fix: Match rustc's annotation overlap

Author: Muscraft

src/renderer/mod.rs

@@ -1167,7 +1167,7 @@ impl Renderer {
         // otherwise the lines would end up needing to go over a message.
 
         let mut annotations = line_info.annotations.clone();
-        annotations.sort_by_key(|a| Reverse(a.start.display));
+        annotations.sort_by_key(|a| Reverse(a.start));
 
         // First, figure out where each label will be positioned.
         //
@@ -1249,8 +1249,8 @@ impl Renderer {
                 {
                     // If we're overlapping with an un-labelled annotation with the same span
                     // we can just merge them in the output
-                    if next.start.display == annotation.start.display
-                        && next.end.display == annotation.end.display
+                    if next.start == annotation.start
+                        && next.end == annotation.end
                         && !next.has_label()
                     {
                         continue;
@@ -1284,7 +1284,7 @@ impl Renderer {
                         && next.takes_space())
                         || (annotation.takes_space() && next.takes_space())
                         || (overlaps(next, annotation, l)
-                        && next.end.display <= annotation.end.display
+                        && next.end <= annotation.end
                         && next.has_label()
                         && p == 0)
                     // Avoid #42595.

src/renderer/source_map.rs

@@ -1,7 +1,7 @@
 use crate::renderer::{char_width, is_different, num_overlap, LineAnnotation, LineAnnotationType};
 use crate::{Annotation, AnnotationKind, Patch};
 use std::borrow::Cow;
-use std::cmp::{max, min};
+use std::cmp::{max, min, Ordering};
 use std::ops::Range;
 
 #[derive(Debug)]
@@ -294,12 +294,16 @@ impl<'a> SourceMap<'a> {
                     .map_or(ann.start.line, |(line, _)| line);
                 for line in ann.start.line + 1..until {
                     // Every `|` that joins the beginning of the span (`___^`) to the end (`|__^`).
-                    self.add_annotation_to_file(&mut annotated_line_infos, line, ann.as_line());
+                    self.add_annotation_to_file(&mut annotated_line_infos, line, ann.as_line(line));
                 }
                 let line_end = ann.end.line - 1;
                 let end_is_empty = self.get_line(line_end).map_or(false, |s| !filter(s));
                 if middle < line_end && !end_is_empty {
-                    self.add_annotation_to_file(&mut annotated_line_infos, line_end, ann.as_line());
+                    self.add_annotation_to_file(
+                        &mut annotated_line_infos,
+                        line_end,
+                        ann.as_line(line_end),
+                    );
                 }
             }
             self.add_annotation_to_file(&mut annotated_line_infos, end_ann.end.line, end_ann);
@@ -575,10 +579,16 @@ impl<'a> MultilineAnnotation<'a> {
         }
     }
 
-    pub(crate) fn as_line(&self) -> LineAnnotation<'a> {
+    pub(crate) fn as_line(&self, line: usize) -> LineAnnotation<'a> {
         LineAnnotation {
-            start: Loc::default(),
-            end: Loc::default(),
+            start: Loc {
+                line,
+                ..Default::default()
+            },
+            end: Loc {
+                line,
+                ..Default::default()
+            },
             kind: self.kind,
             label: None,
             annotation_type: LineAnnotationType::MultilineLine(self.depth),
@@ -604,7 +614,7 @@ pub(crate) struct AnnotatedLineInfo<'a> {
 }
 
 /// A source code location used for error reporting.
-#[derive(Clone, Copy, Debug, Default, PartialOrd, Ord, PartialEq, Eq)]
+#[derive(Clone, Copy, Debug, Default, Eq)]
 pub(crate) struct Loc {
     /// The (1-based) line number.
     pub(crate) line: usize,
@@ -616,6 +626,30 @@ pub(crate) struct Loc {
     pub(crate) byte: usize,
 }
 
+impl PartialEq for Loc {
+    fn eq(&self, other: &Self) -> bool {
+        self.line.eq(&other.line) && self.display.eq(&other.display) && self.char.eq(&other.char)
+    }
+}
+
+impl Ord for Loc {
+    fn cmp(&self, other: &Self) -> Ordering {
+        match self.line.cmp(&other.line) {
+            Ordering::Equal => match self.display.cmp(&other.display) {
+                Ordering::Equal => self.char.cmp(&other.char),
+                c => c,
+            },
+            c => c,
+        }
+    }
+}
+
+impl PartialOrd for Loc {
+    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
+        Some(self.cmp(other))
+    }
+}
+
 struct CursorLines<'a>(&'a str);
 
 impl CursorLines<'_> {

tests/rustc_tests.rs

@@ -3500,8 +3500,9 @@ error: extern blocks should be unsafe
   --> $DIR/unsafe-extern-suggestion.rs:6:1
    |
 LL |   extern "C" {
-   |   ^ help: needs `unsafe` before the extern keyword: `unsafe`
-   |  _|
+   |   ^
+   |   |
+   |  _help: needs `unsafe` before the extern keyword: `unsafe`
    | |
 LL | |     //~^ ERROR extern blocks should be unsafe [missing_unsafe_on_extern]
 LL | |     //~| WARN this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2024!