Auto merge of #96528 - Dylan-DPC:rollup-iedbjli, r=Dylan-DPC

Rollup of 5 pull requests

Successful merges:

 - #95312 (Ensure that `'_` and GAT yields errors)
 - #96405 (Migrate ambiguous plus diagnostic to the new derive macro)
 - #96409 (Recover suggestions to introduce named lifetime under NLL)
 - #96433 (rustc_ast: Harmonize delimiter naming with `proc_macro::Delimiter`)
 - #96480 (Fixed grammatical error in example comment)

Failed merges:

r? `@ghost`
`@rustbot` modify labels: rollup

26 files changed, 320 insertions, 58 deletions

diff --git a/src/librustdoc/clean/render_macro_matchers.rs b/src/librustdoc/clean/render_macro_matchers.rs
index 58ca8869ea9..a9c0fe6f079 100644
--- a/src/librustdoc/clean/render_macro_matchers.rs
+++ b/src/librustdoc/clean/render_macro_matchers.rs
@@ -1,4 +1,4 @@
-use rustc_ast::token::{self, BinOpToken, DelimToken};
+use rustc_ast::token::{self, BinOpToken, Delimiter};
 use rustc_ast::tokenstream::{TokenStream, TokenTree};
 use rustc_ast_pretty::pprust::state::State as Printer;
 use rustc_ast_pretty::pprust::PrintState;
@@ -104,11 +104,11 @@ fn print_tt(printer: &mut Printer<'_>, tt: &TokenTree) {
             let open_delim = printer.token_kind_to_string(&token::OpenDelim(*delim));
             printer.word(open_delim);
             if !tts.is_empty() {
-                if *delim == DelimToken::Brace {
+                if *delim == Delimiter::Brace {
                     printer.space();
                 }
                 print_tts(printer, tts);
-                if *delim == DelimToken::Brace {
+                if *delim == Delimiter::Brace {
                     printer.space();
                 }
             }
@@ -162,9 +162,9 @@ fn print_tts(printer: &mut Printer<'_>, tts: &TokenStream) {
                 (_, _) => (true, Other),
             },
             TokenTree::Delimited(_, delim, _) => match (state, delim) {
-                (Dollar, DelimToken::Paren) => (false, DollarParen),
-                (Pound | PoundBang, DelimToken::Bracket) => (false, Other),
-                (Ident, DelimToken::Paren | DelimToken::Bracket) => (false, Other),
+                (Dollar, Delimiter::Parenthesis) => (false, DollarParen),
+                (Pound | PoundBang, Delimiter::Bracket) => (false, Other),
+                (Ident, Delimiter::Parenthesis | Delimiter::Bracket) => (false, Other),
                 (_, _) => (true, Other),
             },
         };
diff --git a/src/test/ui/generic-associated-types/issue-95305.rs b/src/test/ui/generic-associated-types/issue-95305.rs
new file mode 100644
index 00000000000..9ead347984b
--- /dev/null
+++ b/src/test/ui/generic-associated-types/issue-95305.rs
@@ -0,0 +1,17 @@
+// It's not yet clear how '_ and GATs should interact.
+// Forbid it for now but proper support might be added
+// at some point in the future.
+
+#![feature(generic_associated_types)]
+
+trait Foo {
+    type Item<'a>;
+}
+
+fn foo(x: &impl Foo<Item<'_> = u32>) { }
+                       //~^ ERROR missing lifetime specifier
+
+fn bar(x: &impl for<'a> Foo<Item<'a> = &'_ u32>) { }
+                                      //~^ ERROR missing lifetime specifier
+
+fn main() {}
diff --git a/src/test/ui/generic-associated-types/issue-95305.stderr b/src/test/ui/generic-associated-types/issue-95305.stderr
new file mode 100644
index 00000000000..2b48378dc43
--- /dev/null
+++ b/src/test/ui/generic-associated-types/issue-95305.stderr
@@ -0,0 +1,25 @@
+error[E0106]: missing lifetime specifier
+  --> $DIR/issue-95305.rs:11:26
+   |
+LL | fn foo(x: &impl Foo<Item<'_> = u32>) { }
+   |                          ^^ expected named lifetime parameter
+   |
+help: consider introducing a named lifetime parameter
+   |
+LL | fn foo<'a>(x: &impl Foo<Item<'a> = u32>) { }
+   |       ++++                   ~~
+
+error[E0106]: missing lifetime specifier
+  --> $DIR/issue-95305.rs:14:41
+   |
+LL | fn bar(x: &impl for<'a> Foo<Item<'a> = &'_ u32>) { }
+   |                                         ^^ expected named lifetime parameter
+   |
+help: consider using the `'a` lifetime
+   |
+LL | fn bar(x: &impl for<'a> Foo<Item<'a> = &'a u32>) { }
+   |                                         ~~
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0106`.
diff --git a/src/test/ui/lifetimes/issue-90170-elision-mismatch.nll.stderr b/src/test/ui/lifetimes/issue-90170-elision-mismatch.nll.stderr
index a5bc7450bbf..48fb3fb4a22 100644
--- a/src/test/ui/lifetimes/issue-90170-elision-mismatch.nll.stderr
+++ b/src/test/ui/lifetimes/issue-90170-elision-mismatch.nll.stderr
@@ -6,6 +6,11 @@ LL | pub fn foo(x: &mut Vec<&u8>, y: &u8) { x.push(y); }
    |                        |        |
    |                        |        let's call the lifetime of this reference `'1`
    |                        let's call the lifetime of this reference `'2`
+   |
+help: consider introducing a named lifetime parameter
+   |
+LL | pub fn foo<'a>(x: &mut Vec<&'a u8>, y: &'a u8) { x.push(y); }
+   |           ++++              ++          ++
 
 error: lifetime may not live long enough
   --> $DIR/issue-90170-elision-mismatch.rs:5:44
@@ -15,6 +20,11 @@ LL | pub fn foo2(x: &mut Vec<&'_ u8>, y: &u8) { x.push(y); }
    |                         |           |
    |                         |           let's call the lifetime of this reference `'1`
    |                         let's call the lifetime of this reference `'2`
+   |
+help: consider introducing a named lifetime parameter
+   |
+LL | pub fn foo2<'a>(x: &mut Vec<&'a u8>, y: &'a u8) { x.push(y); }
+   |            ++++              ~~          ++
 
 error: lifetime may not live long enough
   --> $DIR/issue-90170-elision-mismatch.rs:7:63
@@ -24,6 +34,11 @@ LL | pub fn foo3<'a>(_other: &'a [u8], x: &mut Vec<&u8>, y: &u8) { x.push(y); }
    |                                               |        |
    |                                               |        let's call the lifetime of this reference `'1`
    |                                               let's call the lifetime of this reference `'2`
+   |
+help: consider introducing a named lifetime parameter
+   |
+LL | pub fn foo3<'a>(_other: &'a [u8], x: &mut Vec<&'a u8>, y: &'a u8) { x.push(y); }
+   |                                                ++          ++
 
