diff --git a/compiler/rustc_lint/src/builtin.rs b/compiler/rustc_lint/src/builtin.rs
index 0b49e6562f95c..c4acaef21dd63 100644
--- a/compiler/rustc_lint/src/builtin.rs
+++ b/compiler/rustc_lint/src/builtin.rs
@@ -857,11 +857,10 @@ declare_lint! {
     /// ```
     ///
     /// This syntax is now a hard error in the 2018 edition. In the 2015
-    /// edition, this lint is "allow" by default, because the old code is
-    /// still valid, and warning for all old code can be noisy. This lint
+    /// edition, this lint is "warn" by default. This lint
     /// enables the [`cargo fix`] tool with the `--edition` flag to
     /// automatically transition old code from the 2015 edition to 2018. The
-    /// tool will switch this lint to "warn" and will automatically apply the
+    /// tool will run this lint and automatically apply the
     /// suggested fix from the compiler (which is to add `_` to each
     /// parameter). This provides a completely automated way to update old
     /// code for a new edition. See [issue #41686] for more details.
@@ -869,7 +868,7 @@ declare_lint! {
     /// [issue #41686]: https://github.com/rust-lang/rust/issues/41686
     /// [`cargo fix`]: https://doc.rust-lang.org/cargo/commands/cargo-fix.html
     pub ANONYMOUS_PARAMETERS,
-    Allow,
+    Warn,
     "detects anonymous parameters",
     @future_incompatible = FutureIncompatibleInfo {
         reference: "issue #41686 <https://github.com/rust-lang/rust/issues/41686>",
@@ -884,6 +883,10 @@ declare_lint_pass!(
 
 impl EarlyLintPass for AnonymousParameters {
     fn check_trait_item(&mut self, cx: &EarlyContext<'_>, it: &ast::AssocItem) {
+        if cx.sess.edition() != Edition::Edition2015 {
+            // This is a hard error in future editions; avoid linting and erroring
+            return;
+        }
         if let ast::AssocItemKind::Fn(box FnKind(_, ref sig, _, _)) = it.kind {
             for arg in sig.decl.inputs.iter() {
                 if let ast::PatKind::Ident(_, ident, None) = arg.pat.kind {
diff --git a/library/std/src/keyword_docs.rs b/library/std/src/keyword_docs.rs
index 2a3d44fb17d9f..39ed62425cecf 100644
--- a/library/std/src/keyword_docs.rs
+++ b/library/std/src/keyword_docs.rs
@@ -1768,6 +1768,7 @@ mod super_keyword {}
 /// In the 2015 edition the parameters pattern was not needed for traits:
 ///
 /// ```rust,edition2015
+/// # #![allow(anonymous_parameters)]
 /// trait Tr {
 ///     fn f(i32);
 /// }
diff --git a/src/test/ui/anon-params/anon-params-edition-hygiene.rs b/src/test/ui/anon-params/anon-params-edition-hygiene.rs
index 14e11c5696f4a..6936205f8b96d 100644
--- a/src/test/ui/anon-params/anon-params-edition-hygiene.rs
+++ b/src/test/ui/anon-params/anon-params-edition-hygiene.rs
@@ -2,6 +2,9 @@
 // edition:2018
 // aux-build:anon-params-edition-hygiene.rs
 
+// This warning is still surfaced
+#![allow(anonymous_parameters)]
+
 #[macro_use]
 extern crate anon_params_edition_hygiene;
 
diff --git a/src/test/ui/feature-gates/feature-gate-object_safe_for_dispatch.rs b/src/test/ui/feature-gates/feature-gate-object_safe_for_dispatch.rs
index 8945360b7be6d..37348e476d408 100644
--- a/src/test/ui/feature-gates/feature-gate-object_safe_for_dispatch.rs
+++ b/src/test/ui/feature-gates/feature-gate-object_safe_for_dispatch.rs
@@ -12,7 +12,7 @@ trait NonObjectSafe3 {
 }
 
 trait NonObjectSafe4 {
-    fn foo(&self, &Self);
+    fn foo(&self, s: &Self);
 }
 
