Rollup merge of rust-lang#144864 - Muscraft:no-source-fixes, r=jieyouxu

No source fixes

This PR started as a fix for a rendering bug that [got noticed in rust-lang#143661](rust-lang#143661 (comment)), but turned into a fix for any rendering bugs related to files with no source.
- Don't add an end column separator after a file with no source
- Add column separator before secondary messages with no source
- Render continuation between no source labels

Before
```
error[E0423]: expected function, tuple struct or tuple variant, found struct `std::collections::HashMap`
   ╭▸ $DIR/multi-suggestion.rs:17:13
   │
LL │     let _ = std::collections::HashMap();
   │             ━━━━━━━━━━━━━━━━━━━━━━━━━━━
   ╭▸ $SRC_DIR/std/src/collections/hash/map.rs:LL:COL
   │
   ╰ note: `std::collections::HashMap` defined here
   ╰╴
note: constructor is not visible here due to private fields
   ╭▸ $SRC_DIR/alloc/src/boxed.rs:LL:COL
   │
   ╰ note: private field
   │
   ╰ note: private field
```

After
```
error[E0423]: expected function, tuple struct or tuple variant, found struct `std::collections::HashMap`
   ╭▸ $DIR/multi-suggestion.rs:17:13
   │
LL │     let _ = std::collections::HashMap();
   │             ━━━━━━━━━━━━━━━━━━━━━━━━━━━
   ╰╴
   ╭▸ $SRC_DIR/std/src/collections/hash/map.rs:LL:COL
   │
   ╰ note: `std::collections::HashMap` defined here
note: constructor is not visible here due to private fields
   ╭▸ $SRC_DIR/alloc/src/boxed.rs:LL:COL
   │
   ├ note: private field
   │
   ╰ note: private field
```

Note: This PR also makes it so `rustc` and `annotate-snippets` match in these cases

Author: Zalathar

compiler/rustc_errors/src/emitter.rs

@@ -1462,7 +1462,7 @@ impl HumanEmitter {
         max_line_num_len: usize,
         is_secondary: bool,
         is_cont: bool,
-    ) -> io::Result<()> {
+    ) -> io::Result<CodeWindowStatus> {
         let mut buffer = StyledBuffer::new();
 
         if !msp.has_primary_spans() && !msp.has_span_labels() && is_secondary && !self.short_message
@@ -1575,12 +1575,14 @@ impl HumanEmitter {
         }
         let mut annotated_files = FileWithAnnotatedLines::collect_annotations(self, args, msp);
         trace!("{annotated_files:#?}");
+        let mut code_window_status = CodeWindowStatus::Open;
 
         // Make sure our primary file comes first
         let primary_span = msp.primary_span().unwrap_or_default();
         let (Some(sm), false) = (self.sm.as_ref(), primary_span.is_dummy()) else {
             // If we don't have span information, emit and exit
-            return emit_to_destination(&buffer.render(), level, &mut self.dst, self.short_message);
+            return emit_to_destination(&buffer.render(), level, &mut self.dst, self.short_message)
+                .map(|_| code_window_status);
         };
         let primary_lo = sm.lookup_char_pos(primary_span.lo());
         if let Ok(pos) =
@@ -1589,6 +1591,9 @@ impl HumanEmitter {
             annotated_files.swap(0, pos);
         }
 
