Rollup merge of #122158 - estebank:feature-sugg, r=WaffleLapkin

Provide structured suggestion for `#![feature(foo)]`

```
error: `S2<'_>` is forbidden as the type of a const generic parameter
  --> $DIR/lifetime-in-const-param.rs:5:23
   |
LL | struct S<'a, const N: S2>(&'a ());
   |                       ^^
   |
   = note: the only supported types are integers, `bool` and `char`
help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
   |
LL + #![feature(adt_const_params)]
   |
```

Fix #55941.

compiler/rustc_const_eval/src/transform/check_consts/ops.rs

@@ -99,7 +99,7 @@ impl<'tcx> NonConstOp<'tcx> for FnCallNonConst<'tcx> {
     #[allow(rustc::untranslatable_diagnostic)]
     fn build_error(&self, ccx: &ConstCx<'_, 'tcx>, _: Span) -> Diag<'tcx> {
         let FnCallNonConst { caller, callee, args, span, call_source, feature } = *self;
-        let ConstCx { tcx, param_env, .. } = *ccx;
+        let ConstCx { tcx, param_env, body, .. } = *ccx;
 
         let diag_trait = |err, self_ty: Ty<'_>, trait_id| {
             let trait_ref = TraitRef::from_method(tcx, trait_id, args);
@@ -297,10 +297,12 @@ impl<'tcx> NonConstOp<'tcx> for FnCallNonConst<'tcx> {
             ccx.const_kind(),
         ));
 
-        if let Some(feature) = feature
+        if let Some(feature) = feature {
-            && ccx.tcx.sess.is_nightly_build()
+            ccx.tcx.disabled_nightly_features(
-        {
+                &mut err,
-            err.help(format!("add `#![feature({feature})]` to the crate attributes to enable",));
+                body.source.def_id().as_local().map(|local| ccx.tcx.local_def_id_to_hir_id(local)),
+                [(String::new(), feature)],
+            );
         }
 
         if let ConstContext::Static(_) = ccx.const_kind() {

compiler/rustc_hir_analysis/src/astconv/generics.rs

@@ -16,7 +16,7 @@ use rustc_middle::ty::{
     self, GenericArgsRef, GenericParamDef, GenericParamDefKind, IsSuggestable, Ty, TyCtxt,
 };
 use rustc_session::lint::builtin::LATE_BOUND_LIFETIME_ARGUMENTS;
-use rustc_span::symbol::kw;
+use rustc_span::symbol::{kw, sym};
 use smallvec::SmallVec;
 
 /// Report an error that a generic argument did not match the generic parameter that was
@@ -41,9 +41,11 @@ fn generic_arg_mismatch_err(
     if let GenericParamDefKind::Const { .. } = param.kind {
         if matches!(arg, GenericArg::Type(hir::Ty { kind: hir::TyKind::Infer, .. })) {
             err.help("const arguments cannot yet be inferred with `_`");
-            if sess.is_nightly_build() {
+            tcx.disabled_nightly_features(
-                err.help("add `#![feature(generic_arg_infer)]` to the crate attributes to enable");
+                &mut err,
-            }
+                param.def_id.as_local().map(|local| tcx.local_def_id_to_hir_id(local)),
+                [(String::new(), sym::generic_arg_infer)],
+            );
         }
     }
 

compiler/rustc_hir_analysis/src/check/mod.rs

@@ -291,12 +291,16 @@ fn default_body_is_unstable(
         reason: reason_str,
     });
 
+    let inject_span = item_did
+        .as_local()
+        .and_then(|id| tcx.crate_level_attribute_injection_span(tcx.local_def_id_to_hir_id(id)));
     rustc_session::parse::add_feature_diagnostics_for_issue(
         &mut err,
         &tcx.sess,
         feature,
         rustc_feature::GateIssue::Library(issue),
         false,
+        inject_span,
     );
 
     err.emit();

compiler/rustc_hir_analysis/src/check/wfcheck.rs

@@ -999,9 +999,14 @@ fn check_param_wf(tcx: TyCtxt<'_>, param: &hir::GenericParam<'_>) -> Result<(),
                     // Implments `ConstParamTy`, suggest adding the feature to enable.
                     Ok(..) => true,
                 };
-                if may_suggest_feature && tcx.sess.is_nightly_build() {
+                if may_suggest_feature {
-                    diag.help(
+                    tcx.disabled_nightly_features(
-                        "add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types",
+                        &mut diag,
+                        Some(param.hir_id),
+                        [(
+                            " more complex and user defined types".to_string(),
+                            sym::adt_const_params,
+                        )],
                     );
                 }
 

compiler/rustc_hir_typeck/src/method/probe.rs

@@ -1420,15 +1420,13 @@ impl<'tcx> Pick<'tcx> {
                     }
                     _ => {}
                 }
-                if tcx.sess.is_nightly_build() {
+                tcx.disabled_nightly_features(
-                    for (candidate, feature) in &self.unstable_candidates {
+                    lint,
-                        lint.help(format!(
+                    Some(scope_expr_id),
-                            "add `#![feature({})]` to the crate attributes to enable `{}`",
+                    self.unstable_candidates.iter().map(|(candidate, feature)| {
-                            feature,
+                        (format!(" `{}`", tcx.def_path_str(candidate.item.def_id)), *feature)
-                            tcx.def_path_str(candidate.item.def_id),
+                    }),
-                        ));
+                );
-                    }
-                }
             },
         );
     }

compiler/rustc_lint/src/levels.rs

@@ -1078,6 +1078,7 @@ impl<'s, P: LintLevelsProvider> LintLevelsBuilder<'s, P> {
                         feature,
                         GateIssue::Language,
                         lint_from_cli,
+                        None,
                     );
                 },
             );

compiler/rustc_middle/src/ty/context.rs

@@ -43,7 +43,9 @@ use rustc_data_structures::sync::{self, FreezeReadGuard, Lock, Lrc, WorkerLocal}
 #[cfg(parallel_compiler)]
 use rustc_data_structures::sync::{DynSend, DynSync};
 use rustc_data_structures::unord::UnordSet;
-use rustc_errors::{Diag, DiagCtxt, DiagMessage, ErrorGuaranteed, LintDiagnostic, MultiSpan};
+use rustc_errors::{
+    Applicability, Diag, DiagCtxt, DiagMessage, ErrorGuaranteed, LintDiagnostic, MultiSpan,
+};
 use rustc_hir as hir;
 use rustc_hir::def::DefKind;
 use rustc_hir::def_id::{CrateNum, DefId, LocalDefId, LOCAL_CRATE};
@@ -2174,6 +2176,45 @@ impl<'tcx> TyCtxt<'tcx> {
         lint_level(self.sess, lint, level, src, Some(span.into()), msg, decorate);
     }
 
+    /// Find the crate root and the appropriate span where `use` and outer attributes can be
+    /// inserted at.
+    pub fn crate_level_attribute_injection_span(self, hir_id: HirId) -> Option<Span> {
+        for (_hir_id, node) in self.hir().parent_iter(hir_id) {
+            if let hir::Node::Crate(m) = node {
+                return Some(m.spans.inject_use_span.shrink_to_lo());
+            }
+        }
+        None
+    }
+
+    pub fn disabled_nightly_features<E: rustc_errors::EmissionGuarantee>(
+        self,
+        diag: &mut Diag<'_, E>,
+        hir_id: Option<HirId>,
+        features: impl IntoIterator<Item = (String, Symbol)>,
+    ) {
+        if !self.sess.is_nightly_build() {
+            return;
+        }
+
+        let span = hir_id.and_then(|id| self.crate_level_attribute_injection_span(id));
+        for (desc, feature) in features {
+            // FIXME: make this string translatable
+            let msg =
+                format!("add `#![feature({feature})]` to the crate attributes to enable{desc}");
+            if let Some(span) = span {
+                diag.span_suggestion_verbose(
+                    span,
+                    msg,
+                    format!("#![feature({feature})]\n"),
+                    Applicability::MachineApplicable,
+                );
+            } else {
+                diag.help(msg);
+            }
+        }
+    }
+
     /// Emit a lint from a lint struct (some type that implements `LintDiagnostic`, typically
     /// generated by `#[derive(LintDiagnostic)]`).
     #[track_caller]

compiler/rustc_passes/src/check_const.rs

@@ -155,16 +155,11 @@ impl<'tcx> CheckConstVisitor<'tcx> {
                 //
                 // FIXME(ecstaticmorse): Maybe this could be incorporated into `feature_err`? This
                 // is a pretty narrow case, however.
-                if tcx.sess.is_nightly_build() {
+                tcx.disabled_nightly_features(
-                    for gate in missing_secondary {
+                    &mut err,
-                        // FIXME: make this translatable
+                    def_id.map(|id| tcx.local_def_id_to_hir_id(id)),
-                        #[allow(rustc::diagnostic_outside_of_impl)]
+                    missing_secondary.into_iter().map(|gate| (String::new(), *gate)),
-                        #[allow(rustc::untranslatable_diagnostic)]
+                );
-                        err.help(format!(
-                            "add `#![feature({gate})]` to the crate attributes to enable"
-                        ));
-                    }
-                }
 
                 err.emit();
             }

compiler/rustc_session/messages.ftl

@@ -24,6 +24,9 @@ session_feature_diagnostic_for_issue =
 session_feature_diagnostic_help =
     add `#![feature({$feature})]` to the crate attributes to enable
 
+session_feature_diagnostic_suggestion =
+    add `#![feature({$feature})]` to the crate attributes to enable
+
 session_feature_suggest_upgrade_compiler =
     this compiler was built on {$date}; consider upgrading it if it is out of date
 

compiler/rustc_session/src/errors.rs

@@ -54,6 +54,18 @@ pub struct FeatureDiagnosticHelp {
     pub feature: Symbol,
 }
 
+#[derive(Subdiagnostic)]
+#[suggestion(
+    session_feature_diagnostic_suggestion,
+    applicability = "maybe-incorrect",
+    code = "#![feature({feature})]\n"
+)]
+pub struct FeatureDiagnosticSuggestion {
+    pub feature: Symbol,
+    #[primary_span]
+    pub span: Span,
+}
+
 #[derive(Subdiagnostic)]
 #[help(session_cli_feature_diagnostic_help)]
 pub struct CliFeatureDiagnosticHelp {

compiler/rustc_session/src/parse.rs

@@ -3,8 +3,8 @@
 
 use crate::config::{Cfg, CheckCfg};
 use crate::errors::{
-    CliFeatureDiagnosticHelp, FeatureDiagnosticForIssue, FeatureDiagnosticHelp, FeatureGateError,
+    CliFeatureDiagnosticHelp, FeatureDiagnosticForIssue, FeatureDiagnosticHelp,
-    SuggestUpgradeCompiler,
+    FeatureDiagnosticSuggestion, FeatureGateError, SuggestUpgradeCompiler,
 };
 use crate::lint::{
     builtin::UNSTABLE_SYNTAX_PRE_EXPANSION, BufferedEarlyLint, BuiltinLintDiag, Lint, LintId,
@@ -112,7 +112,7 @@ pub fn feature_err_issue(
     }
 
     let mut err = sess.psess.dcx.create_err(FeatureGateError { span, explain: explain.into() });
-    add_feature_diagnostics_for_issue(&mut err, sess, feature, issue, false);
+    add_feature_diagnostics_for_issue(&mut err, sess, feature, issue, false, None);
     err
 }
 
