followed by a semicolon.
This allows code like `vec![1i, 2, 3].len();` to work.
This breaks code that uses macros as statements without putting
semicolons after them, such as:
fn main() {
...
assert!(a == b)
assert!(c == d)
println(...);
}
It also breaks code that uses macros as items without semicolons:
local_data_key!(foo)
fn main() {
println("hello world")
}
Add semicolons to fix this code. Those two examples can be fixed as
follows:
fn main() {
...
assert!(a == b);
assert!(c == d);
println(...);
}
local_data_key!(foo);
fn main() {
println("hello world")
}
RFC #378.
Closes#18635.
[breaking-change]
This breaks code that referred to variant names in the same namespace as
their enum. Reexport the variants in the old location or alter code to
refer to the new locations:
```
pub enum Foo {
A,
B
}
fn main() {
let a = A;
}
```
=>
```
pub use self::Foo::{A, B};
pub enum Foo {
A,
B
}
fn main() {
let a = A;
}
```
or
```
pub enum Foo {
A,
B
}
fn main() {
let a = Foo::A;
}
```
[breaking-change]
https://github.com/rust-lang/rfcs/pull/221
The current terminology of "task failure" often causes problems when
writing or speaking about code. You often want to talk about the
possibility of an operation that returns a Result "failing", but cannot
because of the ambiguity with task failure. Instead, you have to speak
of "the failing case" or "when the operation does not succeed" or other
circumlocutions.
Likewise, we use a "Failure" header in rustdoc to describe when
operations may fail the task, but it would often be helpful to separate
out a section describing the "Err-producing" case.
We have been steadily moving away from task failure and toward Result as
an error-handling mechanism, so we should optimize our terminology
accordingly: Result-producing functions should be easy to describe.
To update your code, rename any call to `fail!` to `panic!` instead.
Assuming you have not created your own macro named `panic!`, this
will work on UNIX based systems:
grep -lZR 'fail!' . | xargs -0 -l sed -i -e 's/fail!/panic!/g'
You can of course also do this by hand.
[breaking-change]
Spring cleaning is here! In the Fall! This commit removes quite a large amount
of deprecated functionality from the standard libraries. I tried to ensure that
only old deprecated functionality was removed.
This is removing lots and lots of deprecated features, so this is a breaking
change. Please consult the deprecation messages of the deleted code to see how
to migrate code forward if it still needs migration.
[breaking-change]
Modify ast::ExprMatch to include a new value of type ast::MatchSource,
making it easy to tell whether the match was written literally or
produced via desugaring. This allows us to customize error messages
appropriately.
This makes it easier to experiment with improved quasiquoting as an ordinary
plugin library.
The list of quote macros in feature_gate.rs was already out of sync;
this commit also prevents that problem in the future.
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 other extension types already worked this way and it can be useful to track some state along with the extension.
I also removed the `BasicMacroExpander` and `BasicIdentMacroExpander` since the span inside of them was never used. The expander function types now directly implement the relevant trait.
For convenience, the traits are implemented for the respective bare
functions. Change code from this:
```rust
ItemDecorator(some_function)
// or
ItemModifier(some_other_function)
```
to
```rust
ItemDecorator(box some_function)
// or
ItemModifier(box some_other_function)
```
[breaking-change]
by-reference upvars.
This partially implements RFC 38. A snapshot will be needed to turn this
on, because stage0 cannot yet parse the keyword.
Part of #12381.
Note: This PR is motivated by an attempt to write an custom syntax extension that tried to use `syntax::fold`, and that could only do so by fixing bugs in it and copying out private functions.
---
Refactored `syntax::fold`
Prior to this, the code there had a few issues:
- Default implementations inconsistenly either had the prefix `noop_` or
not.
- Some default methods where implemented in terms of a public noop function
for user code to call, others where implemented directly on the trait
and did not allow users of the trait to reuse the code.
- Some of the default implementations where private, and thus not reusable
for other implementors.
- There where some bugs where default implemntations called other default
implementations directly, rather than to the underlying Folder, with the
result of some ast nodes never being visted even if the user implemented that
method. (For example, the current Folder never folded struct fields)
This commit solves this situation somewhat radically by making __all__
`fold_...` functions in the module into Folder methods, and implementing
them all in terms of public `noop_...` functions for other implementors to
call out to.
Some public functions had to be renamed to fit the new system, so this is a
breaking change.
---
Also added a few trait implementations to `ast` types
Prior to this, the code there had a few issues:
- Default implementations inconsistently either had the prefix `noop_` or
not.
- Some default methods where implemented in terms of a public noop function
for user code to call, others where implemented directly on the trait
and did not allow users of the trait to reuse the code.