 error: aborting due to 3 previous errors
 
diff --git a/src/test/ui/lifetimes/lifetime-errors/ex3-both-anon-regions-2.nll.stderr b/src/test/ui/lifetimes/lifetime-errors/ex3-both-anon-regions-2.nll.stderr
index a94f9a79906..5a23f1e0e9d 100644
--- a/src/test/ui/lifetimes/lifetime-errors/ex3-both-anon-regions-2.nll.stderr
+++ b/src/test/ui/lifetimes/lifetime-errors/ex3-both-anon-regions-2.nll.stderr
@@ -7,6 +7,11 @@ LL | fn foo(&mut (ref mut v, w): &mut (&u8, &u8), x: &u8) {
    |                                   let's call the lifetime of this reference `'2`
 LL |     *v = x;
    |     ^^^^^^ assignment requires that `'1` must outlive `'2`
+   |
+help: consider introducing a named lifetime parameter
+   |
+LL | fn foo<'a>(&mut (ref mut v, w): &mut (&'a u8, &u8), x: &'a u8) {
+   |       ++++                             ++               ++
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/lifetimes/lifetime-errors/ex3-both-anon-regions-3.nll.stderr b/src/test/ui/lifetimes/lifetime-errors/ex3-both-anon-regions-3.nll.stderr
index 2ed4d6d4401..6ba130308a3 100644
--- a/src/test/ui/lifetimes/lifetime-errors/ex3-both-anon-regions-3.nll.stderr
+++ b/src/test/ui/lifetimes/lifetime-errors/ex3-both-anon-regions-3.nll.stderr
@@ -7,6 +7,11 @@ LL | fn foo(z: &mut Vec<(&u8,&u8)>, (x, y): (&u8, &u8)) {
    |                     let's call the lifetime of this reference `'2`
 LL |     z.push((x,y));
    |     ^^^^^^^^^^^^^ argument requires that `'1` must outlive `'2`
+   |
+help: consider introducing a named lifetime parameter
+   |
+LL | fn foo<'a>(z: &mut Vec<(&'a u8,&u8)>, (x, y): (&'a u8, &u8)) {
+   |       ++++               ++                     ++
 
 error: lifetime may not live long enough
   --> $DIR/ex3-both-anon-regions-3.rs:2:5
@@ -17,6 +22,11 @@ LL | fn foo(z: &mut Vec<(&u8,&u8)>, (x, y): (&u8, &u8)) {
    |                         let's call the lifetime of this reference `'4`
 LL |     z.push((x,y));
    |     ^^^^^^^^^^^^^ argument requires that `'3` must outlive `'4`
+   |
+help: consider introducing a named lifetime parameter
+   |
+LL | fn foo<'a>(z: &mut Vec<(&u8,&'a u8)>, (x, y): (&u8, &'a u8)) {
+   |       ++++                   ++                      ++
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/lifetimes/lifetime-errors/ex3-both-anon-regions-return-type-is-anon.nll.stderr b/src/test/ui/lifetimes/lifetime-errors/ex3-both-anon-regions-return-type-is-anon.nll.stderr
index 1a19e81f235..5601335d275 100644
--- a/src/test/ui/lifetimes/lifetime-errors/ex3-both-anon-regions-return-type-is-anon.nll.stderr
+++ b/src/test/ui/lifetimes/lifetime-errors/ex3-both-anon-regions-return-type-is-anon.nll.stderr
@@ -7,6 +7,11 @@ LL |   fn foo<'a>(&self, x: &i32) -> &i32 {
    |              let's call the lifetime of this reference `'2`
 LL |     x
    |     ^ associated function was supposed to return data with lifetime `'2` but it is returning data with lifetime `'1`
+   |
+help: consider introducing a named lifetime parameter and update trait if needed
+   |
+LL |   fn foo<'a>(&'a self, x: &'a i32) -> &i32 {
+   |               ++           ++
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/lifetimes/lifetime-errors/ex3-both-anon-regions-self-is-anon.nll.stderr b/src/test/ui/lifetimes/lifetime-errors/ex3-both-anon-regions-self-is-anon.nll.stderr
index 87b13dc1591..e221902c4a9 100644
--- a/src/test/ui/lifetimes/lifetime-errors/ex3-both-anon-regions-self-is-anon.nll.stderr
+++ b/src/test/ui/lifetimes/lifetime-errors/ex3-both-anon-regions-self-is-anon.nll.stderr
@@ -7,6 +7,11 @@ LL |     fn foo<'a>(&self, x: &Foo) -> &Foo {
    |                let's call the lifetime of this reference `'2`
 LL |         if true { x } else { self }
    |                   ^ associated function was supposed to return data with lifetime `'2` but it is returning data with lifetime `'1`
+   |
+help: consider introducing a named lifetime parameter and update trait if needed
+   |
+LL |     fn foo<'a>(&'a self, x: &'a Foo) -> &Foo {
+   |                 ++           ++
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/lifetimes/lifetime-errors/ex3-both-anon-regions-using-fn-items.nll.stderr b/src/test/ui/lifetimes/lifetime-errors/ex3-both-anon-regions-using-fn-items.nll.stderr
index 825c45b2434..a909c5fa823 100644
--- a/src/test/ui/lifetimes/lifetime-errors/ex3-both-anon-regions-using-fn-items.nll.stderr
+++ b/src/test/ui/lifetimes/lifetime-errors/ex3-both-anon-regions-using-fn-items.nll.stderr
@@ -7,6 +7,11 @@ LL | fn foo(x:fn(&u8, &u8), y: Vec<&u8>, z: &u8) {
    |                               let's call the lifetime of this reference `'2`
 LL |   y.push(z);
    |   ^^^^^^^^^ argument requires that `'1` must outlive `'2`
+   |
+help: consider introducing a named lifetime parameter
+   |
+LL | fn foo<'a>(x:fn(&u8, &u8), y: Vec<&'a u8>, z: &'a u8) {
+   |       ++++                         ++          ++
 
