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Improve spans when splitting multi-char operator tokens for proc macros.

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This commit is contained in:
Nicholas Nethercote 2022-10-03 13:57:47 +11:00
parent 177b3d2d8b
commit 88dab8d9b3
14 changed files with 79 additions and 67 deletions
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16
compiler/rustc_expand/src/proc_macro_server.rs
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@ -115,8 +115,20 @@ impl FromInternal<(TokenStream, &mut Rustc<'_, '_>)> for Vec<TokenTree<TokenStre
// before that get `joint = true`.
let mut op = |s: &str| {
assert!(s.is_ascii());
trees.extend(s.bytes().enumerate().map(|(idx, ch)| {
let is_final = idx == s.len() - 1;
trees.extend(s.bytes().enumerate().map(|(i, ch)| {
let is_final = i == s.len() - 1;
// Split the token span into single chars. Unless the span
// is an unusual one, e.g. due to proc macro expansion. We
// determine this by assuming any span with a length that
// matches the operator length is a normal one, and any
// span with a different length is an unusual one.
let span = if (span.hi() - span.lo()).to_usize() == s.len() {
let lo = span.lo() + BytePos::from_usize(i);
let hi = lo + BytePos::from_usize(1);
span.with_lo(lo).with_hi(hi)
} else {
span
};
TokenTree::Punct(Punct { ch, joint: if is_final { joint } else { true }, span })
}));
};