1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
|
use rustc_ast::tokenstream::{TokenStream, TokenTree};
use rustc_expand::base::{self, ExtCtxt};
use rustc_span::symbol::kw;
use rustc_span::Span;
pub fn expand_trace_macros(
cx: &mut ExtCtxt<'_>,
sp: Span,
tt: TokenStream,
) -> Box<dyn base::MacResult + 'static> {
let mut cursor = tt.into_trees();
let mut err = false;
let value = match &cursor.next() {
Some(TokenTree::Token(token)) if token.is_keyword(kw::True) => true,
Some(TokenTree::Token(token)) if token.is_keyword(kw::False) => false,
_ => {
err = true;
false
}
};
err |= cursor.next().is_some();
if err {
cx.span_err(sp, "trace_macros! accepts only `true` or `false`")
} else {
cx.set_trace_macros(value);
}
base::DummyResult::any_valid(sp)
}
|