 error[E0596]: cannot borrow `y` as mutable, as it is not declared as mutable
   --> $DIR/ex3-both-anon-regions-using-fn-items.rs:2:3
diff --git a/src/test/ui/lifetimes/lifetime-errors/ex3-both-anon-regions-using-impl-items.nll.stderr b/src/test/ui/lifetimes/lifetime-errors/ex3-both-anon-regions-using-impl-items.nll.stderr
index f3502674849..9661f1e5144 100644
--- a/src/test/ui/lifetimes/lifetime-errors/ex3-both-anon-regions-using-impl-items.nll.stderr
+++ b/src/test/ui/lifetimes/lifetime-errors/ex3-both-anon-regions-using-impl-items.nll.stderr
@@ -7,6 +7,11 @@ LL |     fn foo(x: &mut Vec<&u8>, y: &u8) {
    |                        let's call the lifetime of this reference `'2`
 LL |         x.push(y);
    |         ^^^^^^^^^ argument requires that `'1` must outlive `'2`
+   |
+help: consider introducing a named lifetime parameter and update trait if needed
+   |
+LL |     fn foo<'a>(x: &mut Vec<&'a u8>, y: &'a u8) {
+   |           ++++              ++          ++
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/lifetimes/lifetime-errors/ex3-both-anon-regions-using-trait-objects.nll.stderr b/src/test/ui/lifetimes/lifetime-errors/ex3-both-anon-regions-using-trait-objects.nll.stderr
index 78a828dde86..cce0a31bfbb 100644
--- a/src/test/ui/lifetimes/lifetime-errors/ex3-both-anon-regions-using-trait-objects.nll.stderr
+++ b/src/test/ui/lifetimes/lifetime-errors/ex3-both-anon-regions-using-trait-objects.nll.stderr
@@ -7,6 +7,11 @@ LL | fn foo(x:Box<dyn Fn(&u8, &u8)> , y: Vec<&u8>, z: &u8) {
    |                                         let's call the lifetime of this reference `'2`
 LL |   y.push(z);
    |   ^^^^^^^^^ argument requires that `'1` must outlive `'2`
+   |
+help: consider introducing a named lifetime parameter
+   |
+LL | fn foo<'a>(x:Box<dyn Fn(&'a u8, &'a u8)> , y: Vec<&u8>, z: &u8) {
+   |       ++++               ++      ++
 
 error[E0596]: cannot borrow `y` as mutable, as it is not declared as mutable
   --> $DIR/ex3-both-anon-regions-using-trait-objects.rs:2:3
diff --git a/src/test/ui/lifetimes/lifetime-errors/ex3-both-anon-regions.nll.stderr b/src/test/ui/lifetimes/lifetime-errors/ex3-both-anon-regions.nll.stderr
index 6989acfa196..ec9fac0c288 100644
--- a/src/test/ui/lifetimes/lifetime-errors/ex3-both-anon-regions.nll.stderr
+++ b/src/test/ui/lifetimes/lifetime-errors/ex3-both-anon-regions.nll.stderr
@@ -7,6 +7,11 @@ LL | fn foo(x: &mut Vec<&u8>, y: &u8) {
    |                    let's call the lifetime of this reference `'2`
 LL |     x.push(y);
    |     ^^^^^^^^^ argument requires that `'1` must outlive `'2`
+   |
+help: consider introducing a named lifetime parameter
+   |
+LL | fn foo<'a>(x: &mut Vec<&'a u8>, y: &'a u8) {
+   |       ++++              ++          ++
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/proc-macro/nodelim-groups.rs b/src/test/ui/proc-macro/nodelim-groups.rs
index db2a879f405..ec301990281 100644
--- a/src/test/ui/proc-macro/nodelim-groups.rs
+++ b/src/test/ui/proc-macro/nodelim-groups.rs
@@ -3,7 +3,7 @@
 // compile-flags: -Z span-debug
 // edition:2018
 //
-// Tests the pretty-printing behavior of inserting `NoDelim` groups
+// Tests the pretty-printing behavior of inserting `Invisible`-delimited groups
 
 #![no_std] // Don't load unnecessary hygiene information from std
 extern crate std;
diff --git a/src/test/ui/self/arbitrary_self_types_pin_lifetime_mismatch.nll.stderr b/src/test/ui/self/arbitrary_self_types_pin_lifetime_mismatch.nll.stderr
index b06ebf70477..057146e7cb0 100644
--- a/src/test/ui/self/arbitrary_self_types_pin_lifetime_mismatch.nll.stderr
+++ b/src/test/ui/self/arbitrary_self_types_pin_lifetime_mismatch.nll.stderr
@@ -6,6 +6,11 @@ LL |     fn a(self: Pin<&Foo>, f: &Foo) -> &Foo { f }
    |                    |         |
    |                    |         let's call the lifetime of this reference `'1`
    |                    let's call the lifetime of this reference `'2`
+   |
+help: consider introducing a named lifetime parameter and update trait if needed
+   |
+LL |     fn a<'a>(self: Pin<&'a Foo>, f: &'a Foo) -> &Foo { f }
+   |         ++++            ++           ++
 
 error: lifetime may not live long enough
   --> $DIR/arbitrary_self_types_pin_lifetime_mismatch.rs:14:69
@@ -15,6 +20,11 @@ LL |     fn c(self: Pin<&Self>, f: &Foo, g: &Foo) -> (Pin<&Foo>, &Foo) { (self,
    |                    |          |
    |                    |          let's call the lifetime of this reference `'1`
    |                    let's call the lifetime of this reference `'2`
+   |
+help: consider introducing a named lifetime parameter and update trait if needed
+   |
+LL |     fn c<'a>(self: Pin<&'a Self>, f: &'a Foo, g: &Foo) -> (Pin<&Foo>, &Foo) { (self, f) }
+   |         ++++            ++            ++
 
 error: lifetime may not live long enough
   --> $DIR/arbitrary_self_types_pin_lifetime_mismatch.rs:21:58
diff --git a/src/test/ui/self/elision/lt-ref-self.nll.stderr b/src/test/ui/self/elision/lt-ref-self.nll.stderr
index 1934207527b..2e26c703b65 100644
--- a/src/test/ui/self/elision/lt-ref-self.nll.stderr
+++ b/src/test/ui/self/elision/lt-ref-self.nll.stderr
@@ -7,6 +7,11 @@ LL |     fn ref_self(&self, f: &u32) -> &u32 {
    |                 let's call the lifetime of this reference `'2`
 LL |         f
    |         ^ associated function was supposed to return data with lifetime `'2` but it is returning data with lifetime `'1`
+   |
+help: consider introducing a named lifetime parameter and update trait if needed
+   |
+LL |     fn ref_self<'a>(&'a self, f: &'a u32) -> &u32 {
+   |                ++++  ++           ++
 
 error: lifetime may not live long enough
   --> $DIR/lt-ref-self.rs:23:9
@@ -17,6 +22,11 @@ LL |     fn ref_Self(self: &Self, f: &u32) -> &u32 {
    |                       let's call the lifetime of this reference `'2`
 LL |         f
    |         ^ associated function was supposed to return data with lifetime `'2` but it is returning data with lifetime `'1`
+   |
+help: consider introducing a named lifetime parameter and update trait if needed
+   |
+LL |     fn ref_Self<'a>(self: &'a Self, f: &'a u32) -> &u32 {
+   |                ++++        ++           ++
 