+        // An end column separator should be emitted when a file with with a
+        // source, is followed by one without a source
+        let mut col_sep_before_no_show_source = false;
         let annotated_files_len = annotated_files.len();
         // Print out the annotate source lines that correspond with the error
         for (file_idx, annotated_file) in annotated_files.into_iter().enumerate() {
@@ -1599,6 +1604,26 @@ impl HumanEmitter {
                 &annotated_file.file,
             ) {
                 if !self.short_message {
+                    // Add an end column separator when a file without a source
+                    // comes after one with a source
+                    //    ╭▸ $DIR/deriving-meta-unknown-trait.rs:1:10
+                    //    │
+                    // LL │ #[derive(Eqr)]
+                    //    │          ━━━
+                    //    ╰╴ (<- It prints *this* line)
+                    //    ╭▸ $SRC_DIR/core/src/cmp.rs:356:0
+                    //    │
+                    //    ╰╴note: similarly named derive macro `Eq` defined here
+                    if col_sep_before_no_show_source {
+                        let buffer_msg_line_offset = buffer.num_lines();
+                        self.draw_col_separator_end(
+                            &mut buffer,
+                            buffer_msg_line_offset,
+                            max_line_num_len + 1,
+                        );
+                    }
+                    col_sep_before_no_show_source = false;
+
                     // We'll just print an unannotated message.
                     for (annotation_id, line) in annotated_file.lines.iter().enumerate() {
                         let mut annotations = line.annotations.clone();
@@ -1639,29 +1664,42 @@ impl HumanEmitter {
                             }
                             line_idx += 1;
                         }
-                        for (label, is_primary) in labels.into_iter() {
+                        if is_cont
+                            && file_idx == annotated_files_len - 1
+                            && annotation_id == annotated_file.lines.len() - 1
+                            && !labels.is_empty()
+                        {
+                            code_window_status = CodeWindowStatus::Closed;
+                        }
+                        let labels_len = labels.len();
+                        for (label_idx, (label, is_primary)) in labels.into_iter().enumerate() {
                             let style = if is_primary {
                                 Style::LabelPrimary
                             } else {
                                 Style::LabelSecondary
                             };
-                            let pipe = self.col_separator();
-                            buffer.prepend(line_idx, &format!(" {pipe}"), Style::LineNumber);
-                            for _ in 0..max_line_num_len {
-                                buffer.prepend(line_idx, " ", Style::NoStyle);
-                            }
+                            self.draw_col_separator_no_space(
+                                &mut buffer,
+                                line_idx,
+                                max_line_num_len + 1,
+                            );
                             line_idx += 1;
-                            let chr = self.note_separator();
-                            buffer.append(line_idx, &format!(" {chr} note: "), style);
-                            for _ in 0..max_line_num_len {
-                                buffer.prepend(line_idx, " ", Style::NoStyle);
-                            }
+                            self.draw_note_separator(
+                                &mut buffer,
+                                line_idx,
+                                max_line_num_len + 1,
+                                label_idx != labels_len - 1,
+                            );
+                            buffer.append(line_idx, "note", Style::MainHeaderMsg);
+                            buffer.append(line_idx, ": ", Style::NoStyle);
                             buffer.append(line_idx, label, style);
                             line_idx += 1;
                         }
                     }
                 }
                 continue;
+            } else {
+                col_sep_before_no_show_source = true;
             }
 
             // print out the span location and spacer before we print the annotated source
@@ -1976,7 +2014,7 @@ impl HumanEmitter {
         // final step: take our styled buffer, render it, then output it
         emit_to_destination(&buffer.render(), level, &mut self.dst, self.short_message)?;
 
-        Ok(())
+        Ok(code_window_status)
     }
 
     fn column_width(&self, code_offset: usize) -> usize {
@@ -2491,7 +2529,7 @@ impl HumanEmitter {
             !children.is_empty()
                 || suggestions.iter().any(|s| s.style != SuggestionStyle::CompletelyHidden),
         ) {
-            Ok(()) => {
+            Ok(code_window_status) => {
                 if !children.is_empty()
                     || suggestions.iter().any(|s| s.style != SuggestionStyle::CompletelyHidden)
                 {
@@ -2502,7 +2540,7 @@ impl HumanEmitter {
                         {
                             // We'll continue the vertical bar to point into the next note.
                             self.draw_col_separator_no_space(&mut buffer, 0, max_line_num_len + 1);
-                        } else {
+                        } else if matches!(code_window_status, CodeWindowStatus::Open) {
                             // We'll close the vertical bar to visually end the code window.
                             self.draw_col_separator_end(&mut buffer, 0, max_line_num_len + 1);
                         }
@@ -2829,10 +2867,11 @@ impl HumanEmitter {
         }
     }
 
-    fn note_separator(&self) -> char {
+    fn note_separator(&self, is_cont: bool) -> &'static str {
         match self.theme {
-            OutputTheme::Ascii => '=',
-            OutputTheme::Unicode => '╰',
+            OutputTheme::Ascii => "= ",
+            OutputTheme::Unicode if is_cont => "├ ",
+            OutputTheme::Unicode => "╰ ",
         }
     }
 
@@ -2945,11 +2984,7 @@ impl HumanEmitter {
         col: usize,
         is_cont: bool,
     ) {
-        let chr = match self.theme {
-            OutputTheme::Ascii => "= ",
-            OutputTheme::Unicode if is_cont => "├ ",
-            OutputTheme::Unicode => "╰ ",
-        };
+        let chr = self.note_separator(is_cont);
         buffer.puts(line, col, chr, Style::LineNumber);
     }
 
