Don't emit empty notes

compiler/rustc_errors/src/emitter.rs

@@ -1431,25 +1431,27 @@ impl EmitterWriter {
                         };
                         for (i, annotation) in annotations.into_iter().enumerate() {
                             if let Some(label) = &annotation.label {
-                                let style = if annotation.is_primary {
+                                if !label.is_empty() {
-                                    Style::LabelPrimary
+                                    let style = if annotation.is_primary {
-                                } else {
+                                        Style::LabelPrimary
-                                    Style::LabelSecondary
+                                    } else {
-                                };
+                                        Style::LabelSecondary
-                                if annotation_id == 0 {
+                                    };
-                                    buffer.prepend(line_idx, " |", Style::LineNumber);
+                                    if annotation_id == 0 {
-                                    for _ in 0..max_line_num_len {
+                                        buffer.prepend(line_idx, " |", Style::LineNumber);
-                                        buffer.prepend(line_idx, " ", Style::NoStyle);
+                                        for _ in 0..max_line_num_len {
+                                            buffer.prepend(line_idx, " ", Style::NoStyle);
+                                        }
+                                        line_idx += 1;
+                                        buffer.append(line_idx + i, " = note: ", style);
+                                        for _ in 0..max_line_num_len {
+                                            buffer.prepend(line_idx, " ", Style::NoStyle);
+                                        }
+                                    } else {
+                                        buffer.append(line_idx + i, ": ", style);
                                     }
-                                    line_idx += 1;
+                                    buffer.append(line_idx + i, label, style);
-                                    buffer.append(line_idx + i, " = note: ", style);
-                                    for _ in 0..max_line_num_len {
-                                        buffer.prepend(line_idx, " ", Style::NoStyle);
-                                    }
-                                } else {
-                                    buffer.append(line_idx + i, ": ", style);
                                 }
-                                buffer.append(line_idx + i, label, style);
                             }
                         }
                     }

src/test/ui/error-codes/E0004-2.stderr

@@ -6,8 +6,6 @@ LL |     match x { }
    |
 note: `Option<i32>` defined here
   --> $SRC_DIR/core/src/option.rs:LL:COL
-   |
-   = note: 
 $SRC_DIR/core/src/option.rs:LL:COL: not covered
 $SRC_DIR/core/src/option.rs:LL:COL: not covered
    = note: the matched value is of type `Option<i32>`

src/test/ui/error-codes/E0005.stderr

@@ -8,8 +8,6 @@ LL |     let Some(y) = x;
    = note: for more information, visit https://doc.rust-lang.org/book/ch18-02-refutability.html
 note: `Option<i32>` defined here
   --> $SRC_DIR/core/src/option.rs:LL:COL
-   |
-   = note: 
 $SRC_DIR/core/src/option.rs:LL:COL: not covered
    = note: the matched value is of type `Option<i32>`
 help: you might want to use `if let` to ignore the variant that isn't matched

src/test/ui/error-codes/E0297.stderr

@@ -6,8 +6,6 @@ LL |     for Some(x) in xs {}
    |
 note: `Option<i32>` defined here
   --> $SRC_DIR/core/src/option.rs:LL:COL
-   |
-   = note: 
 $SRC_DIR/core/src/option.rs:LL:COL: not covered
    = note: the matched value is of type `Option<i32>`
 

src/test/ui/feature-gates/feature-gate-exhaustive-patterns.stderr

@@ -8,8 +8,6 @@ LL |     let Ok(_x) = foo();
    = note: for more information, visit https://doc.rust-lang.org/book/ch18-02-refutability.html
 note: `Result<u32, !>` defined here
   --> $SRC_DIR/core/src/result.rs:LL:COL
-   |
-   = note: 
 $SRC_DIR/core/src/result.rs:LL:COL: not covered
    = note: the matched value is of type `Result<u32, !>`
 help: you might want to use `if let` to ignore the variant that isn't matched

src/test/ui/pattern/suggest-adding-appropriate-missing-pattern-excluding-comments.stderr

