rust/tests/ui/attributes/key-value-expansion.rs
Nicholas Nethercote 226edf64fa Improve an error involving attribute values.
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.
2023-12-12 15:54:25 +11:00

56 lines
1.2 KiB
Rust

// Regression tests for issue #55414, expansion happens in the value of a key-value attribute,
// and the expanded expression is more complex than simply a macro call.
// aux-build:key-value-expansion.rs
#![feature(rustc_attrs)]
extern crate key_value_expansion;
// Minimized test case.
macro_rules! bug {
($expr:expr) => {
#[rustc_dummy = $expr] // Any key-value attribute, not necessarily `doc`
struct S;
};
}
// Any expressions containing macro call `X` that's more complex than `X` itself.
// Parentheses will work.
bug!((column!())); //~ ERROR attribute value must be a literal
// Original test case.
macro_rules! bug {
() => {
bug!("bug" + stringify!(found)); //~ ERROR attribute value must be a literal
};
($test:expr) => {
#[doc = $test]
struct Test {}
};
}
bug!();
// Test case from #66804.
macro_rules! doc_comment {
($x:expr) => {
#[doc = $x]
extern {}
};
}
macro_rules! some_macro {
($t1: ty) => {
doc_comment! {format!("{coor}", coor = stringify!($t1)).as_str()}
//~^ ERROR attribute value must be a literal
};
}
some_macro!(u8);
fn main() {}