@@ -3050,6 +3085,12 @@ enum DisplaySuggestion {
     Add,
 }
 
+#[derive(Clone, Copy, Debug)]
+enum CodeWindowStatus {
+    Closed,
+    Open,
+}
+
 impl FileWithAnnotatedLines {
     /// Preprocess all the annotations so that they are grouped by file and by line number
     /// This helps us quickly iterate over the whole message (including secondary file spans)

tests/ui/async-await/in-trait/dont-project-to-specializable-projection.stderr

@@ -25,6 +25,7 @@ error[E0599]: no method named `poll` found for struct `Pin<&mut impl Future<Outp
    |
 LL |         match fut.as_mut().poll(ctx) {
    |                            ^^^^ method not found in `Pin<&mut impl Future<Output = ()>>`
+   |
   --> $SRC_DIR/core/src/future/future.rs:LL:COL
    |
    = note: the method is available for `Pin<&mut impl Future<Output = ()>>` here

tests/ui/c-variadic/issue-86053-1.stderr

@@ -57,10 +57,10 @@ error[E0412]: cannot find type `F` in this scope
    |
 LL |     self , ... ,   self ,   self , ... ) where F : FnOnce ( & 'a & 'b usize ) {
    |                                                ^
+   |
   --> $SRC_DIR/core/src/ops/function.rs:LL:COL
    |
    = note: similarly named trait `Fn` defined here
-   |
 help: a trait with a similar name exists
    |
 LL |     self , ... ,   self ,   self , ... ) where Fn : FnOnce ( & 'a & 'b usize ) {

tests/ui/closures/issue-78720.stderr

@@ -9,10 +9,10 @@ error[E0412]: cannot find type `F` in this scope
    |
 LL |     _func: F,
    |            ^
+   |
   --> $SRC_DIR/core/src/ops/function.rs:LL:COL
    |
    = note: similarly named trait `Fn` defined here
-   |
 help: a trait with a similar name exists
    |
 LL |     _func: Fn,

tests/ui/closures/issue-90871.stderr

@@ -3,6 +3,7 @@ error[E0412]: cannot find type `n` in this scope
    |
 LL |     type_ascribe!(2, n([u8; || 1]))
    |                      ^ help: a trait with a similar name exists: `Fn`
+   |
   --> $SRC_DIR/core/src/ops/function.rs:LL:COL
    |
    = note: similarly named trait `Fn` defined here

tests/ui/const-generics/generic_const_exprs/expected-type-of-closure-body-to-be-a-closure-or-coroutine-ice-113776.stderr

@@ -3,10 +3,10 @@ error[E0412]: cannot find type `F` in this scope
    |
 LL |          let f: F = async { 1 };
    |                 ^
+   |
   --> $SRC_DIR/core/src/ops/function.rs:LL:COL
    |
    = note: similarly named trait `Fn` defined here
-   |
 help: a trait with a similar name exists
    |
 LL |          let f: Fn = async { 1 };

tests/ui/consts/issue-89088.stderr

@@ -6,6 +6,7 @@ LL | const FOO: &A = &A::Field(Cow::Borrowed("foo"));
 ...
 LL |         FOO => todo!(),
    |         ^^^ constant of non-structural type
+   |
   --> $SRC_DIR/alloc/src/borrow.rs:LL:COL
    |
    = note: `Cow<'_, str>` must be annotated with `#[derive(PartialEq)]` to be usable in patterns

tests/ui/derives/deriving-meta-unknown-trait.stderr

@@ -3,6 +3,7 @@ error: cannot find derive macro `Eqr` in this scope
    |
 LL | #[derive(Eqr)]
    |          ^^^ help: a derive macro with a similar name exists: `Eq`
+   |
   --> $SRC_DIR/core/src/cmp.rs:LL:COL
    |
    = note: similarly named derive macro `Eq` defined here
@@ -12,6 +13,7 @@ error: cannot find derive macro `Eqr` in this scope
    |
 LL | #[derive(Eqr)]
    |          ^^^ help: a derive macro with a similar name exists: `Eq`
+   |
   --> $SRC_DIR/core/src/cmp.rs:LL:COL
    |
    = note: similarly named derive macro `Eq` defined here

tests/ui/did_you_mean/println-typo.stderr

@@ -3,6 +3,7 @@ error: cannot find macro `prinltn` in this scope
    |
 LL |     prinltn!();
    |     ^^^^^^^ help: a macro with a similar name exists: `println`
+   |
   --> $SRC_DIR/std/src/macros.rs:LL:COL
    |
    = note: similarly named macro `println` defined here

tests/ui/impl-trait/call_method_without_import.no_import.stderr

@@ -3,6 +3,7 @@ error[E0599]: no method named `fmt` found for opaque type `impl Debug` in the cu
    |
 LL |         x.fmt(f);
    |           ^^^ method not found in `impl Debug`
+   |
   --> $SRC_DIR/core/src/fmt/mod.rs:LL:COL
    |
    = note: the method is available for `impl Debug` here