 error: lifetime may not live long enough
   --> $DIR/lt-ref-self.rs:29:9
@@ -27,6 +37,11 @@ LL |     fn box_ref_Self(self: Box<&Self>, f: &u32) -> &u32 {
    |                               let's call the lifetime of this reference `'2`
 LL |         f
    |         ^ associated function was supposed to return data with lifetime `'2` but it is returning data with lifetime `'1`
+   |
+help: consider introducing a named lifetime parameter and update trait if needed
+   |
+LL |     fn box_ref_Self<'a>(self: Box<&'a Self>, f: &'a u32) -> &u32 {
+   |                    ++++            ++            ++
 
 error: lifetime may not live long enough
   --> $DIR/lt-ref-self.rs:35:9
@@ -37,6 +52,11 @@ LL |     fn pin_ref_Self(self: Pin<&Self>, f: &u32) -> &u32 {
    |                               let's call the lifetime of this reference `'2`
 LL |         f
    |         ^ associated function was supposed to return data with lifetime `'2` but it is returning data with lifetime `'1`
+   |
+help: consider introducing a named lifetime parameter and update trait if needed
+   |
+LL |     fn pin_ref_Self<'a>(self: Pin<&'a Self>, f: &'a u32) -> &u32 {
+   |                    ++++            ++            ++
 
 error: lifetime may not live long enough
   --> $DIR/lt-ref-self.rs:41:9
@@ -47,6 +67,11 @@ LL |     fn box_box_ref_Self(self: Box<Box<&Self>>, f: &u32) -> &u32 {
    |                                       let's call the lifetime of this reference `'2`
 LL |         f
    |         ^ associated function was supposed to return data with lifetime `'2` but it is returning data with lifetime `'1`
+   |
+help: consider introducing a named lifetime parameter and update trait if needed
+   |
+LL |     fn box_box_ref_Self<'a>(self: Box<Box<&'a Self>>, f: &'a u32) -> &u32 {
+   |                        ++++                ++             ++
 
 error: lifetime may not live long enough
   --> $DIR/lt-ref-self.rs:47:9
@@ -57,6 +82,11 @@ LL |     fn box_pin_Self(self: Box<Pin<&Self>>, f: &u32) -> &u32 {
    |                                   let's call the lifetime of this reference `'2`
 LL |         f
    |         ^ associated function was supposed to return data with lifetime `'2` but it is returning data with lifetime `'1`
+   |
+help: consider introducing a named lifetime parameter and update trait if needed
+   |
+LL |     fn box_pin_Self<'a>(self: Box<Pin<&'a Self>>, f: &'a u32) -> &u32 {
+   |                    ++++                ++             ++
 
 error: aborting due to 6 previous errors
 
diff --git a/src/test/ui/self/elision/ref-mut-self.nll.stderr b/src/test/ui/self/elision/ref-mut-self.nll.stderr
index f1f4d341b2b..fd4ecae3cfe 100644
--- a/src/test/ui/self/elision/ref-mut-self.nll.stderr
+++ b/src/test/ui/self/elision/ref-mut-self.nll.stderr
@@ -7,6 +7,11 @@ LL |     fn ref_self(&mut self, f: &u32) -> &u32 {
    |                 let's call the lifetime of this reference `'2`
 LL |         f
    |         ^ associated function was supposed to return data with lifetime `'2` but it is returning data with lifetime `'1`
+   |
+help: consider introducing a named lifetime parameter and update trait if needed
+   |
+LL |     fn ref_self<'a>(&'a mut self, f: &'a u32) -> &u32 {
+   |                ++++  ++               ++
 
 error: lifetime may not live long enough
   --> $DIR/ref-mut-self.rs:23:9
@@ -17,6 +22,11 @@ LL |     fn ref_Self(self: &mut Self, f: &u32) -> &u32 {
    |                       let's call the lifetime of this reference `'2`
 LL |         f
    |         ^ associated function was supposed to return data with lifetime `'2` but it is returning data with lifetime `'1`
+   |
+help: consider introducing a named lifetime parameter and update trait if needed
+   |
+LL |     fn ref_Self<'a>(self: &'a mut Self, f: &'a u32) -> &u32 {
+   |                ++++        ++               ++
 
 error: lifetime may not live long enough
   --> $DIR/ref-mut-self.rs:29:9
@@ -27,6 +37,11 @@ LL |     fn box_ref_Self(self: Box<&mut Self>, f: &u32) -> &u32 {
    |                               let's call the lifetime of this reference `'2`
 LL |         f
    |         ^ associated function was supposed to return data with lifetime `'2` but it is returning data with lifetime `'1`
+   |
+help: consider introducing a named lifetime parameter and update trait if needed
+   |
+LL |     fn box_ref_Self<'a>(self: Box<&'a mut Self>, f: &'a u32) -> &u32 {
+   |                    ++++            ++                ++
 
 error: lifetime may not live long enough
   --> $DIR/ref-mut-self.rs:35:9
@@ -37,6 +52,11 @@ LL |     fn pin_ref_Self(self: Pin<&mut Self>, f: &u32) -> &u32 {
    |                               let's call the lifetime of this reference `'2`
 LL |         f
    |         ^ associated function was supposed to return data with lifetime `'2` but it is returning data with lifetime `'1`
+   |
+help: consider introducing a named lifetime parameter and update trait if needed
+   |
+LL |     fn pin_ref_Self<'a>(self: Pin<&'a mut Self>, f: &'a u32) -> &u32 {
+   |                    ++++            ++                ++
 
 error: lifetime may not live long enough
   --> $DIR/ref-mut-self.rs:41:9
@@ -47,6 +67,11 @@ LL |     fn box_box_ref_Self(self: Box<Box<&mut Self>>, f: &u32) -> &u32 {
    |                                       let's call the lifetime of this reference `'2`
 LL |         f
    |         ^ associated function was supposed to return data with lifetime `'2` but it is returning data with lifetime `'1`
+   |
+help: consider introducing a named lifetime parameter and update trait if needed
+   |
+LL |     fn box_box_ref_Self<'a>(self: Box<Box<&'a mut Self>>, f: &'a u32) -> &u32 {
+   |                        ++++                ++                 ++
 
 error: lifetime may not live long enough
   --> $DIR/ref-mut-self.rs:47:9
@@ -57,6 +82,11 @@ LL |     fn box_pin_ref_Self(self: Box<Pin<&mut Self>>, f: &u32) -> &u32 {
    |                                       let's call the lifetime of this reference `'2`
 LL |         f
    |         ^ associated function was supposed to return data with lifetime `'2` but it is returning data with lifetime `'1`
+   |
+help: consider introducing a named lifetime parameter and update trait if needed
+   |
+LL |     fn box_pin_ref_Self<'a>(self: Box<Pin<&'a mut Self>>, f: &'a u32) -> &u32 {
+   |                        ++++                ++                 ++
 
