diff --git a/compiler/rustc_macros/src/diagnostics/diagnostic_builder.rs b/compiler/rustc_macros/src/diagnostics/diagnostic_builder.rs
index 72f1e599247..1055f27c1e4 100644
--- a/compiler/rustc_macros/src/diagnostics/diagnostic_builder.rs
+++ b/compiler/rustc_macros/src/diagnostics/diagnostic_builder.rs
@@ -253,7 +253,10 @@ fn generate_field_code(&mut self, binding_info: &BindingInfo<'_>) -> TokenStream
         let mut field_binding = binding_info.binding.clone();
         field_binding.set_span(field.ty.span());
 
-        let ident = field.ident.as_ref().unwrap();
+        let Some(ident) = field.ident.as_ref() else {
+            span_err(field.span().unwrap(), "tuple structs are not supported").emit();
+            return TokenStream::new();
+        };
         let ident = format_ident!("{}", ident); // strip `r#` prefix, if present
 
         quote! {
diff --git a/compiler/rustc_macros/src/diagnostics/error.rs b/compiler/rustc_macros/src/diagnostics/error.rs
index 9cdb9fbab12..a78cf2b63d0 100644
--- a/compiler/rustc_macros/src/diagnostics/error.rs
+++ b/compiler/rustc_macros/src/diagnostics/error.rs
@@ -56,7 +56,7 @@ fn path_to_string(path: &syn::Path) -> String {
 /// Returns an error diagnostic on span `span` with msg `msg`.
 #[must_use]
 pub(crate) fn span_err<T: Into<String>>(span: impl MultiSpan, msg: T) -> Diagnostic {
-    Diagnostic::spanned(span, Level::Error, msg)
+    Diagnostic::spanned(span, Level::Error, format!("derive(Diagnostic): {}", msg.into()))
 }
 
 /// Emit a diagnostic on span `$span` with msg `$msg` (optionally performing additional decoration
diff --git a/compiler/rustc_macros/src/diagnostics/utils.rs b/compiler/rustc_macros/src/diagnostics/utils.rs
index 5946b11828e..612a36ba9aa 100644
--- a/compiler/rustc_macros/src/diagnostics/utils.rs
+++ b/compiler/rustc_macros/src/diagnostics/utils.rs
@@ -243,7 +243,7 @@ fn set_once(&mut self, value: T, span: Span) {
                 *self = Some((value, span));
             }
             Some((_, prev_span)) => {
-                span_err(span, "specified multiple times")
+                span_err(span, "attribute specified multiple times")
                     .span_note(*prev_span, "previously specified here")
                     .emit();
             }
diff --git a/tests/ui-fulldeps/session-diagnostic/diagnostic-derive.stderr b/tests/ui-fulldeps/session-diagnostic/diagnostic-derive.stderr
index ff7af388514..03fca17aa55 100644
--- a/tests/ui-fulldeps/session-diagnostic/diagnostic-derive.stderr
+++ b/tests/ui-fulldeps/session-diagnostic/diagnostic-derive.stderr
@@ -1,10 +1,10 @@
-error: unsupported type attribute for diagnostic derive enum
+error: derive(Diagnostic): unsupported type attribute for diagnostic derive enum
   --> $DIR/diagnostic-derive.rs:47:1
    |
 LL | #[diag(no_crate_example, code = E0123)]
    | ^
 
-error: diagnostic slug not specified
+error: derive(Diagnostic): diagnostic slug not specified
   --> $DIR/diagnostic-derive.rs:50:5
    |
 LL |     Foo,
@@ -12,7 +12,7 @@ LL |     Foo,
    |
    = help: specify the slug as the first argument to the `#[diag(...)]` attribute, such as `#[diag(hir_analysis_example_error)]`
 
-error: diagnostic slug not specified
+error: derive(Diagnostic): diagnostic slug not specified
   --> $DIR/diagnostic-derive.rs:52:5
    |
 LL |     Bar,
@@ -20,13 +20,13 @@ LL |     Bar,
    |
    = help: specify the slug as the first argument to the `#[diag(...)]` attribute, such as `#[diag(hir_analysis_example_error)]`
 
-error: `#[nonsense(...)]` is not a valid attribute
+error: derive(Diagnostic): `#[nonsense(...)]` is not a valid attribute
   --> $DIR/diagnostic-derive.rs:63:1
    |
 LL | #[nonsense(no_crate_example, code = E0123)]
    | ^
 
-error: diagnostic slug not specified
+error: derive(Diagnostic): diagnostic slug not specified
   --> $DIR/diagnostic-derive.rs:63:1
    |
 LL | #[nonsense(no_crate_example, code = E0123)]
@@ -34,7 +34,7 @@ LL | #[nonsense(no_crate_example, code = E0123)]
    |
    = help: specify the slug as the first argument to the `#[diag(...)]` attribute, such as `#[diag(hir_analysis_example_error)]`
 
-error: diagnostic slug not specified
+error: derive(Diagnostic): diagnostic slug not specified
   --> $DIR/diagnostic-derive.rs:70:1
    |
 LL | #[diag(code = E0123)]
@@ -42,13 +42,13 @@ LL | #[diag(code = E0123)]
    |
    = help: specify the slug as the first argument to the `#[diag(...)]` attribute, such as `#[diag(hir_analysis_example_error)]`
 
-error: diagnostic slug must be the first argument
+error: derive(Diagnostic): diagnostic slug must be the first argument
   --> $DIR/diagnostic-derive.rs:80:16
    |
 LL | #[diag(nonsense("foo"), code = E0123, slug = "foo")]
    |                ^
 
-error: diagnostic slug not specified
+error: derive(Diagnostic): diagnostic slug not specified
   --> $DIR/diagnostic-derive.rs:80:1
    |
 LL | #[diag(nonsense("foo"), code = E0123, slug = "foo")]
@@ -56,7 +56,7 @@ LL | #[diag(nonsense("foo"), code = E0123, slug = "foo")]
    |
    = help: specify the slug as the first argument to the `#[diag(...)]` attribute, such as `#[diag(hir_analysis_example_error)]`
 
