refactor: Make -Ztrack-diagnostics emit like a note

Author: Muscraft

compiler/rustc_errors/src/emitter.rs

@@ -1392,6 +1392,7 @@ impl HumanEmitter {
         label: &str,
         override_style: Option<Style>,
     ) -> usize {
+        let line_offset = buffer.num_lines().saturating_sub(1);
         // The extra 5 ` ` is padding that's always needed to align to the `note: `:
         //
         //   error: message
@@ -1447,12 +1448,20 @@ impl HumanEmitter {
                 for (i, line) in lines.iter().enumerate() {
                     if i != 0 {
                         line_number += 1;
-                        buffer.append(line_number, &padding, Style::NoStyle);
+                        buffer.append(line_number + line_offset, &padding, Style::NoStyle);
                     }
-                    buffer.append(line_number, line, style_or_override(*style, override_style));
+                    buffer.append(
+                        line_number + line_offset,
+                        line,
+                        style_or_override(*style, override_style),
+                    );
                 }
             } else {
-                buffer.append(line_number, text, style_or_override(*style, override_style));
+                buffer.append(
+                    line_number + line_offset,
+                    text,
+                    style_or_override(*style, override_style),
+                );
             }
         }
         line_number
@@ -2470,8 +2479,9 @@ impl HumanEmitter {
             level,
             max_line_num_len,
             false,
-            !children.is_empty()
-                || suggestions.iter().any(|s| s.style != SuggestionStyle::CompletelyHidden),
+            emitted_at.is_some()
+                || (!children.is_empty()
+                    || suggestions.iter().any(|s| s.style != SuggestionStyle::CompletelyHidden)),
         ) {
             Ok(()) => {
                 let mut buffer = StyledBuffer::new();
@@ -2480,7 +2490,16 @@ impl HumanEmitter {
                     if !self.short_message {
                         self.draw_col_separator_no_space(&mut buffer, 0, max_line_num_len + 1);
                         let track = format!("-Ztrack-diagnostics: created at {tracked}");
-                        buffer.append(1, &track, Style::NoStyle);
+
+                        self.draw_secondary_message(
+                            &mut buffer,
+                            &[(DiagMessage::Str(Cow::Owned(track)), Style::NoStyle)],
+                            args,
+                            1,
+                            &Level::Note,
+                            max_line_num_len,
+                            children.first().is_some_and(|c| c.span.primary_spans().is_empty()),
+                        );
                     }
                 } else if !children.is_empty()
                     || suggestions.iter().any(|s| s.style != SuggestionStyle::CompletelyHidden)

tests/rustdoc-ui/track-diagnostics.stderr

@@ -4,7 +4,7 @@ error[E0308]: mismatched types
 LL | pub const S: A = B;
    |                  ^ expected `A`, found `B`
    |
--Ztrack-diagnostics: created at compiler/rustc_trait_selection/src/error_reporting/infer/mod.rs:LL:CC
+   = note: -Ztrack-diagnostics: created at compiler/rustc_trait_selection/src/error_reporting/infer/mod.rs:LL:CC
 
 error: aborting due to 1 previous error
 

tests/ui/track-diagnostics/track.stderr

@@ -4,23 +4,23 @@ error[E0425]: cannot find value `rust` in this scope
 LL |     break rust
    |           ^^^^ not found in this scope
    |
--Ztrack-diagnostics: created at compiler/rustc_resolve/src/late/diagnostics.rs:LL:CC
+   = note: -Ztrack-diagnostics: created at compiler/rustc_resolve/src/late/diagnostics.rs:LL:CC
 
 error[E0268]: `break` outside of a loop or labeled block
   --> $DIR/track.rs:LL:CC
    |
 LL |     break rust
    |     ^^^^^^^^^^ cannot `break` outside of a loop or labeled block
    |
--Ztrack-diagnostics: created at compiler/rustc_hir_typeck/src/loops.rs:LL:CC
+   = note: -Ztrack-diagnostics: created at compiler/rustc_hir_typeck/src/loops.rs:LL:CC
 