 error: aborting due to 6 previous errors
 
diff --git a/src/test/ui/self/elision/ref-mut-struct.nll.stderr b/src/test/ui/self/elision/ref-mut-struct.nll.stderr
index de7eb02d7a7..ede790c0611 100644
--- a/src/test/ui/self/elision/ref-mut-struct.nll.stderr
+++ b/src/test/ui/self/elision/ref-mut-struct.nll.stderr
@@ -7,6 +7,11 @@ LL |     fn ref_Struct(self: &mut Struct, f: &u32) -> &u32 {
    |                         let's call the lifetime of this reference `'2`
 LL |         f
    |         ^ associated function was supposed to return data with lifetime `'2` but it is returning data with lifetime `'1`
+   |
+help: consider introducing a named lifetime parameter and update trait if needed
+   |
+LL |     fn ref_Struct<'a>(self: &'a mut Struct, f: &'a u32) -> &u32 {
+   |                  ++++        ++                 ++
 
 error: lifetime may not live long enough
   --> $DIR/ref-mut-struct.rs:21:9
@@ -17,6 +22,11 @@ LL |     fn box_ref_Struct(self: Box<&mut Struct>, f: &u32) -> &u32 {
    |                                 let's call the lifetime of this reference `'2`
 LL |         f
    |         ^ associated function was supposed to return data with lifetime `'2` but it is returning data with lifetime `'1`
+   |
+help: consider introducing a named lifetime parameter and update trait if needed
+   |
+LL |     fn box_ref_Struct<'a>(self: Box<&'a mut Struct>, f: &'a u32) -> &u32 {
+   |                      ++++            ++                  ++
 
 error: lifetime may not live long enough
   --> $DIR/ref-mut-struct.rs:27:9
@@ -27,6 +37,11 @@ LL |     fn pin_ref_Struct(self: Pin<&mut Struct>, f: &u32) -> &u32 {
    |                                 let's call the lifetime of this reference `'2`
 LL |         f
    |         ^ associated function was supposed to return data with lifetime `'2` but it is returning data with lifetime `'1`
+   |
+help: consider introducing a named lifetime parameter and update trait if needed
+   |
+LL |     fn pin_ref_Struct<'a>(self: Pin<&'a mut Struct>, f: &'a u32) -> &u32 {
+   |                      ++++            ++                  ++
 
 error: lifetime may not live long enough
   --> $DIR/ref-mut-struct.rs:33:9
@@ -37,6 +52,11 @@ LL |     fn box_box_ref_Struct(self: Box<Box<&mut Struct>>, f: &u32) -> &u32 {
    |                                         let's call the lifetime of this reference `'2`
 LL |         f
    |         ^ associated function was supposed to return data with lifetime `'2` but it is returning data with lifetime `'1`
+   |
+help: consider introducing a named lifetime parameter and update trait if needed
+   |
+LL |     fn box_box_ref_Struct<'a>(self: Box<Box<&'a mut Struct>>, f: &'a u32) -> &u32 {
+   |                          ++++                ++                   ++
 
 error: lifetime may not live long enough
   --> $DIR/ref-mut-struct.rs:39:9
@@ -47,6 +67,11 @@ LL |     fn box_pin_ref_Struct(self: Box<Pin<&mut Struct>>, f: &u32) -> &u32 {
    |                                         let's call the lifetime of this reference `'2`
 LL |         f
    |         ^ associated function was supposed to return data with lifetime `'2` but it is returning data with lifetime `'1`
+   |
+help: consider introducing a named lifetime parameter and update trait if needed
+   |
+LL |     fn box_pin_ref_Struct<'a>(self: Box<Pin<&'a mut Struct>>, f: &'a u32) -> &u32 {
+   |                          ++++                ++                   ++
 
 error: aborting due to 5 previous errors
 
diff --git a/src/test/ui/self/elision/ref-self.nll.stderr b/src/test/ui/self/elision/ref-self.nll.stderr
index f2b7b0ad019..c0efc35fa6c 100644
--- a/src/test/ui/self/elision/ref-self.nll.stderr
+++ b/src/test/ui/self/elision/ref-self.nll.stderr
@@ -7,6 +7,11 @@ LL |     fn ref_self(&self, f: &u32) -> &u32 {
    |                 let's call the lifetime of this reference `'2`
 LL |         f
    |         ^ associated function was supposed to return data with lifetime `'2` but it is returning data with lifetime `'1`
+   |
+help: consider introducing a named lifetime parameter and update trait if needed
+   |
+LL |     fn ref_self<'a>(&'a self, f: &'a u32) -> &u32 {
+   |                ++++  ++           ++
 
 error: lifetime may not live long enough
   --> $DIR/ref-self.rs:33:9
@@ -17,6 +22,11 @@ LL |     fn ref_Self(self: &Self, f: &u32) -> &u32 {
    |                       let's call the lifetime of this reference `'2`
 LL |         f
    |         ^ associated function was supposed to return data with lifetime `'2` but it is returning data with lifetime `'1`
+   |
+help: consider introducing a named lifetime parameter and update trait if needed
+   |
+LL |     fn ref_Self<'a>(self: &'a Self, f: &'a u32) -> &u32 {
+   |                ++++        ++           ++
 
 error: lifetime may not live long enough
   --> $DIR/ref-self.rs:39:9
@@ -27,6 +37,11 @@ LL |     fn box_ref_Self(self: Box<&Self>, f: &u32) -> &u32 {
    |                               let's call the lifetime of this reference `'2`
 LL |         f
    |         ^ associated function was supposed to return data with lifetime `'2` but it is returning data with lifetime `'1`
+   |
+help: consider introducing a named lifetime parameter and update trait if needed
+   |
+LL |     fn box_ref_Self<'a>(self: Box<&'a Self>, f: &'a u32) -> &u32 {
+   |                    ++++            ++            ++
 
 error: lifetime may not live long enough
   --> $DIR/ref-self.rs:45:9
@@ -37,6 +52,11 @@ LL |     fn pin_ref_Self(self: Pin<&Self>, f: &u32) -> &u32 {
    |                               let's call the lifetime of this reference `'2`
 LL |         f
    |         ^ associated function was supposed to return data with lifetime `'2` but it is returning data with lifetime `'1`
+   |
+help: consider introducing a named lifetime parameter and update trait if needed
+   |
+LL |     fn pin_ref_Self<'a>(self: Pin<&'a Self>, f: &'a u32) -> &u32 {
+   |                    ++++            ++            ++
 