@@ -141,7 +141,7 @@ pub fn feature_warn_issue(
     explain: &'static str,
 ) {
     let mut err = sess.psess.dcx.struct_span_warn(span, explain);
-    add_feature_diagnostics_for_issue(&mut err, sess, feature, issue, false);
+    add_feature_diagnostics_for_issue(&mut err, sess, feature, issue, false, None);
 
     // Decorate this as a future-incompatibility lint as in rustc_middle::lint::lint_level
     let lint = UNSTABLE_SYNTAX_PRE_EXPANSION;
@@ -160,7 +160,7 @@ pub fn add_feature_diagnostics<G: EmissionGuarantee>(
     sess: &Session,
     feature: Symbol,
 ) {
-    add_feature_diagnostics_for_issue(err, sess, feature, GateIssue::Language, false);
+    add_feature_diagnostics_for_issue(err, sess, feature, GateIssue::Language, false, None);
 }
 
 /// Adds the diagnostics for a feature to an existing error.
@@ -175,6 +175,7 @@ pub fn add_feature_diagnostics_for_issue<G: EmissionGuarantee>(
     feature: Symbol,
     issue: GateIssue,
     feature_from_cli: bool,
+    inject_span: Option<Span>,
 ) {
     if let Some(n) = find_feature_issue(feature, issue) {
         err.subdiagnostic(sess.dcx(), FeatureDiagnosticForIssue { n });
@@ -184,6 +185,8 @@ pub fn add_feature_diagnostics_for_issue<G: EmissionGuarantee>(
     if sess.psess.unstable_features.is_nightly_build() {
         if feature_from_cli {
             err.subdiagnostic(sess.dcx(), CliFeatureDiagnosticHelp { feature });
+        } else if let Some(span) = inject_span {
+            err.subdiagnostic(sess.dcx(), FeatureDiagnosticSuggestion { feature, span });
         } else {
             err.subdiagnostic(sess.dcx(), FeatureDiagnosticHelp { feature });
         }

compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs

@@ -3510,9 +3510,11 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
             }
             ObligationCauseCode::TrivialBound => {
                 err.help("see issue #48214");
-                if tcx.sess.opts.unstable_features.is_nightly_build() {
+                tcx.disabled_nightly_features(
-                    err.help("add `#![feature(trivial_bounds)]` to the crate attributes to enable");
+                    err,
-                }
+                    Some(tcx.local_def_id_to_hir_id(body_id)),
+                    [(String::new(), sym::trivial_bounds)],
+                );
             }
             ObligationCauseCode::OpaqueReturnType(expr_info) => {
                 if let Some((expr_ty, expr_span)) = expr_info {

src/librustdoc/passes/check_custom_code_classes.rs

@@ -75,6 +75,7 @@ pub(crate) fn look_for_custom_classes<'tcx>(cx: &DocContext<'tcx>, item: &Item)
             sym::custom_code_classes_in_docs,
             GateIssue::Language,
             false,
+            None,
         );
 
         err.note(

tests/ui/check-static-values-constraints.stderr

@@ -36,8 +36,11 @@ LL |     field2: SafeEnum::Variant4("str".to_string()),
    |                                      ^^^^^^^^^^^
    |
    = note: calls in statics are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
    = note: consider wrapping this expression in `Lazy::new(|| ...)` from the `once_cell` crate: https://crates.io/crates/once_cell
+help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+   |
+LL + #![feature(const_trait_impl)]
+   |
 
 error[E0010]: allocations are not allowed in statics
   --> $DIR/check-static-values-constraints.rs:96:5

tests/ui/const-generics/adt_const_params/suggest_feature_only_when_possible.rs

@@ -5,11 +5,16 @@
 // Can never be used as const generics.
 fn uwu_0<const N: &'static mut ()>() {}
 //~^ ERROR: forbidden as the type of a const generic
+//~| HELP: add `#![feature(adt_const_params)]`
+//~| HELP: add `#![feature(adt_const_params)]`
+//~| HELP: add `#![feature(adt_const_params)]`
+//~| HELP: add `#![feature(adt_const_params)]`
+//~| HELP: add `#![feature(adt_const_params)]`
+//~| HELP: add `#![feature(adt_const_params)]`
 
 // Needs the feature but can be used, so suggest adding the feature.
 fn owo_0<const N: &'static u32>() {}
 //~^ ERROR: forbidden as the type of a const generic
-//~^^ HELP: add `#![feature(adt_const_params)]`
 
 // Can only be used in const generics with changes.
 struct Meow {
@@ -18,22 +23,17 @@ struct Meow {
 
 fn meow_0<const N: Meow>() {}
 //~^ ERROR: forbidden as the type of a const generic
-//~^^ HELP: add `#![feature(adt_const_params)]`
 fn meow_1<const N: &'static Meow>() {}
 //~^ ERROR: forbidden as the type of a const generic
-//~^^ HELP: add `#![feature(adt_const_params)]`
 fn meow_2<const N: [Meow; 100]>() {}
 //~^ ERROR: forbidden as the type of a const generic
-//~^^ HELP: add `#![feature(adt_const_params)]`
 fn meow_3<const N: (Meow, u8)>() {}
 //~^ ERROR: forbidden as the type of a const generic
-//~^^ HELP: add `#![feature(adt_const_params)]`
 
 // This is suboptimal that it thinks it can be used
 // but better to suggest the feature to the user.
 fn meow_4<const N: (Meow, String)>() {}
 //~^ ERROR: forbidden as the type of a const generic
-//~^^ HELP: add `#![feature(adt_const_params)]`
 
 // Non-local ADT that does not impl `ConstParamTy`
 fn nya_0<const N: String>() {}

tests/ui/const-generics/adt_const_params/suggest_feature_only_when_possible.stderr

@@ -7,58 +7,76 @@ LL | fn uwu_0<const N: &'static mut ()>() {}
    = note: the only supported types are integers, `bool` and `char`
 
 error: `&'static u32` is forbidden as the type of a const generic parameter
-  --> $DIR/suggest_feature_only_when_possible.rs:10:19
+  --> $DIR/suggest_feature_only_when_possible.rs:16:19
    |
 LL | fn owo_0<const N: &'static u32>() {}
    |                   ^^^^^^^^^^^^
    |
    = note: the only supported types are integers, `bool` and `char`
-   = help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+   |
+LL + #![feature(adt_const_params)]
+   |
 
 error: `Meow` is forbidden as the type of a const generic parameter
-  --> $DIR/suggest_feature_only_when_possible.rs:19:20
+  --> $DIR/suggest_feature_only_when_possible.rs:24:20
    |
 LL | fn meow_0<const N: Meow>() {}
    |                    ^^^^
    |
    = note: the only supported types are integers, `bool` and `char`
-   = help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+   |
+LL + #![feature(adt_const_params)]
+   |
 
 error: `&'static Meow` is forbidden as the type of a const generic parameter
-  --> $DIR/suggest_feature_only_when_possible.rs:22:20
+  --> $DIR/suggest_feature_only_when_possible.rs:26:20
    |
 LL | fn meow_1<const N: &'static Meow>() {}
    |                    ^^^^^^^^^^^^^
    |
    = note: the only supported types are integers, `bool` and `char`
-   = help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+   |
+LL + #![feature(adt_const_params)]
+   |
 
 error: `[Meow; 100]` is forbidden as the type of a const generic parameter
-  --> $DIR/suggest_feature_only_when_possible.rs:25:20
+  --> $DIR/suggest_feature_only_when_possible.rs:28:20
    |
 LL | fn meow_2<const N: [Meow; 100]>() {}
    |                    ^^^^^^^^^^^
    |
    = note: the only supported types are integers, `bool` and `char`
-   = help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+   |
+LL + #![feature(adt_const_params)]
+   |
 
 error: `(Meow, u8)` is forbidden as the type of a const generic parameter
-  --> $DIR/suggest_feature_only_when_possible.rs:28:20
+  --> $DIR/suggest_feature_only_when_possible.rs:30:20
    |
 LL | fn meow_3<const N: (Meow, u8)>() {}
    |                    ^^^^^^^^^^
    |
    = note: the only supported types are integers, `bool` and `char`
-   = help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+   |
+LL + #![feature(adt_const_params)]
+   |
 
 error: `(Meow, String)` is forbidden as the type of a const generic parameter
-  --> $DIR/suggest_feature_only_when_possible.rs:34:20
+  --> $DIR/suggest_feature_only_when_possible.rs:35:20
    |
 LL | fn meow_4<const N: (Meow, String)>() {}
    |                    ^^^^^^^^^^^^^^
    |
    = note: the only supported types are integers, `bool` and `char`
-   = help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+   |
+LL + #![feature(adt_const_params)]
+   |
 
 error: `String` is forbidden as the type of a const generic parameter
   --> $DIR/suggest_feature_only_when_possible.rs:39:19

tests/ui/const-generics/const-param-elided-lifetime.min.stderr

@@ -35,7 +35,10 @@ LL | struct A<const N: &u8>;
    |                   ^^^
    |
    = note: the only supported types are integers, `bool` and `char`
-   = help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+   |
+LL + #![feature(adt_const_params)]
+   |
 
 error: `&u8` is forbidden as the type of a const generic parameter
   --> $DIR/const-param-elided-lifetime.rs:14:15
@@ -44,7 +47,10 @@ LL | impl<const N: &u8> A<N> {
    |               ^^^
    |
    = note: the only supported types are integers, `bool` and `char`
-   = help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+   |
+LL + #![feature(adt_const_params)]
+   |
 
 error: `&u8` is forbidden as the type of a const generic parameter
   --> $DIR/const-param-elided-lifetime.rs:22:15
@@ -53,7 +59,10 @@ LL | impl<const N: &u8> B for A<N> {}
    |               ^^^
    |
    = note: the only supported types are integers, `bool` and `char`
-   = help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+   |
+LL + #![feature(adt_const_params)]
+   |
 
 error: `&u8` is forbidden as the type of a const generic parameter
   --> $DIR/const-param-elided-lifetime.rs:26:17
@@ -62,7 +71,10 @@ LL | fn bar<const N: &u8>() {}
    |                 ^^^
    |
    = note: the only supported types are integers, `bool` and `char`
-   = help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+   |
+LL + #![feature(adt_const_params)]
+   |
 
 error: `&u8` is forbidden as the type of a const generic parameter
   --> $DIR/const-param-elided-lifetime.rs:17:21
@@ -71,7 +83,10 @@ LL |     fn foo<const M: &u8>(&self) {}
    |                     ^^^
    |
    = note: the only supported types are integers, `bool` and `char`
-   = help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+   |
+LL + #![feature(adt_const_params)]
+   |
 
 error: aborting due to 10 previous errors
 

tests/ui/const-generics/const-param-type-depends-on-const-param.min.stderr

@@ -21,7 +21,10 @@ LL | pub struct Dependent<const N: usize, const X: [u8; N]>([(); N]);
    |                                               ^^^^^^^
    |
    = note: the only supported types are integers, `bool` and `char`
-   = help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+   |
+LL + #![feature(adt_const_params)]
+   |
 
 error: `[u8; N]` is forbidden as the type of a const generic parameter
   --> $DIR/const-param-type-depends-on-const-param.rs:15:35
@@ -30,7 +33,10 @@ LL | pub struct SelfDependent<const N: [u8; N]>;
    |                                   ^^^^^^^
    |
    = note: the only supported types are integers, `bool` and `char`
-   = help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+   |
+LL + #![feature(adt_const_params)]
+   |
 
 error: aborting due to 4 previous errors
 

tests/ui/const-generics/generic_const_exprs/array-size-in-generic-struct-param.min.stderr

