Largely adapted from pcwalton's original branch, with following
notable modifications:
Use `regionck::type_must_outlive` to generate `SafeDestructor`
constraints. (this plugged some soundness holes in the analysis).
Avoid exponential time blowup on compile-fail/huge-struct.rs by
keeping the breadcrumbs until end of traversal.
Avoid premature return from regionck::visit_expr.
Factored drop-checking code out into dropck module.
Added `SafeDestructor` to enum `SubregionOrigin` (for error reporting).
----
Since this imposes restrictions on the lifetimes used in types with
destructors, this is a (wait for it)
[breaking-change]
immediately surrounding a node that is a terminating_scope
(e.g. statements, looping forms) during which the destructors run (the
destructors for temporaries from the execution of that node, that is).
Introduced DestructionScopeData newtype wrapper around ast::NodeId, to
preserve invariant that FreeRegion and ScopeChain::BlockScope carry
destruction scopes (rather than arbitrary CodeExtents).
Insert DestructionScope and block Remainder into enclosing CodeExtents
hierarchy.
Add more doc for DestructionScope, complete with ASCII art.
Switch to constructing DestructionScope rather than Misc in a number
of places, mostly related to `ty::ReFree` creation, and use
destruction-scopes of node-ids at various calls to
liberate_late_bound_regions.
middle::resolve_lifetime: Map BlockScope to DestructionScope in `fn resolve_free_lifetime`.
Add the InnermostDeclaringBlock and InnermostEnclosingExpr enums that
are my attempt to clarify the region::Context structure, and that
later commmts build upon.
Improve the debug output for `CodeExtent` attached to `ty::Region::ReScope`.
Loosened an assertion in `rustc_trans::trans::cleanup` to account for
`DestructionScope`. (Perhaps this should just be switched entirely
over to `DestructionScope`, rather than allowing for either `Misc` or
`DestructionScope`.)
----
Even though the DestructionScope is new, this particular commit should
not actually change the semantics of any current code.
This is super black magic internals at the moment, but having it
somewhere semi-public seems good. The current versions weren't being
rendered, and they'll be useful for some people.
Fixes#21281
The live code analysis only visited the function's body when visiting a
method, and not the FnDecl and the generics, resulting in code to be
incorrectly marked as unused when it only appeared in the generics, the
arguments, or the return type, whereas the same code in non-method
functions was correctly detected as used. Fixes#20343.
Rename several remaining `Show`s to Debug, `String`s to Display (mostly in comments and docs).
Update reference.md:
- derive() no longer supports Zero trait
- derive() now supports Copy trait
Simplify cache selection by just using the local cache whenever there
are any where-clauses at all. This seems to be the simplest possible
rule and will (hopefully!) put an end to these annoying "cache leak"
bugs. Fixes#22019.
r? @aturon
No longer legal: `fn foo(a: [D; 5]) { drop(a); a[2] = D::new(); }`;
one must first initialize the entirety of `a` before assigning to its
individual elements.
No longer legal: `fn foo(arr: [D; 5]) -> D { arr[2] }`, unless `D`
implements `Copy`. This "move out-from" restriction only affects
`expr[i]`, and not destructuring (e.g. `f([a, b, c]: Array) { ... }`).
uses mem_categorization to distinguish destructuring-bind from array
indexing.
See discussion on RFC PR 533.
[breaking-change]
are any where-clauses at all. This seems to be the simplest possible
rule and will (hopefully!) put an end to these annoying "cache leak"
bugs. Fixes#22019.
....
The 'stable_features' lint helps people progress from unstable to
stable Rust by telling them when they no longer need a `feature`
attribute because upstream Rust has declared it stable.
This compares to the existing 'unstable_features' lint, which is used
to implement feature staging, and triggers on *any* use
of `#[feature]`.
This is 99% burning ints to the ground, but I also got rid of useless annotations or made code more \"idiomatic\" as I went along. Mostly changes in tests.
This was particularly helpful in the time just after OIBIT's
implementation to make sure things that were supposed to be Copy
continued to be, but it's now creates a lot of noise for types that
intentionally don't want to be Copy.
r? @alexcrichton
The 'stable_features' lint helps people progress from unstable to
stable Rust by telling them when they no longer need a `feature`
attribute because upstream Rust has declared it stable.
This compares to the existing 'unstable_features', which is used
to implement feature staging, and triggers on *any* use
of `#[feature]`.
This was particularly helpful in the time just after OIBIT's
implementation to make sure things that were supposed to be Copy
continued to be, but it's now creates a lot of noise for types that
intentionally don't want to be Copy.
Currently, if a `#![staged_api]` crate contains an exported item without a stability marker (or inherited stability),
the item is useless.
This change introduces a check to ensure that all exported items have a defined stability.
it also introduces the `unmarked_api` feature, which lets users import unmarked features. While this PR should in theory forbid these from existing,
in practice we can't be so sure; so this lets users bypass this check instead of having to wait for the library and/or compiler to be fixed (since otherwise this is a hard error).
r? @aturon
upgrade the inference based on expected type so that it is able to
infer the fn kind in isolation even if the full signature is not
available (and we could perhaps do better still in some cases, such as
extracting just the types of the arguments but not the return value).
possible. There is some amount of duplication as a result (similar to
select) -- I am not happy about this but not sure how to fix it
without deeper rewrites.