 error: lifetime may not live long enough
   --> $DIR/ref-self.rs:51:9
@@ -47,6 +67,11 @@ LL |     fn box_box_ref_Self(self: Box<Box<&Self>>, f: &u32) -> &u32 {
    |                                       let's call the lifetime of this reference `'2`
 LL |         f
    |         ^ associated function was supposed to return data with lifetime `'2` but it is returning data with lifetime `'1`
+   |
+help: consider introducing a named lifetime parameter and update trait if needed
+   |
+LL |     fn box_box_ref_Self<'a>(self: Box<Box<&'a Self>>, f: &'a u32) -> &u32 {
+   |                        ++++                ++             ++
 
 error: lifetime may not live long enough
   --> $DIR/ref-self.rs:57:9
@@ -57,6 +82,11 @@ LL |     fn box_pin_ref_Self(self: Box<Pin<&Self>>, f: &u32) -> &u32 {
    |                                       let's call the lifetime of this reference `'2`
 LL |         f
    |         ^ associated function was supposed to return data with lifetime `'2` but it is returning data with lifetime `'1`
+   |
+help: consider introducing a named lifetime parameter and update trait if needed
+   |
+LL |     fn box_pin_ref_Self<'a>(self: Box<Pin<&'a Self>>, f: &'a u32) -> &u32 {
+   |                        ++++                ++             ++
 
 error: lifetime may not live long enough
   --> $DIR/ref-self.rs:63:9
@@ -67,6 +97,11 @@ LL |     fn wrap_ref_Self_Self(self: Wrap<&Self, Self>, f: &u8) -> &u8 {
    |                                      let's call the lifetime of this reference `'2`
 LL |         f
    |         ^ associated function was supposed to return data with lifetime `'2` but it is returning data with lifetime `'1`
+   |
+help: consider introducing a named lifetime parameter and update trait if needed
+   |
+LL |     fn wrap_ref_Self_Self<'a>(self: Wrap<&'a Self, Self>, f: &'a u8) -> &u8 {
+   |                          ++++             ++                  ++
 
 error: aborting due to 7 previous errors
 
diff --git a/src/test/ui/self/elision/ref-struct.nll.stderr b/src/test/ui/self/elision/ref-struct.nll.stderr
index 70453b0ddfc..226923f59ff 100644
--- a/src/test/ui/self/elision/ref-struct.nll.stderr
+++ b/src/test/ui/self/elision/ref-struct.nll.stderr
@@ -7,6 +7,11 @@ LL |     fn ref_Struct(self: &Struct, f: &u32) -> &u32 {
    |                         let's call the lifetime of this reference `'2`
 LL |         f
    |         ^ associated function was supposed to return data with lifetime `'2` but it is returning data with lifetime `'1`
+   |
+help: consider introducing a named lifetime parameter and update trait if needed
+   |
+LL |     fn ref_Struct<'a>(self: &'a Struct, f: &'a u32) -> &u32 {
+   |                  ++++        ++             ++
 
 error: lifetime may not live long enough
   --> $DIR/ref-struct.rs:21:9
@@ -17,6 +22,11 @@ LL |     fn box_ref_Struct(self: Box<&Struct>, f: &u32) -> &u32 {
    |                                 let's call the lifetime of this reference `'2`
 LL |         f
    |         ^ associated function was supposed to return data with lifetime `'2` but it is returning data with lifetime `'1`
+   |
+help: consider introducing a named lifetime parameter and update trait if needed
+   |
+LL |     fn box_ref_Struct<'a>(self: Box<&'a Struct>, f: &'a u32) -> &u32 {
+   |                      ++++            ++              ++
 
 error: lifetime may not live long enough
   --> $DIR/ref-struct.rs:27:9
@@ -27,6 +37,11 @@ LL |     fn pin_ref_Struct(self: Pin<&Struct>, f: &u32) -> &u32 {
    |                                 let's call the lifetime of this reference `'2`
 LL |         f
    |         ^ associated function was supposed to return data with lifetime `'2` but it is returning data with lifetime `'1`
+   |
+help: consider introducing a named lifetime parameter and update trait if needed
+   |
+LL |     fn pin_ref_Struct<'a>(self: Pin<&'a Struct>, f: &'a u32) -> &u32 {
+   |                      ++++            ++              ++
 
 error: lifetime may not live long enough
   --> $DIR/ref-struct.rs:33:9
@@ -37,6 +52,11 @@ LL |     fn box_box_ref_Struct(self: Box<Box<&Struct>>, f: &u32) -> &u32 {
    |                                         let's call the lifetime of this reference `'2`
 LL |         f
    |         ^ associated function was supposed to return data with lifetime `'2` but it is returning data with lifetime `'1`
+   |
+help: consider introducing a named lifetime parameter and update trait if needed
+   |
+LL |     fn box_box_ref_Struct<'a>(self: Box<Box<&'a Struct>>, f: &'a u32) -> &u32 {
+   |                          ++++                ++               ++
 
 error: lifetime may not live long enough
   --> $DIR/ref-struct.rs:39:9
@@ -47,6 +67,11 @@ LL |     fn box_pin_Struct(self: Box<Pin<&Struct>>, f: &u32) -> &u32 {
    |                                     let's call the lifetime of this reference `'2`
 LL |         f
    |         ^ associated function was supposed to return data with lifetime `'2` but it is returning data with lifetime `'1`
+   |
+help: consider introducing a named lifetime parameter and update trait if needed
+   |
+LL |     fn box_pin_Struct<'a>(self: Box<Pin<&'a Struct>>, f: &'a u32) -> &u32 {
+   |                      ++++                ++               ++
 
 error: aborting due to 5 previous errors
 
diff --git a/src/test/ui/underscore-lifetime/underscore-lifetime-elison-mismatch.nll.stderr b/src/test/ui/underscore-lifetime/underscore-lifetime-elison-mismatch.nll.stderr
index 8e10242cb13..a4dece320ec 100644
--- a/src/test/ui/underscore-lifetime/underscore-lifetime-elison-mismatch.nll.stderr
+++ b/src/test/ui/underscore-lifetime/underscore-lifetime-elison-mismatch.nll.stderr
@@ -6,6 +6,11 @@ LL | fn foo(x: &mut Vec<&'_ u8>, y: &'_ u8) { x.push(y); }
    |                    |           |
    |                    |           let's call the lifetime of this reference `'1`
    |                    let's call the lifetime of this reference `'2`
+   |
+help: consider introducing a named lifetime parameter
+   |
+LL | fn foo<'a>(x: &mut Vec<&'a u8>, y: &'a u8) { x.push(y); }
+   |       ++++              ~~          ~~
 
 error: aborting due to previous error
 
diff --git a/src/tools/rustfmt/src/expr.rs b/src/tools/rustfmt/src/expr.rs
index cd724373f4d..741f3350801 100644
--- a/src/tools/rustfmt/src/expr.rs
+++ b/src/tools/rustfmt/src/expr.rs
@@ -2,7 +2,7 @@ use std::borrow::Cow;
 use std::cmp::min;
 
 use itertools::Itertools;
-use rustc_ast::token::{DelimToken, LitKind};
+use rustc_ast::token::{Delimiter, LitKind};
 use rustc_ast::{ast, ptr};
 use rustc_span::{BytePos, Span};
 
