bjoernager/rust
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Remove NtPat.

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The one notable test change is `tests/ui/macros/trace_faulty_macros.rs`.
This commit removes the complicated `Interpolated` handling in
`expected_expression_found` that results in a longer error message. But
I think the new, shorter message is actually an improvement.

The original complaint was in #71039, when the error message started
with "error: expected expression, found `1 + 1`". That was confusing
because `1 + 1` is an expression. Other than that, the reporter said
"the whole error message is not too bad if you ignore the first line".

Subsequently, extra complexity and wording was added to the error
message. But I don't think the extra wording actually helps all that
much. In particular, it still says of the `1+1` that "this is expected
to be expression". This repeats the problem from the original complaint!

This commit removes the extra complexity, reverting to a simpler error
message. This is primarily because the traversal is a pain without
`Interpolated` tokens. Nonetheless, I think the error message is
*improved*. It now starts with "expected expression, found `pat`
metavariable", which is much clearer and the real problem. It also
doesn't say anything specific about `1+1`, which is good, because the
`1+1` isn't really relevant to the error -- it's the `$e:pat` that's
important.
This commit is contained in:
Nicholas Nethercote 2024-04-18 12:44:11 +10:00
parent 00f245915b
commit ef1114a964
16 changed files with 77 additions and 102 deletions
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18
compiler/rustc_expand/src/mbe/transcribe.rs
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@ -279,9 +279,9 @@ pub(super) fn transcribe<'a>(
if let Some(cur_matched) = lookup_cur_matched(ident, interp, &repeats) {
// We wrap the tokens in invisible delimiters, unless they are already wrapped
// in invisible delimiters with the same `MetaVarKind`. Because some proc
// macros can't multiple layers of invisible delimiters of the same
// macros can't handle multiple layers of invisible delimiters of the same
// `MetaVarKind`. This loses some span info, though it hopefully won't matter.
let mut mk_delimited = |mv_kind, mut stream: TokenStream| {
let mut mk_delimited = |mk_span, mv_kind, mut stream: TokenStream| {
if stream.len() == 1 {
let tree = stream.iter().next().unwrap();
if let TokenTree::Delimited(_, _, delim, inner) = tree
@ -295,6 +295,7 @@ pub(super) fn transcribe<'a>(
// Emit as a token stream within `Delimiter::Invisible` to maintain
// parsing priorities.
marker.visit_span(&mut sp);
with_metavar_spans(|mspans| mspans.insert(mk_span, sp));
// Both the open delim and close delim get the same span, which covers the
// `$foo` in the decl macro RHS.
TokenTree::Delimited(
@ -322,12 +323,21 @@ pub(super) fn transcribe<'a>(
let kind = token::NtLifetime(*ident, *is_raw);
TokenTree::token_alone(kind, sp)
}
MatchedSingle(ParseNtResult::Pat(pat, pat_kind)) => mk_delimited(
pat.span,
MetaVarKind::Pat(*pat_kind),
TokenStream::from_ast(pat),
),
MatchedSingle(ParseNtResult::Ty(ty)) => {
let is_path = matches!(&ty.kind, TyKind::Path(None, _path));
mk_delimited(MetaVarKind::Ty { is_path }, TokenStream::from_ast(ty))
mk_delimited(
ty.span,
MetaVarKind::Ty { is_path },
TokenStream::from_ast(ty),
)
}
MatchedSingle(ParseNtResult::Vis(vis)) => {
mk_delimited(MetaVarKind::Vis, TokenStream::from_ast(vis))
mk_delimited(vis.span, MetaVarKind::Vis, TokenStream::from_ast(vis))
}
MatchedSingle(ParseNtResult::Nt(nt)) => {
// Other variables are emitted into the output stream as groups with