This is an implementation of [RFC 578][rfc] which adds a new `std::env` module
to replace most of the functionality in the current `std::os` module. More
details can be found in the RFC itself, but as a summary the following methods
have all been deprecated:
[rfc]: https://github.com/rust-lang/rfcs/pull/578
* `os::args_as_bytes` => `env::args`
* `os::args` => `env::args`
* `os::consts` => `env::consts`
* `os::dll_filename` => no replacement, use `env::consts` directly
* `os::page_size` => `env::page_size`
* `os::make_absolute` => use `env::current_dir` + `join` instead
* `os::getcwd` => `env::current_dir`
* `os::change_dir` => `env::set_current_dir`
* `os::homedir` => `env::home_dir`
* `os::tmpdir` => `env::temp_dir`
* `os::join_paths` => `env::join_paths`
* `os::split_paths` => `env::split_paths`
* `os::self_exe_name` => `env::current_exe`
* `os::self_exe_path` => use `env::current_exe` + `pop`
* `os::set_exit_status` => `env::set_exit_status`
* `os::get_exit_status` => `env::get_exit_status`
* `os::env` => `env::vars`
* `os::env_as_bytes` => `env::vars`
* `os::getenv` => `env::var` or `env::var_string`
* `os::getenv_as_bytes` => `env::var`
* `os::setenv` => `env::set_var`
* `os::unsetenv` => `env::remove_var`
Many function signatures have also been tweaked for various purposes, but the
main changes were:
* `Vec`-returning APIs now all return iterators instead
* All APIs are now centered around `OsString` instead of `Vec<u8>` or `String`.
There is currently on convenience API, `env::var_string`, which can be used to
get the value of an environment variable as a unicode `String`.
All old APIs are `#[deprecated]` in-place and will remain for some time to allow
for migrations. The semantics of the APIs have been tweaked slightly with regard
to dealing with invalid unicode (panic instead of replacement).
The new `std::env` module is all contained within the `env` feature, so crates
must add the following to access the new APIs:
#![feature(env)]
[breaking-change]
Update the coherence rules to "covered first" -- the first type parameter to contain either a local type or a type parameter must contain only covered type parameters.
cc #19470.
Fixes#20974.
Fixes#20749.
r? @aturon
This commits adds an associated type to the `FromStr` trait representing an
error payload for parses which do not succeed. The previous return value,
`Option<Self>` did not allow for this form of payload. After the associated type
was added, the following attributes were applied:
* `FromStr` is now stable
* `FromStr::Err` is now stable
* `FromStr::from_str` is now stable
* `StrExt::parse` is now stable
* `FromStr for bool` is now stable
* `FromStr for $float` is now stable
* `FromStr for $integral` is now stable
* Errors returned from stable `FromStr` implementations are stable
* Errors implement `Display` and `Error` (both impl blocks being `#[stable]`)
Closes#15138
This commit performs a final stabilization pass over the std::fmt module,
marking all necessary APIs as stable. One of the more interesting aspects of
this module is that it exposes a good deal of its runtime representation to the
outside world in order for `format_args!` to be able to construct the format
strings. Instead of hacking the compiler to assume that these items are stable,
this commit instead lays out a story for the stabilization and evolution of
these APIs.
There are three primary details used by the `format_args!` macro:
1. `Arguments` - an opaque package of a "compiled format string". This structure
is passed around and the `write` function is the source of truth for
transforming a compiled format string into a string at runtime. This must be
able to be constructed in stable code.
2. `Argument` - an opaque structure representing an argument to a format string.
This is *almost* a trait object as it's just a pointer/function pair, but due
to the function originating from one of many traits, it's not actually a
trait object. Like `Arguments`, this must be constructed from stable code.
3. `fmt::rt` - this module contains the runtime type definitions primarily for
the `rt::Argument` structure. Whenever an argument is formatted with
nonstandard flags, a corresponding `rt::Argument` is generated describing how
the argument is being formatted. This can be used to construct an
`Arguments`.
The primary interface to `std::fmt` is the `Arguments` structure, and as such
this type name is stabilize as-is today. It is expected for libraries to pass
around an `Arguments` structure to represent a pending formatted computation.
The remaining portions are largely "cruft" which would rather not be stabilized,
but due to the stability checks they must be. As a result, almost all pieces
have been renamed to represent that they are "version 1" of the formatting
representation. The theory is that at a later date if we change the
representation of these types we can add new definitions called "version 2" and
corresponding constructors for `Arguments`.
One of the other remaining large questions about the fmt module were how the
pending I/O reform would affect the signatures of methods in the module. Due to
[RFC 526][rfc], however, the writers of fmt are now incompatible with the
writers of io, so this question has largely been solved. As a result the
interfaces are largely stabilized as-is today.