- Some of the default implementations where private, and thus not reusable
for other implementors.
- There where some bugs where default implementations called other default
implementations directly, rather than to the underlying Folder, with the
result of some AST nodes never being visited even if the user implemented that
method. (For example, the current Folder never folded struct fields)
This commit solves this situation somewhat radically by making _all_
`fold_...` functions in the module into Folder methods, and implementing
them all in terms of public `noop_...` functions for other implementors to
call out to.
Some public functions had to be renamed to fit the new system, so this is a
breaking change.
[breaking-change]
This makes edge cases in which the `Iterator` trait was not in scope
and/or `Option` or its variants were not in scope work properly.
This breaks code that looks like:
struct MyStruct { ... }
impl MyStruct {
fn next(&mut self) -> Option<int> { ... }
}
for x in MyStruct { ... } { ... }
Change ad-hoc `next` methods like the above to implementations of the
`Iterator` trait. For example:
impl Iterator<int> for MyStruct {
fn next(&mut self) -> Option<int> { ... }
}
Closes#15392.
[breaking-change]
In f1ad425199, I changed the handling
of macros, to prevent macro invocations from occurring in fully expanded
source. Instead, I added a side table. It contained only the
spans of the macros, because this was the only information required
in order to make macro export work.
However, librustdoc was also affected by this change, since it
extracts macro information in a similar way. As a result of the earlier
change, exported macros were no longer documented.
In order to repair this, I've adjusted the side table to contain whole
items, rather than just the spans.
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 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.
Our AST definition can include macro invocations, which can expand into all kinds of things. Macro invocations are expanded away during expansion time, and the rest of the compiler doesn't have to deal with them. However, we have no way of enforcing this.
This patch adds two protective mechanisms.
First, it adds a (quick) explicit check that ensures there are no macro invocations remaining in the AST after expansion. Second, it updates the visit and fold mechanisms so that by default, they will not traverse macro invocations. It's easy enough to add this, if desired (it's documented in the source, and examples appear, e.g. in the IdentFinder.
Along the way, I also consulted with @sfackler to refactor the macro export mechanism so that it stores macro text spans in a side table, rather than leaving them in the AST.
the Macro Exterminator ensures that there are no macro invocations in
an AST. This should help make later passes confident that there aren't
hidden items, methods, expressions, etc.
macros can expand into arbitrary items, exprs, etc. This
means that using a default walker or folder on an AST before
macro expansion is complete will miss things (the things that
the macros expand into). As a partial fence against this, this
commit moves the default traversal of macros into a separate
procedure, and makes the default trait implementation signal
an error. This means that Folders and Visitors can traverse
macros if they want to, but they need to explicitly add an
impl that calls the walk_mac or fold_mac procedure
This should prevent problems down the road.
Per discussion with @sfackler, refactored the expander to
change the way that exported macros are collected. Specifically,
a crate now contains a side table of spans that exported macros
go into.
This has two benefits. First, the encoder doesn't need to scan through
the expanded crate in order to discover exported macros. Second, the
expander can drop all expanded macros from the crate, with the pleasant
result that a fully expanded crate contains no macro invocations (which
include macro definitions).
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.
The let-syntax expander is different in that it doesn't apply
a mark to its token trees before expansion. This is used
for macro_rules, and it's because macro_rules is essentially
MTWT's let-syntax. You don't want to mark before expand sees
let-syntax, because there's no "after" syntax to mark again.
In some sense, the cleaner approach might be to introduce a new
AST node that macro_rules expands into; this would make it clearer
that the expansion of a macro is distinct from the addition of a
new macro binding.
This should work for now, though...
This commit removes all support in the compiler for the #[crate_id] attribute
and all of its derivative infrastructure. A list of the functionality removed is:
* The #[crate_id] attribute no longer exists
* There is no longer the concept of a version of a crate
* Version numbers are no longer appended to symbol names
* The --crate-id command line option has been removed
To migrate forward, rename #[crate_id] to #[crate_name] and only the name of the
crate itself should be mentioned. The version/path of the old crate id should be
removed.
For a transitionary state, the #[crate_id] attribute is still accepted if
the #[crate_name] is not present, but it is warned about if it is the only
identifier present.
RFC: 0035-remove-crate-id
[breaking-change]
Rationale: for what appear to be historical reasons only, the PatIdent contains
a Path rather than an Ident. This means that there are many places in the code
where an ident is artificially promoted to a path, and---much more problematically---
a bunch of elements from a path are simply thrown away, which seems like an invitation
to some really nasty bugs.
This commit replaces the Path in a PatIdent with a SpannedIdent, which just contains an ident
and a span.
