nested_impl_trait -> error

9 files changed, 57 insertions, 300 deletions

diff --git a/src/librustc/lint/builtin.rs b/src/librustc/lint/builtin.rs
index 2e7db404747..4ffb8dabe3b 100644
--- a/src/librustc/lint/builtin.rs
+++ b/src/librustc/lint/builtin.rs
@@ -447,16 +447,6 @@ declare_lint! {
 }
 
 declare_lint! {
-    pub NESTED_IMPL_TRAIT,
-    Warn,
-    "nested occurrence of `impl Trait` type",
-    @future_incompatible = FutureIncompatibleInfo {
-        reference: "issue #59014 <https://github.com/rust-lang/rust/issues/59014>",
-        edition: None,
-    };
-}
-
-declare_lint! {
     pub MUTABLE_BORROW_RESERVATION_CONFLICT,
     Warn,
     "reservation of a two-phased borrow conflicts with other shared borrows",
@@ -534,7 +524,6 @@ declare_lint_pass! {
         parser::META_VARIABLE_MISUSE,
         DEPRECATED_IN_FUTURE,
         AMBIGUOUS_ASSOCIATED_ITEMS,
-        NESTED_IMPL_TRAIT,
         MUTABLE_BORROW_RESERVATION_CONFLICT,
         INDIRECT_STRUCTURAL_MATCH,
         SOFT_UNSTABLE,
@@ -553,7 +542,6 @@ pub enum BuiltinLintDiagnostics {
     ElidedLifetimesInPaths(usize, Span, bool, Span, String),
     UnknownCrateTypes(Span, String, String),
     UnusedImports(String, Vec<(Span, String)>),
-    NestedImplTrait { outer_impl_trait_span: Span, inner_impl_trait_span: Span },
     RedundantImport(Vec<(Span, bool)>, ast::Ident),
     DeprecatedMacro(Option<Symbol>, Span),
 }
@@ -662,12 +650,6 @@ impl BuiltinLintDiagnostics {
                     );
                 }
             }
-            BuiltinLintDiagnostics::NestedImplTrait {
-                outer_impl_trait_span, inner_impl_trait_span
-            } => {
-                db.span_label(outer_impl_trait_span, "outer `impl Trait`");
-                db.span_label(inner_impl_trait_span, "nested `impl Trait` here");
-            }
             BuiltinLintDiagnostics::RedundantImport(spans, ident) => {
                 for (span, is_imported) in spans {
                     let introduced = if is_imported { "imported" } else { "defined" };
diff --git a/src/librustc_lint/lib.rs b/src/librustc_lint/lib.rs
index 6310ff3b847..2ca3d4b19b2 100644
--- a/src/librustc_lint/lib.rs
+++ b/src/librustc_lint/lib.rs
@@ -344,6 +344,8 @@ fn register_builtins(store: &mut lint::LintStore, no_interleave_lints: bool) {
         "converted into hard error, see https://github.com/rust-lang/rust/issues/42238");
     store.register_removed("duplicate_macro_exports",
         "converted into hard error, see https://github.com/rust-lang/rust/issues/35896");
+    store.register_removed("nested_impl_trait",
+        "converted into hard error, see https://github.com/rust-lang/rust/issues/59014");
 }
 
 fn register_internals(store: &mut lint::LintStore) {
diff --git a/src/librustc_passes/ast_validation.rs b/src/librustc_passes/ast_validation.rs
index e046f6c2a07..4577b6e1e07 100644
--- a/src/librustc_passes/ast_validation.rs
+++ b/src/librustc_passes/ast_validation.rs
@@ -9,7 +9,6 @@
 use std::mem;
 use syntax::print::pprust;
 use rustc::lint;
-use rustc::lint::builtin::{BuiltinLintDiagnostics, NESTED_IMPL_TRAIT};
 use rustc::session::Session;
 use rustc_data_structures::fx::FxHashMap;
 use syntax::ast::*;
@@ -23,31 +22,6 @@ use syntax::{span_err, struct_span_err, walk_list};
 use syntax_pos::{Span, MultiSpan};
 use errors::{Applicability, FatalError};
 