[rfc]: https://github.com/rust-lang/rfcs/blob/master/text/0526-fmt-text-writer.md
Specifically, the following changes were made:
* The contents of `fmt::rt` were all moved under `fmt::rt::v1`
* `fmt::rt` is stable
* `fmt::rt::v1` is stable
* `Error` is stable
* `Writer` is stable
* `Writer::write_str` is stable
* `Writer::write_fmt` is stable
* `Formatter` is stable
* `Argument` has been renamed to `ArgumentV1` and is stable
* `ArgumentV1::new` is stable
* `ArgumentV1::from_uint` is stable
* `Arguments::new_v1` is stable (renamed from `new`)
* `Arguments::new_v1_formatted` is stable (renamed from `with_placeholders`)
* All formatting traits are now stable, as well as the `fmt` method.
* `fmt::write` is stable
* `fmt::format` is stable
* `Formatter::pad_integral` is stable
* `Formatter::pad` is stable
* `Formatter::write_str` is stable
* `Formatter::write_fmt` is stable
* Some assorted top level items which were only used by `format_args!` were
removed in favor of static functions on `ArgumentV1` as well.
* The formatting-flag-accessing methods remain unstable
Within the contents of the `fmt::rt::v1` module, the following actions were
taken:
* Reexports of all enum variants were removed
* All prefixes on enum variants were removed
* A few miscellaneous enum variants were renamed
* Otherwise all structs, fields, and variants were marked stable.
In addition to these actions in the `std::fmt` module, many implementations of
`Show` and `String` were stabilized as well.
In some other modules:
* `ToString` is now stable
* `ToString::to_string` is now stable
* `Vec` no longer implements `fmt::Writer` (this has moved to `String`)
This is a breaking change due to all of the changes to the `fmt::rt` module, but
this likely will not have much impact on existing programs.
Closes#20661
[breaking-change]
This commits adds an associated type to the `FromStr` trait representing an
error payload for parses which do not succeed. The previous return value,
`Option<Self>` did not allow for this form of payload. After the associated type
was added, the following attributes were applied:
* `FromStr` is now stable
* `FromStr::Err` is now stable
* `FromStr::from_str` is now stable
* `StrExt::parse` is now stable
* `FromStr for bool` is now stable
* `FromStr for $float` is now stable
* `FromStr for $integral` is now stable
* Errors returned from stable `FromStr` implementations are stable
* Errors implement `Display` and `Error` (both impl blocks being `#[stable]`)
Closes#15138
Note: Do not merge until we get a newer snapshot that includes #21374
There was some type inference fallout (see 4th commit) because type inference with `a..b` is not as good as with `range(a, b)` (see #21672).
r? @alexcrichton
the compiler that assumed two input types to assume two ouputs; we also have to teach `project.rs`
to project `Output` from the unboxed closure and fn traits.
This implements the remaining bits of 'feature staging', as described in [RFC 507](https://github.com/rust-lang/rfcs/blob/master/text/0507-release-channels.md).
This is not quite done, but the substance of the work is complete so submitting for early review.
Key changes:
* `unstable`, `stable` and `deprecated` attributes all require 'feature' and 'since', and support an optional 'reason'.
* The `unstable` lint is removed.
* A new 'stability checking' pass warns when a used unstable library feature has not been activated with the `feature` attribute. At 1.0 beta this will become an error.
* A new 'unused feature checking' pass emits a lint ('unused_feature', renamed from 'unknown_feature') for any features that were activated but not used.
* A new tidy script `featureck.py` performs some global sanity checking, particularly that 'since' numbers agree, and also prints out a summary of features.
Differences from RFC:
* As implemented `unstable` requires a `since` attribute. I do not know if this is useful. I included it in the original sed script and just left it.
* RFC didn't specify the name of the optional 'reason' attribute.
* This continues to use 'unstable', 'stable' and 'deprecated' names (the 'nice' names) instead of 'staged_unstable', but only activates them with the crate-level 'staged_api' attribute.
I intend to update the RFC based on the outcome of this PR.
Issues:
* The unused feature check doesn't account for language features - i.e. you can activate a language feature, not use it, and not get the error.
Open questions:
* All unstable and deprecated features are named 'unnamed_feature', which i picked just because it is uniquely greppable. This is the 'catch-all' feature. What should it be?
* All stable features are named 'grandfathered'. What should this be?
TODO:
* Add check that all `deprecated` attributes are paired with a `stable` attribute in order to preserve the knowledge about when a feature became stable.
* Update rustdoc in various ways.
* Remove obsolete stability discussion from reference.
* Add features for 'path', 'io', 'os', 'hash' and 'rand'.
cc #20445 @alexcrichton @aturon
This new variant introduces finer-grain code extents, i.e. we now
track that a binding lives only for a suffix of a block, and
(importantly) will be dropped when it goes out of scope *before* the
bindings that occurred earlier in the block.
Both of these notions are neatly captured by marking the block (and
each suffix) as an enclosing scope of the next suffix beneath it.
This is work that is part of the foundation for issue #8861.
(It actually has been seen in earlier posted pull requests; I have
just factored it out into its own PR to ease my own rebasing.)
