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-rw-r--r-- | compiler/rustc_error_codes/src/error_codes/E0537.md | 30 |
1 files changed, 30 insertions, 0 deletions
diff --git a/compiler/rustc_error_codes/src/error_codes/E0537.md b/compiler/rustc_error_codes/src/error_codes/E0537.md new file mode 100644 index 000000000..123efd4f5 --- /dev/null +++ b/compiler/rustc_error_codes/src/error_codes/E0537.md @@ -0,0 +1,30 @@ +An unknown predicate was used inside the `cfg` attribute. + +Erroneous code example: + +```compile_fail,E0537 +#[cfg(unknown())] // error: invalid predicate `unknown` +pub fn something() {} + +pub fn main() {} +``` + +The `cfg` attribute supports only three kinds of predicates: + + * any + * all + * not + +Example: + +``` +#[cfg(not(target_os = "linux"))] // ok! +pub fn something() {} + +pub fn main() {} +``` + +For more information about the `cfg` attribute, read the section on +[Conditional Compilation][conditional-compilation] in the Reference. + +[conditional-compilation]: https://doc.rust-lang.org/reference/conditional-compilation.html |