 fn takes_non_object_safe_ref<T>(obj: &dyn NonObjectSafe1) {
diff --git a/src/test/ui/feature-gates/feature-gate-object_safe_for_dispatch.stderr b/src/test/ui/feature-gates/feature-gate-object_safe_for_dispatch.stderr
index b61d560445582..12195bc1071a0 100644
--- a/src/test/ui/feature-gates/feature-gate-object_safe_for_dispatch.stderr
+++ b/src/test/ui/feature-gates/feature-gate-object_safe_for_dispatch.stderr
@@ -57,12 +57,12 @@ LL | fn return_non_object_safe_rc() -> std::rc::Rc<dyn NonObjectSafe4> {
    |
    = help: consider moving `foo` to another trait
 note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
-  --> $DIR/feature-gate-object_safe_for_dispatch.rs:15:19
+  --> $DIR/feature-gate-object_safe_for_dispatch.rs:15:22
    |
 LL | trait NonObjectSafe4 {
    |       -------------- this trait cannot be made into an object...
-LL |     fn foo(&self, &Self);
-   |                   ^^^^^ ...because method `foo` references the `Self` type in this parameter
+LL |     fn foo(&self, s: &Self);
+   |                      ^^^^^ ...because method `foo` references the `Self` type in this parameter
 
 error[E0038]: the trait `NonObjectSafe1` cannot be made into an object
   --> $DIR/feature-gate-object_safe_for_dispatch.rs:38:16
diff --git a/src/test/ui/issues/issue-78720.rs b/src/test/ui/issues/issue-78720.rs
index 57615d1a207fd..4cdb9f491130c 100644
--- a/src/test/ui/issues/issue-78720.rs
+++ b/src/test/ui/issues/issue-78720.rs
@@ -4,7 +4,7 @@ fn server() -> impl {
 }
 
 trait FilterBase2 {
-    fn map2<F>(self, F) -> Map2<F> {}
+    fn map2<F>(self, f: F) -> Map2<F> {}
     //~^ ERROR mismatched types
     //~^^ ERROR the size for values of type `Self` cannot be known at compilation time
 }
diff --git a/src/test/ui/issues/issue-78720.stderr b/src/test/ui/issues/issue-78720.stderr
index a3a14e34acbc1..ee15826d18941 100644
--- a/src/test/ui/issues/issue-78720.stderr
+++ b/src/test/ui/issues/issue-78720.stderr
@@ -25,10 +25,10 @@ LL | struct Map2<Segment2, F> {
    |                     ^^^
 
 error[E0308]: mismatched types
-  --> $DIR/issue-78720.rs:7:36
+  --> $DIR/issue-78720.rs:7:39
    |
-LL |     fn map2<F>(self, F) -> Map2<F> {}
-   |                                    ^^ expected struct `Map2`, found `()`
+LL |     fn map2<F>(self, f: F) -> Map2<F> {}
+   |                                       ^^ expected struct `Map2`, found `()`
    |
    = note: expected struct `Map2<F>`
            found unit type `()`
@@ -36,17 +36,17 @@ LL |     fn map2<F>(self, F) -> Map2<F> {}
 error[E0277]: the size for values of type `Self` cannot be known at compilation time
   --> $DIR/issue-78720.rs:7:16
    |
-LL |     fn map2<F>(self, F) -> Map2<F> {}
+LL |     fn map2<F>(self, f: F) -> Map2<F> {}
    |                ^^^^ doesn't have a size known at compile-time
    |
    = help: unsized fn params are gated as an unstable feature
 help: consider further restricting `Self`
    |
-LL |     fn map2<F>(self, F) -> Map2<F> where Self: Sized {}
-   |                                    ^^^^^^^^^^^^^^^^^
+LL |     fn map2<F>(self, f: F) -> Map2<F> where Self: Sized {}
+   |                                       ^^^^^^^^^^^^^^^^^
 help: function arguments must have a statically known size, borrowed types always have a known size
    |
-LL |     fn map2<F>(&self, F) -> Map2<F> {}
+LL |     fn map2<F>(&self, f: F) -> Map2<F> {}
    |                ^
 