-error: unknown argument
+error: derive(Diagnostic): unknown argument
   --> $DIR/diagnostic-derive.rs:86:8
    |
 LL | #[diag(nonsense = "...", code = E0123, slug = "foo")]
@@ -64,7 +64,7 @@ LL | #[diag(nonsense = "...", code = E0123, slug = "foo")]
    |
    = note: only the `code` parameter is valid after the slug
 
-error: diagnostic slug not specified
+error: derive(Diagnostic): diagnostic slug not specified
   --> $DIR/diagnostic-derive.rs:86:1
    |
 LL | #[diag(nonsense = "...", code = E0123, slug = "foo")]
@@ -72,7 +72,7 @@ LL | #[diag(nonsense = "...", code = E0123, slug = "foo")]
    |
    = help: specify the slug as the first argument to the `#[diag(...)]` attribute, such as `#[diag(hir_analysis_example_error)]`
 
-error: unknown argument
+error: derive(Diagnostic): unknown argument
   --> $DIR/diagnostic-derive.rs:92:8
    |
 LL | #[diag(nonsense = 4, code = E0123, slug = "foo")]
@@ -80,7 +80,7 @@ LL | #[diag(nonsense = 4, code = E0123, slug = "foo")]
    |
    = note: only the `code` parameter is valid after the slug
 
-error: diagnostic slug not specified
+error: derive(Diagnostic): diagnostic slug not specified
   --> $DIR/diagnostic-derive.rs:92:1
    |
 LL | #[diag(nonsense = 4, code = E0123, slug = "foo")]
@@ -88,7 +88,7 @@ LL | #[diag(nonsense = 4, code = E0123, slug = "foo")]
    |
    = help: specify the slug as the first argument to the `#[diag(...)]` attribute, such as `#[diag(hir_analysis_example_error)]`
 
-error: unknown argument
+error: derive(Diagnostic): unknown argument
   --> $DIR/diagnostic-derive.rs:98:40
    |
 LL | #[diag(no_crate_example, code = E0123, slug = "foo")]
@@ -96,13 +96,13 @@ LL | #[diag(no_crate_example, code = E0123, slug = "foo")]
    |
    = note: only the `code` parameter is valid after the slug
 
-error: `#[suggestion = ...]` is not a valid attribute
+error: derive(Diagnostic): `#[suggestion = ...]` is not a valid attribute
   --> $DIR/diagnostic-derive.rs:105:5
    |
 LL |     #[suggestion = "bar"]
    |     ^
 
-error: specified multiple times
+error: derive(Diagnostic): attribute specified multiple times
   --> $DIR/diagnostic-derive.rs:112:8
    |
 LL | #[diag(no_crate_example, code = E0456)]
@@ -114,7 +114,7 @@ note: previously specified here
 LL | #[diag(no_crate_example, code = E0123)]
    |        ^^^^^^^^^^^^^^^^
 
-error: specified multiple times
+error: derive(Diagnostic): attribute specified multiple times
   --> $DIR/diagnostic-derive.rs:112:26
    |
 LL | #[diag(no_crate_example, code = E0456)]
@@ -126,7 +126,7 @@ note: previously specified here
 LL | #[diag(no_crate_example, code = E0123)]
    |                          ^^^^
 
-error: specified multiple times
+error: derive(Diagnostic): attribute specified multiple times
   --> $DIR/diagnostic-derive.rs:118:40
    |
 LL | #[diag(no_crate_example, code = E0123, code = E0456)]
@@ -138,13 +138,13 @@ note: previously specified here
 LL | #[diag(no_crate_example, code = E0123, code = E0456)]
    |                          ^^^^
 
-error: diagnostic slug must be the first argument
+error: derive(Diagnostic): diagnostic slug must be the first argument
   --> $DIR/diagnostic-derive.rs:123:43
    |
 LL | #[diag(no_crate_example, no_crate::example, code = E0123)]
    |                                           ^
 
-error: diagnostic slug not specified
+error: derive(Diagnostic): diagnostic slug not specified
   --> $DIR/diagnostic-derive.rs:128:1
    |
 LL | struct KindNotProvided {}
@@ -152,7 +152,7 @@ LL | struct KindNotProvided {}
    |
    = help: specify the slug as the first argument to the `#[diag(...)]` attribute, such as `#[diag(hir_analysis_example_error)]`
 
-error: diagnostic slug not specified
+error: derive(Diagnostic): diagnostic slug not specified
   --> $DIR/diagnostic-derive.rs:131:1
    |
 LL | #[diag(code = E0123)]
@@ -160,25 +160,25 @@ LL | #[diag(code = E0123)]
    |
    = help: specify the slug as the first argument to the `#[diag(...)]` attribute, such as `#[diag(hir_analysis_example_error)]`
 
-error: the `#[primary_span]` attribute can only be applied to fields of type `Span` or `MultiSpan`
+error: derive(Diagnostic): the `#[primary_span]` attribute can only be applied to fields of type `Span` or `MultiSpan`
   --> $DIR/diagnostic-derive.rs:142:5
    |
 LL |     #[primary_span]
    |     ^
 
-error: `#[nonsense]` is not a valid attribute
+error: derive(Diagnostic): `#[nonsense]` is not a valid attribute
   --> $DIR/diagnostic-derive.rs:150:5
    |
 LL |     #[nonsense]
    |     ^
 
-error: the `#[label(...)]` attribute can only be applied to fields of type `Span` or `MultiSpan`
+error: derive(Diagnostic): the `#[label(...)]` attribute can only be applied to fields of type `Span` or `MultiSpan`
   --> $DIR/diagnostic-derive.rs:167:5
    |
 LL |     #[label(no_crate_label)]
    |     ^
 
-error: `name` doesn't refer to a field on this type
+error: derive(Diagnostic): `name` doesn't refer to a field on this type
   --> $DIR/diagnostic-derive.rs:175:46
    |
 LL |     #[suggestion(no_crate_suggestion, code = "{name}")]
@@ -202,19 +202,19 @@ LL | #[derive(Diagnostic)]
    = note: if you intended to print `}`, you can escape it using `}}`
    = note: this error originates in the derive macro `Diagnostic` (in Nightly builds, run with -Z macro-backtrace for more info)
 