-#[derive(Copy, Clone, Debug)]
-struct OuterImplTrait {
-    span: Span,
-
-    /// rust-lang/rust#57979: a bug in original implementation caused
-    /// us to fail sometimes to record an outer `impl Trait`.
-    /// Therefore, in order to reliably issue a warning (rather than
-    /// an error) in the *precise* places where we are newly injecting
-    /// the diagnostic, we have to distinguish between the places
-    /// where the outer `impl Trait` has always been recorded, versus
-    /// the places where it has only recently started being recorded.
-    only_recorded_since_pull_request_57730: bool,
-}
-
-impl OuterImplTrait {
-    /// This controls whether we should downgrade the nested impl
-    /// trait diagnostic to a warning rather than an error, based on
-    /// whether the outer impl trait had been improperly skipped in
-    /// earlier implementations of the analysis on the stable
-    /// compiler.
-    fn should_warn_instead_of_error(&self) -> bool {
-        self.only_recorded_since_pull_request_57730
-    }
-}
-
 struct AstValidator<'a> {
     session: &'a Session,
     has_proc_macro_decls: bool,
@@ -55,7 +29,7 @@ struct AstValidator<'a> {
     /// Used to ban nested `impl Trait`, e.g., `impl Into<impl Debug>`.
     /// Nested `impl Trait` _is_ allowed in associated type position,
     /// e.g., `impl Iterator<Item = impl Debug>`.
-    outer_impl_trait: Option<OuterImplTrait>,
+    outer_impl_trait: Option<Span>,
 
     /// Used to ban `impl Trait` in path projections like `<impl Iterator>::Item`
     /// or `Foo::Bar<impl Trait>`
@@ -65,26 +39,10 @@ struct AstValidator<'a> {
     /// certain positions.
     is_assoc_ty_bound_banned: bool,
 
-    /// rust-lang/rust#57979: the ban of nested `impl Trait` was buggy
-    /// until PRs #57730 and #57981 landed: it would jump directly to
-    /// walk_ty rather than visit_ty (or skip recurring entirely for
-    /// impl trait in projections), and thus miss some cases. We track
-    /// whether we should downgrade to a warning for short-term via
-    /// these booleans.
-    warning_period_57979_didnt_record_next_impl_trait: bool,
-    warning_period_57979_impl_trait_in_proj: bool,
-
     lint_buffer: &'a mut lint::LintBuffer,
 }
 
 impl<'a> AstValidator<'a> {
-    fn with_impl_trait_in_proj_warning<T>(&mut self, v: bool, f: impl FnOnce(&mut Self) -> T) -> T {
-        let old = mem::replace(&mut self.warning_period_57979_impl_trait_in_proj, v);
-        let ret = f(self);
-        self.warning_period_57979_impl_trait_in_proj = old;
-        ret
-    }
-
     fn with_banned_impl_trait(&mut self, f: impl FnOnce(&mut Self)) {
         let old = mem::replace(&mut self.is_impl_trait_banned, true);
         f(self);
@@ -97,7 +55,7 @@ impl<'a> AstValidator<'a> {
         self.is_assoc_ty_bound_banned = old;
     }
 
-    fn with_impl_trait(&mut self, outer: Option<OuterImplTrait>, f: impl FnOnce(&mut Self)) {
+    fn with_impl_trait(&mut self, outer: Option<Span>, f: impl FnOnce(&mut Self)) {
         let old = mem::replace(&mut self.outer_impl_trait, outer);
         f(self);
         self.outer_impl_trait = old;
@@ -105,14 +63,7 @@ impl<'a> AstValidator<'a> {
 