 error: aborting due to 4 previous errors
diff --git a/src/test/ui/parser/variadic-ffi-semantic-restrictions.rs b/src/test/ui/parser/variadic-ffi-semantic-restrictions.rs
index 404f409075519..fe993a6ee1302 100644
--- a/src/test/ui/parser/variadic-ffi-semantic-restrictions.rs
+++ b/src/test/ui/parser/variadic-ffi-semantic-restrictions.rs
@@ -1,4 +1,5 @@
 #![feature(c_variadic)]
+#![allow(anonymous_parameters)]
 
 fn main() {}
 
diff --git a/src/test/ui/parser/variadic-ffi-semantic-restrictions.stderr b/src/test/ui/parser/variadic-ffi-semantic-restrictions.stderr
index ebfe4979fb6f2..10fd05c0bef3f 100644
--- a/src/test/ui/parser/variadic-ffi-semantic-restrictions.stderr
+++ b/src/test/ui/parser/variadic-ffi-semantic-restrictions.stderr
@@ -1,203 +1,203 @@
 error: only foreign or `unsafe extern "C" functions may be C-variadic
-  --> $DIR/variadic-ffi-semantic-restrictions.rs:5:19
+  --> $DIR/variadic-ffi-semantic-restrictions.rs:6:19
    |
 LL | fn f1_1(x: isize, ...) {}
    |                   ^^^
 
 error: C-variadic function must be declared with at least one named argument
-  --> $DIR/variadic-ffi-semantic-restrictions.rs:8:9
+  --> $DIR/variadic-ffi-semantic-restrictions.rs:9:9
    |
 LL | fn f1_2(...) {}
    |         ^^^
 
 error: only foreign or `unsafe extern "C" functions may be C-variadic
-  --> $DIR/variadic-ffi-semantic-restrictions.rs:8:9
+  --> $DIR/variadic-ffi-semantic-restrictions.rs:9:9
    |
 LL | fn f1_2(...) {}
    |         ^^^
 
 error: only foreign or `unsafe extern "C" functions may be C-variadic
-  --> $DIR/variadic-ffi-semantic-restrictions.rs:12:30
+  --> $DIR/variadic-ffi-semantic-restrictions.rs:13:30
    |
 LL | extern "C" fn f2_1(x: isize, ...) {}
    |                              ^^^
 
 error: C-variadic function must be declared with at least one named argument
-  --> $DIR/variadic-ffi-semantic-restrictions.rs:15:20
+  --> $DIR/variadic-ffi-semantic-restrictions.rs:16:20
    |
 LL | extern "C" fn f2_2(...) {}
    |                    ^^^
 
 error: only foreign or `unsafe extern "C" functions may be C-variadic
-  --> $DIR/variadic-ffi-semantic-restrictions.rs:15:20
+  --> $DIR/variadic-ffi-semantic-restrictions.rs:16:20
    |
 LL | extern "C" fn f2_2(...) {}
    |                    ^^^
 
 error: `...` must be the last argument of a C-variadic function
-  --> $DIR/variadic-ffi-semantic-restrictions.rs:19:20
+  --> $DIR/variadic-ffi-semantic-restrictions.rs:20:20
    |
 LL | extern "C" fn f2_3(..., x: isize) {}
    |                    ^^^
 
 error: only foreign or `unsafe extern "C" functions may be C-variadic
-  --> $DIR/variadic-ffi-semantic-restrictions.rs:19:20
+  --> $DIR/variadic-ffi-semantic-restrictions.rs:20:20
    |
 LL | extern "C" fn f2_3(..., x: isize) {}
    |                    ^^^
 
 error: only foreign or `unsafe extern "C" functions may be C-variadic
-  --> $DIR/variadic-ffi-semantic-restrictions.rs:23:30
+  --> $DIR/variadic-ffi-semantic-restrictions.rs:24:30
    |
 LL | extern "C" fn f3_1(x: isize, ...) {}
    |                              ^^^
 
 error: C-variadic function must be declared with at least one named argument
-  --> $DIR/variadic-ffi-semantic-restrictions.rs:26:20
+  --> $DIR/variadic-ffi-semantic-restrictions.rs:27:20
    |
 LL | extern "C" fn f3_2(...) {}
    |                    ^^^
 