-error: the `#[label(...)]` attribute can only be applied to fields of type `Span` or `MultiSpan`
+error: derive(Diagnostic): the `#[label(...)]` attribute can only be applied to fields of type `Span` or `MultiSpan`
   --> $DIR/diagnostic-derive.rs:210:5
    |
 LL |     #[label(no_crate_label)]
    |     ^
 
-error: suggestion without `code = "..."`
+error: derive(Diagnostic): suggestion without `code = "..."`
   --> $DIR/diagnostic-derive.rs:229:5
    |
 LL |     #[suggestion(no_crate_suggestion)]
    |     ^
 
-error: invalid nested attribute
+error: derive(Diagnostic): invalid nested attribute
   --> $DIR/diagnostic-derive.rs:237:18
    |
 LL |     #[suggestion(nonsense = "bar")]
@@ -222,13 +222,13 @@ LL |     #[suggestion(nonsense = "bar")]
    |
    = help: only `no_span`, `style`, `code` and `applicability` are valid nested attributes
 
-error: suggestion without `code = "..."`
+error: derive(Diagnostic): suggestion without `code = "..."`
   --> $DIR/diagnostic-derive.rs:237:5
    |
 LL |     #[suggestion(nonsense = "bar")]
    |     ^
 
-error: invalid nested attribute
+error: derive(Diagnostic): invalid nested attribute
   --> $DIR/diagnostic-derive.rs:246:18
    |
 LL |     #[suggestion(msg = "bar")]
@@ -236,13 +236,13 @@ LL |     #[suggestion(msg = "bar")]
    |
    = help: only `no_span`, `style`, `code` and `applicability` are valid nested attributes
 
-error: suggestion without `code = "..."`
+error: derive(Diagnostic): suggestion without `code = "..."`
   --> $DIR/diagnostic-derive.rs:246:5
    |
 LL |     #[suggestion(msg = "bar")]
    |     ^
 
-error: wrong field type for suggestion
+error: derive(Diagnostic): wrong field type for suggestion
   --> $DIR/diagnostic-derive.rs:269:5
    |
 LL |     #[suggestion(no_crate_suggestion, code = "This is suggested code")]
@@ -250,7 +250,7 @@ LL |     #[suggestion(no_crate_suggestion, code = "This is suggested code")]
    |
    = help: `#[suggestion(...)]` should be applied to fields of type `Span` or `(Span, Applicability)`
 
-error: specified multiple times
+error: derive(Diagnostic): attribute specified multiple times
   --> $DIR/diagnostic-derive.rs:285:24
    |
 LL |     suggestion: (Span, Span, Applicability),
@@ -262,7 +262,7 @@ note: previously specified here
 LL |     suggestion: (Span, Span, Applicability),
    |                  ^^^^
 
-error: specified multiple times
+error: derive(Diagnostic): attribute specified multiple times
   --> $DIR/diagnostic-derive.rs:293:33
    |
 LL |     suggestion: (Applicability, Applicability, Span),
@@ -274,13 +274,13 @@ note: previously specified here
 LL |     suggestion: (Applicability, Applicability, Span),
    |                  ^^^^^^^^^^^^^
 
-error: `#[label = ...]` is not a valid attribute
+error: derive(Diagnostic): `#[label = ...]` is not a valid attribute
   --> $DIR/diagnostic-derive.rs:300:5
    |
 LL |     #[label = "bar"]
    |     ^
 
-error: specified multiple times
+error: derive(Diagnostic): attribute specified multiple times
   --> $DIR/diagnostic-derive.rs:451:5
    |
 LL |     #[suggestion(no_crate_suggestion, code = "...", applicability = "maybe-incorrect")]
@@ -292,37 +292,37 @@ note: previously specified here
 LL |     suggestion: (Span, Applicability),
    |                        ^^^^^^^^^^^^^
 
-error: invalid applicability
+error: derive(Diagnostic): invalid applicability
   --> $DIR/diagnostic-derive.rs:459:69
    |
 LL |     #[suggestion(no_crate_suggestion, code = "...", applicability = "batman")]
    |                                                                     ^^^^^^^^
 
-error: the `#[help(...)]` attribute can only be applied to fields of type `Span`, `MultiSpan`, `bool` or `()`
+error: derive(Diagnostic): the `#[help(...)]` attribute can only be applied to fields of type `Span`, `MultiSpan`, `bool` or `()`
   --> $DIR/diagnostic-derive.rs:526:5
    |
 LL |     #[help(no_crate_help)]
    |     ^
 
-error: a diagnostic slug must be the first argument to the attribute
+error: derive(Diagnostic): a diagnostic slug must be the first argument to the attribute
   --> $DIR/diagnostic-derive.rs:535:32
    |
 LL |     #[label(no_crate_label, foo)]
    |                                ^
 
-error: only `no_span` is a valid nested attribute
+error: derive(Diagnostic): only `no_span` is a valid nested attribute
   --> $DIR/diagnostic-derive.rs:543:29
    |
 LL |     #[label(no_crate_label, foo = "...")]
    |                             ^^^
 
-error: only `no_span` is a valid nested attribute
+error: derive(Diagnostic): only `no_span` is a valid nested attribute
   --> $DIR/diagnostic-derive.rs:551:29
    |
 LL |     #[label(no_crate_label, foo("..."))]
    |                             ^^^
 
-error: `#[primary_span]` is not a valid attribute
+error: derive(Diagnostic): `#[primary_span]` is not a valid attribute
   --> $DIR/diagnostic-derive.rs:563:5
    |
 LL |     #[primary_span]
@@ -330,13 +330,13 @@ LL |     #[primary_span]
    |
    = help: the `primary_span` field attribute is not valid for lint diagnostics
 
-error: `#[error(...)]` is not a valid attribute
+error: derive(Diagnostic): `#[error(...)]` is not a valid attribute
   --> $DIR/diagnostic-derive.rs:583:1
    |
 LL | #[error(no_crate_example, code = E0123)]
    | ^
 
-error: diagnostic slug not specified
+error: derive(Diagnostic): diagnostic slug not specified
   --> $DIR/diagnostic-derive.rs:583:1
    |
 LL | #[error(no_crate_example, code = E0123)]
@@ -344,13 +344,13 @@ LL | #[error(no_crate_example, code = E0123)]
    |
    = help: specify the slug as the first argument to the `#[diag(...)]` attribute, such as `#[diag(hir_analysis_example_error)]`
 