     fn visit_assoc_ty_constraint_from_generic_args(&mut self, constraint: &'a AssocTyConstraint) {
         match constraint.kind {
-            AssocTyConstraintKind::Equality { ref ty } => {
-                // rust-lang/rust#57979: bug in old `visit_generic_args` called
-                // `walk_ty` rather than `visit_ty`, skipping outer `impl Trait`
-                // if it happened to occur at `ty`.
-                if let TyKind::ImplTrait(..) = ty.kind {
-                    self.warning_period_57979_didnt_record_next_impl_trait = true;
-                }
-            }
+            AssocTyConstraintKind::Equality { .. } => {}
             AssocTyConstraintKind::Bound { .. } => {
                 if self.is_assoc_ty_bound_banned {
                     self.err_handler().span_err(constraint.span,
@@ -124,37 +75,11 @@ impl<'a> AstValidator<'a> {
         self.visit_assoc_ty_constraint(constraint);
     }
 
-    fn visit_ty_from_generic_args(&mut self, ty: &'a Ty) {
-        // rust-lang/rust#57979: bug in old `visit_generic_args` called
-        // `walk_ty` rather than `visit_ty`, skippping outer `impl Trait`
-        // if it happened to occur at `ty`.
-        if let TyKind::ImplTrait(..) = ty.kind {
-            self.warning_period_57979_didnt_record_next_impl_trait = true;
-        }
-        self.visit_ty(ty);
-    }
-
-    fn outer_impl_trait(&mut self, span: Span) -> OuterImplTrait {
-        let only_recorded_since_pull_request_57730 =
-            self.warning_period_57979_didnt_record_next_impl_trait;
-
-        // (This flag is designed to be set to `true`, and then only
-        // reach the construction point for the outer impl trait once,
-        // so its safe and easiest to unconditionally reset it to
-        // false.)
-        self.warning_period_57979_didnt_record_next_impl_trait = false;
-
-        OuterImplTrait {
-            span, only_recorded_since_pull_request_57730,
-        }
-    }
-
     // Mirrors `visit::walk_ty`, but tracks relevant state.
     fn walk_ty(&mut self, t: &'a Ty) {
         match t.kind {
             TyKind::ImplTrait(..) => {
-                let outer_impl_trait = self.outer_impl_trait(t.span);
-                self.with_impl_trait(Some(outer_impl_trait), |this| visit::walk_ty(this, t))
+                self.with_impl_trait(Some(t.span), |this| visit::walk_ty(this, t))
             }
             TyKind::Path(ref qself, ref path) => {
                 // We allow these:
@@ -484,32 +409,21 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
             }
             TyKind::ImplTrait(_, ref bounds) => {
                 if self.is_impl_trait_banned {
-                    if self.warning_period_57979_impl_trait_in_proj {
-                        self.lint_buffer.buffer_lint(
-                            NESTED_IMPL_TRAIT, ty.id, ty.span,
-                            "`impl Trait` is not allowed in path parameters");
-                    } else {
-                        struct_span_err!(self.session, ty.span, E0667,
-                            "`impl Trait` is not allowed in path parameters").emit();
-                    }
+                    struct_span_err!(
+                        self.session, ty.span, E0667,
+                        "`impl Trait` is not allowed in path parameters"
+                    )
+                    .emit();
                 }
 
-                if let Some(outer_impl_trait) = self.outer_impl_trait {
-                    if outer_impl_trait.should_warn_instead_of_error() {
-                        self.lint_buffer.buffer_lint_with_diagnostic(
-                            NESTED_IMPL_TRAIT, ty.id, ty.span,
-                            "nested `impl Trait` is not allowed",
-                            BuiltinLintDiagnostics::NestedImplTrait {
-                                outer_impl_trait_span: outer_impl_trait.span,
-                                inner_impl_trait_span: ty.span,
-                            });
-                    } else {
-                        struct_span_err!(self.session, ty.span, E0666,
-                            "nested `impl Trait` is not allowed")
-                            .span_label(outer_impl_trait.span, "outer `impl Trait`")
-                            .span_label(ty.span, "nested `impl Trait` here")
-                            .emit();
-                    }
+                if let Some(outer_impl_trait_sp) = self.outer_impl_trait {
+                    struct_span_err!(
+                        self.session, ty.span, E0666,
+                        "nested `impl Trait` is not allowed"
+                    )
+                    .span_label(outer_impl_trait_sp, "outer `impl Trait`")
+                    .span_label(ty.span, "nested `impl Trait` here")
+                    .emit();
                 }
 
                 if !bounds.iter()
@@ -517,7 +431,7 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
                     self.err_handler().span_err(ty.span, "at least one trait must be specified");
                 }
 