 error: only foreign or `unsafe extern "C" functions may be C-variadic
-  --> $DIR/variadic-ffi-semantic-restrictions.rs:26:20
+  --> $DIR/variadic-ffi-semantic-restrictions.rs:27:20
    |
 LL | extern "C" fn f3_2(...) {}
    |                    ^^^
 
 error: `...` must be the last argument of a C-variadic function
-  --> $DIR/variadic-ffi-semantic-restrictions.rs:30:20
+  --> $DIR/variadic-ffi-semantic-restrictions.rs:31:20
    |
 LL | extern "C" fn f3_3(..., x: isize) {}
    |                    ^^^
 
 error: only foreign or `unsafe extern "C" functions may be C-variadic
-  --> $DIR/variadic-ffi-semantic-restrictions.rs:30:20
+  --> $DIR/variadic-ffi-semantic-restrictions.rs:31:20
    |
 LL | extern "C" fn f3_3(..., x: isize) {}
    |                    ^^^
 
 error: C-variadic function must be declared with at least one named argument
-  --> $DIR/variadic-ffi-semantic-restrictions.rs:35:13
+  --> $DIR/variadic-ffi-semantic-restrictions.rs:36:13
    |
 LL |     fn e_f1(...);
    |             ^^^
 
 error: `...` must be the last argument of a C-variadic function
-  --> $DIR/variadic-ffi-semantic-restrictions.rs:37:13
+  --> $DIR/variadic-ffi-semantic-restrictions.rs:38:13
    |
 LL |     fn e_f2(..., x: isize);
    |             ^^^
 
 error: only foreign or `unsafe extern "C" functions may be C-variadic
-  --> $DIR/variadic-ffi-semantic-restrictions.rs:44:23
+  --> $DIR/variadic-ffi-semantic-restrictions.rs:45:23
    |
 LL |     fn i_f1(x: isize, ...) {}
    |                       ^^^
 
 error: C-variadic function must be declared with at least one named argument
-  --> $DIR/variadic-ffi-semantic-restrictions.rs:46:13
+  --> $DIR/variadic-ffi-semantic-restrictions.rs:47:13
    |
 LL |     fn i_f2(...) {}
    |             ^^^
 
 error: only foreign or `unsafe extern "C" functions may be C-variadic
-  --> $DIR/variadic-ffi-semantic-restrictions.rs:46:13
+  --> $DIR/variadic-ffi-semantic-restrictions.rs:47:13
    |
 LL |     fn i_f2(...) {}
    |             ^^^
 
 error: `...` must be the last argument of a C-variadic function
-  --> $DIR/variadic-ffi-semantic-restrictions.rs:49:13
+  --> $DIR/variadic-ffi-semantic-restrictions.rs:50:13
    |
 LL |     fn i_f3(..., x: isize, ...) {}
    |             ^^^
 
 error: only foreign or `unsafe extern "C" functions may be C-variadic
-  --> $DIR/variadic-ffi-semantic-restrictions.rs:49:13
+  --> $DIR/variadic-ffi-semantic-restrictions.rs:50:13
    |
 LL |     fn i_f3(..., x: isize, ...) {}
    |             ^^^
 
 error: only foreign or `unsafe extern "C" functions may be C-variadic
-  --> $DIR/variadic-ffi-semantic-restrictions.rs:49:28
+  --> $DIR/variadic-ffi-semantic-restrictions.rs:50:28
    |
 LL |     fn i_f3(..., x: isize, ...) {}
    |                            ^^^
 
 error: `...` must be the last argument of a C-variadic function
-  --> $DIR/variadic-ffi-semantic-restrictions.rs:53:13
+  --> $DIR/variadic-ffi-semantic-restrictions.rs:54:13
    |
 LL |     fn i_f4(..., x: isize, ...) {}
    |             ^^^
 
 error: only foreign or `unsafe extern "C" functions may be C-variadic
-  --> $DIR/variadic-ffi-semantic-restrictions.rs:53:13
+  --> $DIR/variadic-ffi-semantic-restrictions.rs:54:13
    |
 LL |     fn i_f4(..., x: isize, ...) {}
    |             ^^^
 
 error: only foreign or `unsafe extern "C" functions may be C-variadic
-  --> $DIR/variadic-ffi-semantic-restrictions.rs:53:28
+  --> $DIR/variadic-ffi-semantic-restrictions.rs:54:28
    |
 LL |     fn i_f4(..., x: isize, ...) {}
    |                            ^^^
 