@@ -23,7 +23,10 @@ LL | struct B<const CFG: Config> {
    |                     ^^^^^^
    |
    = note: the only supported types are integers, `bool` and `char`
-   = help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+   |
+LL + #![feature(adt_const_params)]
+   |
 
 error: aborting due to 3 previous errors
 

tests/ui/const-generics/generic_const_exprs/unify-op-with-fn-call.stderr

@@ -54,7 +54,10 @@ note: impl defined here, but it is not `const`
 LL | impl const std::ops::Add for Foo {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    = note: calls in constants are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(effects)]` to the crate attributes to enable
+help: add `#![feature(effects)]` to the crate attributes to enable
+   |
+LL + #![feature(effects)]
+   |
 
 error[E0015]: cannot call non-const fn `<Foo as Add>::add` in constants
   --> $DIR/unify-op-with-fn-call.rs:21:13
@@ -63,7 +66,10 @@ LL |     bar::<{ std::ops::Add::add(N, N) }>();
    |             ^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: calls in constants are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(effects)]` to the crate attributes to enable
+help: add `#![feature(effects)]` to the crate attributes to enable
+   |
+LL + #![feature(effects)]
+   |
 
 error[E0015]: cannot call non-const fn `<usize as Add>::add` in constants
   --> $DIR/unify-op-with-fn-call.rs:30:14
@@ -72,7 +78,10 @@ LL |     bar2::<{ std::ops::Add::add(N, N) }>();
    |              ^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: calls in constants are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(effects)]` to the crate attributes to enable
+help: add `#![feature(effects)]` to the crate attributes to enable
+   |
+LL + #![feature(effects)]
+   |
 
 error: aborting due to 7 previous errors
 

tests/ui/const-generics/intrinsics-type_name-as-const-argument.min.stderr

@@ -14,7 +14,10 @@ LL | trait Trait<const S: &'static str> {}
    |                      ^^^^^^^^^^^^
    |
    = note: the only supported types are integers, `bool` and `char`
-   = help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+   |
+LL + #![feature(adt_const_params)]
+   |
 
 error: aborting due to 2 previous errors
 

tests/ui/const-generics/issue-93647.stderr

@@ -6,7 +6,10 @@ LL |     (||1usize)()
    |
    = note: closures need an RFC before allowed to be called in constants
    = note: calls in constants are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+   |
+LL + #![feature(const_trait_impl)]
+   |
 
 error: aborting due to 1 previous error
 

tests/ui/const-generics/issues/issue-56445-1.min.stderr

@@ -13,7 +13,10 @@ LL | struct Bug<'a, const S: &'a str>(PhantomData<&'a ()>);
    |                         ^^^^^^^
    |
    = note: the only supported types are integers, `bool` and `char`
-   = help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+   |
+LL + #![feature(adt_const_params)]
+   |
 
 error: aborting due to 2 previous errors
 

tests/ui/const-generics/issues/issue-62878.min.stderr

@@ -13,7 +13,10 @@ LL | fn foo<const N: usize, const A: [u8; N]>() {}
    |                                 ^^^^^^^
    |
    = note: the only supported types are integers, `bool` and `char`
-   = help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+   |
+LL + #![feature(adt_const_params)]
+   |
 
 error[E0747]: type provided when a constant was expected
   --> $DIR/issue-62878.rs:10:11
@@ -22,7 +25,10 @@ LL |     foo::<_, { [1] }>();
    |           ^
    |
    = help: const arguments cannot yet be inferred with `_`
-   = help: add `#![feature(generic_arg_infer)]` to the crate attributes to enable
+help: add `#![feature(generic_arg_infer)]` to the crate attributes to enable
+   |
+LL + #![feature(generic_arg_infer)]
+   |
 
 error: aborting due to 3 previous errors
 

tests/ui/const-generics/issues/issue-63322-forbid-dyn.min.stderr

@@ -5,7 +5,10 @@ LL | fn test<const T: &'static dyn A>() {
    |                  ^^^^^^^^^^^^^^
    |
    = note: the only supported types are integers, `bool` and `char`
-   = help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+   |
+LL + #![feature(adt_const_params)]
+   |
 
 error: aborting due to 1 previous error
 

tests/ui/const-generics/issues/issue-67185-2.stderr

@@ -8,7 +8,10 @@ LL |     <u8 as Baz>::Quaks: Bar,
              [u16; 4]
              [[u16; 3]; 3]
    = help: see issue #48214
-   = help: add `#![feature(trivial_bounds)]` to the crate attributes to enable
+help: add `#![feature(trivial_bounds)]` to the crate attributes to enable
+   |
+LL + #![feature(trivial_bounds)]
+   |
 
 error[E0277]: the trait bound `[[u16; 3]; 2]: Bar` is not satisfied
   --> $DIR/issue-67185-2.rs:14:5
@@ -20,7 +23,10 @@ LL |     [<u8 as Baz>::Quaks; 2]: Bar,
              [u16; 4]
              [[u16; 3]; 3]
    = help: see issue #48214
-   = help: add `#![feature(trivial_bounds)]` to the crate attributes to enable
+help: add `#![feature(trivial_bounds)]` to the crate attributes to enable
+   |
+LL + #![feature(trivial_bounds)]
+   |
 
 error[E0277]: the trait bound `[u16; 3]: Bar` is not satisfied
   --> $DIR/issue-67185-2.rs:21:6

tests/ui/const-generics/issues/issue-68366.full.stderr

@@ -5,7 +5,10 @@ LL | struct Collatz<const N: Option<usize>>;
    |                         ^^^^^^^^^^^^^
    |
    = note: the only supported types are integers, `bool` and `char`
-   = help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+   |
+LL + #![feature(adt_const_params)]
+   |
 
 error[E0207]: the const parameter `N` is not constrained by the impl trait, self type, or predicates
   --> $DIR/issue-68366.rs:12:7

tests/ui/const-generics/issues/issue-68366.min.stderr

@@ -14,7 +14,10 @@ LL | struct Collatz<const N: Option<usize>>;
    |                         ^^^^^^^^^^^^^
    |
    = note: the only supported types are integers, `bool` and `char`
-   = help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+   |
+LL + #![feature(adt_const_params)]
+   |
 
 error[E0207]: the const parameter `N` is not constrained by the impl trait, self type, or predicates
   --> $DIR/issue-68366.rs:12:7

tests/ui/const-generics/issues/issue-68615-adt.min.stderr

@@ -5,7 +5,10 @@ LL | struct Const<const V: [usize; 0]> {}
    |                       ^^^^^^^^^^
    |
    = note: the only supported types are integers, `bool` and `char`
-   = help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+   |
+LL + #![feature(adt_const_params)]
+   |
 
 error: aborting due to 1 previous error
 

tests/ui/const-generics/issues/issue-68615-array.min.stderr

@@ -5,7 +5,10 @@ LL | struct Foo<const V: [usize; 0] > {}
    |                     ^^^^^^^^^^
    |
    = note: the only supported types are integers, `bool` and `char`
-   = help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+   |
+LL + #![feature(adt_const_params)]
+   |
 
 error: aborting due to 1 previous error
 

tests/ui/const-generics/issues/issue-71169.min.stderr

@@ -13,7 +13,10 @@ LL | fn foo<const LEN: usize, const DATA: [u8; LEN]>() {}
    |                                      ^^^^^^^^^
    |
    = note: the only supported types are integers, `bool` and `char`
-   = help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+   |
+LL + #![feature(adt_const_params)]
+   |
 
 error: aborting due to 2 previous errors
 

tests/ui/const-generics/issues/issue-73491.min.stderr

@@ -5,7 +5,10 @@ LL | fn hoge<const IN: [u32; LEN]>() {}
    |                   ^^^^^^^^^^
    |
    = note: the only supported types are integers, `bool` and `char`
-   = help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+   |
+LL + #![feature(adt_const_params)]
+   |
 
 error: aborting due to 1 previous error
 

tests/ui/const-generics/issues/issue-73727-static-reference-array-const-param.min.stderr

@@ -5,7 +5,10 @@ LL | fn a<const X: &'static [u32]>() {}
    |               ^^^^^^^^^^^^^^
    |
    = note: the only supported types are integers, `bool` and `char`
-   = help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+   |
+LL + #![feature(adt_const_params)]
+   |
 
 error: aborting due to 1 previous error
 

tests/ui/const-generics/issues/issue-74101.min.stderr

@@ -5,7 +5,10 @@ LL | fn test<const N: [u8; 1 + 2]>() {}
    |                  ^^^^^^^^^^^
    |
    = note: the only supported types are integers, `bool` and `char`
-   = help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+   |
+LL + #![feature(adt_const_params)]
+   |
 
 error: `[u8; 1 + 2]` is forbidden as the type of a const generic parameter
   --> $DIR/issue-74101.rs:9:21
@@ -14,7 +17,10 @@ LL | struct Foo<const N: [u8; 1 + 2]>;
    |                     ^^^^^^^^^^^
    |
    = note: the only supported types are integers, `bool` and `char`
-   = help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+   |
+LL + #![feature(adt_const_params)]
+   |
 
 error: aborting due to 2 previous errors
 

tests/ui/const-generics/issues/issue-74255.min.stderr

@@ -5,7 +5,10 @@ LL |     fn ice_struct_fn<const I: IceEnum>() {}
    |                               ^^^^^^^
    |
    = note: the only supported types are integers, `bool` and `char`
-   = help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+   |
+LL + #![feature(adt_const_params)]
+   |
 
 error: aborting due to 1 previous error
 

tests/ui/const-generics/issues/issue-74950.min.stderr

@@ -5,7 +5,10 @@ LL | struct Outer<const I: Inner>;
    |                       ^^^^^
    |
    = note: the only supported types are integers, `bool` and `char`
-   = help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+   |
+LL + #![feature(adt_const_params)]
+   |
 
 error: `Inner` is forbidden as the type of a const generic parameter
   --> $DIR/issue-74950.rs:19:23
@@ -14,8 +17,11 @@ LL | struct Outer<const I: Inner>;
    |                       ^^^^^
    |
    = note: the only supported types are integers, `bool` and `char`
-   = help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+   |
+LL + #![feature(adt_const_params)]
+   |
 
 error: `Inner` is forbidden as the type of a const generic parameter
   --> $DIR/issue-74950.rs:19:23
@@ -24,8 +30,11 @@ LL | struct Outer<const I: Inner>;
    |                       ^^^^^
    |
    = note: the only supported types are integers, `bool` and `char`
-   = help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+   |
+LL + #![feature(adt_const_params)]
+   |
 
 error: `Inner` is forbidden as the type of a const generic parameter
   --> $DIR/issue-74950.rs:19:23
@@ -34,8 +43,11 @@ LL | struct Outer<const I: Inner>;
    |                       ^^^^^
    |
    = note: the only supported types are integers, `bool` and `char`
-   = help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+   |
+LL + #![feature(adt_const_params)]
+   |
 
 error: aborting due to 4 previous errors
 

tests/ui/const-generics/issues/issue-75047.min.stderr

@@ -5,7 +5,10 @@ LL | struct Foo<const N: [u8; Bar::<u32>::value()]>;
    |                     ^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: the only supported types are integers, `bool` and `char`
-   = help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+   |
+LL + #![feature(adt_const_params)]
+   |
 
 error: aborting due to 1 previous error
 

tests/ui/const-generics/issues/issue-90318.stderr

@@ -29,7 +29,10 @@ LL |     If<{ TypeId::of::<T>() != TypeId::of::<()>() }>: True,
 note: impl defined here, but it is not `const`
   --> $SRC_DIR/core/src/any.rs:LL:COL
    = note: calls in constants are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+   |
+LL + #![feature(const_trait_impl)]
+   |
 