----
These finer grained scopes do mean that some code is newly rejected by
`rustc`; for example:
```rust
let mut map : HashMap<u8, &u8> = HashMap::new();
let tmp = Box::new(2);
map.insert(43, &*tmp);
```
This will now fail to compile with a message that `*tmp` does not live
long enough, because the scope of `tmp` is now strictly smaller than
that of `map`, and the use of `&u8` in map's type requires that the
borrowed references are all to data that live at least as long as the
map.
The usual fix for a case like this is to move the binding for `tmp`
up above that of `map`; note that you can still leave the initialization
in the original spot, like so:
```rust
let tmp;
let mut map : HashMap<u8, &u8> = HashMap::new();
tmp = box 2;
map.insert(43, &*tmp);
```
Similarly, one can encounter an analogous situation with `Vec`: one
would need to rewrite:
```rust
let mut vec = Vec::new();
let tmp = 'c';
vec.push(&tmp);
```
as:
```
let tmp;
let mut vec = Vec::new();
tmp = 'c';
vec.push(&tmp);
```
----
In some corner cases, it does not suffice to reorder the bindings; in
particular, when the types for both bindings need to reflect exactly
the *same* code extent, and a parent/child relationship between them
does not work.
In pnkfelix's experience this has arisen most often when mixing uses
of cyclic data structures while also allowing a lifetime parameter
`'a` to flow into a type parameter context where the type is
*invariant* with respect to the type parameter. An important instance
of this is `arena::TypedArena<T>`, which is invariant with respect
to `T`.
(The reason that variance is relevant is this: *if* `TypedArena` were
covariant with respect to its type parameter, then we could assign it
the longer lifetime when it is initialized, and then convert it to a
subtype (via covariance) with a shorter lifetime when necessary. But
`TypedArena` is invariant with respect to its type parameter, and thus
if `S` is a subtype of `T` (in particular, if `S` has a lifetime
parameter that is shorter than that of `T`), then a `TypedArena<S>` is
unrelated to `TypedArena<T>`.)
Concretely, consider code like this:
```rust
struct Node<'a> { sibling: Option<&'a Node<'a>> }
struct Context<'a> {
// because of this field, `Context<'a>` is invariant with respect to `'a`.
arena: &'a TypedArena<Node<'a>>,
...
}
fn new_ctxt<'a>(arena: &'a TypedArena<Node<'a>>) -> Context<'a> { ... }
fn use_ctxt<'a>(fcx: &'a Context<'a>) { ... }
let arena = TypedArena::new();
let ctxt = new_ctxt(&arena);
use_ctxt(&ctxt);
```
In these situations, if you try to introduce two bindings via two
distinct `let` statements, each is (with this commit) assigned a
distinct extent, and the region inference system cannot find a single
region to assign to the lifetime `'a` that works for both of the
bindings. So you get an error that `ctxt` does not live long enough;
but moving its binding up above that of `arena` just shifts the error
so now the compiler complains that `arena` does not live long enough.
SO: What to do? The easiest fix in this case is to ensure that the two
bindings *do* get assigned the same static extent, by stuffing both
bindings into the same let statement, like so:
```rust
let (arena, ctxt): (TypedArena, Context);
arena = TypedArena::new();
ctxt = new_ctxt(&arena);
use_ctxt(&ctxt);
```
Due to the new code rejections outlined above, this is a ...
[breaking-change]
In preparation for the I/O rejuvination of the standard library, this commit
renames the current `io` module to `old_io` in order to make room for the new
I/O modules. It is expected that the I/O RFCs will land incrementally over time
instead of all at once, and this provides a fresh clean path for new modules to
enter into as well as guaranteeing that all old infrastructure will remain in
place for some time.
As each `old_io` module is replaced it will be deprecated in-place for new
structures in `std::{io, fs, net}` (as appropriate).
This commit does *not* leave a reexport of `old_io as io` as the deprecation
lint does not currently warn on this form of use. This is quite a large breaking
change for all imports in existing code, but all functionality is retained
precisely as-is and path statements simply need to be renamed from `io` to
`old_io`.
[breaking-change]
E.g. `fn foo() { foo() }`, or, more subtlely
impl Foo for Box<Foo+'static> {
fn bar(&self) {
self.bar();
}
}
The compiler will warn and point out the points where recursion occurs,
if it determines that the function cannot return without calling itself.
Closes#17899.
---
This is highly non-perfect, in particular, my wording above is quite precise, and I have some unresolved questions: This currently will warn about
```rust
fn foo() {
if bar { loop {} }
foo()
}
```
even though `foo` may never be called (i.e. our apparent "unconditional" recursion is actually conditional). I don't know if we should handle this case, and ones like it with `panic!()` instead of `loop` (or anything else that "returns" `!`).
However, strictly speaking, it seems to me that changing the above to not warn will require changing
```rust
fn foo() {
while bar {}
foo()
}
```
to also not warn since it could be that the `while` is an infinite loop and doesn't ever hit the `foo`.
