rust/src/librustc_passes/diagnostics.rs

// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

#![allow(non_snake_case)]

register_long_diagnostics! {
/*
E0014: r##"
Constants can only be initialized by a constant value or, in a future
version of Rust, a call to a const function. This error indicates the use
of a path (like a::b, or x) denoting something other than one of these
allowed items. Erroneous code xample:

```compile_fail
const FOO: i32 = { let x = 0; x }; // 'x' isn't a constant nor a function!
```

To avoid it, you have to replace the non-constant value:

```
const FOO: i32 = { const X : i32 = 0; X };
// or even:
const FOO2: i32 = { 0 }; // but brackets are useless here
```
"##,
*/
E0030: r##"
When matching against a range, the compiler verifies that the range is
non-empty.  Range patterns include both end-points, so this is equivalent to
requiring the start of the range to be less than or equal to the end of the
range.

For example:

```compile_fail
match 5u32 {
    // This range is ok, albeit pointless.
    1 ... 1 => {}
    // This range is empty, and the compiler can tell.
    1000 ... 5 => {}
}
```
"##,

E0130: r##"
You declared a pattern as an argument in a foreign function declaration.
Erroneous code example:

```compile_fail
extern {
    fn foo((a, b): (u32, u32)); // error: patterns aren't allowed in foreign
                                //        function declarations
}
```

Please replace the pattern argument with a regular one. Example:

```
struct SomeStruct {
    a: u32,
    b: u32,
}

extern {
    fn foo(s: SomeStruct); // ok!
}
```

Or:

```
extern {
    fn foo(a: (u32, u32)); // ok!
}
```
"##,

E0197: r##"
Inherent implementations (one that do not implement a trait but provide
methods associated with a type) are always safe because they are not
implementing an unsafe trait. Removing the `unsafe` keyword from the inherent
implementation will resolve this error.

```compile_fail,E0197
struct Foo;

// this will cause this error
unsafe impl Foo { }
// converting it to this will fix it
impl Foo { }
```
"##,

E0198: r##"
A negative implementation is one that excludes a type from implementing a
particular trait. Not being able to use a trait is always a safe operation,
so negative implementations are always safe and never need to be marked as
unsafe.

```compile_fail
#![feature(optin_builtin_traits)]

struct Foo;

// unsafe is unnecessary
unsafe impl !Clone for Foo { }
```

This will compile:

```ignore (ignore auto_trait future compatibility warning)
#![feature(optin_builtin_traits)]

struct Foo;

auto trait Enterprise {}

impl !Enterprise for Foo { }
```

Please note that negative impls are only allowed for auto traits.
"##,

E0265: r##"
This error indicates that a static or constant references itself.
All statics and constants need to resolve to a value in an acyclic manner.

For example, neither of the following can be sensibly compiled:

```compile_fail,E0265
const X: u32 = X;
```

```compile_fail,E0265
const X: u32 = Y;
const Y: u32 = X;
```
"##,

E0267: r##"
This error indicates the use of a loop keyword (`break` or `continue`) inside a
closure but outside of any loop. Erroneous code example:

```compile_fail,E0267
let w = || { break; }; // error: `break` inside of a closure
```

`break` and `continue` keywords can be used as normal inside closures as long as
they are also contained within a loop. To halt the execution of a closure you
should instead use a return statement. Example:

```
let w = || {
    for _ in 0..10 {
        break;
    }
};

w();
```
"##,

E0268: r##"
This error indicates the use of a loop keyword (`break` or `continue`) outside
of a loop. Without a loop to break out of or continue in, no sensible action can
be taken. Erroneous code example:

```compile_fail,E0268
fn some_func() {
    break; // error: `break` outside of loop
}
```

Please verify that you are using `break` and `continue` only in loops. Example:

```
fn some_func() {
    for _ in 0..10 {
        break; // ok!
    }
}
```
"##,

E0379: r##"
Trait methods cannot be declared `const` by design. For more information, see
[RFC 911].

[RFC 911]: https://github.com/rust-lang/rfcs/pull/911
"##,

E0380: r##"
Auto traits cannot have methods or associated items.
For more information see the [opt-in builtin traits RFC][RFC 19].

[RFC 19]: https://github.com/rust-lang/rfcs/blob/master/text/0019-opt-in-builtin-traits.md
"##,

E0449: r##"
A visibility qualifier was used when it was unnecessary. Erroneous code
examples:

```compile_fail,E0449
struct Bar;

trait Foo {
    fn foo();
}

pub impl Bar {} // error: unnecessary visibility qualifier

pub impl Foo for Bar { // error: unnecessary visibility qualifier
    pub fn foo() {} // error: unnecessary visibility qualifier
}
```

To fix this error, please remove the visibility qualifier when it is not
required. Example:

```
struct Bar;

trait Foo {
    fn foo();
}

// Directly implemented methods share the visibility of the type itself,
// so `pub` is unnecessary here
impl Bar {}

// Trait methods share the visibility of the trait, so `pub` is
// unnecessary in either case
impl Foo for Bar {
    fn foo() {}
}
```
"##,


E0579: r##"
When matching against an exclusive range, the compiler verifies that the range
is non-empty. Exclusive range patterns include the start point but not the end
point, so this is equivalent to requiring the start of the range to be less
than the end of the range.

For example:

```compile_fail
match 5u32 {
    // This range is ok, albeit pointless.
    1 .. 2 => {}
    // This range is empty, and the compiler can tell.
    5 .. 5 => {}
}
```
"##,

E0590: r##"
`break` or `continue` must include a label when used in the condition of a
`while` loop.

Example of erroneous code:

```compile_fail
while break {}
```

To fix this, add a label specifying which loop is being broken out of:
```
'foo: while break 'foo {}
```
"##,

E0571: r##"
A `break` statement with an argument appeared in a non-`loop` loop.

Example of erroneous code:

```compile_fail,E0571
# let mut i = 1;
# fn satisfied(n: usize) -> bool { n % 23 == 0 }
let result = while true {
    if satisfied(i) {
        break 2*i; // error: `break` with value from a `while` loop
    }
    i += 1;
};
```

The `break` statement can take an argument (which will be the value of the loop
expression if the `break` statement is executed) in `loop` loops, but not
`for`, `while`, or `while let` loops.

Make sure `break value;` statements only occur in `loop` loops:

```
# let mut i = 1;
# fn satisfied(n: usize) -> bool { n % 23 == 0 }
let result = loop { // ok!
    if satisfied(i) {
        break 2*i;
    }
    i += 1;
};
```
"##
}

register_diagnostics! {
    E0226, // only a single explicit lifetime bound is permitted
    E0472, // asm! is unsupported on this target
    E0561, // patterns aren't allowed in function pointer types
    E0567, // auto traits can not have generic parameters
    E0568, // auto traits can not have super traits
    E0642, // patterns aren't allowed in methods without bodies
}