-                self.with_impl_trait_in_proj_warning(true, |this| this.walk_ty(ty));
+                self.walk_ty(ty);
                 return;
             }
             _ => {}
@@ -726,7 +640,7 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
                 if let Some(ref type_) = data.output {
                     // `-> Foo` syntax is essentially an associated type binding,
                     // so it is also allowed to contain nested `impl Trait`.
-                    self.with_impl_trait(None, |this| this.visit_ty_from_generic_args(type_));
+                    self.with_impl_trait(None, |this| this.visit_ty(type_));
                 }
             }
         }
@@ -844,8 +758,6 @@ pub fn check_crate(session: &Session, krate: &Crate, lints: &mut lint::LintBuffe
         outer_impl_trait: None,
         is_impl_trait_banned: false,
         is_assoc_ty_bound_banned: false,
-        warning_period_57979_didnt_record_next_impl_trait: false,
-        warning_period_57979_impl_trait_in_proj: false,
         lint_buffer: lints,
     };
     visit::walk_crate(&mut validator, krate);
diff --git a/src/test/ui/impl-trait/issues/issue-57979-deeply-nested-impl-trait-in-assoc-proj.rs b/src/test/ui/impl-trait/issues/issue-57979-deeply-nested-impl-trait-in-assoc-proj.rs
index 5eef6a39325..0daec3305c0 100644
--- a/src/test/ui/impl-trait/issues/issue-57979-deeply-nested-impl-trait-in-assoc-proj.rs
+++ b/src/test/ui/impl-trait/issues/issue-57979-deeply-nested-impl-trait-in-assoc-proj.rs
@@ -1,42 +1,17 @@
 // rust-lang/rust#57979 : the initial support for `impl Trait` didn't
 // properly check syntax hidden behind an associated type projection,
 // but it did catch *some cases*. This is checking that we continue to
-// properly emit errors for those, even with the new
-// future-incompatibility warnings.
+// properly emit errors for those.
 //
 // issue-57979-nested-impl-trait-in-assoc-proj.rs shows the main case
 // that we were previously failing to catch.
 
 struct Deeper<T>(T);
 
-mod allowed {
-    #![allow(nested_impl_trait)]
-
-    pub trait Foo<T> { }
-    pub trait Bar { }
-    pub trait Quux { type Assoc; }
-    pub fn demo(_: impl Quux<Assoc=super::Deeper<impl Foo<impl Bar>>>) { }
-    //~^ ERROR nested `impl Trait` is not allowed
-}
-
-mod warned {
-    #![warn(nested_impl_trait)]
-
-    pub trait Foo<T> { }
-    pub trait Bar { }
-    pub trait Quux { type Assoc; }
-    pub fn demo(_: impl Quux<Assoc=super::Deeper<impl Foo<impl Bar>>>) { }
-    //~^ ERROR nested `impl Trait` is not allowed
-}
-
-mod denied {
-    #![deny(nested_impl_trait)]
-
-    pub trait Foo<T> { }
-    pub trait Bar { }
-    pub trait Quux { type Assoc; }
-    pub fn demo(_: impl Quux<Assoc=super::Deeper<impl Foo<impl Bar>>>) { }
-    //~^ ERROR nested `impl Trait` is not allowed
-}
+pub trait Foo<T> { }
+pub trait Bar { }
+pub trait Quux { type Assoc; }
+pub fn demo(_: impl Quux<Assoc=Deeper<impl Foo<impl Bar>>>) { }
+//~^ ERROR nested `impl Trait` is not allowed
 