I'm inclined to think we let these cases warn since true edge cases like the first one seem rare, and if they do occur they seem like they would usually be typos in the function call. (I could imagine someone accidentally having code like `fn foo() { assert!(bar()); foo() /* meant to be boo() */ }` which won't warn if the `loop` case is "fixed".)
(Part of the reason this is unresolved is wanting feedback, part of the reason is I couldn't devise a strategy that worked in all cases.)
---
The name `unconditional_self_calls` is kinda clunky; and this reconstructs the CFG for each function that is linted which may or may not be very expensive, I don't know.
This allows one to look at an `ExprMethodCall` `foo.bar()` where `bar`
is a method in some trait and (sometimes) extract the `impl` that `bar`
is defined in, e.g.
trait Foo {
fn bar(&self);
}
impl Foo for uint { // <A>
fn bar(&self) {}
}
fn main() {
1u.bar(); // impl_def_id == Some(<A>)
}
This definitely doesn't handle all cases, but is correct when it is
known, meaning it should only be used for certain linting/heuristic
purposes; no safety analysis.
This does the bare minimum to make registration of error codes work again. After this patch, every call to `span_err!` with an error code gets that error code validated against a list in that crate and a new tidy script `errorck.py` validates that no error codes are duplicated globally.
There are further improvements to be made yet, detailed in #19624.
r? @nikomatsakis
This commit is an implementation of [RFC 565][rfc] which is a stabilization of
the `std::fmt` module and the implementations of various formatting traits.
Specifically, the following changes were performed:
[rfc]: https://github.com/rust-lang/rfcs/blob/master/text/0565-show-string-guidelines.md
* The `Show` trait is now deprecated, it was renamed to `Debug`
* The `String` trait is now deprecated, it was renamed to `Display`
* Many `Debug` and `Display` implementations were audited in accordance with the
RFC and audited implementations now have the `#[stable]` attribute
* Integers and floats no longer print a suffix
* Smart pointers no longer print details that they are a smart pointer
* Paths with `Debug` are now quoted and escape characters
* The `unwrap` methods on `Result` now require `Display` instead of `Debug`
* The `Error` trait no longer has a `detail` method and now requires that
`Display` must be implemented. With the loss of `String`, this has moved into
libcore.
* `impl<E: Error> FromError<E> for Box<Error>` now exists
* `derive(Show)` has been renamed to `derive(Debug)`. This is not currently
warned about due to warnings being emitted on stage1+
While backwards compatibility is attempted to be maintained with a blanket
implementation of `Display` for the old `String` trait (and the same for
`Show`/`Debug`) this is still a breaking change due to primitives no longer
implementing `String` as well as modifications such as `unwrap` and the `Error`
trait. Most code is fairly straightforward to update with a rename or tweaks of
method calls.
[breaking-change]
Closes#21436
This commit aims to stabilize the `TypeId` abstraction by moving it out of the
`intrinsics` module into the `any` module of the standard library. Specifically,
* `TypeId` is now defined at `std::any::TypeId`
* `TypeId::hash` has been removed in favor of an implementation of `Hash`.
This commit also performs a final pass over the `any` module, confirming the
following:
* `Any::get_type_id` remains unstable as *usage* of the `Any` trait will likely
never require this, and the `Any` trait does not need to be implemented for
any other types. As a result, this implementation detail can remain unstable
until associated statics are implemented.
* `Any::downcast_ref` is now stable
* `Any::downcast_mut` is now stable
* `BoxAny` remains unstable. While a direct impl on `Box<Any>` is allowed today
it does not allow downcasting of trait objects like `Box<Any + Send>` (those
returned from `Thread::join`). This is covered by #18737.
* `BoxAny::downcast` is now stable.
This commit modifies resolve to prevent conflicts with typedef names in the same
method that conflits are prevented with enum names. This is a breaking change
due to the differing semantics in resolve, and any errors generated on behalf of
this change require that a conflicting typedef, module, or structure to be
renamed so they do not conflict.
[breaking-change]
Closes#6936
This commit aims to stabilize the `TypeId` abstraction by moving it out of the
`intrinsics` module into the `any` module of the standard library. Specifically,
* `TypeId` is now defined at `std::any::TypeId`
* `TypeId::hash` has been removed in favor of an implementation of `Hash`.
This commit also performs a final pass over the `any` module, confirming the
following:
* `Any::get_type_id` remains unstable as *usage* of the `Any` trait will likely
never require this, and the `Any` trait does not need to be implemented for
any other types. As a result, this implementation detail can remain unstable
until associated statics are implemented.
* `Any::downcast_ref` is now stable
* `Any::downcast_mut` is now stable
* `BoxAny` remains unstable. While a direct impl on `Box<Any>` is allowed today
it does not allow downcasting of trait objects like `Box<Any + Send>` (those
returned from `Thread::join`). This is covered by #18737.
* `BoxAny::downcast` is now stable.
Add `--xpretty flowgraph,unlabelled` variant to the (unstable) flowgraph printing `rustc` option.
This makes the tests much easier to maintain; the particular details of the labels attached to exiting scopes is not worth the effort required to keep it up to date as things change in the compiler internals.