 error: only foreign or `unsafe extern "C" functions may be C-variadic
-  --> $DIR/variadic-ffi-semantic-restrictions.rs:60:23
+  --> $DIR/variadic-ffi-semantic-restrictions.rs:61:23
    |
 LL |     fn t_f1(x: isize, ...) {}
    |                       ^^^
 
 error: only foreign or `unsafe extern "C" functions may be C-variadic
-  --> $DIR/variadic-ffi-semantic-restrictions.rs:62:23
+  --> $DIR/variadic-ffi-semantic-restrictions.rs:63:23
    |
 LL |     fn t_f2(x: isize, ...);
    |                       ^^^
 
 error: C-variadic function must be declared with at least one named argument
-  --> $DIR/variadic-ffi-semantic-restrictions.rs:64:13
+  --> $DIR/variadic-ffi-semantic-restrictions.rs:65:13
    |
 LL |     fn t_f3(...) {}
    |             ^^^
 
 error: only foreign or `unsafe extern "C" functions may be C-variadic
-  --> $DIR/variadic-ffi-semantic-restrictions.rs:64:13
+  --> $DIR/variadic-ffi-semantic-restrictions.rs:65:13
    |
 LL |     fn t_f3(...) {}
    |             ^^^
 
 error: C-variadic function must be declared with at least one named argument
-  --> $DIR/variadic-ffi-semantic-restrictions.rs:67:13
+  --> $DIR/variadic-ffi-semantic-restrictions.rs:68:13
    |
 LL |     fn t_f4(...);
    |             ^^^
 
 error: only foreign or `unsafe extern "C" functions may be C-variadic
-  --> $DIR/variadic-ffi-semantic-restrictions.rs:67:13
+  --> $DIR/variadic-ffi-semantic-restrictions.rs:68:13
    |
 LL |     fn t_f4(...);
    |             ^^^
 
 error: `...` must be the last argument of a C-variadic function
-  --> $DIR/variadic-ffi-semantic-restrictions.rs:70:13
+  --> $DIR/variadic-ffi-semantic-restrictions.rs:71:13
    |
 LL |     fn t_f5(..., x: isize) {}
    |             ^^^
 
 error: only foreign or `unsafe extern "C" functions may be C-variadic
-  --> $DIR/variadic-ffi-semantic-restrictions.rs:70:13
+  --> $DIR/variadic-ffi-semantic-restrictions.rs:71:13
    |
 LL |     fn t_f5(..., x: isize) {}
    |             ^^^
 
 error: `...` must be the last argument of a C-variadic function
-  --> $DIR/variadic-ffi-semantic-restrictions.rs:73:13
+  --> $DIR/variadic-ffi-semantic-restrictions.rs:74:13
    |
 LL |     fn t_f6(..., x: isize);
    |             ^^^
 
 error: only foreign or `unsafe extern "C" functions may be C-variadic
-  --> $DIR/variadic-ffi-semantic-restrictions.rs:73:13
+  --> $DIR/variadic-ffi-semantic-restrictions.rs:74:13
    |
 LL |     fn t_f6(..., x: isize);
    |             ^^^
diff --git a/src/test/ui/proc-macro/trait-fn-args-2015.rs b/src/test/ui/proc-macro/trait-fn-args-2015.rs
index 3a448d4b2201d..6b8df78a061c7 100644
--- a/src/test/ui/proc-macro/trait-fn-args-2015.rs
+++ b/src/test/ui/proc-macro/trait-fn-args-2015.rs
@@ -3,6 +3,8 @@
 // check-pass
 // aux-build:test-macros.rs
 
+#![allow(anonymous_parameters)]
+
 #[macro_use]
 extern crate test_macros;
 
diff --git a/src/test/ui/rfc-2565-param-attrs/proc-macro-cannot-be-used.rs b/src/test/ui/rfc-2565-param-attrs/proc-macro-cannot-be-used.rs
index fcfa610ec8554..54f2f451bbe53 100644
--- a/src/test/ui/rfc-2565-param-attrs/proc-macro-cannot-be-used.rs
+++ b/src/test/ui/rfc-2565-param-attrs/proc-macro-cannot-be-used.rs
@@ -1,6 +1,7 @@
 // aux-build:ident-mac.rs
 
