Auto merge of #111820 - matthiaskrgr:rollup-9sb2lw9, r=matthiaskrgr

Rollup of 5 pull requests

Successful merges:

 - #111745 (Fix overflow in error emitter)
 - #111770 (Read beta version from the version file if building from a source tarball)
 - #111797 (Migrate GUI colors test to original CSS color format)
 - #111809 (Unset MIRI_BLESS for mir-opt-level 4 miri tests)
 - #111817 (Migrate GUI colors test to original CSS color format)

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

2 files changed, 24 insertions, 22 deletions

diff --git a/compiler/rustc_errors/src/emitter.rs b/compiler/rustc_errors/src/emitter.rs
index 68e57de5e08..3e38d6afb0b 100644
--- a/compiler/rustc_errors/src/emitter.rs
+++ b/compiler/rustc_errors/src/emitter.rs
@@ -2303,22 +2303,25 @@ impl EmitterWriter {
 
         // Colorize addition/replacements with green.
         for &SubstitutionHighlight { start, end } in highlight_parts {
-            // Account for tabs when highlighting (#87972).
-            let tabs: usize = line_to_add
-                .chars()
-                .take(start)
-                .map(|ch| match ch {
-                    '\t' => 3,
-                    _ => 0,
-                })
-                .sum();
-            buffer.set_style_range(
-                *row_num,
-                max_line_num_len + 3 + start + tabs,
-                max_line_num_len + 3 + end + tabs,
-                Style::Addition,
-                true,
-            );
+            // This is a no-op for empty ranges
+            if start != end {
+                // Account for tabs when highlighting (#87972).
+                let tabs: usize = line_to_add
+                    .chars()
+                    .take(start)
+                    .map(|ch| match ch {
+                        '\t' => 3,
+                        _ => 0,
+                    })
+                    .sum();
+                buffer.set_style_range(
+                    *row_num,
+                    max_line_num_len + 3 + start + tabs,
+                    max_line_num_len + 3 + end + tabs,
+                    Style::Addition,
+                    true,
+                );
+            }
         }
         *row_num += 1;
     }
diff --git a/compiler/rustc_errors/src/lib.rs b/compiler/rustc_errors/src/lib.rs
index d5855527242..5a80024f19b 100644
--- a/compiler/rustc_errors/src/lib.rs
+++ b/compiler/rustc_errors/src/lib.rs
@@ -330,12 +330,11 @@ impl CodeSuggestion {
                     });
                     buf.push_str(&part.snippet);
                     let cur_hi = sm.lookup_char_pos(part.span.hi());
-                    if cur_hi.line == cur_lo.line && !part.snippet.is_empty() {
-                        // Account for the difference between the width of the current code and the
-                        // snippet being suggested, so that the *later* suggestions are correctly
-                        // aligned on the screen.
-                        acc += len - (cur_hi.col.0 - cur_lo.col.0) as isize;
-                    }
+                    // Account for the difference between the width of the current code and the
+                    // snippet being suggested, so that the *later* suggestions are correctly
+                    // aligned on the screen. Note that cur_hi and cur_lo can be on different
+                    // lines, so cur_hi.col can be smaller than cur_lo.col
+                    acc += len - (cur_hi.col.0 as isize - cur_lo.col.0 as isize);
                     prev_hi = cur_hi;
                     prev_line = sf.get_line(prev_hi.line - 1);
                     for line in part.snippet.split('\n').skip(1) {