Refactor compare_impl_method into its own file. Modify the
code to stop comparing individual parameter bounds.
Instead we now use the predicates list attached to the trait
and implementation generics. This ensures consistency even
when bounds are declared in different places (i.e on
a parameter vs. in a where clause).
#### Updated 1/12/2014
I updated the multi-line testcase to current but didn't modify the others. The spew code was broke by the `matches!` macro no longer working and I'm not interested in fixing the testcase.
I additionally added one testcase below.
Errors will in general look similar to below if the error is either `mismatched types` or a few other types. The rest are ignored.
---
#### Extra testcase:
```rust
pub trait Foo {
type A;
fn boo(&self) -> <Self as Foo>::A;
}
struct Bar;
impl Foo for i32 {
type A = u32;
fn boo(&self) -> u32 {
42
}
}
fn foo1<I: Foo<A=Bar>>(x: I) {
let _: Bar = x.boo();
}
fn foo2<I: Foo>(x: I) {
let _: Bar = x.boo();
}
pub fn baz(x: &Foo<A=Bar>) {
let _: Bar = x.boo();
}
pub fn main() {
let a = 42i32;
foo1(a);
baz(&a);
}
```
#### Multi-line output:
```cmd
$ ./rustc test3.rs
test3.rs:20:18: 20:25 error: mismatched types:
expected `Bar`,
found `<I as Foo>::A`
(expected struct `Bar`,
found associated type)
test3.rs:20 let _: Bar = x.boo();
^~~~~~~
test3.rs:31:5: 31:9 error: type mismatch resolving `<i32 as Foo>::A == Bar`:
expected u32,
found struct `Bar`
test3.rs:31 foo1(a);
^~~~
test3.rs:31:5: 31:9 note: required by `foo1`
test3.rs:31 foo1(a);
^~~~
test3.rs:32:9: 32:11 error: type mismatch resolving `<i32 as Foo>::A == Bar`:
expected u32,
found struct `Bar`
test3.rs:32 baz(&a);
^~
test3.rs:32:9: 32:11 note: required for the cast to the object type `Foo`
test3.rs:32 baz(&a);
^~
error: aborting due to 3 previous errors
```
---
This is a continuation of #19203 which I apparently broke by force pushing after it was closed. I'm attempting to add multi-line errors where they are largely beneficial - to help differentiate different types in compiler messages. As before, this is still a simple fix.
#### Testcase:
```rust
struct S;
fn test() -> Option<i32> {
let s: S;
s
}
fn test2() -> Option<i32> {
Ok(7) // Should be Some(7)
}
impl Iterator for S {
type Item = i32;
fn next(&mut self) -> Result<i32, i32> { Ok(7) }
}
fn main(){
test();
test2();
}
```
---
#### Single-line playpen errors:
```cmd
<anon>:6:5: 6:6 error: mismatched types: expected `core::option::Option<int>`, found `S` (expected enum core::option::Option, found struct S)
<anon>:6 s
^
<anon>:10:5: 10:10 error: mismatched types: expected `core::option::Option<int>`, found `core::result::Result<_, _>` (expected enum core::option::Option, found enum core::result::Result)
<anon>:10 Ok(7) // Should be Some(7)
^~~~~
<anon>:14:5: 14:55 error: method `next` has an incompatible type for trait: expected enum core::option::Option, found enum core::result::Result [E0053]
<anon>:14 fn next(&mut self) -> Result<uint, uint> { Ok(7) }
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
error: aborting due to 3 previous errors
playpen: application terminated with error code 101
```
---
#### Multi-line errors:
```cmd
$ ./rustc test.rs
test.rs:6:5: 6:6 error: mismatched types:
expected `core::option::Option<i32>`,
found `S`
(expected enum `core::option::Option`,
found struct `S`)
test.rs:6 s
^
test.rs:10:5: 10:10 error: mismatched types:
expected `core::option::Option<i32>`,
found `core::result::Result<_, _>`
(expected enum `core::option::Option`,
found enum `core::result::Result`)
test.rs:10 Ok(7) // Should be Some(7)
^~~~~
test.rs:15:5: 15:53 error: method `next` has an incompatible type for trait: expected enum `core::option::Option`, found enum `core::result::Result` [E0053]
test.rs:15 fn next(&mut self) -> Result<i32, i32> { Ok(7) }
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
error: aborting due to 3 previous errors
```
---
#### Positive notes
* Vim worked fine with it: https://github.com/rust-lang/rust/pull/19203#issuecomment-66861668
* `make check` didn't find any errors
* Fixed *backtick* placement suggested by @p1start at https://github.com/rust-lang/rust/pull/19203#issuecomment-64062052
#### Negative notes
* Didn't check Emacs support but also wasn't provided a testcase...
