coverage: Build an "expansion tree" and use it to unexpand raw spans

1 files changed, 1 insertions, 47 deletions

diff --git a/compiler/rustc_mir_transform/src/coverage/unexpand.rs b/compiler/rustc_mir_transform/src/coverage/unexpand.rs
index cb861544736..922edd3cc4f 100644
--- a/compiler/rustc_mir_transform/src/coverage/unexpand.rs
+++ b/compiler/rustc_mir_transform/src/coverage/unexpand.rs
@@ -1,4 +1,4 @@
-use rustc_span::{ExpnKind, Span};
+use rustc_span::Span;
 
 /// Walks through the expansion ancestors of `original_span` to find a span that
 /// is contained in `body_span` and has the same [syntax context] as `body_span`.
@@ -7,49 +7,3 @@ pub(crate) fn unexpand_into_body_span(original_span: Span, body_span: Span) -> O
     // we can just delegate directly to `find_ancestor_inside_same_ctxt`.
     original_span.find_ancestor_inside_same_ctxt(body_span)
 }
-
-/// Walks through the expansion ancestors of `original_span` to find a span that
-/// is contained in `body_span` and has the same [syntax context] as `body_span`.
-///
-/// If the returned span represents a bang-macro invocation (e.g. `foo!(..)`),
-/// the returned symbol will be the name of that macro (e.g. `foo`).
-pub(crate) fn unexpand_into_body_span_with_expn_kind(
-    original_span: Span,
-    body_span: Span,
-) -> Option<(Span, Option<ExpnKind>)> {
-    let (span, prev) = unexpand_into_body_span_with_prev(original_span, body_span)?;
-
-    let expn_kind = prev.map(|prev| prev.ctxt().outer_expn_data().kind);
-
-    Some((span, expn_kind))
-}
-
-/// Walks through the expansion ancestors of `original_span` to find a span that
-/// is contained in `body_span` and has the same [syntax context] as `body_span`.
-/// The ancestor that was traversed just before the matching span (if any) is
-/// also returned.
-///
-/// For example, a return value of `Some((ancestor, Some(prev)))` means that:
-/// - `ancestor == original_span.find_ancestor_inside_same_ctxt(body_span)`
-/// - `prev.parent_callsite() == ancestor`
-///
-/// [syntax context]: rustc_span::SyntaxContext
-fn unexpand_into_body_span_with_prev(
-    original_span: Span,
-    body_span: Span,
-) -> Option<(Span, Option<Span>)> {
-    let mut prev = None;
-    let mut curr = original_span;
-
-    while !body_span.contains(curr) || !curr.eq_ctxt(body_span) {
-        prev = Some(curr);
-        curr = curr.parent_callsite()?;
-    }
-
-    debug_assert_eq!(Some(curr), original_span.find_ancestor_inside_same_ctxt(body_span));
-    if let Some(prev) = prev {
-        debug_assert_eq!(Some(curr), prev.parent_callsite());
-    }
-
-    Some((curr, prev))
-}