rust/compiler/rustc_errors/src/codes.rs
Nicholas Nethercote 5d9dfbd08f Stop using String for error codes.
Error codes are integers, but `String` is used everywhere to represent
them. Gross!

This commit introduces `ErrCode`, an integral newtype for error codes,
replacing `String`. It also introduces a constant for every error code,
e.g. `E0123`, and removes the `error_code!` macro. The constants are
imported wherever used with `use rustc_errors::codes::*`.

With the old code, we have three different ways to specify an error code
at a use point:
```
error_code!(E0123)  // macro call

struct_span_code_err!(dcx, span, E0123, "msg");  // bare ident arg to macro call

\#[diag(name, code = "E0123")]  // string
struct Diag;
```

With the new code, they all use the `E0123` constant.
```
E0123  // constant

struct_span_code_err!(dcx, span, E0123, "msg");  // constant

\#[diag(name, code = E0123)]  // constant
struct Diag;
```

The commit also changes the structure of the error code definitions:
- `rustc_error_codes` now just defines a higher-order macro listing the
  used error codes and nothing else.
- Because that's now the only thing in the `rustc_error_codes` crate, I
  moved it into the `lib.rs` file and removed the `error_codes.rs` file.
- `rustc_errors` uses that macro to define everything, e.g. the error
  code constants and the `DIAGNOSTIC_TABLES`. This is in its new
  `codes.rs` file.
2024-01-29 07:41:41 +11:00

40 lines
1.1 KiB
Rust

//! This module defines the following.
//! - The `ErrCode` type.
//! - A constant for every error code, with a name like `E0123`.
//! - A static table `DIAGNOSTICS` pairing every error code constant with its
//! long description text.
use std::fmt;
rustc_index::newtype_index! {
#[max = 9999] // Because all error codes have four digits.
#[orderable]
#[encodable]
#[debug_format = "ErrCode({})"]
pub struct ErrCode {}
}
impl fmt::Display for ErrCode {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "E{:04}", self.as_u32())
}
}
macro_rules! define_error_code_constants_and_diagnostics_table {
($($name:ident: $num:literal,)*) => (
$(
pub const $name: $crate::ErrCode = $crate::ErrCode::from_u32($num);
)*
pub static DIAGNOSTICS: &[($crate::ErrCode, &str)] = &[
$( (
$name,
include_str!(
concat!("../../rustc_error_codes/src/error_codes/", stringify!($name), ".md")
)
), )*
];
)
}
rustc_error_codes::error_codes!(define_error_code_constants_and_diagnostics_table);