Simplify the pattern unpeeling in lower_pattern_range_endpoint · rust-lang/rust@2fb1261 (original) (raw)
`@@ -161,35 +161,34 @@ impl<'a, 'tcx> PatCtxt<'a, 'tcx> {
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`) -> Result<Option<PatRangeBoundary<'tcx>>, ErrorGuaranteed> {
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`let Some(expr) = expr else { return Ok(None) };
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``
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let (kind, ascr, inline_const) = match self.lower_lit(expr) {
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``
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PatKind::ExpandedConstant { subpattern, def_id, is_inline: true } => {
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``
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(subpattern.kind, None, def_id.as_local())
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``
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}
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``
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PatKind::ExpandedConstant { subpattern, is_inline: false, .. } => {
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``
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(subpattern.kind, None, None)
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``
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}
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``
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PatKind::AscribeUserType { ascription, subpattern: box Pat { kind, .. } } => {
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``
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(kind, Some(ascription), None)
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``
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}
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``
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kind => (kind, None, None),
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``
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};
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``
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let value = match kind {
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``
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PatKind::Constant { value } => value,
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``
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PatKind::ExpandedConstant { subpattern, .. }
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``
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if let PatKind::Constant { value } = subpattern.kind =>
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{
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value
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``
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}
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``
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_ => {
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``
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let msg = format!(
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"found bad range pattern endpoint {expr:?} outside of error recovery"
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``
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);
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``
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return Err(self.tcx.dcx().span_delayed_bug(expr.span, msg));
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`` +
// Lower the endpoint into a temporary PatKind that will then be
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`+
// deconstructed to obtain the constant value and other data.
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`+
let mut kind: PatKind<'tcx> = self.lower_lit(expr);
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+
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// Unpeel any ascription or inline-const wrapper nodes.
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loop {
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match kind {
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PatKind::AscribeUserType { ascription, subpattern } => {
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ascriptions.push(ascription);
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kind = subpattern.kind;
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}
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PatKind::ExpandedConstant { is_inline, def_id, subpattern } => {
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if is_inline {
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inline_consts.extend(def_id.as_local());
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}
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kind = subpattern.kind;
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}
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_ => break,
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`}
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}
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``
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// The unpeeled kind should now be a constant, giving us the endpoint value.
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let PatKind::Constant { value } = kind else {
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let msg =
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format!("found bad range pattern endpoint {expr:?} outside of error recovery");
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return Err(self.tcx.dcx().span_delayed_bug(expr.span, msg));
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`};
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``
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``
`-
ascriptions.extend(ascr);
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``
`-
inline_consts.extend(inline_const);
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`Ok(Some(PatRangeBoundary::Finite(value)))
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`}
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``