 #![feature(c_variadic)]
+#![allow(anonymous_parameters)]
 
 extern crate ident_mac;
 use ident_mac::id;
diff --git a/src/test/ui/rfc-2565-param-attrs/proc-macro-cannot-be-used.stderr b/src/test/ui/rfc-2565-param-attrs/proc-macro-cannot-be-used.stderr
index 38c5050f3428d..e74d05d49b8d7 100644
--- a/src/test/ui/rfc-2565-param-attrs/proc-macro-cannot-be-used.stderr
+++ b/src/test/ui/rfc-2565-param-attrs/proc-macro-cannot-be-used.stderr
@@ -1,173 +1,173 @@
 error: expected non-macro attribute, found attribute macro `id`
-  --> $DIR/proc-macro-cannot-be-used.rs:10:23
+  --> $DIR/proc-macro-cannot-be-used.rs:11:23
    |
 LL | extern "C" { fn ffi(#[id] arg1: i32, #[id] ...); }
    |                       ^^ not a non-macro attribute
 
 error: expected non-macro attribute, found attribute macro `id`
-  --> $DIR/proc-macro-cannot-be-used.rs:10:40
+  --> $DIR/proc-macro-cannot-be-used.rs:11:40
    |
 LL | extern "C" { fn ffi(#[id] arg1: i32, #[id] ...); }
    |                                        ^^ not a non-macro attribute
 
 error: expected non-macro attribute, found attribute macro `id`
-  --> $DIR/proc-macro-cannot-be-used.rs:14:40
+  --> $DIR/proc-macro-cannot-be-used.rs:15:40
    |
 LL | unsafe extern "C" fn cvar(arg1: i32, #[id] mut args: ...) {}
    |                                        ^^ not a non-macro attribute
 
 error: expected non-macro attribute, found attribute macro `id`
-  --> $DIR/proc-macro-cannot-be-used.rs:17:30
+  --> $DIR/proc-macro-cannot-be-used.rs:18:30
    |
 LL | type Alias = extern "C" fn(#[id] u8, #[id] ...);
    |                              ^^ not a non-macro attribute
 
 error: expected non-macro attribute, found attribute macro `id`
-  --> $DIR/proc-macro-cannot-be-used.rs:17:40
+  --> $DIR/proc-macro-cannot-be-used.rs:18:40
    |
 LL | type Alias = extern "C" fn(#[id] u8, #[id] ...);
    |                                        ^^ not a non-macro attribute
 
 error: expected non-macro attribute, found attribute macro `id`
-  --> $DIR/proc-macro-cannot-be-used.rs:21:11
+  --> $DIR/proc-macro-cannot-be-used.rs:22:11
    |
 LL | fn free(#[id] arg1: u8) {
    |           ^^ not a non-macro attribute
 
 error: expected non-macro attribute, found attribute macro `id`
-  --> $DIR/proc-macro-cannot-be-used.rs:23:18
+  --> $DIR/proc-macro-cannot-be-used.rs:24:18
    |
 LL |     let lam = |#[id] W(x), #[id] y: usize| ();
    |                  ^^ not a non-macro attribute
 
 error: expected non-macro attribute, found attribute macro `id`
-  --> $DIR/proc-macro-cannot-be-used.rs:23:30
+  --> $DIR/proc-macro-cannot-be-used.rs:24:30
    |
 LL |     let lam = |#[id] W(x), #[id] y: usize| ();
    |                              ^^ not a non-macro attribute
 
 error: expected non-macro attribute, found attribute macro `id`
-  --> $DIR/proc-macro-cannot-be-used.rs:29:20
+  --> $DIR/proc-macro-cannot-be-used.rs:30:20
    |
 LL |     fn inherent1(#[id] self, #[id] arg1: u8) {}
    |                    ^^ not a non-macro attribute
 
 error: expected non-macro attribute, found attribute macro `id`
-  --> $DIR/proc-macro-cannot-be-used.rs:29:32
+  --> $DIR/proc-macro-cannot-be-used.rs:30:32
    |
 LL |     fn inherent1(#[id] self, #[id] arg1: u8) {}
    |                                ^^ not a non-macro attribute
 