-error: `#[warn_(...)]` is not a valid attribute
+error: derive(Diagnostic): `#[warn_(...)]` is not a valid attribute
   --> $DIR/diagnostic-derive.rs:590:1
    |
 LL | #[warn_(no_crate_example, code = E0123)]
    | ^
 
-error: diagnostic slug not specified
+error: derive(Diagnostic): diagnostic slug not specified
   --> $DIR/diagnostic-derive.rs:590:1
    |
 LL | #[warn_(no_crate_example, code = E0123)]
@@ -358,13 +358,13 @@ LL | #[warn_(no_crate_example, code = E0123)]
    |
    = help: specify the slug as the first argument to the `#[diag(...)]` attribute, such as `#[diag(hir_analysis_example_error)]`
 
-error: `#[lint(...)]` is not a valid attribute
+error: derive(Diagnostic): `#[lint(...)]` is not a valid attribute
   --> $DIR/diagnostic-derive.rs:597:1
    |
 LL | #[lint(no_crate_example, code = E0123)]
    | ^
 
-error: diagnostic slug not specified
+error: derive(Diagnostic): diagnostic slug not specified
   --> $DIR/diagnostic-derive.rs:597:1
    |
 LL | #[lint(no_crate_example, code = E0123)]
@@ -372,13 +372,13 @@ LL | #[lint(no_crate_example, code = E0123)]
    |
    = help: specify the slug as the first argument to the `#[diag(...)]` attribute, such as `#[diag(hir_analysis_example_error)]`
 
-error: `#[lint(...)]` is not a valid attribute
+error: derive(Diagnostic): `#[lint(...)]` is not a valid attribute
   --> $DIR/diagnostic-derive.rs:604:1
    |
 LL | #[lint(no_crate_example, code = E0123)]
    | ^
 
-error: diagnostic slug not specified
+error: derive(Diagnostic): diagnostic slug not specified
   --> $DIR/diagnostic-derive.rs:604:1
    |
 LL | #[lint(no_crate_example, code = E0123)]
@@ -386,7 +386,7 @@ LL | #[lint(no_crate_example, code = E0123)]
    |
    = help: specify the slug as the first argument to the attribute, such as `#[diag(compiletest_example)]`
 
-error: specified multiple times
+error: derive(Diagnostic): attribute specified multiple times
   --> $DIR/diagnostic-derive.rs:613:53
    |
 LL |     #[suggestion(no_crate_suggestion, code = "...", code = ",,,")]
@@ -398,7 +398,7 @@ note: previously specified here
 LL |     #[suggestion(no_crate_suggestion, code = "...", code = ",,,")]
    |                                       ^^^^
 
-error: wrong types for suggestion
+error: derive(Diagnostic): wrong types for suggestion
   --> $DIR/diagnostic-derive.rs:622:24
    |
 LL |     suggestion: (Span, usize),
@@ -406,7 +406,7 @@ LL |     suggestion: (Span, usize),
    |
    = help: `#[suggestion(...)]` on a tuple field must be applied to fields of type `(Span, Applicability)`
 
-error: wrong types for suggestion
+error: derive(Diagnostic): wrong types for suggestion
   --> $DIR/diagnostic-derive.rs:630:17
    |
 LL |     suggestion: (Span,),
@@ -414,13 +414,13 @@ LL |     suggestion: (Span,),
    |
    = help: `#[suggestion(...)]` on a tuple field must be applied to fields of type `(Span, Applicability)`
 
-error: suggestion without `code = "..."`
+error: derive(Diagnostic): suggestion without `code = "..."`
   --> $DIR/diagnostic-derive.rs:637:5
    |
 LL |     #[suggestion(no_crate_suggestion)]
    |     ^
 
-error: `#[multipart_suggestion(...)]` is not a valid attribute
+error: derive(Diagnostic): `#[multipart_suggestion(...)]` is not a valid attribute
   --> $DIR/diagnostic-derive.rs:644:1
    |
 LL | #[multipart_suggestion(no_crate_suggestion)]
@@ -428,7 +428,7 @@ LL | #[multipart_suggestion(no_crate_suggestion)]
    |
    = help: consider creating a `Subdiagnostic` instead
 
-error: `#[multipart_suggestion(...)]` is not a valid attribute
+error: derive(Diagnostic): `#[multipart_suggestion(...)]` is not a valid attribute
   --> $DIR/diagnostic-derive.rs:647:1
    |
 LL | #[multipart_suggestion()]
@@ -436,7 +436,7 @@ LL | #[multipart_suggestion()]
    |
    = help: consider creating a `Subdiagnostic` instead
 
-error: `#[multipart_suggestion(...)]` is not a valid attribute
+error: derive(Diagnostic): `#[multipart_suggestion(...)]` is not a valid attribute
   --> $DIR/diagnostic-derive.rs:651:5
    |
 LL |     #[multipart_suggestion(no_crate_suggestion)]
@@ -444,7 +444,7 @@ LL |     #[multipart_suggestion(no_crate_suggestion)]
    |
    = help: consider creating a `Subdiagnostic` instead
 
-error: `#[suggestion(...)]` is not a valid attribute
+error: derive(Diagnostic): `#[suggestion(...)]` is not a valid attribute
   --> $DIR/diagnostic-derive.rs:659:1
    |
 LL | #[suggestion(no_crate_suggestion, code = "...")]
@@ -452,7 +452,7 @@ LL | #[suggestion(no_crate_suggestion, code = "...")]
    |
    = help: `#[label]` and `#[suggestion]` can only be applied to fields
 
-error: `#[label]` is not a valid attribute
+error: derive(Diagnostic): `#[label]` is not a valid attribute
   --> $DIR/diagnostic-derive.rs:668:1
    |
 LL | #[label]
@@ -460,61 +460,61 @@ LL | #[label]
    |
    = help: `#[label]` and `#[suggestion]` can only be applied to fields
 
-error: `#[subdiagnostic(...)]` is not a valid attribute
+error: derive(Diagnostic): `#[subdiagnostic(...)]` is not a valid attribute
   --> $DIR/diagnostic-derive.rs:702:5
    |
 LL |     #[subdiagnostic(bad)]
    |     ^
 