* Needs to be tested with macro errors but I don't have a good testcase yet
* I would like to move the `E[0053]` earlier (see https://github.com/rust-lang/rust/issues/19464#issuecomment-65334301) but I don't know how
* It might be better to indent the types slightly like so (but I don't know how):
```cmd
test.rs:6:5: 6:6 error: mismatched types:
expected `core::option::Option<int>`,
found `S`
(expected enum `core::option::Option`,
found struct `S`)
test.rs:6 s
```
* Deep whitespace indentation may be a bad idea because early wrapping will cause misalignment between lines
#### Other
* I thought that compiler flags or something else (environment variables maybe) might be required because of comments against it but now that seems too much of a burden for users and for too little gain.
* There was concern that it will make large quantities of errors difficult to distinguish but I don't find that an issue. They both look awful and multi-line errors makes the types easier to understand.
---
#### Single lined spew:
```cmd
$ rustc test2.rs
test2.rs:161:9: 170:10 error: method `next` has an incompatible type for trait: expected enum core::option::Option, found enum core::result::Result [E0053]
test2.rs:161 fn next(&mut self) -> Result<&'a str, int> {
test2.rs:162 self.curr = self.next;
test2.rs:163
test2.rs:164 if let (Some(open), Some(close)) = Parens::find_parens(self.all, self.next) {
test2.rs:165 self.next = if self.all.char_at(self.next) == '(' { close }
test2.rs:166 else { open }
...
test2.rs:164:21: 164:31 error: mismatched types: expected `core::result::Result<uint, int>`, found `core::option::Option<_>` (expected enum core::result::Result, found enum core::option::Option)
test2.rs:164 if let (Some(open), Some(close)) = Parens::find_parens(self.all, self.next) {
^~~~~~~~~~
test2.rs:164:33: 164:44 error: mismatched types: expected `core::result::Result<uint, int>`, found `core::option::Option<_>` (expected enum core::result::Result, found enum core::option::Option)
test2.rs:164 if let (Some(open), Some(close)) = Parens::find_parens(self.all, self.next) {
^~~~~~~~~~~
test2.rs:169:40: 169:76 error: mismatched types: expected `core::result::Result<&'a str, int>`, found `core::option::Option<&str>` (expected enum core::result::Result, found enum core::option::Option)
test2.rs:169 if self.curr != self.len { Some(self.all[self.curr..self.next]) } else { None }
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
test2.rs:169:86: 169:90 error: mismatched types: expected `core::result::Result<&'a str, int>`, found `core::option::Option<_>` (expected enum core::result::Result, found enum core::option::Option)
test2.rs:169 if self.curr != self.len { Some(self.all[self.curr..self.next]) } else { None }
^~~~
test2.rs:205:14: 205:18 error: mismatched types: expected `core::result::Result<uint, int>`, found `core::option::Option<uint>` (expected enum core::result::Result, found enum core::option::Option)
test2.rs:205 (open, close)
^~~~
test2.rs:205:20: 205:25 error: mismatched types: expected `core::result::Result<uint, int>`, found `core::option::Option<uint>` (expected enum core::result::Result, found enum core::option::Option)
test2.rs:205 (open, close)
^~~~~
test2.rs:210:21: 210:31 error: mismatched types: expected `core::result::Result<uint, int>`, found `core::option::Option<_>` (expected enum core::result::Result, found enum core::option::Option)
test2.rs:210 if let (Some(open), _) = Parens::find_parens(self.all, 0) {
^~~~~~~~~~
test2.rs:210:13: 212:28 error: mismatched types: expected `core::option::Option<&'a int>`, found `core::option::Option<&str>` (expected int, found str)
test2.rs:210 if let (Some(open), _) = Parens::find_parens(self.all, 0) {
test2.rs:211 Some(self.all[0..open])
test2.rs:212 } else { None }
test2.rs:299:48: 299:58 error: mismatched types: expected `Box<translate::Entity>`, found `collections::vec::Vec<_>` (expected box, found struct collections::vec::Vec)
test2.rs:299 pub fn new() -> Entity { Entity::Group(Vec::new()) }
^~~~~~~~~~
test2.rs:359:51: 359:58 error: type `&mut Box<translate::Entity>` does not implement any method in scope named `push`
test2.rs:359 Entity::Group(ref mut vec) => vec.push(e),
^~~~~~~
test2.rs:366:51: 366:85 error: type `&mut Box<translate::Entity>` does not implement any method in scope named `push`
test2.rs:366 Entity::Group(ref mut vec) => vec.push(Entity::Inner(s.to_string())),
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
error: aborting due to 12 previous errors
```
---
#### Multi-line spew:
```cmd
$ ./rustc test2.rs
test2.rs:161:9: 170:10 error: method `next` has an incompatible type for trait:
expected enum `core::option::Option`,
found enum `core::result::Result` [E0053]
test2.rs:161 fn next(&mut self) -> Result<&'a str, int> {
test2.rs:162 self.curr = self.next;
test2.rs:163
test2.rs:164 if let (Some(open), Some(close)) = Parens::find_parens(self.all, self.next) {
test2.rs:165 self.next = if self.all.char_at(self.next) == '(' { close }
test2.rs:166 else { open }
...