 error[E0015]: cannot call non-const operator in constants
   --> $DIR/issue-90318.rs:22:10
@@ -40,7 +43,10 @@ LL |     If<{ TypeId::of::<T>() != TypeId::of::<()>() }>: True,
 note: impl defined here, but it is not `const`
   --> $SRC_DIR/core/src/any.rs:LL:COL
    = note: calls in constants are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+   |
+LL + #![feature(const_trait_impl)]
+   |
 
 error: aborting due to 4 previous errors
 

tests/ui/const-generics/lifetime-in-const-param.stderr

@@ -11,7 +11,10 @@ LL | struct S<'a, const N: S2>(&'a ());
    |                       ^^
    |
    = note: the only supported types are integers, `bool` and `char`
-   = help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+   |
+LL + #![feature(adt_const_params)]
+   |
 
 error: aborting due to 2 previous errors
 

tests/ui/const-generics/min_const_generics/complex-types.stderr

@@ -5,7 +5,10 @@ LL | struct Foo<const N: [u8; 0]>;
    |                     ^^^^^^^
    |
    = note: the only supported types are integers, `bool` and `char`
-   = help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+   |
+LL + #![feature(adt_const_params)]
+   |
 
 error: `()` is forbidden as the type of a const generic parameter
   --> $DIR/complex-types.rs:6:21
@@ -14,7 +17,10 @@ LL | struct Bar<const N: ()>;
    |                     ^^
    |
    = note: the only supported types are integers, `bool` and `char`
-   = help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+   |
+LL + #![feature(adt_const_params)]
+   |
 
 error: `No` is forbidden as the type of a const generic parameter
   --> $DIR/complex-types.rs:11:21
@@ -23,7 +29,10 @@ LL | struct Fez<const N: No>;
    |                     ^^
    |
    = note: the only supported types are integers, `bool` and `char`
-   = help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+   |
+LL + #![feature(adt_const_params)]
+   |
 
 error: `&'static u8` is forbidden as the type of a const generic parameter
   --> $DIR/complex-types.rs:14:21
@@ -32,7 +41,10 @@ LL | struct Faz<const N: &'static u8>;
    |                     ^^^^^^^^^^^
    |
    = note: the only supported types are integers, `bool` and `char`
-   = help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+   |
+LL + #![feature(adt_const_params)]
+   |
 
 error: `!` is forbidden as the type of a const generic parameter
   --> $DIR/complex-types.rs:17:21
@@ -49,7 +61,10 @@ LL | enum Goo<const N: ()> { A, B }
    |                   ^^
    |
    = note: the only supported types are integers, `bool` and `char`
-   = help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+   |
+LL + #![feature(adt_const_params)]
+   |
 
 error: `()` is forbidden as the type of a const generic parameter
   --> $DIR/complex-types.rs:23:20
@@ -58,7 +73,10 @@ LL | union Boo<const N: ()> { a: () }
    |                    ^^
    |
    = note: the only supported types are integers, `bool` and `char`
-   = help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+   |
+LL + #![feature(adt_const_params)]
+   |
 
 error: aborting due to 7 previous errors
 

tests/ui/const-generics/nested-type.min.stderr

@@ -30,7 +30,10 @@ LL | | }]>;
    | |__^
    |
    = note: the only supported types are integers, `bool` and `char`
-   = help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+   |
+LL + #![feature(adt_const_params)]
+   |
 
 error: aborting due to 2 previous errors
 

tests/ui/const-generics/slice-const-param-mismatch.min.stderr

@@ -5,7 +5,10 @@ LL | struct ConstString<const T: &'static str>;
    |                             ^^^^^^^^^^^^
    |
    = note: the only supported types are integers, `bool` and `char`
-   = help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+   |
+LL + #![feature(adt_const_params)]
+   |
 
 error: `&'static [u8]` is forbidden as the type of a const generic parameter
   --> $DIR/slice-const-param-mismatch.rs:9:28
@@ -14,7 +17,10 @@ LL | struct ConstBytes<const T: &'static [u8]>;
    |                            ^^^^^^^^^^^^^
    |
    = note: the only supported types are integers, `bool` and `char`
-   = help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+   |
+LL + #![feature(adt_const_params)]
+   |
 
 error[E0308]: mismatched types
   --> $DIR/slice-const-param-mismatch.rs:14:35

tests/ui/const-generics/std/const-generics-range.min.stderr

@@ -5,7 +5,10 @@ LL | struct _Range<const R: std::ops::Range<usize>>;
    |                        ^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: the only supported types are integers, `bool` and `char`
-   = help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+   |
+LL + #![feature(adt_const_params)]
+   |
 
 error: `RangeFrom<usize>` is forbidden as the type of a const generic parameter
   --> $DIR/const-generics-range.rs:13:28
@@ -14,7 +17,10 @@ LL | struct _RangeFrom<const R: std::ops::RangeFrom<usize>>;
    |                            ^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: the only supported types are integers, `bool` and `char`
-   = help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+   |
+LL + #![feature(adt_const_params)]
+   |
 
 error: `RangeFull` is forbidden as the type of a const generic parameter
   --> $DIR/const-generics-range.rs:18:28
@@ -23,7 +29,10 @@ LL | struct _RangeFull<const R: std::ops::RangeFull>;
    |                            ^^^^^^^^^^^^^^^^^^^
    |
    = note: the only supported types are integers, `bool` and `char`
-   = help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+   |
+LL + #![feature(adt_const_params)]
+   |
 
 error: `RangeInclusive<usize>` is forbidden as the type of a const generic parameter
   --> $DIR/const-generics-range.rs:24:33
@@ -32,7 +41,10 @@ LL | struct _RangeInclusive<const R: std::ops::RangeInclusive<usize>>;
    |                                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: the only supported types are integers, `bool` and `char`
-   = help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+   |
+LL + #![feature(adt_const_params)]
+   |
 
 error: `RangeTo<usize>` is forbidden as the type of a const generic parameter
   --> $DIR/const-generics-range.rs:29:26
@@ -41,7 +53,10 @@ LL | struct _RangeTo<const R: std::ops::RangeTo<usize>>;
    |                          ^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: the only supported types are integers, `bool` and `char`
-   = help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+   |
+LL + #![feature(adt_const_params)]
+   |
 
 error: `RangeToInclusive<usize>` is forbidden as the type of a const generic parameter
   --> $DIR/const-generics-range.rs:34:35
@@ -50,7 +65,10 @@ LL | struct _RangeToInclusive<const R: std::ops::RangeToInclusive<usize>>;
    |                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: the only supported types are integers, `bool` and `char`
-   = help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+   |
+LL + #![feature(adt_const_params)]
+   |
 
 error: aborting due to 6 previous errors
 

tests/ui/const-generics/transmute-const-param-static-reference.min.stderr

@@ -5,7 +5,10 @@ LL | struct Const<const P: &'static ()>;
    |                       ^^^^^^^^^^^
    |
    = note: the only supported types are integers, `bool` and `char`
-   = help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+   |
+LL + #![feature(adt_const_params)]
+   |
 
 error: aborting due to 1 previous error
 

tests/ui/const-generics/type-dependent/issue-71348.min.stderr

@@ -5,7 +5,10 @@ LL | trait Get<'a, const N: &'static str> {
    |                        ^^^^^^^^^^^^
    |
    = note: the only supported types are integers, `bool` and `char`
-   = help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+   |
+LL + #![feature(adt_const_params)]
+   |
 
 error: `&'static str` is forbidden as the type of a const generic parameter
   --> $DIR/issue-71348.rs:18:25
@@ -14,7 +17,10 @@ LL |     fn ask<'a, const N: &'static str>(&'a self) -> &'a <Self as Get<N>>::Ta
    |                         ^^^^^^^^^^^^
    |
    = note: the only supported types are integers, `bool` and `char`
-   = help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+   |
+LL + #![feature(adt_const_params)]
+   |
 
 error: aborting due to 2 previous errors
 

tests/ui/consts/const-fn-error.stderr

@@ -23,7 +23,10 @@ LL |     for i in 0..x {
 note: impl defined here, but it is not `const`
   --> $SRC_DIR/core/src/iter/traits/collect.rs:LL:COL
    = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+   |
+LL + #![feature(const_trait_impl)]
+   |
 
 error[E0658]: mutable references are not allowed in constant functions
   --> $DIR/const-fn-error.rs:5:14
@@ -42,7 +45,10 @@ LL |     for i in 0..x {
    |              ^^^^
    |
    = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+   |
+LL + #![feature(const_trait_impl)]
+   |
 
 error: aborting due to 4 previous errors
 

tests/ui/consts/const-for-feature-gate.stderr

@@ -17,7 +17,10 @@ LL |     for _ in 0..5 {}
 note: impl defined here, but it is not `const`
   --> $SRC_DIR/core/src/iter/traits/collect.rs:LL:COL
    = note: calls in constants are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+   |
+LL + #![feature(const_trait_impl)]
+   |
 
 error[E0658]: mutable references are not allowed in constants
   --> $DIR/const-for-feature-gate.rs:4:14
@@ -36,7 +39,10 @@ LL |     for _ in 0..5 {}
    |              ^^^^
    |
    = note: calls in constants are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+   |
+LL + #![feature(const_trait_impl)]
+   |
 
 error: aborting due to 4 previous errors
 

tests/ui/consts/const-for.stderr

@@ -7,7 +7,10 @@ LL |     for _ in 0..5 {}
 note: impl defined here, but it is not `const`
   --> $SRC_DIR/core/src/iter/traits/collect.rs:LL:COL
    = note: calls in constants are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+   |
+LL + #![feature(const_trait_impl)]
+   |
 
 error[E0015]: cannot call non-const fn `<std::ops::Range<i32> as Iterator>::next` in constants
   --> $DIR/const-for.rs:5:14
@@ -16,7 +19,10 @@ LL |     for _ in 0..5 {}
    |              ^^^^
    |
    = note: calls in constants are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+   |
+LL + #![feature(const_trait_impl)]
+   |
 
 error: aborting due to 2 previous errors
 

tests/ui/consts/const-try-feature-gate.stderr

@@ -17,7 +17,10 @@ LL |     Some(())?;
 note: impl defined here, but it is not `const`
   --> $SRC_DIR/core/src/option.rs:LL:COL
    = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+   |
+LL + #![feature(const_trait_impl)]
+   |
 
 error[E0015]: `?` cannot convert from residual of `Option<()>` in constant functions
   --> $DIR/const-try-feature-gate.rs:4:5
@@ -28,7 +31,10 @@ LL |     Some(())?;
 note: impl defined here, but it is not `const`
   --> $SRC_DIR/core/src/option.rs:LL:COL
    = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+   |
+LL + #![feature(const_trait_impl)]
+   |
 
 error: aborting due to 3 previous errors
 

tests/ui/consts/const-try.stderr

@@ -10,7 +10,10 @@ note: impl defined here, but it is not `const`
 LL | impl const Try for TryMe {
    | ^^^^^^^^^^^^^^^^^^^^^^^^
    = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(effects)]` to the crate attributes to enable
+help: add `#![feature(effects)]` to the crate attributes to enable
+   |
+LL + #![feature(effects)]
+   |
 
 error[E0015]: `?` cannot convert from residual of `TryMe` in constant functions
   --> $DIR/const-try.rs:33:5
@@ -24,7 +27,10 @@ note: impl defined here, but it is not `const`
 LL | impl const FromResidual<Error> for TryMe {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(effects)]` to the crate attributes to enable
+help: add `#![feature(effects)]` to the crate attributes to enable
+   |
+LL + #![feature(effects)]
+   |
 