-error: `#[subdiagnostic = ...]` is not a valid attribute
+error: derive(Diagnostic): `#[subdiagnostic = ...]` is not a valid attribute
   --> $DIR/diagnostic-derive.rs:710:5
    |
 LL |     #[subdiagnostic = "bad"]
    |     ^
 
-error: `#[subdiagnostic(...)]` is not a valid attribute
+error: derive(Diagnostic): `#[subdiagnostic(...)]` is not a valid attribute
   --> $DIR/diagnostic-derive.rs:718:5
    |
 LL |     #[subdiagnostic(bad, bad)]
    |     ^
 
-error: `#[subdiagnostic(...)]` is not a valid attribute
+error: derive(Diagnostic): `#[subdiagnostic(...)]` is not a valid attribute
   --> $DIR/diagnostic-derive.rs:726:5
    |
 LL |     #[subdiagnostic("bad")]
    |     ^
 
-error: `#[subdiagnostic(...)]` is not a valid attribute
+error: derive(Diagnostic): `#[subdiagnostic(...)]` is not a valid attribute
   --> $DIR/diagnostic-derive.rs:734:5
    |
 LL |     #[subdiagnostic(eager)]
    |     ^
 
-error: `#[subdiagnostic(...)]` is not a valid attribute
+error: derive(Diagnostic): `#[subdiagnostic(...)]` is not a valid attribute
   --> $DIR/diagnostic-derive.rs:742:5
    |
 LL |     #[subdiagnostic(eager)]
    |     ^
 
-error: `#[subdiagnostic(...)]` is not a valid attribute
+error: derive(Diagnostic): `#[subdiagnostic(...)]` is not a valid attribute
   --> $DIR/diagnostic-derive.rs:763:5
    |
 LL |     #[subdiagnostic(eager)]
    |     ^
 
-error: expected at least one string literal for `code(...)`
+error: derive(Diagnostic): expected at least one string literal for `code(...)`
   --> $DIR/diagnostic-derive.rs:794:23
    |
 LL |     #[suggestion(code())]
    |                       ^
 
-error: `code(...)` must contain only string literals
+error: derive(Diagnostic): `code(...)` must contain only string literals
   --> $DIR/diagnostic-derive.rs:802:23
    |
 LL |     #[suggestion(code(foo))]
    |                       ^^^
 
-error: `#[suggestion(...)]` is not a valid attribute
+error: derive(Diagnostic): `#[suggestion(...)]` is not a valid attribute
   --> $DIR/diagnostic-derive.rs:826:5
    |
 LL |     #[suggestion(no_crate_suggestion, code = "")]
diff --git a/tests/ui-fulldeps/session-diagnostic/enforce_slug_naming.stderr b/tests/ui-fulldeps/session-diagnostic/enforce_slug_naming.stderr
index df1bad3cad0..4f54239f0fa 100644
--- a/tests/ui-fulldeps/session-diagnostic/enforce_slug_naming.stderr
+++ b/tests/ui-fulldeps/session-diagnostic/enforce_slug_naming.stderr
@@ -1,4 +1,4 @@
-error: diagnostic slug and crate name do not match
+error: derive(Diagnostic): diagnostic slug and crate name do not match
   --> $DIR/enforce_slug_naming.rs:22:8
    |
 LL | #[diag(compiletest_example, code = E0123)]
diff --git a/tests/ui-fulldeps/session-diagnostic/subdiagnostic-derive.stderr b/tests/ui-fulldeps/session-diagnostic/subdiagnostic-derive.stderr
index 96f6ef06d1d..0ae7ba4c497 100644
--- a/tests/ui-fulldeps/session-diagnostic/subdiagnostic-derive.stderr
+++ b/tests/ui-fulldeps/session-diagnostic/subdiagnostic-derive.stderr
@@ -1,142 +1,142 @@
-error: label without `#[primary_span]` field
+error: derive(Diagnostic): label without `#[primary_span]` field
   --> $DIR/subdiagnostic-derive.rs:51:1
    |
 LL | #[label(no_crate_example)]
    | ^
 
-error: diagnostic slug must be first argument of a `#[label(...)]` attribute
+error: derive(Diagnostic): diagnostic slug must be first argument of a `#[label(...)]` attribute
   --> $DIR/subdiagnostic-derive.rs:58:1
    |
 LL | #[label]
    | ^
 
-error: `#[foo]` is not a valid attribute
+error: derive(Diagnostic): `#[foo]` is not a valid attribute
   --> $DIR/subdiagnostic-derive.rs:67:1
    |
 LL | #[foo]
    | ^
 
-error: `#[label = ...]` is not a valid attribute
+error: derive(Diagnostic): `#[label = ...]` is not a valid attribute
   --> $DIR/subdiagnostic-derive.rs:77:1
    |
 LL | #[label = "..."]
    | ^
 
-error: only `no_span` is a valid nested attribute
+error: derive(Diagnostic): only `no_span` is a valid nested attribute
   --> $DIR/subdiagnostic-derive.rs:86:9
    |
 LL | #[label(bug = "...")]
    |         ^^^
 
-error: diagnostic slug must be first argument of a `#[label(...)]` attribute
+error: derive(Diagnostic): diagnostic slug must be first argument of a `#[label(...)]` attribute
   --> $DIR/subdiagnostic-derive.rs:86:1
    |
 LL | #[label(bug = "...")]
    | ^
 
-error: only `no_span` is a valid nested attribute
+error: derive(Diagnostic): only `no_span` is a valid nested attribute
   --> $DIR/subdiagnostic-derive.rs:106:9
    |
 LL | #[label(slug = 4)]
    |         ^^^^
 
-error: diagnostic slug must be first argument of a `#[label(...)]` attribute
+error: derive(Diagnostic): diagnostic slug must be first argument of a `#[label(...)]` attribute
   --> $DIR/subdiagnostic-derive.rs:106:1
    |
 LL | #[label(slug = 4)]
    | ^
 
-error: only `no_span` is a valid nested attribute
+error: derive(Diagnostic): only `no_span` is a valid nested attribute
   --> $DIR/subdiagnostic-derive.rs:116:9
    |
 LL | #[label(slug("..."))]
    |         ^^^^
 