test2.rs:164:21: 164:31 error: mismatched types:
expected `core::result::Result<uint, int>`,
found `core::option::Option<_>`
(expected enum `core::result::Result`,
found enum `core::option::Option`)
test2.rs:164 if let (Some(open), Some(close)) = Parens::find_parens(self.all, self.next) {
^~~~~~~~~~
test2.rs:164:33: 164:44 error: mismatched types:
expected `core::result::Result<uint, int>`,
found `core::option::Option<_>`
(expected enum `core::result::Result`,
found enum `core::option::Option`)
test2.rs:164 if let (Some(open), Some(close)) = Parens::find_parens(self.all, self.next) {
^~~~~~~~~~~
test2.rs:169:40: 169:76 error: mismatched types:
expected `core::result::Result<&'a str, int>`,
found `core::option::Option<&str>`
(expected enum `core::result::Result`,
found enum `core::option::Option`)
test2.rs:169 if self.curr != self.len { Some(self.all[self.curr..self.next]) } else { None }
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
test2.rs:169:86: 169:90 error: mismatched types:
expected `core::result::Result<&'a str, int>`,
found `core::option::Option<_>`
(expected enum `core::result::Result`,
found enum `core::option::Option`)
test2.rs:169 if self.curr != self.len { Some(self.all[self.curr..self.next]) } else { None }
^~~~
test2.rs:205:14: 205:18 error: mismatched types:
expected `core::result::Result<uint, int>`,
found `core::option::Option<uint>`
(expected enum `core::result::Result`,
found enum `core::option::Option`)
test2.rs:205 (open, close)
^~~~
test2.rs:205:20: 205:25 error: mismatched types:
expected `core::result::Result<uint, int>`,
found `core::option::Option<uint>`
(expected enum `core::result::Result`,
found enum `core::option::Option`)
test2.rs:205 (open, close)
^~~~~
test2.rs:210:21: 210:31 error: mismatched types:
expected `core::result::Result<uint, int>`,
found `core::option::Option<_>`
(expected enum `core::result::Result`,
found enum `core::option::Option`)
test2.rs:210 if let (Some(open), _) = Parens::find_parens(self.all, 0) {
^~~~~~~~~~
test2.rs:210:13: 212:28 error: mismatched types:
expected `core::option::Option<&'a int>`,
found `core::option::Option<&str>`
(expected int,
found str)
test2.rs:210 if let (Some(open), _) = Parens::find_parens(self.all, 0) {
test2.rs:211 Some(self.all[0..open])
test2.rs:212 } else { None }
test2.rs:229:57: 229:96 error: the trait `core::ops::Fn<(char,), bool>` is not implemented for the type `|char| -> bool`
test2.rs:229 .map(|s| s.trim_chars(|c: char| c.is_whitespace()))
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
test2.rs:238:46: 239:75 error: type `core::str::CharSplits<'_, |char| -> bool>` does not implement any method in scope named `filter_map`
test2.rs:238 .filter_map(|s| if !s.is_empty() { Some(s.trim_chars('\'')) }
test2.rs:239 else { None })
test2.rs:237:46: 237:91 error: the trait `core::ops::Fn<(char,), bool>` is not implemented for the type `|char| -> bool`
test2.rs:237 let vec: Vec<&str> = value[].split(|c: char| matches!(c, '(' | ')' | ','))
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
test2.rs:238:65: 238:77 error: the type of this value must be known in this context
test2.rs:238 .filter_map(|s| if !s.is_empty() { Some(s.trim_chars('\'')) }
^~~~~~~~~~~~
test2.rs:299:48: 299:58 error: mismatched types:
expected `Box<translate::Entity>`,
found `collections::vec::Vec<_>`
(expected box,
found struct `collections::vec::Vec`)
test2.rs:299 pub fn new() -> Entity { Entity::Group(Vec::new()) }
^~~~~~~~~~
test2.rs:321:36: 322:65 error: type `core::str::CharSplits<'_, |char| -> bool>` does not implement any method in scope named `filter_map`
test2.rs:321 .filter_map(|s| if !s.is_empty() { Some(s.trim_chars('\'')) }
test2.rs:322 else { None })
test2.rs:320:36: 320:81 error: the trait `core::ops::Fn<(char,), bool>` is not implemented for the type `|char| -> bool`
test2.rs:320 let vec: Vec<&str> = s.split(|c: char| matches!(c, '(' | ')' | ','))
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
test2.rs:321:55: 321:67 error: the type of this value must be known in this context
test2.rs:321 .filter_map(|s| if !s.is_empty() { Some(s.trim_chars('\'')) }
^~~~~~~~~~~~
test2.rs:359:51: 359:58 error: type `&mut Box<translate::Entity>` does not implement any method in scope named `push`
test2.rs:359 Entity::Group(ref mut vec) => vec.push(e),
^~~~~~~
test2.rs:366:51: 366:85 error: type `&mut Box<translate::Entity>` does not implement any method in scope named `push`
test2.rs:366 Entity::Group(ref mut vec) => vec.push(Entity::Inner(s.to_string())),
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
error: aborting due to 24 previous errors
```
Closes#18946#19464
cc @P1start @jakub- @tomjakubowski @kballard @chris-morgan