 error: aborting due to 2 previous errors
 

tests/ui/consts/constifconst-call-in-const-position.stderr

@@ -14,7 +14,10 @@ LL |     [0; T::a()]
    |         ^^^^^^
    |
    = note: calls in constants are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(effects)]` to the crate attributes to enable
+help: add `#![feature(effects)]` to the crate attributes to enable
+   |
+LL + #![feature(effects)]
+   |
 
 error[E0015]: cannot call non-const fn `<T as Tr>::a` in constants
   --> $DIR/constifconst-call-in-const-position.rs:16:38
@@ -23,7 +26,10 @@ LL | const fn foo<T: ~const Tr>() -> [u8; T::a()] {
    |                                      ^^^^^^
    |
    = note: calls in constants are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(effects)]` to the crate attributes to enable
+help: add `#![feature(effects)]` to the crate attributes to enable
+   |
+LL + #![feature(effects)]
+   |
 
 error: aborting due to 2 previous errors; 1 warning emitted
 

tests/ui/consts/control-flow/loop.stderr

@@ -37,7 +37,10 @@ LL |     for i in 0..4 {
 note: impl defined here, but it is not `const`
   --> $SRC_DIR/core/src/iter/traits/collect.rs:LL:COL
    = note: calls in constants are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+   |
+LL + #![feature(const_trait_impl)]
+   |
 
 error[E0658]: mutable references are not allowed in constants
   --> $DIR/loop.rs:53:14
@@ -56,7 +59,10 @@ LL |     for i in 0..4 {
    |              ^^^^
    |
    = note: calls in constants are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+   |
+LL + #![feature(const_trait_impl)]
+   |
 
 error[E0015]: cannot convert `std::ops::Range<i32>` into an iterator in constants
   --> $DIR/loop.rs:60:14
@@ -67,7 +73,10 @@ LL |     for i in 0..4 {
 note: impl defined here, but it is not `const`
   --> $SRC_DIR/core/src/iter/traits/collect.rs:LL:COL
    = note: calls in constants are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+   |
+LL + #![feature(const_trait_impl)]
+   |
 
 error[E0658]: mutable references are not allowed in constants
   --> $DIR/loop.rs:60:14
@@ -86,7 +95,10 @@ LL |     for i in 0..4 {
    |              ^^^^
    |
    = note: calls in constants are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+   |
+LL + #![feature(const_trait_impl)]
+   |
 
 error: aborting due to 8 previous errors
 

tests/ui/consts/control-flow/try.stderr

@@ -17,7 +17,10 @@ LL |     x?;
 note: impl defined here, but it is not `const`
   --> $SRC_DIR/core/src/option.rs:LL:COL
    = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+   |
+LL + #![feature(const_trait_impl)]
+   |
 
 error[E0015]: `?` cannot convert from residual of `Option<i32>` in constant functions
   --> $DIR/try.rs:6:5
@@ -28,7 +31,10 @@ LL |     x?;
 note: impl defined here, but it is not `const`
   --> $SRC_DIR/core/src/option.rs:LL:COL
    = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+   |
+LL + #![feature(const_trait_impl)]
+   |
 
 error: aborting due to 3 previous errors
 

tests/ui/consts/fn_trait_refs.stderr

@@ -81,7 +81,10 @@ LL |         assert!(test_one == (1, 1, 1));
    |                 ^^^^^^^^^^^^^^^^^^^^^
    |
    = note: calls in constants are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(effects)]` to the crate attributes to enable
+help: add `#![feature(effects)]` to the crate attributes to enable
+   |
+LL + #![feature(effects)]
+   |
 
 error[E0015]: cannot call non-const operator in constants
   --> $DIR/fn_trait_refs.rs:75:17
@@ -90,7 +93,10 @@ LL |         assert!(test_two == (2, 2));
    |                 ^^^^^^^^^^^^^^^^^^
    |
    = note: calls in constants are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(effects)]` to the crate attributes to enable
+help: add `#![feature(effects)]` to the crate attributes to enable
+   |
+LL + #![feature(effects)]
+   |
 
 error[E0015]: cannot call non-const closure in constant functions
   --> $DIR/fn_trait_refs.rs:17:5
@@ -99,11 +105,14 @@ LL |     f()
    |     ^^^
    |
    = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(effects)]` to the crate attributes to enable
 help: consider further restricting this bound
    |
 LL |     T: ~const Fn<()> + ~const Destruct + ~const std::ops::Fn<()>,
    |                                        +++++++++++++++++++++++++
+help: add `#![feature(effects)]` to the crate attributes to enable
+   |
+LL + #![feature(effects)]
+   |
 
 error[E0493]: destructor of `T` cannot be evaluated at compile-time
   --> $DIR/fn_trait_refs.rs:13:23
@@ -121,11 +130,14 @@ LL |     f()
    |     ^^^
    |
    = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(effects)]` to the crate attributes to enable
 help: consider further restricting this bound
    |
 LL |     T: ~const FnMut<()> + ~const Destruct + ~const std::ops::FnMut<()>,
    |                                           ++++++++++++++++++++++++++++
+help: add `#![feature(effects)]` to the crate attributes to enable
+   |
+LL + #![feature(effects)]
+   |
 
 error[E0493]: destructor of `T` cannot be evaluated at compile-time
   --> $DIR/fn_trait_refs.rs:20:27
@@ -143,11 +155,14 @@ LL |     f()
    |     ^^^
    |
    = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(effects)]` to the crate attributes to enable
 help: consider further restricting this bound
    |
 LL |     T: ~const FnOnce<()> + ~const std::ops::FnOnce<()>,
    |                          +++++++++++++++++++++++++++++
+help: add `#![feature(effects)]` to the crate attributes to enable
+   |
+LL + #![feature(effects)]
+   |
 
 error[E0493]: destructor of `T` cannot be evaluated at compile-time
   --> $DIR/fn_trait_refs.rs:34:21

tests/ui/consts/invalid-inline-const-in-match-arm.stderr

@@ -6,7 +6,10 @@ LL |         const { (|| {})() } => {}
    |
    = note: closures need an RFC before allowed to be called in constants
    = note: calls in constants are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+   |
+LL + #![feature(const_trait_impl)]
+   |
 
 error: aborting due to 1 previous error
 

tests/ui/consts/issue-103790.stderr

@@ -62,7 +62,10 @@ LL | struct S<const S: (), const S: S = { S }>;
    |                   ^^
    |
    = note: the only supported types are integers, `bool` and `char`
-   = help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+   |
+LL + #![feature(adt_const_params)]
+   |
 
 error: aborting due to 5 previous errors
 

tests/ui/consts/issue-28113.stderr

@@ -6,7 +6,10 @@ LL |     || -> u8 { 5 }()
    |
    = note: closures need an RFC before allowed to be called in constants
    = note: calls in constants are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+   |
+LL + #![feature(const_trait_impl)]
+   |
 
 error: aborting due to 1 previous error
 

tests/ui/consts/issue-56164.stderr

@@ -6,7 +6,10 @@ LL | const fn foo() { (||{})() }
    |
    = note: closures need an RFC before allowed to be called in constant functions
    = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+   |
+LL + #![feature(const_trait_impl)]
+   |
 
 error: function pointer calls are not allowed in constant functions
   --> $DIR/issue-56164.rs:5:5

tests/ui/consts/issue-68542-closure-in-array-len.stderr

@@ -6,7 +6,10 @@ LL |     a: [(); (|| { 0 })()]
    |
    = note: closures need an RFC before allowed to be called in constants
    = note: calls in constants are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+   |
+LL + #![feature(const_trait_impl)]
+   |
 
 error: aborting due to 1 previous error
 

tests/ui/consts/issue-73976-monomorphic.stderr

@@ -7,7 +7,10 @@ LL |     GetTypeId::<T>::VALUE == GetTypeId::<usize>::VALUE
 note: impl defined here, but it is not `const`
   --> $SRC_DIR/core/src/any.rs:LL:COL
    = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(effects)]` to the crate attributes to enable
+help: add `#![feature(effects)]` to the crate attributes to enable
+   |
+LL + #![feature(effects)]
+   |
 
 error: aborting due to 1 previous error
 

tests/ui/consts/issue-90870.fixed

@@ -1,37 +0,0 @@
-// Regression test for issue #90870.
-
-//@ run-rustfix
-
-#![allow(dead_code)]
-
-const fn f(a: &u8, b: &u8) -> bool {
-    *a == *b
-    //~^ ERROR: cannot call non-const operator in constant functions [E0015]
-    //~| HELP: consider dereferencing here
-    //~| HELP: add `#![feature(const_trait_impl)]`
-}
-
-const fn g(a: &&&&i64, b: &&&&i64) -> bool {
-    ****a == ****b
-    //~^ ERROR: cannot call non-const operator in constant functions [E0015]
-    //~| HELP: consider dereferencing here
-    //~| HELP: add `#![feature(const_trait_impl)]`
-}
-
-const fn h(mut a: &[u8], mut b: &[u8]) -> bool {
-    while let ([l, at @ ..], [r, bt @ ..]) = (a, b) {
-        if *l == *r {
-        //~^ ERROR: cannot call non-const operator in constant functions [E0015]
-        //~| HELP: consider dereferencing here
-        //~| HELP: add `#![feature(const_trait_impl)]`
-            a = at;
-            b = bt;
-        } else {
-            return false;
-        }
-    }
-
-    a.is_empty() && b.is_empty()
-}
-
-fn main() {}

tests/ui/consts/issue-90870.rs

@@ -1,21 +1,20 @@
 // Regression test for issue #90870.
 
-//@ run-rustfix
-
 #![allow(dead_code)]
 
 const fn f(a: &u8, b: &u8) -> bool {
+//~^ HELP: add `#![feature(const_trait_impl)]`
+//~| HELP: add `#![feature(const_trait_impl)]`
+//~| HELP: add `#![feature(const_trait_impl)]`
     a == b
     //~^ ERROR: cannot call non-const operator in constant functions [E0015]
     //~| HELP: consider dereferencing here
-    //~| HELP: add `#![feature(const_trait_impl)]`
 }
 
 const fn g(a: &&&&i64, b: &&&&i64) -> bool {
     a == b
     //~^ ERROR: cannot call non-const operator in constant functions [E0015]
     //~| HELP: consider dereferencing here
-    //~| HELP: add `#![feature(const_trait_impl)]`
 }
 
 const fn h(mut a: &[u8], mut b: &[u8]) -> bool {
@@ -23,7 +22,6 @@ const fn h(mut a: &[u8], mut b: &[u8]) -> bool {
         if l == r {
         //~^ ERROR: cannot call non-const operator in constant functions [E0015]
         //~| HELP: consider dereferencing here
-        //~| HELP: add `#![feature(const_trait_impl)]`
             a = at;
             b = bt;
         } else {

tests/ui/consts/issue-90870.stderr

@@ -1,15 +1,18 @@
 error[E0015]: cannot call non-const operator in constant functions
-  --> $DIR/issue-90870.rs:8:5
+  --> $DIR/issue-90870.rs:9:5
    |
 LL |     a == b
    |     ^^^^^^
    |
    = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
 help: consider dereferencing here
    |
 LL |     *a == *b
    |     +     +
+help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+   |
+LL + #![feature(const_trait_impl)]
+   |
 
