. Type flag was set when impl was seen. The problem is, for cross-crate situations, when reexport is involved, it is possible that impl is seen too late because metadata is loaded lazily.
Fix#15664.
This small patch causes the stability lint to bail out when traversing
any AST produced via a macro expansion. Ultimately, we would like to
lint the contents of the macro at the place where the macro is defined,
but regardless we should not be linting it at the use site.
Closes#15703
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]
This small patch causes the stability lint to bail out when traversing
any AST produced via a macro expansion. Ultimately, we would like to
lint the contents of the macro at the place where the macro is defined,
but regardless we should not be linting it at the use site.
Closes#15703
Closes#15525
The important bit of this are the changes from line 445 in mem_categorization.rs. Most of the other changes are about adding an Implicit PointerKind, and this is only necessary for getting a decent error message :-s An alternative would have been to add an implciti/explicit flag to cat_deref, which could be mostly ignored and so would mean much fewer changes. However, the implicit state would only be valid if the PointerKind was BorrowedPtr, so it felt like it ought to be another kind of PointerKind. I still don't know which is the better design.
This branch has a fix for #15557 (a2bcef9) as well as a variety of patches I found useful while debugging this issue. These include adding `Show` impls to a variety of types, including the majority of `syntax::ast` and some of `middle::ty`.
In order to have the spawning semantics be the same for unix/windows, the
child's PATH environment variable needs to be searched rather than the parent's
environment variable.
If the child is inheriting the parent's PATH, then no action need be taken as
windows will do the heavy lifting. If the child specifies its own PATH, then it
is searched beforehand for the target program and the result is favored if a hit
is found.
cc #15149, but does not close the issue because libgreen still needs to be
updated.
In order to have the spawning semantics be the same for unix/windows, the
child's PATH environment variable needs to be searched rather than the parent's
environment variable.
If the child is inheriting the parent's PATH, then no action need be taken as
windows will do the heavy lifting. If the child specifies its own PATH, then it
is searched beforehand for the target program and the result is favored if a hit
is found.
cc #15149, but does not close the issue because libgreen still needs to be
updated.
This PR is the outcome of the library stabilization meeting for the
`liballoc::owned` and `libcore::cell` modules.
Aside from the stability attributes, there are a few breaking changes:
* The `owned` modules is now named `boxed`, to better represent its
contents. (`box` was unavailable, since it's a keyword.) This will
help avoid the misconception that `Box` plays a special role wrt
ownership.
* The `AnyOwnExt` extension trait is renamed to `BoxAny`, and its `move`
method is renamed to `downcast`, in both cases to improve clarity.
* The recently-added `AnySendOwnExt` extension trait is removed; it was
not being used and is unnecessary.
[breaking-change]
This PR is the outcome of the library stabilization meeting for the
`liballoc::owned` and `libcore::cell` modules.
Aside from the stability attributes, there are a few breaking changes:
* The `owned` modules is now named `boxed`, to better represent its
contents. (`box` was unavailable, since it's a keyword.) This will
help avoid the misconception that `Box` plays a special role wrt
ownership.
* The `AnyOwnExt` extension trait is renamed to `BoxAny`, and its `move`
method is renamed to `downcast`, in both cases to improve clarity.
* The recently-added `AnySendOwnExt` extension trait is removed; it was
not being used and is unnecessary.
[breaking-change]
This patch adds support for macros in method position. It follows roughly the template for Item macros, where an outer `Method` wrapper contains a `Method_` enum which can either be a macro invocation or a standard macro definition.
One note; adding support for macros that expand into multiple methods is not included here, but should be a simple parser change, since this patch updates the type of fold_macro to return a smallvector of methods.
For reviewers, please pay special attention to the parser changes; these are the ones I'm most concerned about.
Because of the small change to the interface of fold_method, this is a ...
[breaking change]
* Don't warn about `#[crate_name]` if `--crate-name` is specified
* Don't warn about non camel case identifiers on `#[repr(C)]` structs
* Switch `mode` to `mode_t` in libc.
