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226edf64fa
Attribute values must be literals. The error you get when that doesn't hold is pretty bad, e.g.: ``` unexpected expression: 1 + 1 ``` You also get the same error if the attribute value is a literal, but an invalid literal, e.g.: ``` unexpected expression: "foo"suffix ``` This commit does two things. - Changes the error message to "attribute value must be a literal", which gives a better idea of what the problem is and how to fix it. It also no longer prints the invalid expression, because the carets below highlight it anyway. - Separates the "not a literal" case from the "invalid literal" case. Which means invalid literals now get the specific error at the literal level, rather than at the attribute level.
15 lines
423 B
Rust
15 lines
423 B
Rust
#![feature(rustc_attrs)]
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#[rustc_dummy = stringify!(a)] // OK
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macro_rules! bar {
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() => {};
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}
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// FIXME?: `bar` here expands before `stringify` has a chance to expand.
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// `#[rustc_dummy = ...]` is validated and dropped during expansion of `bar`,
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// the "attribute value must be a literal" error comes from the validation.
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#[rustc_dummy = stringify!(b)] //~ ERROR attribute value must be a literal
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bar!();
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fn main() {}
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