-error: diagnostic slug must be first argument of a `#[label(...)]` attribute
+error: derive(Diagnostic): diagnostic slug must be first argument of a `#[label(...)]` attribute
   --> $DIR/subdiagnostic-derive.rs:116:1
    |
 LL | #[label(slug("..."))]
    | ^
 
-error: diagnostic slug must be first argument of a `#[label(...)]` attribute
+error: derive(Diagnostic): diagnostic slug must be first argument of a `#[label(...)]` attribute
   --> $DIR/subdiagnostic-derive.rs:136:1
    |
 LL | #[label()]
    | ^
 
-error: only `no_span` is a valid nested attribute
+error: derive(Diagnostic): only `no_span` is a valid nested attribute
   --> $DIR/subdiagnostic-derive.rs:145:27
    |
 LL | #[label(no_crate_example, code = "...")]
    |                           ^^^^
 
-error: only `no_span` is a valid nested attribute
+error: derive(Diagnostic): only `no_span` is a valid nested attribute
   --> $DIR/subdiagnostic-derive.rs:154:27
    |
 LL | #[label(no_crate_example, applicability = "machine-applicable")]
    |                           ^^^^^^^^^^^^^
 
-error: unsupported type attribute for subdiagnostic enum
+error: derive(Diagnostic): unsupported type attribute for subdiagnostic enum
   --> $DIR/subdiagnostic-derive.rs:163:1
    |
 LL | #[foo]
    | ^
 
-error: `#[bar]` is not a valid attribute
+error: derive(Diagnostic): `#[bar]` is not a valid attribute
   --> $DIR/subdiagnostic-derive.rs:177:5
    |
 LL |     #[bar]
    |     ^
 
-error: `#[bar = ...]` is not a valid attribute
+error: derive(Diagnostic): `#[bar = ...]` is not a valid attribute
   --> $DIR/subdiagnostic-derive.rs:189:5
    |
 LL |     #[bar = "..."]
    |     ^
 
-error: `#[bar = ...]` is not a valid attribute
+error: derive(Diagnostic): `#[bar = ...]` is not a valid attribute
   --> $DIR/subdiagnostic-derive.rs:201:5
    |
 LL |     #[bar = 4]
    |     ^
 
-error: `#[bar(...)]` is not a valid attribute
+error: derive(Diagnostic): `#[bar(...)]` is not a valid attribute
   --> $DIR/subdiagnostic-derive.rs:213:5
    |
 LL |     #[bar("...")]
    |     ^
 
-error: only `no_span` is a valid nested attribute
+error: derive(Diagnostic): only `no_span` is a valid nested attribute
   --> $DIR/subdiagnostic-derive.rs:225:13
    |
 LL |     #[label(code = "...")]
    |             ^^^^
 
-error: diagnostic slug must be first argument of a `#[label(...)]` attribute
+error: derive(Diagnostic): diagnostic slug must be first argument of a `#[label(...)]` attribute
   --> $DIR/subdiagnostic-derive.rs:225:5
    |
 LL |     #[label(code = "...")]
    |     ^
 
-error: the `#[primary_span]` attribute can only be applied to fields of type `Span` or `MultiSpan`
+error: derive(Diagnostic): the `#[primary_span]` attribute can only be applied to fields of type `Span` or `MultiSpan`
   --> $DIR/subdiagnostic-derive.rs:254:5
    |
 LL |     #[primary_span]
    |     ^
 
-error: label without `#[primary_span]` field
+error: derive(Diagnostic): label without `#[primary_span]` field
   --> $DIR/subdiagnostic-derive.rs:251:1
    |
 LL | #[label(no_crate_example)]
    | ^
 
-error: `#[applicability]` is only valid on suggestions
+error: derive(Diagnostic): `#[applicability]` is only valid on suggestions
   --> $DIR/subdiagnostic-derive.rs:264:5
    |
 LL |     #[applicability]
    |     ^
 
-error: `#[bar]` is not a valid attribute
+error: derive(Diagnostic): `#[bar]` is not a valid attribute
   --> $DIR/subdiagnostic-derive.rs:274:5
    |
 LL |     #[bar]
@@ -144,13 +144,13 @@ LL |     #[bar]
    |
    = help: only `primary_span`, `applicability` and `skip_arg` are valid field attributes
 
-error: `#[bar = ...]` is not a valid attribute
+error: derive(Diagnostic): `#[bar = ...]` is not a valid attribute
   --> $DIR/subdiagnostic-derive.rs:285:5
    |
 LL |     #[bar = "..."]
    |     ^
 
-error: `#[bar(...)]` is not a valid attribute
+error: derive(Diagnostic): `#[bar(...)]` is not a valid attribute
   --> $DIR/subdiagnostic-derive.rs:296:5
    |
 LL |     #[bar("...")]
@@ -158,13 +158,13 @@ LL |     #[bar("...")]
    |
    = help: only `primary_span`, `applicability` and `skip_arg` are valid field attributes
 
-error: a diagnostic slug must be the first argument to the attribute
+error: derive(Diagnostic): a diagnostic slug must be the first argument to the attribute
   --> $DIR/subdiagnostic-derive.rs:328:44
    |
 LL | #[label(no_crate_example, no_crate::example)]
    |                                            ^
 
-error: specified multiple times
+error: derive(Diagnostic): attribute specified multiple times
   --> $DIR/subdiagnostic-derive.rs:341:5
    |
 LL |     #[primary_span]
@@ -176,13 +176,13 @@ note: previously specified here
 LL |     #[primary_span]
    |     ^
 
-error: subdiagnostic kind not specified
+error: derive(Diagnostic): subdiagnostic kind not specified
   --> $DIR/subdiagnostic-derive.rs:347:8
    |
 LL | struct AG {
    |        ^^
 
-error: specified multiple times
+error: derive(Diagnostic): attribute specified multiple times
   --> $DIR/subdiagnostic-derive.rs:384:46
    |
 LL | #[suggestion(no_crate_example, code = "...", code = "...")]
@@ -194,7 +194,7 @@ note: previously specified here
 LL | #[suggestion(no_crate_example, code = "...", code = "...")]
    |                                ^^^^
 
-error: specified multiple times
+error: derive(Diagnostic): attribute specified multiple times
   --> $DIR/subdiagnostic-derive.rs:402:5
    |
 LL |     #[applicability]
@@ -206,49 +206,49 @@ note: previously specified here
 LL |     #[applicability]
    |     ^
 