@@ -412,7 +412,7 @@ pub(crate) fn rewrite_array<'a, T: 'a + IntoOverflowableItem<'a>>(
     context: &'a RewriteContext<'_>,
     shape: Shape,
     force_separator_tactic: Option<SeparatorTactic>,
-    delim_token: Option<DelimToken>,
+    delim_token: Option<Delimiter>,
 ) -> Option<String> {
     overflow::rewrite_with_square_brackets(
         context,
diff --git a/src/tools/rustfmt/src/macros.rs b/src/tools/rustfmt/src/macros.rs
index 92606902c57..26c429eb94f 100644
--- a/src/tools/rustfmt/src/macros.rs
+++ b/src/tools/rustfmt/src/macros.rs
@@ -12,7 +12,7 @@
 use std::collections::HashMap;
 use std::panic::{catch_unwind, AssertUnwindSafe};
 
-use rustc_ast::token::{BinOpToken, DelimToken, Token, TokenKind};
+use rustc_ast::token::{BinOpToken, Delimiter, Token, TokenKind};
 use rustc_ast::tokenstream::{Cursor, Spacing, TokenStream, TokenTree};
 use rustc_ast::{ast, ptr};
 use rustc_ast_pretty::pprust;
@@ -203,7 +203,7 @@ fn rewrite_macro_inner(
     let is_forced_bracket = FORCED_BRACKET_MACROS.contains(&&macro_name[..]);
 
     let style = if is_forced_bracket && !is_nested_macro {
-        DelimToken::Bracket
+        Delimiter::Bracket
     } else {
         original_style
     };
@@ -212,15 +212,15 @@ fn rewrite_macro_inner(
     let has_comment = contains_comment(context.snippet(mac.span()));
     if ts.is_empty() && !has_comment {
         return match style {
-            DelimToken::Paren if position == MacroPosition::Item => {
+            Delimiter::Parenthesis if position == MacroPosition::Item => {
                 Some(format!("{}();", macro_name))
             }
-            DelimToken::Bracket if position == MacroPosition::Item => {
+            Delimiter::Bracket if position == MacroPosition::Item => {
                 Some(format!("{}[];", macro_name))
             }
-            DelimToken::Paren => Some(format!("{}()", macro_name)),
-            DelimToken::Bracket => Some(format!("{}[]", macro_name)),
-            DelimToken::Brace => Some(format!("{} {{}}", macro_name)),
+            Delimiter::Parenthesis => Some(format!("{}()", macro_name)),
+            Delimiter::Bracket => Some(format!("{}[]", macro_name)),
+            Delimiter::Brace => Some(format!("{} {{}}", macro_name)),
             _ => unreachable!(),
         };
     }
@@ -260,7 +260,7 @@ fn rewrite_macro_inner(
     }
 
     match style {
-        DelimToken::Paren => {
+        Delimiter::Parenthesis => {
             // Handle special case: `vec!(expr; expr)`
             if vec_with_semi {
                 handle_vec_semi(context, shape, arg_vec, macro_name, style)
@@ -286,7 +286,7 @@ fn rewrite_macro_inner(
                 })
             }
         }
-        DelimToken::Bracket => {
+        Delimiter::Bracket => {
             // Handle special case: `vec![expr; expr]`
             if vec_with_semi {
                 handle_vec_semi(context, shape, arg_vec, macro_name, style)
@@ -323,7 +323,7 @@ fn rewrite_macro_inner(
                 Some(format!("{}{}", rewrite, comma))
             }
         }
-        DelimToken::Brace => {
+        Delimiter::Brace => {
             // For macro invocations with braces, always put a space between
             // the `macro_name!` and `{ /* macro_body */ }` but skip modifying
             // anything in between the braces (for now).
@@ -342,11 +342,11 @@ fn handle_vec_semi(
     shape: Shape,
     arg_vec: Vec<MacroArg>,
     macro_name: String,
-    delim_token: DelimToken,
+    delim_token: Delimiter,
 ) -> Option<String> {
     let (left, right) = match delim_token {
-        DelimToken::Paren => ("(", ")"),
-        DelimToken::Bracket => ("[", "]"),
+        Delimiter::Parenthesis => ("(", ")"),
+        Delimiter::Bracket => ("[", "]"),
         _ => unreachable!(),
     };
 
@@ -528,7 +528,7 @@ enum MacroArgKind {
     /// e.g., `$($foo: expr),*`
     Repeat(
         /// `()`, `[]` or `{}`.
-        DelimToken,
+        Delimiter,
         /// Inner arguments inside delimiters.
         Vec<ParsedMacroArg>,
         /// Something after the closing delimiter and the repeat token, if available.
@@ -537,7 +537,7 @@ enum MacroArgKind {
         Token,
     ),
     /// e.g., `[derive(Debug)]`
-    Delimited(DelimToken, Vec<ParsedMacroArg>),
+    Delimited(Delimiter, Vec<ParsedMacroArg>),
     /// A possible separator. e.g., `,` or `;`.
     Separator(String, String),
     /// Other random stuff that does not fit to other kinds.
@@ -547,22 +547,22 @@ enum MacroArgKind {
 
 fn delim_token_to_str(
     context: &RewriteContext<'_>,
-    delim_token: DelimToken,
+    delim_token: Delimiter,
     shape: Shape,
     use_multiple_lines: bool,
     inner_is_empty: bool,
 ) -> (String, String) {
     let (lhs, rhs) = match delim_token {
-        DelimToken::Paren => ("(", ")"),
-        DelimToken::Bracket => ("[", "]"),
-        DelimToken::Brace => {
+        Delimiter::Parenthesis => ("(", ")"),
+        Delimiter::Bracket => ("[", "]"),
+        Delimiter::Brace => {
             if inner_is_empty || use_multiple_lines {
                 ("{", "}")
             } else {
                 ("{ ", " }")
             }
         }
-        DelimToken::NoDelim => unreachable!(),
+        Delimiter::Invisible => unreachable!(),
     };
     if use_multiple_lines {
         let indent_str = shape.indent.to_string_with_newline(context.config);
@@ -583,8 +583,8 @@ impl MacroArgKind {
     fn starts_with_brace(&self) -> bool {
         matches!(
             *self,
-            MacroArgKind::Repeat(DelimToken::Brace, _, _, _)
-                | MacroArgKind::Delimited(DelimToken::Brace, _)
+            MacroArgKind::Repeat(Delimiter::Brace, _, _, _)
+                | MacroArgKind::Delimited(Delimiter::Brace, _)
         )
     }
 