 fn main() { }
diff --git a/src/test/ui/impl-trait/issues/issue-57979-deeply-nested-impl-trait-in-assoc-proj.stderr b/src/test/ui/impl-trait/issues/issue-57979-deeply-nested-impl-trait-in-assoc-proj.stderr
index 2b6f15e6d3e..6bebbc01f3d 100644
--- a/src/test/ui/impl-trait/issues/issue-57979-deeply-nested-impl-trait-in-assoc-proj.stderr
+++ b/src/test/ui/impl-trait/issues/issue-57979-deeply-nested-impl-trait-in-assoc-proj.stderr
@@ -1,30 +1,12 @@
 error[E0666]: nested `impl Trait` is not allowed
-  --> $DIR/issue-57979-deeply-nested-impl-trait-in-assoc-proj.rs:18:59
+  --> $DIR/issue-57979-deeply-nested-impl-trait-in-assoc-proj.rs:14:48
    |
-LL |     pub fn demo(_: impl Quux<Assoc=super::Deeper<impl Foo<impl Bar>>>) { }
-   |                                                  ---------^^^^^^^^-
-   |                                                  |        |
-   |                                                  |        nested `impl Trait` here
-   |                                                  outer `impl Trait`
+LL | pub fn demo(_: impl Quux<Assoc=Deeper<impl Foo<impl Bar>>>) { }
+   |                                       ---------^^^^^^^^-
+   |                                       |        |
+   |                                       |        nested `impl Trait` here
+   |                                       outer `impl Trait`
 
-error[E0666]: nested `impl Trait` is not allowed
-  --> $DIR/issue-57979-deeply-nested-impl-trait-in-assoc-proj.rs:28:59
-   |
-LL |     pub fn demo(_: impl Quux<Assoc=super::Deeper<impl Foo<impl Bar>>>) { }
-   |                                                  ---------^^^^^^^^-
-   |                                                  |        |
-   |                                                  |        nested `impl Trait` here
-   |                                                  outer `impl Trait`
-
-error[E0666]: nested `impl Trait` is not allowed
-  --> $DIR/issue-57979-deeply-nested-impl-trait-in-assoc-proj.rs:38:59
-   |
-LL |     pub fn demo(_: impl Quux<Assoc=super::Deeper<impl Foo<impl Bar>>>) { }
-   |                                                  ---------^^^^^^^^-
-   |                                                  |        |
-   |                                                  |        nested `impl Trait` here
-   |                                                  outer `impl Trait`
-
-error: aborting due to 3 previous errors
+error: aborting due to previous error
 
 For more information about this error, try `rustc --explain E0666`.
diff --git a/src/test/ui/impl-trait/issues/issue-57979-impl-trait-in-path.rs b/src/test/ui/impl-trait/issues/issue-57979-impl-trait-in-path.rs
index 84fcb5e2880..c5ecd1caae1 100644
--- a/src/test/ui/impl-trait/issues/issue-57979-impl-trait-in-path.rs
+++ b/src/test/ui/impl-trait/issues/issue-57979-impl-trait-in-path.rs
@@ -3,35 +3,10 @@
 // Here we test behavior of occurrences of `impl Trait` within a path
 // component in that context.
 
