fix: Match how rustc handles annotating newlines

src/renderer/source_map.rs

@@ -73,20 +73,16 @@ impl<'a> SourceMap<'a> {
         let end_info = self
             .lines
             .iter()
-            .find(|info| info.end_byte > span.end.saturating_sub(1))
+            .find(|info| span.end >= info.start_byte && span.end < info.end_byte)
             .unwrap_or(self.lines.last().unwrap());
-        let (mut end_char_pos, end_display_pos) = end_info.line
+        let (end_char_pos, end_display_pos) = end_info.line
             [0..(span.end - end_info.start_byte).min(end_info.line.len())]
             .chars()
             .fold((0, 0), |(char_pos, byte_pos), c| {
                 let display = char_width(c);
                 (char_pos + 1, byte_pos + display)
             });
 
-        // correct the char pos if we are highlighting the end of a line
-        if (span.end - end_info.start_byte).saturating_sub(end_info.line.len()) > 0 {
-            end_char_pos += 1;
-        }
         let mut end = Loc {
             line: end_info.line_index,
             char: end_char_pos,

tests/formatter.rs

@@ -415,9 +415,9 @@ fn char_eol_annotate_char() {
 error: 
  --> file/path:3:1
   |
-3 | a
-  | ^
-4 | b
+3 | / a
+4 | | b
+  | |_^
 "#]];
     let renderer = Renderer::plain().anonymized_line_numbers(false);
     assert_data_eq!(renderer.render(input), expected);
@@ -437,10 +437,11 @@ fn char_eol_annotate_char_double_width() {
 error: 
  --> <current file>:1:2
   |
-1 | こん
-  |   ^^
-2 | にちは
-3 | 世界
+1 |   こん
+  |  ___^
+2 | | にちは
+  | |_^
+3 |   世界
 "#]];
 
     let renderer = Renderer::plain();
@@ -485,9 +486,10 @@ fn annotate_eol2() {
 error: 
  --> file/path:3:2
   |
-3 | a
-  |  ^
-4 | b
+3 |   a
+  |  __^
+4 | | b
+  | |_^
 "#]];
     let renderer = Renderer::plain().anonymized_line_numbers(false);
     assert_data_eq!(renderer.render(input), expected);
@@ -508,9 +510,10 @@ fn annotate_eol3() {
 error: 
  --> file/path:3:3
   |
-3 | a
-  |  ^
-4 | b
+3 |   a
+  |  __^
+4 | | b
+  | |_^
 "#]];
     let renderer = Renderer::plain().anonymized_line_numbers(false);
     assert_data_eq!(renderer.render(input), expected);
@@ -553,10 +556,11 @@ fn annotate_eol_double_width() {
 error: 
  --> <current file>:1:4
   |
-1 | こん
-  |     ^
-2 | にちは
-3 | 世界
+1 |   こん
+  |  _____^
+2 | | にちは
+  | |_^
+3 |   世界
 "#]];
 
     let renderer = Renderer::plain();
@@ -678,8 +682,8 @@ error:
 3 |   a
   |  __^
 4 | | b
-  | |__^
-5 |   c
+5 | | c
+  | |_^
 "#]];
     let renderer = Renderer::plain().anonymized_line_numbers(false);
     assert_data_eq!(renderer.render(input), expected);
@@ -728,8 +732,8 @@ error:
 3 |   a
   |  __^
 4 | | b
-  | |__^
-5 |   c
+5 | | c
+  | |_^
 "#]];
     let renderer = Renderer::plain().anonymized_line_numbers(false);
     assert_data_eq!(renderer.render(input), expected);
@@ -1532,6 +1536,7 @@ LL -     T
 LL -     :
 LL -     ?
 LL -     Sized
+LL + {
    |
 "#]];
     let renderer = Renderer::plain().anonymized_line_numbers(true);
@@ -1640,8 +1645,12 @@ LL | struct Wrapper<T>(T);
    |                this could be changed to `T: ?Sized`...
 help: consider removing the `?Sized` bound to make the type parameter `Sized`
    |
-LL ~ and 
-LL ~ + Send{
+LL - and where
+LL -     T
+LL -     :
+LL -     ?
+LL -     Sized
+LL + and + Send{
    |
 "#]];
     let renderer = Renderer::plain().anonymized_line_numbers(true);