Auto merge of #127326 - matthiaskrgr:rollup-kz7vd3w, r=matthiaskrgr

Rollup of 9 pull requests

Successful merges:

 - #123043 (Disable dead variant removal for `#[repr(C)]` enums.)
 - #126405 (Migrate some rustc_builtin_macros to SessionDiagnostic)
 - #127037 (Remove some duplicated tests)
 - #127283 (Reject SmartPointer constructions not serving the purpose)
 - #127301 (Tweak some structured suggestions to be more verbose and accurate)
 - #127307 (Allow to have different types for arguments of `Rustc::remap_path_prefix`)
 - #127309 (jsondocck: add `$FILE` built-in variable)
 - #127314 (Trivial update on tidy bless note)
 - #127319 (Remove a use of `StructuredDiag`, which is incompatible with automatic error tainting and error translations)

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

1 files changed, 20 insertions, 3 deletions

diff --git a/compiler/rustc_errors/src/emitter.rs b/compiler/rustc_errors/src/emitter.rs
index 45118bcc58a..aa47ca16676 100644
--- a/compiler/rustc_errors/src/emitter.rs
+++ b/compiler/rustc_errors/src/emitter.rs
@@ -2273,9 +2273,26 @@ impl HumanEmitter {
                     &normalize_whitespace(last_line),
                     Style::NoStyle,
                 );
-                buffer.puts(*row_num, 0, &self.maybe_anonymized(line_num), Style::LineNumber);
-                buffer.puts(*row_num, max_line_num_len + 1, "+ ", Style::Addition);
-                buffer.append(*row_num, &normalize_whitespace(line_to_add), Style::NoStyle);
+                if !line_to_add.trim().is_empty() {
+                    // Check if after the removal, the line is left with only whitespace. If so, we
+                    // will not show an "addition" line, as removing the whole line is what the user
+                    // would really want.
+                    // For example, for the following:
+                    //   |
+                    // 2 -     .await
+                    // 2 +     (note the left over whitepsace)
+                    //   |
+                    // We really want
+                    //   |
+                    // 2 -     .await
+                    //   |
+                    // *row_num -= 1;
+                    buffer.puts(*row_num, 0, &self.maybe_anonymized(line_num), Style::LineNumber);
+                    buffer.puts(*row_num, max_line_num_len + 1, "+ ", Style::Addition);
+                    buffer.append(*row_num, &normalize_whitespace(line_to_add), Style::NoStyle);
+                } else {
+                    *row_num -= 1;
+                }
             } else {
                 *row_num -= 2;
             }