-error: the `#[applicability]` attribute can only be applied to fields of type `Applicability`
+error: derive(Diagnostic): the `#[applicability]` attribute can only be applied to fields of type `Applicability`
   --> $DIR/subdiagnostic-derive.rs:412:5
    |
 LL |     #[applicability]
    |     ^
 
-error: suggestion without `code = "..."`
+error: derive(Diagnostic): suggestion without `code = "..."`
   --> $DIR/subdiagnostic-derive.rs:425:1
    |
 LL | #[suggestion(no_crate_example)]
    | ^
 
-error: invalid applicability
+error: derive(Diagnostic): invalid applicability
   --> $DIR/subdiagnostic-derive.rs:435:62
    |
 LL | #[suggestion(no_crate_example, code = "...", applicability = "foo")]
    |                                                              ^^^^^
 
-error: suggestion without `#[primary_span]` field
+error: derive(Diagnostic): suggestion without `#[primary_span]` field
   --> $DIR/subdiagnostic-derive.rs:453:1
    |
 LL | #[suggestion(no_crate_example, code = "...")]
    | ^
 
-error: unsupported type attribute for subdiagnostic enum
+error: derive(Diagnostic): unsupported type attribute for subdiagnostic enum
   --> $DIR/subdiagnostic-derive.rs:467:1
    |
 LL | #[label]
    | ^
 
-error: `var` doesn't refer to a field on this type
+error: derive(Diagnostic): `var` doesn't refer to a field on this type
   --> $DIR/subdiagnostic-derive.rs:487:39
    |
 LL | #[suggestion(no_crate_example, code = "{var}", applicability = "machine-applicable")]
    |                                       ^^^^^^^
 
-error: `var` doesn't refer to a field on this type
+error: derive(Diagnostic): `var` doesn't refer to a field on this type
   --> $DIR/subdiagnostic-derive.rs:506:43
    |
 LL |     #[suggestion(no_crate_example, code = "{var}", applicability = "machine-applicable")]
    |                                           ^^^^^^^
 
-error: `#[suggestion_part]` is not a valid attribute
+error: derive(Diagnostic): `#[suggestion_part]` is not a valid attribute
   --> $DIR/subdiagnostic-derive.rs:529:5
    |
 LL |     #[suggestion_part]
@@ -256,7 +256,7 @@ LL |     #[suggestion_part]
    |
    = help: `#[suggestion_part(...)]` is only valid in multipart suggestions, use `#[primary_span]` instead
 
-error: `#[suggestion_part(...)]` is not a valid attribute
+error: derive(Diagnostic): `#[suggestion_part(...)]` is not a valid attribute
   --> $DIR/subdiagnostic-derive.rs:532:5
    |
 LL |     #[suggestion_part(code = "...")]
@@ -264,13 +264,13 @@ LL |     #[suggestion_part(code = "...")]
    |
    = help: `#[suggestion_part(...)]` is only valid in multipart suggestions
 
-error: suggestion without `#[primary_span]` field
+error: derive(Diagnostic): suggestion without `#[primary_span]` field
   --> $DIR/subdiagnostic-derive.rs:526:1
    |
 LL | #[suggestion(no_crate_example, code = "...")]
    | ^
 
-error: invalid nested attribute
+error: derive(Diagnostic): invalid nested attribute
   --> $DIR/subdiagnostic-derive.rs:541:42
    |
 LL | #[multipart_suggestion(no_crate_example, code = "...", applicability = "machine-applicable")]
@@ -278,25 +278,25 @@ LL | #[multipart_suggestion(no_crate_example, code = "...", applicability = "mac
    |
    = help: only `no_span`, `style` and `applicability` are valid nested attributes
 
-error: multipart suggestion without any `#[suggestion_part(...)]` fields
+error: derive(Diagnostic): multipart suggestion without any `#[suggestion_part(...)]` fields
   --> $DIR/subdiagnostic-derive.rs:541:1
    |
 LL | #[multipart_suggestion(no_crate_example, code = "...", applicability = "machine-applicable")]
    | ^
 
-error: `#[suggestion_part(...)]` attribute without `code = "..."`
+error: derive(Diagnostic): `#[suggestion_part(...)]` attribute without `code = "..."`
   --> $DIR/subdiagnostic-derive.rs:551:5
    |
 LL |     #[suggestion_part]
    |     ^
 
-error: `#[suggestion_part(...)]` attribute without `code = "..."`
+error: derive(Diagnostic): `#[suggestion_part(...)]` attribute without `code = "..."`
   --> $DIR/subdiagnostic-derive.rs:559:5
    |
 LL |     #[suggestion_part()]
    |     ^
 
-error: `#[primary_span]` is not a valid attribute
+error: derive(Diagnostic): `#[primary_span]` is not a valid attribute
   --> $DIR/subdiagnostic-derive.rs:568:5
    |
 LL |     #[primary_span]
@@ -304,43 +304,43 @@ LL |     #[primary_span]
    |
    = help: multipart suggestions use one or more `#[suggestion_part]`s rather than one `#[primary_span]`
 
-error: multipart suggestion without any `#[suggestion_part(...)]` fields
+error: derive(Diagnostic): multipart suggestion without any `#[suggestion_part(...)]` fields
   --> $DIR/subdiagnostic-derive.rs:565:1
    |
 LL | #[multipart_suggestion(no_crate_example)]
    | ^
 
-error: `#[suggestion_part(...)]` attribute without `code = "..."`
+error: derive(Diagnostic): `#[suggestion_part(...)]` attribute without `code = "..."`
   --> $DIR/subdiagnostic-derive.rs:576:5
    |
 LL |     #[suggestion_part]
    |     ^
 
-error: `#[suggestion_part(...)]` attribute without `code = "..."`
+error: derive(Diagnostic): `#[suggestion_part(...)]` attribute without `code = "..."`
   --> $DIR/subdiagnostic-derive.rs:579:5
    |
 LL |     #[suggestion_part()]
    |     ^
 
-error: `code` is the only valid nested attribute
+error: derive(Diagnostic): `code` is the only valid nested attribute
   --> $DIR/subdiagnostic-derive.rs:582:23
    |
 LL |     #[suggestion_part(foo = "bar")]
    |                       ^^^
 
