Auto merge of #146946 - matthiaskrgr:rollup-fsmrqez, r=matthiaskrgr

Rollup of 6 pull requests

Successful merges:

 - rust-lang/rust#146818 (constify {float}::total_cmp())
 - rust-lang/rust#146896 (rustc-dev-guide subtree update)
 - rust-lang/rust#146898 (Update books)
 - rust-lang/rust#146899 (Fix a crash/mislex when more than one frontmatter closing possibility is considered)
 - rust-lang/rust#146904 (rust-lang/rust#140368 Mutex/RwLock/ReentrantLock::data_ptr to be const fn)
 - rust-lang/rust#146907 (add regression test for issue 146537)

r? `@ghost`
`@rustbot` modify labels: rollup

1 files changed, 3 insertions, 1 deletions

diff --git a/compiler/rustc_lexer/src/lib.rs b/compiler/rustc_lexer/src/lib.rs
index c29ab569f47..f6790f7ed1e 100644
--- a/compiler/rustc_lexer/src/lib.rs
+++ b/compiler/rustc_lexer/src/lib.rs
@@ -599,14 +599,16 @@ impl Cursor<'_> {
             if potential_closing.is_none() {
                 // a less fortunate recovery if all else fails which finds any dashes preceded by whitespace
                 // on a standalone line. Might be wrong.
+                let mut base_index = 0;
                 while let Some(closing) = rest.find("---") {
                     let preceding_chars_start = rest[..closing].rfind("\n").map_or(0, |i| i + 1);
                     if rest[preceding_chars_start..closing].chars().all(is_horizontal_whitespace) {
                         // candidate found
-                        potential_closing = Some(closing);
+                        potential_closing = Some(closing + base_index);
                         break;
                     } else {
                         rest = &rest[closing + 3..];
+                        base_index += closing + 3;
                     }
                 }
             }