 error[E0015]: cannot call non-const operator in constant functions
   --> $DIR/issue-90870.rs:15:5
@@ -18,24 +21,30 @@ LL |     a == b
    |     ^^^^^^
    |
    = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
 help: consider dereferencing here
    |
 LL |     ****a == ****b
    |     ++++     ++++
+help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+   |
+LL + #![feature(const_trait_impl)]
+   |
 
 error[E0015]: cannot call non-const operator in constant functions
-  --> $DIR/issue-90870.rs:23:12
+  --> $DIR/issue-90870.rs:22:12
    |
 LL |         if l == r {
    |            ^^^^^^
    |
    = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
 help: consider dereferencing here
    |
 LL |         if *l == *r {
    |            +     +
+help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+   |
+LL + #![feature(const_trait_impl)]
+   |
 
 error: aborting due to 3 previous errors
 

tests/ui/consts/issue-94675.stderr

@@ -15,7 +15,10 @@ LL |         self.bar[0] = baz.len();
 note: impl defined here, but it is not `const`
   --> $SRC_DIR/alloc/src/vec/mod.rs:LL:COL
    = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(effects)]` to the crate attributes to enable
+help: add `#![feature(effects)]` to the crate attributes to enable
+   |
+LL + #![feature(effects)]
+   |
 
 error: aborting due to 2 previous errors
 

tests/ui/consts/try-operator.stderr

@@ -13,7 +13,10 @@ LL |         Err(())?;
 note: impl defined here, but it is not `const`
   --> $SRC_DIR/core/src/result.rs:LL:COL
    = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(effects)]` to the crate attributes to enable
+help: add `#![feature(effects)]` to the crate attributes to enable
+   |
+LL + #![feature(effects)]
+   |
 
 error[E0015]: `?` cannot convert from residual of `Result<bool, ()>` in constant functions
   --> $DIR/try-operator.rs:10:9
@@ -24,7 +27,10 @@ LL |         Err(())?;
 note: impl defined here, but it is not `const`
   --> $SRC_DIR/core/src/result.rs:LL:COL
    = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(effects)]` to the crate attributes to enable
+help: add `#![feature(effects)]` to the crate attributes to enable
+   |
+LL + #![feature(effects)]
+   |
 
 error[E0015]: `?` cannot determine the branch of `Option<()>` in constant functions
   --> $DIR/try-operator.rs:18:9
@@ -35,7 +41,10 @@ LL |         None?;
 note: impl defined here, but it is not `const`
   --> $SRC_DIR/core/src/option.rs:LL:COL
    = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(effects)]` to the crate attributes to enable
+help: add `#![feature(effects)]` to the crate attributes to enable
+   |
+LL + #![feature(effects)]
+   |
 
 error[E0015]: `?` cannot convert from residual of `Option<()>` in constant functions
   --> $DIR/try-operator.rs:18:9
@@ -46,7 +55,10 @@ LL |         None?;
 note: impl defined here, but it is not `const`
   --> $SRC_DIR/core/src/option.rs:LL:COL
    = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(effects)]` to the crate attributes to enable
+help: add `#![feature(effects)]` to the crate attributes to enable
+   |
+LL + #![feature(effects)]
+   |
 
 error: aborting due to 5 previous errors
 

tests/ui/consts/unstable-const-fn-in-libcore.stderr

@@ -11,11 +11,14 @@ LL |             Opt::None => f(),
    |                          ^^^
    |
    = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(effects)]` to the crate attributes to enable
 help: consider further restricting this bound
    |
 LL |     const fn unwrap_or_else<F: ~const FnOnce() -> T + ~const std::ops::FnOnce<()>>(self, f: F) -> T {
    |                                                     +++++++++++++++++++++++++++++
+help: add `#![feature(effects)]` to the crate attributes to enable
+   |
+LL + #![feature(effects)]
+   |
 
 error[E0493]: destructor of `F` cannot be evaluated at compile-time
   --> $DIR/unstable-const-fn-in-libcore.rs:19:60

tests/ui/cross/cross-fn-cache-hole.stderr

@@ -10,7 +10,10 @@ help: this trait has no implementations, consider adding one
 LL | trait Bar<X> { }
    | ^^^^^^^^^^^^
    = help: see issue #48214
-   = help: add `#![feature(trivial_bounds)]` to the crate attributes to enable
+help: add `#![feature(trivial_bounds)]` to the crate attributes to enable
+   |
+LL + #![feature(trivial_bounds)]
+   |
 
 error[E0277]: the trait bound `i32: Bar<u32>` is not satisfied
   --> $DIR/cross-fn-cache-hole.rs:30:15

tests/ui/feature-gates/feature-gate-adt_const_params.stderr

@@ -5,7 +5,10 @@ LL | struct Foo<const NAME: &'static str>;
    |                        ^^^^^^^^^^^^
    |
    = note: the only supported types are integers, `bool` and `char`
-   = help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+   |
+LL + #![feature(adt_const_params)]
+   |
 
 error: aborting due to 1 previous error
 

tests/ui/feature-gates/feature-gate-generic_arg_infer.normal.stderr

@@ -27,7 +27,10 @@ LL |     let _x = foo::<_>([1,2]);
    |                    ^
    |
    = help: const arguments cannot yet be inferred with `_`
-   = help: add `#![feature(generic_arg_infer)]` to the crate attributes to enable
+help: add `#![feature(generic_arg_infer)]` to the crate attributes to enable
+   |
+LL + #![feature(generic_arg_infer)]
+   |
 
 error[E0658]: using `_` for array lengths is unstable
   --> $DIR/feature-gate-generic_arg_infer.rs:11:27

tests/ui/feature-gates/feature-gate-trivial_bounds.stderr

@@ -6,7 +6,10 @@ LL | enum E where i32: Foo { V }
    |
    = help: the trait `Foo` is implemented for `()`
    = help: see issue #48214
-   = help: add `#![feature(trivial_bounds)]` to the crate attributes to enable
+help: add `#![feature(trivial_bounds)]` to the crate attributes to enable
+   |
+LL + #![feature(trivial_bounds)]
+   |
 
 error[E0277]: the trait bound `i32: Foo` is not satisfied
   --> $DIR/feature-gate-trivial_bounds.rs:12:16
@@ -16,7 +19,10 @@ LL | struct S where i32: Foo;
    |
    = help: the trait `Foo` is implemented for `()`
    = help: see issue #48214
-   = help: add `#![feature(trivial_bounds)]` to the crate attributes to enable
+help: add `#![feature(trivial_bounds)]` to the crate attributes to enable
+   |
+LL + #![feature(trivial_bounds)]
+   |
 
 error[E0277]: the trait bound `i32: Foo` is not satisfied
   --> $DIR/feature-gate-trivial_bounds.rs:14:15
@@ -26,7 +32,10 @@ LL | trait T where i32: Foo {}
    |
    = help: the trait `Foo` is implemented for `()`
    = help: see issue #48214
-   = help: add `#![feature(trivial_bounds)]` to the crate attributes to enable
+help: add `#![feature(trivial_bounds)]` to the crate attributes to enable
+   |
+LL + #![feature(trivial_bounds)]
+   |
 
 error[E0277]: the trait bound `i32: Foo` is not satisfied
   --> $DIR/feature-gate-trivial_bounds.rs:16:15
@@ -36,7 +45,10 @@ LL | union U where i32: Foo { f: i32 }
    |
    = help: the trait `Foo` is implemented for `()`
    = help: see issue #48214
-   = help: add `#![feature(trivial_bounds)]` to the crate attributes to enable
+help: add `#![feature(trivial_bounds)]` to the crate attributes to enable
+   |
+LL + #![feature(trivial_bounds)]
+   |
 
 error[E0277]: the trait bound `i32: Foo` is not satisfied
   --> $DIR/feature-gate-trivial_bounds.rs:20:23
@@ -46,7 +58,10 @@ LL | impl Foo for () where i32: Foo {
    |
    = help: the trait `Foo` is implemented for `()`
    = help: see issue #48214
-   = help: add `#![feature(trivial_bounds)]` to the crate attributes to enable
+help: add `#![feature(trivial_bounds)]` to the crate attributes to enable
+   |
+LL + #![feature(trivial_bounds)]
+   |
 
 error[E0277]: the trait bound `i32: Foo` is not satisfied
   --> $DIR/feature-gate-trivial_bounds.rs:28:14
@@ -56,7 +71,10 @@ LL | fn f() where i32: Foo
    |
    = help: the trait `Foo` is implemented for `()`
    = help: see issue #48214
-   = help: add `#![feature(trivial_bounds)]` to the crate attributes to enable
+help: add `#![feature(trivial_bounds)]` to the crate attributes to enable
+   |
+LL + #![feature(trivial_bounds)]
+   |
 
 error[E0277]: the trait bound `String: Neg` is not satisfied
   --> $DIR/feature-gate-trivial_bounds.rs:36:38
@@ -65,7 +83,10 @@ LL | fn use_op(s: String) -> String where String: ::std::ops::Neg<Output=String>
    |                                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Neg` is not implemented for `String`
    |
    = help: see issue #48214
-   = help: add `#![feature(trivial_bounds)]` to the crate attributes to enable
+help: add `#![feature(trivial_bounds)]` to the crate attributes to enable
+   |
+LL + #![feature(trivial_bounds)]
+   |
 
 error[E0277]: `i32` is not an iterator
   --> $DIR/feature-gate-trivial_bounds.rs:40:20
@@ -75,7 +96,10 @@ LL | fn use_for() where i32: Iterator {
    |
    = help: the trait `Iterator` is not implemented for `i32`
    = help: see issue #48214
-   = help: add `#![feature(trivial_bounds)]` to the crate attributes to enable
+help: add `#![feature(trivial_bounds)]` to the crate attributes to enable
+   |
+LL + #![feature(trivial_bounds)]
+   |
 
 error[E0277]: the size for values of type `str` cannot be known at compilation time
   --> $DIR/feature-gate-trivial_bounds.rs:52:32
@@ -85,7 +109,10 @@ LL | struct TwoStrs(str, str) where str: Sized;
    |
    = help: the trait `Sized` is not implemented for `str`
    = help: see issue #48214
-   = help: add `#![feature(trivial_bounds)]` to the crate attributes to enable
+help: add `#![feature(trivial_bounds)]` to the crate attributes to enable
+   |
+LL + #![feature(trivial_bounds)]
+   |
 
 error[E0277]: the size for values of type `(dyn A + 'static)` cannot be known at compilation time
   --> $DIR/feature-gate-trivial_bounds.rs:55:26
@@ -100,7 +127,10 @@ note: required because it appears within the type `Dst<(dyn A + 'static)>`
 LL | struct Dst<X: ?Sized> {
    |        ^^^
    = help: see issue #48214
-   = help: add `#![feature(trivial_bounds)]` to the crate attributes to enable
+help: add `#![feature(trivial_bounds)]` to the crate attributes to enable
+   |
+LL + #![feature(trivial_bounds)]
+   |
 
 error[E0277]: the size for values of type `str` cannot be known at compilation time
   --> $DIR/feature-gate-trivial_bounds.rs:59:30
@@ -110,7 +140,10 @@ LL | fn return_str() -> str where str: Sized {
    |
    = help: the trait `Sized` is not implemented for `str`
    = help: see issue #48214
-   = help: add `#![feature(trivial_bounds)]` to the crate attributes to enable
+help: add `#![feature(trivial_bounds)]` to the crate attributes to enable
+   |
+LL + #![feature(trivial_bounds)]
+   |
 