-mod allowed {
-    #![allow(nested_impl_trait)]
-
-    pub trait Bar { }
-    pub trait Quux<T> { type Assoc; }
-    pub fn demo(_: impl Quux<(), Assoc=<() as Quux<impl Bar>>::Assoc>) { }
-    impl<T> Quux<T> for () { type Assoc = u32; }
-}
-
-mod warned {
-    #![warn(nested_impl_trait)]
-
-    pub trait Bar { }
-    pub trait Quux<T> { type Assoc; }
-    pub fn demo(_: impl Quux<(), Assoc=<() as Quux<impl Bar>>::Assoc>) { }
-    //~^ WARN `impl Trait` is not allowed in path parameters
-    //~| WARN will become a hard error in a future release!
-    impl<T> Quux<T> for () { type Assoc = u32; }
-}
-
-mod denied {
-    #![deny(nested_impl_trait)]
-
-    pub trait Bar { }
-    pub trait Quux<T> { type Assoc; }
-    pub fn demo(_: impl Quux<(), Assoc=<() as Quux<impl Bar>>::Assoc>) { }
-    //~^ ERROR `impl Trait` is not allowed in path parameters
-    //~| WARN will become a hard error in a future release!
-    impl<T> Quux<T> for () { type Assoc = u32; }
-}
+pub trait Bar { }
+pub trait Quux<T> { type Assoc; }
+pub fn demo(_: impl Quux<(), Assoc=<() as Quux<impl Bar>>::Assoc>) { }
+//~^ ERROR `impl Trait` is not allowed in path parameters
+impl<T> Quux<T> for () { type Assoc = u32; }
 
 fn main() { }
diff --git a/src/test/ui/impl-trait/issues/issue-57979-impl-trait-in-path.stderr b/src/test/ui/impl-trait/issues/issue-57979-impl-trait-in-path.stderr
index 982ecba291f..f64545d83b8 100644
--- a/src/test/ui/impl-trait/issues/issue-57979-impl-trait-in-path.stderr
+++ b/src/test/ui/impl-trait/issues/issue-57979-impl-trait-in-path.stderr
@@ -1,30 +1,8 @@
-warning: `impl Trait` is not allowed in path parameters
-  --> $DIR/issue-57979-impl-trait-in-path.rs:20:52
+error[E0667]: `impl Trait` is not allowed in path parameters
+  --> $DIR/issue-57979-impl-trait-in-path.rs:8:48
    |
-LL |     pub fn demo(_: impl Quux<(), Assoc=<() as Quux<impl Bar>>::Assoc>) { }
-   |                                                    ^^^^^^^^
-   |
-note: lint level defined here
-  --> $DIR/issue-57979-impl-trait-in-path.rs:16:13
-   |
-LL |     #![warn(nested_impl_trait)]
-   |             ^^^^^^^^^^^^^^^^^
-   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
-   = note: for more information, see issue #59014 <https://github.com/rust-lang/rust/issues/59014>
-
-error: `impl Trait` is not allowed in path parameters
-  --> $DIR/issue-57979-impl-trait-in-path.rs:31:52
-   |
-LL |     pub fn demo(_: impl Quux<(), Assoc=<() as Quux<impl Bar>>::Assoc>) { }
-   |                                                    ^^^^^^^^
-   |
-note: lint level defined here
-  --> $DIR/issue-57979-impl-trait-in-path.rs:27:13
-   |
-LL |     #![deny(nested_impl_trait)]
-   |             ^^^^^^^^^^^^^^^^^
-   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
-   = note: for more information, see issue #59014 <https://github.com/rust-lang/rust/issues/59014>
+LL | pub fn demo(_: impl Quux<(), Assoc=<() as Quux<impl Bar>>::Assoc>) { }
+   |                                                ^^^^^^^^
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/impl-trait/issues/issue-57979-nested-impl-trait-in-assoc-proj.rs b/src/test/ui/impl-trait/issues/issue-57979-nested-impl-trait-in-assoc-proj.rs
index 5c20ffc7c67..5a444d3dfdd 100644
--- a/src/test/ui/impl-trait/issues/issue-57979-nested-impl-trait-in-assoc-proj.rs
+++ b/src/test/ui/impl-trait/issues/issue-57979-nested-impl-trait-in-assoc-proj.rs
@@ -3,35 +3,10 @@
 // Here we test behavior of occurrences of `impl Trait` within an
 // `impl Trait` in that context.
 
