Pretty print parens around casts on the LHS of `<`/`<<`
When pretty printing a cast expression occuring on the LHS of a `<` or `<<` expression, we should add parens around the cast. Otherwise, the `<`/`<<` gets interpreted as the beginning of the generics for the type on the RHS of the cast.
Consider:
$ cat parens_cast.rs
macro_rules! negative {
($e:expr) => { $e < 0 }
}
fn main() {
negative!(1 as i32);
}
Before this PR, the output of the following is not valid Rust:
$ rustc -Z unstable-options --pretty=expanded parens_cast.rs
#![feature(prelude_import)]
#![no_std]
#[prelude_import]
use std::prelude::v1::*;
#[macro_use]
extern crate std as std;
macro_rules! negative(( $ e : expr ) => { $ e < 0 });
fn main() { 1 as i32 < 0; }
After this PR, the output of the following is valid Rust:
$ rustc -Z unstable-options --pretty=expanded parens_cast.rs
#![feature(prelude_import)]
#![no_std]
#[prelude_import]
use std::prelude::v1::*;
#[macro_use]
extern crate std as std;
macro_rules! negative(( $ e : expr ) => { $ e < 0 });
fn main() { (1 as i32) < 0; }
I've gone through several README/wiki style documents but I'm still not sure where to test this though. I'm not even sure if this sort of thing is tested...
Remove attr-variant-data.rs since it relies on quirks
in legacy custom derive resolution (undefined derives
only print a warning).
Add a new test which uses a defined proc macro derive,
and tests pretty printing of proc macro derive
attributes.
Most of the Rust community agrees that the vec! macro is clearer when
called using square brackets [] instead of regular brackets (). Most of
these ocurrences are from before macros allowed using different types of
brackets.
There is one left unchanged in a pretty-print test, as the pretty
printer still wants it to have regular brackets.
This adds support to the pretty printer to print attributes
added to tuple struct elements. Furthermore, it adds a test
that makes sure we will print attributes on all variant data
types.
syntax: Always pretty print a newline after doc comments
Before this patch, code that had a doc comment as the first
line, as in:
```rust
/// Foo
struct Foo;
```
Was pretty printed into:
```rust
///Foostruct Foo;
```
This makes sure that that there is always a trailing newline
after a doc comment.
Closes#31722
Before this patch, code that had a doc comment as the first
line, as in:
```rust
/// Foo
struct Foo;
```
Was pretty printed into:
```rust
///Foostruct Foo;
```
This makes sure that that there is always a trailing newline
after a doc comment.
Closes#31722
Pretty printing of macro with braces but without terminated semicolon
removed more boxes from stack than it put there, resulting in panic.
This fixes the issue #30731.
nodes in statement position.
Extended #[cfg] folder to allow removal of statements, and
of expressions in optional positions like expression lists and trailing
block expressions.
Extended lint checker to recognize lint levels on expressions and
locals.
Most of these are old, but some specific messages for specific tests:
* trait-contravariant-self.rs: failed due to a soundess hole:
05e3248a79
* process-detatch: 15966c3c1f
says "this test is being ignored until signals are implemented" That's
not happening for a long time, and when it is, we'll write tests for
it.
* deep-vector{,2}.rs: "too big for our poor macro infrastructure", and has
been ignored over a year.
* borrowck-nested-calls.rs's FIXME #6268 was closed in favor of
rust-lang/rfcs#811
* issue-15167.rs works properly now
* issue-9737.rs works properly now
* match-var-hygiene.rs works properly now
Addresses a chunk of #3965
The compiler will now issue a warning for crates that have syntax of the form
`extern crate "foo" as bar`, but it will still continue to accept this syntax.
Additionally, the string `foo-bar` will match the crate name `foo_bar` to assist
in the transition period as well.
This patch will land hopefully in tandem with a Cargo patch that will start
translating all crate names to have underscores instead of hyphens.
cc #23533
The compiler will now issue a warning for crates that have syntax of the form
`extern crate "foo" as bar`, but it will still continue to accept this syntax.
Additionally, the string `foo-bar` will match the crate name `foo_bar` to assist
in the transition period as well.
This patch will land hopefully in tandem with a Cargo patch that will start
translating all crate names to have underscores instead of hyphens.
cc #23533
This permits all coercions to be performed in casts, but adds lints to warn in those cases.
Part of this patch moves cast checking to a later stage of type checking. We acquire obligations to check casts as part of type checking where we previously checked them. Once we have type checked a function or module, then we check any cast obligations which have been acquired. That means we have more type information available to check casts (this was crucial to making coercions work properly in place of some casts), but it means that casts cannot feed input into type inference.
[breaking change]
* Adds two new lints for trivial casts and trivial numeric casts, these are warn by default, but can cause errors if you build with warnings as errors. Previously, trivial numeric casts and casts to trait objects were allowed.
* The unused casts lint has gone.
* Interactions between casting and type inference have changed in subtle ways. Two ways this might manifest are:
- You may need to 'direct' casts more with extra type information, for example, in some cases where `foo as _ as T` succeeded, you may now need to specify the type for `_`
- Casts do not influence inference of integer types. E.g., the following used to type check:
```
let x = 42;
let y = &x as *const u32;
```
Because the cast would inform inference that `x` must have type `u32`. This no longer applies and the compiler will fallback to `i32` for `x` and thus there will be a type error in the cast. The solution is to add more type information:
```
let x: u32 = 42;
let y = &x as *const u32;
```
