diff --git a/compiler/rustc_lint_defs/src/builtin.rs b/compiler/rustc_lint_defs/src/builtin.rs index 20052ad9bfc..658372ac336 100644 --- a/compiler/rustc_lint_defs/src/builtin.rs +++ b/compiler/rustc_lint_defs/src/builtin.rs @@ -238,41 +238,22 @@ declare_lint! { /// /// ```rust,compile_fail /// #![allow(unconditional_panic)] - /// let x: &'static i32 = &(1 / 0); + /// const C: i32 = 1/0; /// ``` /// /// {{produces}} /// /// ### Explanation /// - /// This lint detects code that is very likely incorrect. If this lint is - /// allowed, then the code will not be evaluated at compile-time, and - /// instead continue to generate code to evaluate at runtime, which may - /// panic during runtime. + /// This lint detects constants that fail to evaluate. Allowing the lint will accept the + /// constant declaration, but any use of this constant will still lead to a hard error. This is + /// a future incompatibility lint; the plan is to eventually entirely forbid even declaring + /// constants that cannot be evaluated. See [issue #71800] for more details. /// - /// Note that this lint may trigger in either inside or outside of a - /// [const context]. Outside of a [const context], the compiler can - /// sometimes evaluate an expression at compile-time in order to generate - /// more efficient code. As the compiler becomes better at doing this, it - /// needs to decide what to do when it encounters code that it knows for - /// certain will panic or is otherwise incorrect. Making this a hard error - /// would prevent existing code that exhibited this behavior from - /// compiling, breaking backwards-compatibility. However, this is almost - /// certainly incorrect code, so this is a deny-by-default lint. For more - /// details, see [RFC 1229] and [issue #28238]. - /// - /// Note that there are several other more specific lints associated with - /// compile-time evaluation, such as [`arithmetic_overflow`], - /// [`unconditional_panic`]. - /// - /// [const context]: https://doc.rust-lang.org/reference/const_eval.html#const-context - /// [RFC 1229]: https://github.com/rust-lang/rfcs/blob/master/text/1229-compile-time-asserts.md - /// [issue #28238]: https://github.com/rust-lang/rust/issues/28238 - /// [`arithmetic_overflow`]: deny-by-default.html#arithmetic-overflow - /// [`unconditional_panic`]: deny-by-default.html#unconditional-panic + /// [issue #71800]: https://github.com/rust-lang/rust/issues/71800 pub CONST_ERR, Deny, - "constant evaluation detected erroneous expression", + "constant evaluation encountered erroneous expression", report_in_external_macro }