This is a continuation of @brson's work from https://github.com/rust-lang/rust/pull/12144.
This implements the minimal scaffolding that allows mapping diagnostic messages to alpha-numeric codes, which could improve the searchability of errors. In addition, there's a new compiler option, `--explain {code}` which takes an error code and prints out a somewhat detailed explanation of the error. Example:
```rust
fn f(x: Option<bool>) {
match x {
Some(true) | Some(false) => (),
None => (),
Some(true) => ()
}
}
```
```shell
[~/rust]$ ./build/x86_64-apple-darwin/stage2/bin/rustc ./diagnostics.rs --crate-type dylib
diagnostics.rs:5:3: 5:13 error: unreachable pattern [E0001] (pass `--explain E0001` to see a detailed explanation)
diagnostics.rs:5 Some(true) => ()
^~~~~~~~~~
error: aborting due to previous error
[~/rust]$ ./build/x86_64-apple-darwin/stage2/bin/rustc --explain E0001
This error suggests that the expression arm corresponding to the noted pattern
will never be reached as for all possible values of the expression being matched,
one of the preceeding patterns will match.
This means that perhaps some of the preceeding patterns are too general, this
one is too specific or the ordering is incorrect.
```
I've refrained from migrating many errors to actually use the new macros as it can be done in an incremental fashion but if we're happy with the approach, it'd be good to do all of them sooner rather than later.
Originally, I was going to make libdiagnostics a separate crate but that's posing some interesting challenges with semi-circular dependencies. In particular, librustc would have a plugin-phase dependency on libdiagnostics, which itself depends on librustc. Per my conversation with @alexcrichton, it seems like the snapshotting process would also have to change. So for now the relevant modules from libdiagnostics are included using `#[path = ...] mod`.
This commit adds `env_insert` and `env_remove` methods to the `Command`
builder, easing updates to the environment variables for the child
process. The existing method, `env`, is still available for overriding
the entire environment in one shot (after which the `env_insert` and
`env_remove` methods can be used to make further adjustments).
To support these new methods, the internal `env` representation for
`Command` has been changed to an optional `HashMap` holding owned
`CString`s (to support non-utf8 data). The `HashMap` is only
materialized if the environment is updated. The implementation does not
try hard to avoid allocation, since the cost of launching a process will
dwarf any allocation cost.
This patch also adds `PartialOrd`, `Eq`, and `Hash` implementations for
`CString`.
This commit changes the `io::process::Command` API to provide
fine-grained control over the environment:
* The `env` method now inserts/updates a key/value pair.
* The `env_remove` method removes a key from the environment.
* The old `env` method, which sets the entire environment in one shot,
is renamed to `env_set_all`. It can be used in conjunction with the
finer-grained methods. This renaming is a breaking change.
To support these new methods, the internal `env` representation for
`Command` has been changed to an optional `HashMap` holding owned
`CString`s (to support non-utf8 data). The `HashMap` is only
materialized if the environment is updated. The implementation does not
try hard to avoid allocation, since the cost of launching a process will
dwarf any allocation cost.
This patch also adds `PartialOrd`, `Eq`, and `Hash` implementations for
`CString`.
[breaking-change]
C structs predominately do not use camel case identifiers, and we have a clear
indicator for what's a C struct now, so excuse all of them from this stylistic
lint.
Similar to the stability attributes, a type annotated with `#[must_use =
"informative snippet"]` will print the normal warning message along with
"informative snippet". This allows the type author to provide some
guidance about why the type should be used.
---
It can be a little unintuitive that something like `v.iter().map(|x|
println!("{}", x));` does nothing: the majority of the iterator adaptors
are lazy and do not execute anything until something calls `next`, e.g.
a `for` loop, `collect`, `fold`, etc.
The majority of such errors can be seen by someone writing something
like the above, i.e. just calling an iterator adaptor and doing nothing
with it (and doing this is certainly useless), so we can co-opt the
`must_use` lint, using the message functionality to give a hint to the
reason why.
Fixes#14666.