 error: aborting due to 11 previous errors
 

tests/ui/generic-const-items/elided-lifetimes.stderr

@@ -28,7 +28,10 @@ LL | const I<const S: &str>: &str = "";
    |                  ^^^^
    |
    = note: the only supported types are integers, `bool` and `char`
-   = help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+   |
+LL + #![feature(adt_const_params)]
+   |
 
 error: aborting due to 4 previous errors
 

tests/ui/impl-trait/normalize-tait-in-const.stderr

@@ -11,11 +11,14 @@ LL |     fun(filter_positive());
    |     ^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(effects)]` to the crate attributes to enable
 help: consider further restricting this bound
    |
 LL | const fn with_positive<F: ~const for<'a> Fn(&'a Alias<'a>) + ~const Destruct + ~const std::ops::Fn<(&Alias<'_>,)>>(fun: F) {
    |                                                                              ++++++++++++++++++++++++++++++++++++
+help: add `#![feature(effects)]` to the crate attributes to enable
+   |
+LL + #![feature(effects)]
+   |
 
 error[E0493]: destructor of `F` cannot be evaluated at compile-time
   --> $DIR/normalize-tait-in-const.rs:25:79

tests/ui/inference/inference_unstable.stderr

@@ -7,8 +7,11 @@ LL |     assert_eq!('x'.ipu_flatten(), 1);
    = warning: once this associated item is added to the standard library, the ambiguity may cause an error or change in behavior!
    = note: for more information, see issue #48919 <https://github.com/rust-lang/rust/issues/48919>
    = help: call with fully qualified syntax `inference_unstable_itertools::IpuItertools::ipu_flatten(...)` to keep using the current method
-   = help: add `#![feature(ipu_flatten)]` to the crate attributes to enable `inference_unstable_iterator::IpuIterator::ipu_flatten`
    = note: `#[warn(unstable_name_collisions)]` on by default
+help: add `#![feature(ipu_flatten)]` to the crate attributes to enable `inference_unstable_iterator::IpuIterator::ipu_flatten`
+   |
+LL + #![feature(ipu_flatten)]
+   |
 
 warning: a method with this name may be added to the standard library in the future
   --> $DIR/inference_unstable.rs:19:20
@@ -19,7 +22,10 @@ LL |     assert_eq!('x'.ipu_by_value_vs_by_ref(), 1);
    = warning: once this associated item is added to the standard library, the ambiguity may cause an error or change in behavior!
    = note: for more information, see issue #48919 <https://github.com/rust-lang/rust/issues/48919>
    = help: call with fully qualified syntax `inference_unstable_itertools::IpuItertools::ipu_by_value_vs_by_ref(...)` to keep using the current method
-   = help: add `#![feature(ipu_flatten)]` to the crate attributes to enable `inference_unstable_iterator::IpuIterator::ipu_by_value_vs_by_ref`
+help: add `#![feature(ipu_flatten)]` to the crate attributes to enable `inference_unstable_iterator::IpuIterator::ipu_by_value_vs_by_ref`
+   |
+LL + #![feature(ipu_flatten)]
+   |
 
 warning: a method with this name may be added to the standard library in the future
   --> $DIR/inference_unstable.rs:22:20
@@ -30,7 +36,10 @@ LL |     assert_eq!('x'.ipu_by_ref_vs_by_ref_mut(), 1);
    = warning: once this associated item is added to the standard library, the ambiguity may cause an error or change in behavior!
    = note: for more information, see issue #48919 <https://github.com/rust-lang/rust/issues/48919>
    = help: call with fully qualified syntax `inference_unstable_itertools::IpuItertools::ipu_by_ref_vs_by_ref_mut(...)` to keep using the current method
-   = help: add `#![feature(ipu_flatten)]` to the crate attributes to enable `inference_unstable_iterator::IpuIterator::ipu_by_ref_vs_by_ref_mut`
+help: add `#![feature(ipu_flatten)]` to the crate attributes to enable `inference_unstable_iterator::IpuIterator::ipu_by_ref_vs_by_ref_mut`
+   |
+LL + #![feature(ipu_flatten)]
+   |
 
 warning: a method with this name may be added to the standard library in the future
   --> $DIR/inference_unstable.rs:25:40
@@ -41,17 +50,27 @@ LL |     assert_eq!((&mut 'x' as *mut char).ipu_by_mut_ptr_vs_by_const_ptr(), 1)
    = warning: once this associated item is added to the standard library, the ambiguity may cause an error or change in behavior!
    = note: for more information, see issue #48919 <https://github.com/rust-lang/rust/issues/48919>
    = help: call with fully qualified syntax `inference_unstable_itertools::IpuItertools::ipu_by_mut_ptr_vs_by_const_ptr(...)` to keep using the current method
-   = help: add `#![feature(ipu_flatten)]` to the crate attributes to enable `inference_unstable_iterator::IpuIterator::ipu_by_mut_ptr_vs_by_const_ptr`
+help: add `#![feature(ipu_flatten)]` to the crate attributes to enable `inference_unstable_iterator::IpuIterator::ipu_by_mut_ptr_vs_by_const_ptr`
+   |
+LL + #![feature(ipu_flatten)]
+   |
 
 warning: an associated constant with this name may be added to the standard library in the future
   --> $DIR/inference_unstable.rs:28:16
    |
 LL |     assert_eq!(char::C, 1);
-   |                ^^^^^^^ help: use the fully qualified path to the associated const: `<char as IpuItertools>::C`
+   |                ^^^^^^^
    |
    = warning: once this associated item is added to the standard library, the ambiguity may cause an error or change in behavior!
    = note: for more information, see issue #48919 <https://github.com/rust-lang/rust/issues/48919>
-   = help: add `#![feature(assoc_const_ipu_iter)]` to the crate attributes to enable `inference_unstable_iterator::IpuIterator::C`
+help: use the fully qualified path to the associated const
+   |
+LL |     assert_eq!(<char as IpuItertools>::C, 1);
+   |                ~~~~~~~~~~~~~~~~~~~~~~~~~
+help: add `#![feature(assoc_const_ipu_iter)]` to the crate attributes to enable `inference_unstable_iterator::IpuIterator::C`
+   |
+LL + #![feature(assoc_const_ipu_iter)]
+   |
 
 warning: 5 warnings emitted
 

tests/ui/issues/issue-25901.stderr

@@ -16,8 +16,11 @@ note: impl defined here, but it is not `const`
 LL | impl Deref for A {
    | ^^^^^^^^^^^^^^^^
    = note: calls in statics are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
    = note: consider wrapping this expression in `Lazy::new(|| ...)` from the `once_cell` crate: https://crates.io/crates/once_cell
+help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+   |
+LL + #![feature(const_trait_impl)]
+   |
 
 error: aborting due to 1 previous error
 

tests/ui/lifetimes/unusual-rib-combinations.stderr

@@ -56,7 +56,10 @@ LL | fn d<const C: S>() {}
    |               ^
    |
    = note: the only supported types are integers, `bool` and `char`
-   = help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+   |
+LL + #![feature(adt_const_params)]
+   |
 
 error: aborting due to 8 previous errors
 

tests/ui/never_type/issue-52443.stderr

@@ -50,7 +50,10 @@ LL |     [(); { for _ in 0usize.. {}; 0}];
 note: impl defined here, but it is not `const`
   --> $SRC_DIR/core/src/iter/traits/collect.rs:LL:COL
    = note: calls in constants are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+   |
+LL + #![feature(const_trait_impl)]
+   |
 
 error[E0658]: mutable references are not allowed in constants
   --> $DIR/issue-52443.rs:9:21
@@ -69,7 +72,10 @@ LL |     [(); { for _ in 0usize.. {}; 0}];
    |                     ^^^^^^^^
    |
    = note: calls in constants are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+   |
+LL + #![feature(const_trait_impl)]
+   |
 
 error: aborting due to 6 previous errors; 1 warning emitted
 

tests/ui/parser/impl-item-type-no-body-semantic-fail.stderr

@@ -89,12 +89,15 @@ LL |     type W: Ord where Self: Eq;
    |                       ^^^^^^^^ the trait `Eq` is not implemented for `X`
    |
    = help: see issue #48214
-   = help: add `#![feature(trivial_bounds)]` to the crate attributes to enable
 help: consider annotating `X` with `#[derive(Eq)]`
    |
 LL + #[derive(Eq)]
 LL | struct X;
    |
+help: add `#![feature(trivial_bounds)]` to the crate attributes to enable
+   |
+LL + #![feature(trivial_bounds)]
+   |
 
 error[E0277]: the trait bound `X: Eq` is not satisfied
   --> $DIR/impl-item-type-no-body-semantic-fail.rs:18:18
@@ -103,12 +106,15 @@ LL |     type W where Self: Eq;
    |                  ^^^^^^^^ the trait `Eq` is not implemented for `X`
    |
    = help: see issue #48214
-   = help: add `#![feature(trivial_bounds)]` to the crate attributes to enable
 help: consider annotating `X` with `#[derive(Eq)]`
    |
 LL + #[derive(Eq)]
 LL | struct X;
    |
+help: add `#![feature(trivial_bounds)]` to the crate attributes to enable
+   |
+LL + #![feature(trivial_bounds)]
+   |
 
 error[E0592]: duplicate definitions with name `W`
   --> $DIR/impl-item-type-no-body-semantic-fail.rs:18:5

tests/ui/parser/issues/issue-35813-postfix-after-cast.stderr

@@ -352,8 +352,11 @@ LL | static bar: &[i32] = &(&[1,2,3] as &[i32][0..1]);
    |                                          ^^^^^^
    |
    = note: calls in statics are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
    = note: consider wrapping this expression in `Lazy::new(|| ...)` from the `once_cell` crate: https://crates.io/crates/once_cell
+help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+   |
+LL + #![feature(const_trait_impl)]
+   |
 
 error: aborting due to 40 previous errors
 

tests/ui/resolve/issue-39559-2.stderr

@@ -5,7 +5,10 @@ LL |     let array: [usize; Dim3::dim()]
    |                        ^^^^^^^^^^^
    |
    = note: calls in constants are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+   |
+LL + #![feature(const_trait_impl)]
+   |
 
 error[E0015]: cannot call non-const fn `<Dim3 as Dim>::dim` in constants
   --> $DIR/issue-39559-2.rs:16:15
@@ -14,7 +17,10 @@ LL |         = [0; Dim3::dim()];
    |               ^^^^^^^^^^^
    |
    = note: calls in constants are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+   |
+LL + #![feature(const_trait_impl)]
+   |
 
 error: aborting due to 2 previous errors
 

tests/ui/rfcs/rfc-2632-const-trait-impl/call-const-trait-method-pass.stderr

@@ -10,7 +10,10 @@ note: impl defined here, but it is not `const`
 LL | impl const std::ops::Add for Int {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    = note: calls in constants are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(effects)]` to the crate attributes to enable
+help: add `#![feature(effects)]` to the crate attributes to enable
+   |
+LL + #![feature(effects)]
+   |
 
 error[E0015]: cannot call non-const fn `<i32 as Plus>::plus` in constant functions
   --> $DIR/call-const-trait-method-pass.rs:36:7
@@ -19,7 +22,10 @@ LL |     a.plus(b)
    |       ^^^^^^^
    |
    = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(effects)]` to the crate attributes to enable
+help: add `#![feature(effects)]` to the crate attributes to enable
+   |
+LL + #![feature(effects)]
+   |
 