-mod allowed {
-    #![allow(nested_impl_trait)]
-
-    pub trait Foo<T> { }
-    pub trait Bar { }
-    pub trait Quux { type Assoc; }
-    pub fn demo(_: impl Quux<Assoc=impl Foo<impl Bar>>) { }
-}
-
-mod warned {
-    #![warn(nested_impl_trait)]
-
-    pub trait Foo<T> { }
-    pub trait Bar { }
-    pub trait Quux { type Assoc; }
-    pub fn demo(_: impl Quux<Assoc=impl Foo<impl Bar>>) { }
-    //~^ WARN nested `impl Trait` is not allowed
-    //~| WARN will become a hard error in a future release!
-}
-
-mod denied {
-    #![deny(nested_impl_trait)]
-
-    pub trait Foo<T> { }
-    pub trait Bar { }
-    pub trait Quux { type Assoc; }
-    pub fn demo(_: impl Quux<Assoc=impl Foo<impl Bar>>) { }
-    //~^ ERROR nested `impl Trait` is not allowed
-    //~| WARN will become a hard error in a future release!
-}
+pub trait Foo<T> { }
+pub trait Bar { }
+pub trait Quux { type Assoc; }
+pub fn demo(_: impl Quux<Assoc=impl Foo<impl Bar>>) { }
+//~^ ERROR nested `impl Trait` is not allowed
 
 fn main() { }
diff --git a/src/test/ui/impl-trait/issues/issue-57979-nested-impl-trait-in-assoc-proj.stderr b/src/test/ui/impl-trait/issues/issue-57979-nested-impl-trait-in-assoc-proj.stderr
index 508aea24321..8d3d4b5e206 100644
--- a/src/test/ui/impl-trait/issues/issue-57979-nested-impl-trait-in-assoc-proj.stderr
+++ b/src/test/ui/impl-trait/issues/issue-57979-nested-impl-trait-in-assoc-proj.stderr
@@ -1,36 +1,12 @@
-warning: nested `impl Trait` is not allowed
-  --> $DIR/issue-57979-nested-impl-trait-in-assoc-proj.rs:21:45
-   |
-LL |     pub fn demo(_: impl Quux<Assoc=impl Foo<impl Bar>>) { }
-   |                                    ---------^^^^^^^^-
-   |                                    |        |
-   |                                    |        nested `impl Trait` here
-   |                                    outer `impl Trait`
-   |
-note: lint level defined here
-  --> $DIR/issue-57979-nested-impl-trait-in-assoc-proj.rs:16:13
-   |
-LL |     #![warn(nested_impl_trait)]
-   |             ^^^^^^^^^^^^^^^^^
-   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
-   = note: for more information, see issue #59014 <https://github.com/rust-lang/rust/issues/59014>
-
-error: nested `impl Trait` is not allowed
-  --> $DIR/issue-57979-nested-impl-trait-in-assoc-proj.rs:32:45
-   |
-LL |     pub fn demo(_: impl Quux<Assoc=impl Foo<impl Bar>>) { }
-   |                                    ---------^^^^^^^^-
-   |                                    |        |
-   |                                    |        nested `impl Trait` here
-   |                                    outer `impl Trait`
-   |
-note: lint level defined here
-  --> $DIR/issue-57979-nested-impl-trait-in-assoc-proj.rs:27:13
-   |
-LL |     #![deny(nested_impl_trait)]
-   |             ^^^^^^^^^^^^^^^^^
-   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
-   = note: for more information, see issue #59014 <https://github.com/rust-lang/rust/issues/59014>
+error[E0666]: nested `impl Trait` is not allowed
+  --> $DIR/issue-57979-nested-impl-trait-in-assoc-proj.rs:9:41
+   |
+LL | pub fn demo(_: impl Quux<Assoc=impl Foo<impl Bar>>) { }
+   |                                ---------^^^^^^^^-
+   |                                |        |
+   |                                |        nested `impl Trait` here
+   |                                outer `impl Trait`
 
 error: aborting due to previous error
 
+For more information about this error, try `rustc --explain E0666`.