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rustc_span: More consistent span combination operations

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This commit is contained in:
Vadim Petrochenkov 2024-01-05 17:30:14 +03:00
parent fb1cca2937
commit 508d1ff7d8
3 changed files with 50 additions and 52 deletions
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2
compiler/rustc_parse/src/parser/expr.rs
View file

@ -2489,7 +2489,7 @@ impl<'a> Parser<'a> {
}
ExprKind::Block(_, None) => {
this.dcx().emit_err(errors::IfExpressionMissingCondition {
if_span: lo.shrink_to_hi(),
if_span: lo.with_neighbor(cond.span).shrink_to_hi(),
block_span: self.sess.source_map().start_point(cond_span),
});
std::mem::replace(&mut cond, this.mk_expr_err(cond_span.shrink_to_hi()))

4
compiler/rustc_parse/src/parser/item.rs
View file

@ -2118,7 +2118,7 @@ impl<'a> Parser<'a> {
Applicability::MaybeIncorrect,
);
err.span_suggestion(
span.shrink_to_hi(),
span.with_neighbor(self.token.span).shrink_to_hi(),
"add a semicolon",
';',
Applicability::MaybeIncorrect,
@ -2632,7 +2632,7 @@ impl<'a> Parser<'a> {
let is_name_required = match this.token.kind {
token::DotDotDot => false,
_ => req_name(this.token.span.edition()),
_ => req_name(this.token.span.with_neighbor(this.prev_token.span).edition()),
};
let (pat, ty) = if is_name_required || this.is_named_param() {
debug!("parse_param_general parse_pat (is_name_required:{})", is_name_required);

96
compiler/rustc_span/src/lib.rs
View file

@ -826,6 +826,39 @@ impl Span {
)
}
/// Prepare two spans to a combine operation like `to` or `between`.
/// FIXME: consider using declarative macro metavariable spans for the given spans if they are
/// better suitable for combining (#119412).
fn prepare_to_combine(
a_orig: Span,
b_orig: Span,
) -> Result<(SpanData, SpanData, Option<LocalDefId>), Span> {
let (a, b) = (a_orig.data(), b_orig.data());
if a.ctxt != b.ctxt {
// Context mismatches usually happen when procedural macros combine spans copied from
// the macro input with spans produced by the macro (`Span::*_site`).
// In that case we consider the combined span to be produced by the macro and return
// the original macro-produced span as the result.
// Otherwise we just fall back to returning the first span.
// Combining locations typically doesn't make sense in case of context mismatches.
// `is_root` here is a fast path optimization.
let a_is_callsite = a.ctxt.is_root() || a.ctxt == b.span().source_callsite().ctxt();
return Err(if a_is_callsite { b_orig } else { a_orig });
}
let parent = if a.parent == b.parent { a.parent } else { None };
Ok((a, b, parent))
}
/// This span, but in a larger context, may switch to the metavariable span if suitable.
pub fn with_neighbor(self, neighbor: Span) -> Span {
match Span::prepare_to_combine(self, neighbor) {
Ok((this, ..)) => Span::new(this.lo, this.hi, this.ctxt, this.parent),
Err(_) => self,
}
}
/// Returns a `Span` that would enclose both `self` and `end`.
///
/// Note that this can also be used to extend the span "backwards":
@ -837,26 +870,12 @@ impl Span {
/// ^^^^^^^^^^^^^^^^^^^^
/// ```
pub fn to(self, end: Span) -> Span {
let span_data = self.data();
let end_data = end.data();
// FIXME(jseyfried): `self.ctxt` should always equal `end.ctxt` here (cf. issue #23480).
// Return the macro span on its own to avoid weird diagnostic output. It is preferable to
// have an incomplete span than a completely nonsensical one.
if span_data.ctxt != end_data.ctxt {
if span_data.ctxt.is_root() {
return end;
} else if end_data.ctxt.is_root() {
return self;
match Span::prepare_to_combine(self, end) {
Ok((from, to, parent)) => {
Span::new(cmp::min(from.lo, to.lo), cmp::max(from.hi, to.hi), from.ctxt, parent)
}
// Both spans fall within a macro.
// FIXME(estebank): check if it is the *same* macro.
Err(fallback) => fallback,
}
Span::new(
cmp::min(span_data.lo, end_data.lo),
cmp::max(span_data.hi, end_data.hi),
if span_data.ctxt.is_root() { end_data.ctxt } else { span_data.ctxt },
if span_data.parent == end_data.parent { span_data.parent } else { None },
)
}
/// Returns a `Span` between the end of `self` to the beginning of `end`.
@ -867,14 +886,12 @@ impl Span {
/// ^^^^^^^^^^^^^
/// ```
pub fn between(self, end: Span) -> Span {
let span = self.data();
let end = end.data();
Span::new(
span.hi,
end.lo,
if end.ctxt.is_root() { end.ctxt } else { span.ctxt },
if span.parent == end.parent { span.parent } else { None },
)
match Span::prepare_to_combine(self, end) {
Ok((from, to, parent)) => {
Span::new(cmp::min(from.hi, to.hi), cmp::max(from.lo, to.lo), from.ctxt, parent)
}
Err(fallback) => fallback,
}
}
/// Returns a `Span` from the beginning of `self` until the beginning of `end`.
@ -885,31 +902,12 @@ impl Span {
/// ^^^^^^^^^^^^^^^^^
/// ```
pub fn until(self, end: Span) -> Span {
// Most of this function's body is copied from `to`.
// We can't just do `self.to(end.shrink_to_lo())`,
// because to also does some magic where it uses min/max so
// it can handle overlapping spans. Some advanced mis-use of
// `until` with different ctxts makes this visible.
let span_data = self.data();
let end_data = end.data();
// FIXME(jseyfried): `self.ctxt` should always equal `end.ctxt` here (cf. issue #23480).
// Return the macro span on its own to avoid weird diagnostic output. It is preferable to
// have an incomplete span than a completely nonsensical one.
if span_data.ctxt != end_data.ctxt {
if span_data.ctxt.is_root() {
return end;
} else if end_data.ctxt.is_root() {
return self;
match Span::prepare_to_combine(self, end) {
Ok((from, to, parent)) => {
Span::new(cmp::min(from.lo, to.lo), cmp::max(from.lo, to.lo), from.ctxt, parent)
}
// Both spans fall within a macro.
// FIXME(estebank): check if it is the *same* macro.
Err(fallback) => fallback,
}
Span::new(
span_data.lo,
end_data.lo,
if end_data.ctxt.is_root() { end_data.ctxt } else { span_data.ctxt },
if span_data.parent == end_data.parent { span_data.parent } else { None },
)
}
pub fn from_inner(self, inner: InnerSpan) -> Span {