 error: aborting due to 2 previous errors
 

tests/ui/rfcs/rfc-2632-const-trait-impl/const-closure-trait-method-fail.stderr

@@ -11,11 +11,14 @@ LL |     x(())
    |     ^^^^^
    |
    = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(effects)]` to the crate attributes to enable
 help: consider further restricting this bound
    |
 LL | const fn need_const_closure<T: ~const FnOnce(()) -> i32 + ~const std::ops::FnOnce<((),)>>(x: T) -> i32 {
    |                                                         ++++++++++++++++++++++++++++++++
+help: add `#![feature(effects)]` to the crate attributes to enable
+   |
+LL + #![feature(effects)]
+   |
 
 error: aborting due to 2 previous errors
 

tests/ui/rfcs/rfc-2632-const-trait-impl/const-closure-trait-method.stderr

@@ -11,11 +11,14 @@ LL |     x(())
    |     ^^^^^
    |
    = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(effects)]` to the crate attributes to enable
 help: consider further restricting this bound
    |
 LL | const fn need_const_closure<T: ~const FnOnce(()) -> i32 + ~const std::ops::FnOnce<((),)>>(x: T) -> i32 {
    |                                                         ++++++++++++++++++++++++++++++++
+help: add `#![feature(effects)]` to the crate attributes to enable
+   |
+LL + #![feature(effects)]
+   |
 
 error: aborting due to 2 previous errors
 

tests/ui/rfcs/rfc-2632-const-trait-impl/const-closures.stderr

@@ -29,11 +29,14 @@ LL |     f() + f()
    |     ^^^
    |
    = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(effects)]` to the crate attributes to enable
 help: consider further restricting this bound
    |
 LL | const fn answer<F: ~const Fn() -> u8 + ~const std::ops::Fn<()>>(f: &F) -> u8 {
    |                                      +++++++++++++++++++++++++
+help: add `#![feature(effects)]` to the crate attributes to enable
+   |
+LL + #![feature(effects)]
+   |
 
 error[E0015]: cannot call non-const closure in constant functions
   --> $DIR/const-closures.rs:24:11
@@ -42,11 +45,14 @@ LL |     f() + f()
    |           ^^^
    |
    = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(effects)]` to the crate attributes to enable
 help: consider further restricting this bound
    |
 LL | const fn answer<F: ~const Fn() -> u8 + ~const std::ops::Fn<()>>(f: &F) -> u8 {
    |                                      +++++++++++++++++++++++++
+help: add `#![feature(effects)]` to the crate attributes to enable
+   |
+LL + #![feature(effects)]
+   |
 
 error[E0015]: cannot call non-const closure in constant functions
   --> $DIR/const-closures.rs:12:5
@@ -55,11 +61,14 @@ LL |     f() * 7
    |     ^^^
    |
    = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(effects)]` to the crate attributes to enable
 help: consider further restricting this bound
    |
 LL |         F: ~const FnOnce() -> u8 + ~const std::ops::Fn<()>,
    |                                  +++++++++++++++++++++++++
+help: add `#![feature(effects)]` to the crate attributes to enable
+   |
+LL + #![feature(effects)]
+   |
 
 error: aborting due to 7 previous errors
 

tests/ui/rfcs/rfc-2632-const-trait-impl/cross-crate.stock.stderr

@@ -5,7 +5,10 @@ LL |     Const.func();
    |           ^^^^^^
    |
    = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+   |
+LL + #![feature(const_trait_impl)]
+   |
 
 error: aborting due to 1 previous error
 

tests/ui/rfcs/rfc-2632-const-trait-impl/cross-crate.stocknc.stderr

@@ -5,7 +5,10 @@ LL |     NonConst.func();
    |              ^^^^^^
    |
    = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+   |
+LL + #![feature(const_trait_impl)]
+   |
 
 error[E0015]: cannot call non-const fn `<cross_crate::Const as cross_crate::MyTrait>::func` in constant functions
   --> $DIR/cross-crate.rs:20:11
@@ -14,7 +17,10 @@ LL |     Const.func();
    |           ^^^^^^
    |
    = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+   |
+LL + #![feature(const_trait_impl)]
+   |
 
 error: aborting due to 2 previous errors
 

tests/ui/rfcs/rfc-2632-const-trait-impl/generic-bound.stderr

@@ -10,7 +10,10 @@ note: impl defined here, but it is not `const`
 LL | impl<T> const std::ops::Add for S<T> {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(effects)]` to the crate attributes to enable
+help: add `#![feature(effects)]` to the crate attributes to enable
+   |
+LL + #![feature(effects)]
+   |
 
 error: aborting due to 1 previous error
 

tests/ui/rfcs/rfc-2632-const-trait-impl/issue-102985.stderr

@@ -6,7 +6,10 @@ LL |         n => n(),
    |
    = note: closures need an RFC before allowed to be called in constants
    = note: calls in constants are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(effects)]` to the crate attributes to enable
+help: add `#![feature(effects)]` to the crate attributes to enable
+   |
+LL + #![feature(effects)]
+   |
 
 error: aborting due to 1 previous error
 

tests/ui/rfcs/rfc-2632-const-trait-impl/issue-88155.stderr

@@ -5,7 +5,10 @@ LL |     T::assoc()
    |     ^^^^^^^^^^
    |
    = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(effects)]` to the crate attributes to enable
+help: add `#![feature(effects)]` to the crate attributes to enable
+   |
+LL + #![feature(effects)]
+   |
 
 error: aborting due to 1 previous error
 

tests/ui/rfcs/rfc-2632-const-trait-impl/match-non-const-eq.gated.stderr

@@ -6,7 +6,10 @@ LL |         "a" => (), //FIXME [gated]~ ERROR can't compare `str` with `str` in
    |
    = note: `str` cannot be compared in compile-time, and therefore cannot be used in `match`es
    = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(effects)]` to the crate attributes to enable
+help: add `#![feature(effects)]` to the crate attributes to enable
+   |
+LL + #![feature(effects)]
+   |
 
 error: aborting due to 1 previous error
 

tests/ui/rfcs/rfc-2632-const-trait-impl/match-non-const-eq.stock.stderr

@@ -6,7 +6,10 @@ LL |         "a" => (), //FIXME [gated]~ ERROR can't compare `str` with `str` in
    |
    = note: `str` cannot be compared in compile-time, and therefore cannot be used in `match`es
    = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+   |
+LL + #![feature(const_trait_impl)]
+   |
 
 error: aborting due to 1 previous error
 

tests/ui/rfcs/rfc-2632-const-trait-impl/non-const-op-const-closure-non-const-outer.stderr

@@ -5,7 +5,10 @@ LL |     (const || { (()).foo() })();
    |                      ^^^^^
    |
    = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(effects)]` to the crate attributes to enable
+help: add `#![feature(effects)]` to the crate attributes to enable
+   |
+LL + #![feature(effects)]
+   |
 
 error: aborting due to 1 previous error
 

tests/ui/rfcs/rfc-2632-const-trait-impl/staged-api-user-crate.stderr

@@ -5,7 +5,10 @@ LL |     Unstable::func();
    |     ^^^^^^^^^^^^^^^^
    |
    = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+   |
+LL + #![feature(const_trait_impl)]
+   |
 
 error: aborting due to 1 previous error
 

tests/ui/rfcs/rfc-2632-const-trait-impl/std-impl-gate.gated.stderr

@@ -11,7 +11,10 @@ LL |     Default::default()
    |     ^^^^^^^^^^^^^^^^^^
    |
    = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(effects)]` to the crate attributes to enable
+help: add `#![feature(effects)]` to the crate attributes to enable
+   |
+LL + #![feature(effects)]
+   |
 
 error: aborting due to 2 previous errors
 

tests/ui/rfcs/rfc-2632-const-trait-impl/std-impl-gate.stock.stderr

@@ -5,7 +5,10 @@ LL |     Default::default()
    |     ^^^^^^^^^^^^^^^^^^
    |
    = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+   |
+LL + #![feature(const_trait_impl)]
+   |
 
 error: aborting due to 1 previous error
 

tests/ui/specialization/const_trait_impl.stderr

@@ -23,7 +23,10 @@ LL | const _: () = assert!(<()>::a() == 42);
    |                       ^^^^^^^^^
    |
    = note: calls in constants are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(effects)]` to the crate attributes to enable
+help: add `#![feature(effects)]` to the crate attributes to enable
+   |
+LL + #![feature(effects)]
+   |
 
 error[E0015]: cannot call non-const fn `<u8 as A>::a` in constants
   --> $DIR/const_trait_impl.rs:53:23
@@ -32,7 +35,10 @@ LL | const _: () = assert!(<u8>::a() == 3);
    |                       ^^^^^^^^^
    |
    = note: calls in constants are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(effects)]` to the crate attributes to enable
+help: add `#![feature(effects)]` to the crate attributes to enable
+   |
+LL + #![feature(effects)]
+   |
 
 error[E0015]: cannot call non-const fn `<u16 as A>::a` in constants
   --> $DIR/const_trait_impl.rs:54:23
@@ -41,7 +47,10 @@ LL | const _: () = assert!(<u16>::a() == 2);
    |                       ^^^^^^^^^^
    |
    = note: calls in constants are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(effects)]` to the crate attributes to enable
+help: add `#![feature(effects)]` to the crate attributes to enable
+   |
+LL + #![feature(effects)]
+   |
 
 error: aborting due to 6 previous errors
 

tests/ui/specialization/defaultimpl/validation.stderr

@@ -35,7 +35,10 @@ LL | default unsafe impl Send for S {}
    = help: the trait `Send` is not implemented for `S`
    = help: the trait `Send` is implemented for `S`
    = help: see issue #48214
-   = help: add `#![feature(trivial_bounds)]` to the crate attributes to enable
+help: add `#![feature(trivial_bounds)]` to the crate attributes to enable
+   |
+LL + #![feature(trivial_bounds)]
+   |
 
 error: impls of auto traits cannot be default
   --> $DIR/validation.rs:11:15

tests/ui/trait-bounds/super-assoc-mismatch.stderr

@@ -78,7 +78,10 @@ help: this trait has no implementations, consider adding one
 LL | trait Sub: Super<Assoc = u16> {}
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    = help: see issue #48214
-   = help: add `#![feature(trivial_bounds)]` to the crate attributes to enable
+help: add `#![feature(trivial_bounds)]` to the crate attributes to enable
+   |
+LL + #![feature(trivial_bounds)]
+   |
 
 error[E0277]: the trait bound `(): SubGeneric<u16>` is not satisfied
   --> $DIR/super-assoc-mismatch.rs:55:22

tests/ui/typeck/typeck_type_placeholder_item.stderr

@@ -673,7 +673,10 @@ LL | const _: _ = (1..10).filter(|x| x % 2 == 0).map(|x| x * x);
    |                      ^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: calls in constants are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+   |
+LL + #![feature(const_trait_impl)]
+   |
 
 error[E0015]: cannot call non-const fn `<Filter<std::ops::Range<i32>, {closure@$DIR/typeck_type_placeholder_item.rs:230:29: 230:32}> as Iterator>::map::<i32, {closure@$DIR/typeck_type_placeholder_item.rs:230:49: 230:52}>` in constants
   --> $DIR/typeck_type_placeholder_item.rs:230:45
@@ -682,7 +685,10 @@ LL | const _: _ = (1..10).filter(|x| x % 2 == 0).map(|x| x * x);
    |                                             ^^^^^^^^^^^^^^
    |
    = note: calls in constants are limited to constant functions, tuple structs and tuple variants
-   = help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+   |
+LL + #![feature(const_trait_impl)]
+   |
 
 error[E0515]: cannot return reference to function parameter `x`
   --> $DIR/typeck_type_placeholder_item.rs:50:5