 error: expected non-macro attribute, found attribute macro `id`
-  --> $DIR/proc-macro-cannot-be-used.rs:32:20
+  --> $DIR/proc-macro-cannot-be-used.rs:33:20
    |
 LL |     fn inherent2(#[id] &self, #[id] arg1: u8) {}
    |                    ^^ not a non-macro attribute
 
 error: expected non-macro attribute, found attribute macro `id`
-  --> $DIR/proc-macro-cannot-be-used.rs:32:33
+  --> $DIR/proc-macro-cannot-be-used.rs:33:33
    |
 LL |     fn inherent2(#[id] &self, #[id] arg1: u8) {}
    |                                 ^^ not a non-macro attribute
 
 error: expected non-macro attribute, found attribute macro `id`
-  --> $DIR/proc-macro-cannot-be-used.rs:35:24
+  --> $DIR/proc-macro-cannot-be-used.rs:36:24
    |
 LL |     fn inherent3<'a>(#[id] &'a mut self, #[id] arg1: u8) {}
    |                        ^^ not a non-macro attribute
 
 error: expected non-macro attribute, found attribute macro `id`
-  --> $DIR/proc-macro-cannot-be-used.rs:35:44
+  --> $DIR/proc-macro-cannot-be-used.rs:36:44
    |
 LL |     fn inherent3<'a>(#[id] &'a mut self, #[id] arg1: u8) {}
    |                                            ^^ not a non-macro attribute
 
 error: expected non-macro attribute, found attribute macro `id`
-  --> $DIR/proc-macro-cannot-be-used.rs:38:24
+  --> $DIR/proc-macro-cannot-be-used.rs:39:24
    |
 LL |     fn inherent4<'a>(#[id] self: Box<Self>, #[id] arg1: u8) {}
    |                        ^^ not a non-macro attribute
 
 error: expected non-macro attribute, found attribute macro `id`
-  --> $DIR/proc-macro-cannot-be-used.rs:38:47
+  --> $DIR/proc-macro-cannot-be-used.rs:39:47
    |
 LL |     fn inherent4<'a>(#[id] self: Box<Self>, #[id] arg1: u8) {}
    |                                               ^^ not a non-macro attribute
 
 error: expected non-macro attribute, found attribute macro `id`
-  --> $DIR/proc-macro-cannot-be-used.rs:41:40
+  --> $DIR/proc-macro-cannot-be-used.rs:42:40
    |
 LL |     fn issue_64682_associated_fn<'a>(#[id] arg1: u8, #[id] arg2: u8) {}
    |                                        ^^ not a non-macro attribute
 
 error: expected non-macro attribute, found attribute macro `id`
-  --> $DIR/proc-macro-cannot-be-used.rs:41:56
+  --> $DIR/proc-macro-cannot-be-used.rs:42:56
    |
 LL |     fn issue_64682_associated_fn<'a>(#[id] arg1: u8, #[id] arg2: u8) {}
    |                                                        ^^ not a non-macro attribute
 
 error: expected non-macro attribute, found attribute macro `id`
-  --> $DIR/proc-macro-cannot-be-used.rs:47:17
+  --> $DIR/proc-macro-cannot-be-used.rs:48:17
    |
 LL |     fn trait1(#[id] self, #[id] arg1: u8);
    |                 ^^ not a non-macro attribute
 
 error: expected non-macro attribute, found attribute macro `id`
-  --> $DIR/proc-macro-cannot-be-used.rs:47:29
+  --> $DIR/proc-macro-cannot-be-used.rs:48:29
    |
 LL |     fn trait1(#[id] self, #[id] arg1: u8);
    |                             ^^ not a non-macro attribute
 
 error: expected non-macro attribute, found attribute macro `id`
-  --> $DIR/proc-macro-cannot-be-used.rs:50:17
+  --> $DIR/proc-macro-cannot-be-used.rs:51:17
    |
 LL |     fn trait2(#[id] &self, #[id] arg1: u8);
    |                 ^^ not a non-macro attribute
 