-error: the `#[suggestion_part(...)]` attribute can only be applied to fields of type `Span` or `MultiSpan`
+error: derive(Diagnostic): the `#[suggestion_part(...)]` attribute can only be applied to fields of type `Span` or `MultiSpan`
   --> $DIR/subdiagnostic-derive.rs:587:5
    |
 LL |     #[suggestion_part(code = "...")]
    |     ^
 
-error: the `#[suggestion_part(...)]` attribute can only be applied to fields of type `Span` or `MultiSpan`
+error: derive(Diagnostic): the `#[suggestion_part(...)]` attribute can only be applied to fields of type `Span` or `MultiSpan`
   --> $DIR/subdiagnostic-derive.rs:590:5
    |
 LL |     #[suggestion_part()]
    |     ^
 
-error: specified multiple times
+error: derive(Diagnostic): attribute specified multiple times
   --> $DIR/subdiagnostic-derive.rs:598:37
    |
 LL |     #[suggestion_part(code = "...", code = ",,,")]
@@ -352,37 +352,37 @@ note: previously specified here
 LL |     #[suggestion_part(code = "...", code = ",,,")]
    |                       ^^^^
 
-error: `#[applicability]` has no effect if all `#[suggestion]`/`#[multipart_suggestion]` attributes have a static `applicability = "..."`
+error: derive(Diagnostic): `#[applicability]` has no effect if all `#[suggestion]`/`#[multipart_suggestion]` attributes have a static `applicability = "..."`
   --> $DIR/subdiagnostic-derive.rs:627:5
    |
 LL |     #[applicability]
    |     ^
 
-error: expected exactly one string literal for `code = ...`
+error: derive(Diagnostic): expected exactly one string literal for `code = ...`
   --> $DIR/subdiagnostic-derive.rs:675:34
    |
 LL |     #[suggestion_part(code("foo"))]
    |                                  ^
 
-error: expected exactly one string literal for `code = ...`
+error: derive(Diagnostic): expected exactly one string literal for `code = ...`
   --> $DIR/subdiagnostic-derive.rs:686:41
    |
 LL |     #[suggestion_part(code("foo", "bar"))]
    |                                         ^
 
-error: expected exactly one string literal for `code = ...`
+error: derive(Diagnostic): expected exactly one string literal for `code = ...`
   --> $DIR/subdiagnostic-derive.rs:697:30
    |
 LL |     #[suggestion_part(code(3))]
    |                              ^
 
-error: expected exactly one string literal for `code = ...`
+error: derive(Diagnostic): expected exactly one string literal for `code = ...`
   --> $DIR/subdiagnostic-derive.rs:708:29
    |
 LL |     #[suggestion_part(code())]
    |                             ^
 
-error: specified multiple times
+error: derive(Diagnostic): attribute specified multiple times
   --> $DIR/subdiagnostic-derive.rs:763:1
    |
 LL | #[suggestion(no_crate_example, code = "", style = "hidden", style = "normal")]
@@ -394,7 +394,7 @@ note: previously specified here
 LL | #[suggestion(no_crate_example, code = "", style = "hidden", style = "normal")]
    | ^
 
-error: `#[suggestion_hidden(...)]` is not a valid attribute
+error: derive(Diagnostic): `#[suggestion_hidden(...)]` is not a valid attribute
   --> $DIR/subdiagnostic-derive.rs:772:1
    |
 LL | #[suggestion_hidden(no_crate_example, code = "")]
@@ -402,7 +402,7 @@ LL | #[suggestion_hidden(no_crate_example, code = "")]
    |
    = help: Use `#[suggestion(..., style = "hidden")]` instead
 
-error: `#[suggestion_hidden(...)]` is not a valid attribute
+error: derive(Diagnostic): `#[suggestion_hidden(...)]` is not a valid attribute
   --> $DIR/subdiagnostic-derive.rs:780:1
    |
 LL | #[suggestion_hidden(no_crate_example, code = "", style = "normal")]
@@ -410,7 +410,7 @@ LL | #[suggestion_hidden(no_crate_example, code = "", style = "normal")]
    |
    = help: Use `#[suggestion(..., style = "hidden")]` instead
 
-error: invalid suggestion style
+error: derive(Diagnostic): invalid suggestion style
   --> $DIR/subdiagnostic-derive.rs:788:51
    |
 LL | #[suggestion(no_crate_example, code = "", style = "foo")]
@@ -418,25 +418,25 @@ LL | #[suggestion(no_crate_example, code = "", style = "foo")]
    |
    = help: valid styles are `normal`, `short`, `hidden`, `verbose` and `tool-only`
 
-error: expected `= "xxx"`
+error: derive(Diagnostic): expected `= "xxx"`
   --> $DIR/subdiagnostic-derive.rs:796:49
    |
 LL | #[suggestion(no_crate_example, code = "", style = 42)]
    |                                                 ^
 
-error: a diagnostic slug must be the first argument to the attribute
+error: derive(Diagnostic): a diagnostic slug must be the first argument to the attribute
   --> $DIR/subdiagnostic-derive.rs:804:48
    |
 LL | #[suggestion(no_crate_example, code = "", style)]
    |                                                ^
 
-error: expected `= "xxx"`
+error: derive(Diagnostic): expected `= "xxx"`
   --> $DIR/subdiagnostic-derive.rs:812:48
    |
 LL | #[suggestion(no_crate_example, code = "", style("foo"))]
    |                                                ^
 
-error: `#[primary_span]` is not a valid attribute
+error: derive(Diagnostic): `#[primary_span]` is not a valid attribute
   --> $DIR/subdiagnostic-derive.rs:825:5
    |
 LL |     #[primary_span]
@@ -445,7 +445,7 @@ LL |     #[primary_span]
    = note: there must be exactly one primary span
    = help: to create a suggestion with multiple spans, use `#[multipart_suggestion]` instead
 
-error: suggestion without `#[primary_span]` field
+error: derive(Diagnostic): suggestion without `#[primary_span]` field
   --> $DIR/subdiagnostic-derive.rs:822:1
    |
 LL | #[suggestion(no_crate_example, code = "")]