 error: internal compiler error: It looks like you're trying to break rust; would you like some ICE?
   --> $DIR/track.rs:LL:CC
    |
 LL |     break rust
    |     ^^^^^^^^^^
    |
--Ztrack-diagnostics: created at compiler/rustc_hir_typeck/src/lib.rs:LL:CC
+   = note: -Ztrack-diagnostics: created at compiler/rustc_hir_typeck/src/lib.rs:LL:CC
    = note: the compiler expectedly panicked. this is a feature.
    = note: we would appreciate a joke overview: https://github.com/rust-lang/rust/issues/43162#issuecomment-320764675
    = note: rustc $VERSION running on $TARGET

tests/ui/track-diagnostics/track2.stderr

@@ -7,7 +7,7 @@ LL |     let _moved @ _from = String::from("foo");
    |         |        value moved here
    |         value used here after move
    |
--Ztrack-diagnostics: created at compiler/rustc_borrowck/src/borrowck_errors.rs:LL:CC
+   = note: -Ztrack-diagnostics: created at compiler/rustc_borrowck/src/borrowck_errors.rs:LL:CC
 help: borrow this binding in the pattern to avoid moving the value
    |
 LL |     let ref _moved @ ref _from = String::from("foo");

tests/ui/track-diagnostics/track3.stderr

@@ -4,15 +4,15 @@ error[E0422]: cannot find struct, variant or union type `Blah` in this scope
 LL |     let _unimported = Blah { field: u8 };
    |                       ^^^^ not found in this scope
    |
--Ztrack-diagnostics: created at compiler/rustc_resolve/src/late/diagnostics.rs:LL:CC
+   = note: -Ztrack-diagnostics: created at compiler/rustc_resolve/src/late/diagnostics.rs:LL:CC
 
 error[E0423]: expected value, found builtin type `u8`
   --> $DIR/track3.rs:LL:CC
    |
 LL |     let _unimported = Blah { field: u8 };
    |                                     ^^ not a value
    |
--Ztrack-diagnostics: created at compiler/rustc_resolve/src/late/diagnostics.rs:LL:CC
+   = note: -Ztrack-diagnostics: created at compiler/rustc_resolve/src/late/diagnostics.rs:LL:CC
 
 error: aborting due to 2 previous errors
 

tests/ui/track-diagnostics/track4.stderr

@@ -4,7 +4,7 @@ error: missing `enum` for enum definition
 LL | pub onion {
    | ^^^^^^^^^
    |
--Ztrack-diagnostics: created at compiler/rustc_parse/src/parser/item.rs:LL:CC
+   = note: -Ztrack-diagnostics: created at compiler/rustc_parse/src/parser/item.rs:LL:CC
 help: add `enum` here to parse `onion` as an enum
    |
 LL | pub enum onion {

tests/ui/track-diagnostics/track5.stderr

@@ -4,7 +4,7 @@ error: unexpected closing delimiter: `}`
 LL | }
    | ^ unexpected closing delimiter
    |
--Ztrack-diagnostics: created at compiler/rustc_parse/src/lexer/tokentrees.rs:LL:CC
+   = note: -Ztrack-diagnostics: created at compiler/rustc_parse/src/lexer/tokentrees.rs:LL:CC
 
 error: aborting due to 1 previous error
 

tests/ui/track-diagnostics/track6.stderr

@@ -4,7 +4,7 @@ error[E0658]: specialization is unstable
 LL |     default fn bar() {}
    |     ^^^^^^^^^^^^^^^^^^^
    |
--Ztrack-diagnostics: created at compiler/rustc_ast_passes/src/feature_gate.rs:LL:CC
+   = note: -Ztrack-diagnostics: created at compiler/rustc_ast_passes/src/feature_gate.rs:LL:CC
    = note: see issue #31844 <https://github.com/rust-lang/rust/issues/31844> for more information
    = help: add `#![feature(specialization)]` to the crate attributes to enable
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date