 error: expected non-macro attribute, found attribute macro `id`
-  --> $DIR/proc-macro-cannot-be-used.rs:50:30
+  --> $DIR/proc-macro-cannot-be-used.rs:51:30
    |
 LL |     fn trait2(#[id] &self, #[id] arg1: u8);
    |                              ^^ not a non-macro attribute
 
 error: expected non-macro attribute, found attribute macro `id`
-  --> $DIR/proc-macro-cannot-be-used.rs:53:21
+  --> $DIR/proc-macro-cannot-be-used.rs:54:21
    |
 LL |     fn trait3<'a>(#[id] &'a mut self, #[id] arg1: u8);
    |                     ^^ not a non-macro attribute
 
 error: expected non-macro attribute, found attribute macro `id`
-  --> $DIR/proc-macro-cannot-be-used.rs:53:41
+  --> $DIR/proc-macro-cannot-be-used.rs:54:41
    |
 LL |     fn trait3<'a>(#[id] &'a mut self, #[id] arg1: u8);
    |                                         ^^ not a non-macro attribute
 
 error: expected non-macro attribute, found attribute macro `id`
-  --> $DIR/proc-macro-cannot-be-used.rs:56:21
+  --> $DIR/proc-macro-cannot-be-used.rs:57:21
    |
 LL |     fn trait4<'a>(#[id] self: Box<Self>, #[id] arg1: u8, #[id] Vec<u8>);
    |                     ^^ not a non-macro attribute
 
 error: expected non-macro attribute, found attribute macro `id`
-  --> $DIR/proc-macro-cannot-be-used.rs:56:44
+  --> $DIR/proc-macro-cannot-be-used.rs:57:44
    |
 LL |     fn trait4<'a>(#[id] self: Box<Self>, #[id] arg1: u8, #[id] Vec<u8>);
    |                                            ^^ not a non-macro attribute
 
 error: expected non-macro attribute, found attribute macro `id`
-  --> $DIR/proc-macro-cannot-be-used.rs:56:60
+  --> $DIR/proc-macro-cannot-be-used.rs:57:60
    |
 LL |     fn trait4<'a>(#[id] self: Box<Self>, #[id] arg1: u8, #[id] Vec<u8>);
    |                                                            ^^ not a non-macro attribute
 
 error: expected non-macro attribute, found attribute macro `id`
-  --> $DIR/proc-macro-cannot-be-used.rs:60:40
+  --> $DIR/proc-macro-cannot-be-used.rs:61:40
    |
 LL |     fn issue_64682_associated_fn<'a>(#[id] arg1: u8, #[id] arg2: u8);
    |                                        ^^ not a non-macro attribute
 
 error: expected non-macro attribute, found attribute macro `id`
-  --> $DIR/proc-macro-cannot-be-used.rs:60:56
+  --> $DIR/proc-macro-cannot-be-used.rs:61:56
    |
 LL |     fn issue_64682_associated_fn<'a>(#[id] arg1: u8, #[id] arg2: u8);
    |                                                        ^^ not a non-macro attribute
diff --git a/src/test/ui/specialization/issue-39448.rs b/src/test/ui/specialization/issue-39448.rs
index 9dd47a4a17e43..a15c4bd6b7ffc 100644
--- a/src/test/ui/specialization/issue-39448.rs
+++ b/src/test/ui/specialization/issue-39448.rs
@@ -18,7 +18,7 @@ impl FromA<u8> for u16 {
 }
 
 trait FromA<T> {
-    fn from(T) -> Self;
+    fn from(t: T) -> Self;
 }
 
 impl<T: A, U: A + FromA<T>> FromA<T> for U {
diff --git a/src/test/ui/typeck/issue-65611.rs b/src/test/ui/typeck/issue-65611.rs
index b74ee1b0c6e54..7645311496d8c 100644
--- a/src/test/ui/typeck/issue-65611.rs
+++ b/src/test/ui/typeck/issue-65611.rs
@@ -17,7 +17,7 @@ pub unsafe trait Array {
 
 pub trait Index : PartialEq + Copy {
     fn to_usize(self) -> usize;
-    fn from(usize) -> Self;
+    fn from(i: usize) -> Self;
 }
 
 impl Index for usize {