@@ -6,8 +6,6 @@ LL |     match Some(1) {
    |
 note: `Option<i32>` defined here
   --> $SRC_DIR/core/src/option.rs:LL:COL
-   |
-   = note: 
 $SRC_DIR/core/src/option.rs:LL:COL: not covered
    = note: the matched value is of type `Option<i32>`
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown

src/test/ui/pattern/usefulness/doc-hidden-non-exhaustive.stderr

@@ -66,8 +66,6 @@ LL |     match None {
    |
 note: `Option<HiddenEnum>` defined here
   --> $SRC_DIR/core/src/option.rs:LL:COL
-   |
-   = note: 
 $SRC_DIR/core/src/option.rs:LL:COL: not covered
    = note: the matched value is of type `Option<HiddenEnum>`
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern, a match arm with multiple or-patterns as shown, or multiple match arms

src/test/ui/pattern/usefulness/issue-35609.stderr

@@ -107,8 +107,6 @@ LL |     match Some(A) {
    |
 note: `Option<Enum>` defined here
   --> $SRC_DIR/core/src/option.rs:LL:COL
-   |
-   = note: 
    = note: the matched value is of type `Option<Enum>`
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern as shown, or multiple match arms
    |

src/test/ui/pattern/usefulness/issue-3601.stderr

@@ -8,7 +8,7 @@ note: `Box<ElementKind>` defined here
   --> $SRC_DIR/alloc/src/boxed.rs:LL:COL
 $SRC_DIR/alloc/src/boxed.rs:LL:COL
 $SRC_DIR/alloc/src/boxed.rs:LL:COL
-$SRC_DIR/alloc/src/boxed.rs:LL:COL: 
+$SRC_DIR/alloc/src/boxed.rs:LL:COL
    = note: the matched value is of type `Box<ElementKind>`
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
    |

src/test/ui/pattern/usefulness/match-arm-statics-2.stderr

@@ -19,8 +19,6 @@ LL |     match Some(Some(North)) {
    |
 note: `Option<Option<Direction>>` defined here
   --> $SRC_DIR/core/src/option.rs:LL:COL
-   |
-   = note: 
 $SRC_DIR/core/src/option.rs:LL:COL: not covered
 : not covered
    = note: the matched value is of type `Option<Option<Direction>>`

src/test/ui/pattern/usefulness/match-privately-empty.stderr

@@ -6,8 +6,6 @@ LL |     match private::DATA {
    |
 note: `Option<Private>` defined here
   --> $SRC_DIR/core/src/option.rs:LL:COL
-   |
-   = note: 
 $SRC_DIR/core/src/option.rs:LL:COL: not covered
    = note: the matched value is of type `Option<Private>`
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown

src/test/ui/pattern/usefulness/non-exhaustive-match.stderr

@@ -36,8 +36,6 @@ LL |     match Some(10) {
    |
 note: `Option<i32>` defined here
   --> $SRC_DIR/core/src/option.rs:LL:COL
-   |
-   = note: 
 $SRC_DIR/core/src/option.rs:LL:COL: not covered
    = note: the matched value is of type `Option<i32>`
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown

src/test/ui/recursion/recursive-types-are-not-uninhabited.stderr

@@ -8,8 +8,6 @@ LL |     let Ok(x) = res;
    = note: for more information, visit https://doc.rust-lang.org/book/ch18-02-refutability.html
 note: `Result<u32, &R<'_>>` defined here
   --> $SRC_DIR/core/src/result.rs:LL:COL
-   |
-   = note: 
 $SRC_DIR/core/src/result.rs:LL:COL: not covered
    = note: the matched value is of type `Result<u32, &R<'_>>`
 help: you might want to use `if let` to ignore the variant that isn't matched

src/test/ui/uninhabited/uninhabited-matches-feature-gated.stderr

@@ -6,8 +6,6 @@ LL |     let _ = match x {
    |
 note: `Result<u32, &Void>` defined here
   --> $SRC_DIR/core/src/result.rs:LL:COL
-   |
-   = note: 
 $SRC_DIR/core/src/result.rs:LL:COL: not covered
    = note: the matched value is of type `Result<u32, &Void>`
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
@@ -85,8 +83,6 @@ LL |     let _ = match x {
    |
 note: `Result<u32, Void>` defined here
   --> $SRC_DIR/core/src/result.rs:LL:COL
-   |
-   = note: 
 $SRC_DIR/core/src/result.rs:LL:COL: not covered
    = note: the matched value is of type `Result<u32, Void>`
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
@@ -105,8 +101,6 @@ LL |     let Ok(x) = x;
    = note: for more information, visit https://doc.rust-lang.org/book/ch18-02-refutability.html
 note: `Result<u32, Void>` defined here
   --> $SRC_DIR/core/src/result.rs:LL:COL
-   |
-   = note: 
 $SRC_DIR/core/src/result.rs:LL:COL: not covered
    = note: the matched value is of type `Result<u32, Void>`
 help: you might want to use `if let` to ignore the variant that isn't matched