@@ -753,7 +753,7 @@ impl MacroArgParser {
         }
     }
 
-    fn add_delimited(&mut self, inner: Vec<ParsedMacroArg>, delim: DelimToken) {
+    fn add_delimited(&mut self, inner: Vec<ParsedMacroArg>, delim: Delimiter) {
         self.result.push(ParsedMacroArg {
             kind: MacroArgKind::Delimited(delim, inner),
         });
@@ -763,7 +763,7 @@ impl MacroArgParser {
     fn add_repeat(
         &mut self,
         inner: Vec<ParsedMacroArg>,
-        delim: DelimToken,
+        delim: Delimiter,
         iter: &mut Cursor,
     ) -> Option<()> {
         let mut buffer = String::new();
@@ -1083,18 +1083,18 @@ pub(crate) fn convert_try_mac(
     }
 }
 
-pub(crate) fn macro_style(mac: &ast::MacCall, context: &RewriteContext<'_>) -> DelimToken {
+pub(crate) fn macro_style(mac: &ast::MacCall, context: &RewriteContext<'_>) -> Delimiter {
     let snippet = context.snippet(mac.span());
     let paren_pos = snippet.find_uncommented("(").unwrap_or(usize::max_value());
     let bracket_pos = snippet.find_uncommented("[").unwrap_or(usize::max_value());
     let brace_pos = snippet.find_uncommented("{").unwrap_or(usize::max_value());
 
     if paren_pos < bracket_pos && paren_pos < brace_pos {
-        DelimToken::Paren
+        Delimiter::Parenthesis
     } else if bracket_pos < brace_pos {
-        DelimToken::Bracket
+        Delimiter::Bracket
     } else {
-        DelimToken::Brace
+        Delimiter::Brace
     }
 }
 
@@ -1174,7 +1174,7 @@ struct Macro {
 // rather than clone them, if we can make the borrowing work out.
 struct MacroBranch {
     span: Span,
-    args_paren_kind: DelimToken,
+    args_paren_kind: Delimiter,
     args: TokenStream,
     body: Span,
     whole_body: Span,
@@ -1188,7 +1188,7 @@ impl MacroBranch {
         multi_branch_style: bool,
     ) -> Option<String> {
         // Only attempt to format function-like macros.
-        if self.args_paren_kind != DelimToken::Paren {
+        if self.args_paren_kind != Delimiter::Parenthesis {
             // FIXME(#1539): implement for non-sugared macros.
             return None;
         }
@@ -1350,18 +1350,18 @@ fn rewrite_macro_with_items(
     items: &[MacroArg],
     macro_name: &str,
     shape: Shape,
-    style: DelimToken,
+    style: Delimiter,
     position: MacroPosition,
     span: Span,
 ) -> Option<String> {
     let (opener, closer) = match style {
-        DelimToken::Paren => ("(", ")"),
-        DelimToken::Bracket => ("[", "]"),
-        DelimToken::Brace => (" {", "}"),
+        Delimiter::Parenthesis => ("(", ")"),
+        Delimiter::Bracket => ("[", "]"),
+        Delimiter::Brace => (" {", "}"),
         _ => return None,
     };
     let trailing_semicolon = match style {
-        DelimToken::Paren | DelimToken::Bracket if position == MacroPosition::Item => ";",
+        Delimiter::Parenthesis | Delimiter::Bracket if position == MacroPosition::Item => ";",
         _ => "",
     };
 
diff --git a/src/tools/rustfmt/src/overflow.rs b/src/tools/rustfmt/src/overflow.rs
index 80aed998d73..f115e7d0261 100644
--- a/src/tools/rustfmt/src/overflow.rs
+++ b/src/tools/rustfmt/src/overflow.rs
@@ -3,7 +3,7 @@
 use std::cmp::min;
 
 use itertools::Itertools;
-use rustc_ast::token::DelimToken;
+use rustc_ast::token::Delimiter;
 use rustc_ast::{ast, ptr};
 use rustc_span::Span;
 
@@ -297,11 +297,11 @@ pub(crate) fn rewrite_with_square_brackets<'a, T: 'a + IntoOverflowableItem<'a>>
     shape: Shape,
     span: Span,
     force_separator_tactic: Option<SeparatorTactic>,
-    delim_token: Option<DelimToken>,
+    delim_token: Option<Delimiter>,
 ) -> Option<String> {
     let (lhs, rhs) = match delim_token {
-        Some(DelimToken::Paren) => ("(", ")"),
-        Some(DelimToken::Brace) => ("{", "}"),
+        Some(Delimiter::Parenthesis) => ("(", ")"),
+        Some(Delimiter::Brace) => ("{", "}"),
         _ => ("[", "]"),
     };
     Context::new(
diff --git a/src/tools/rustfmt/src/parse/macros/cfg_if.rs b/src/tools/rustfmt/src/parse/macros/cfg_if.rs
index 306b6bb745e..09b3e32df31 100644
--- a/src/tools/rustfmt/src/parse/macros/cfg_if.rs
+++ b/src/tools/rustfmt/src/parse/macros/cfg_if.rs
@@ -1,7 +1,7 @@
 use std::panic::{catch_unwind, AssertUnwindSafe};
 
 use rustc_ast::ast;
-use rustc_ast::token::{DelimToken, TokenKind};
+use rustc_ast::token::{Delimiter, TokenKind};
 use rustc_parse::parser::ForceCollect;
 use rustc_span::symbol::kw;
 
@@ -47,11 +47,11 @@ fn parse_cfg_if_inner<'a>(
                 .map_err(|_| "Failed to parse attributes")?;
         }
 
-        if !parser.eat(&TokenKind::OpenDelim(DelimToken::Brace)) {
+        if !parser.eat(&TokenKind::OpenDelim(Delimiter::Brace)) {
             return Err("Expected an opening brace");
         }
 
-        while parser.token != TokenKind::CloseDelim(DelimToken::Brace)
+        while parser.token != TokenKind::CloseDelim(Delimiter::Brace)
             && parser.token.kind != TokenKind::Eof
         {
             let item = match parser.parse_item(ForceCollect::No) {
@@ -70,7 +70,7 @@ fn parse_cfg_if_inner<'a>(
             }
         }
 
-        if !parser.eat(&TokenKind::CloseDelim(DelimToken::Brace)) {
+        if !parser.eat(&TokenKind::CloseDelim(Delimiter::Brace)) {
             return Err("Expected a closing brace");
         }
 
diff --git a/src/tools/rustfmt/src/parse/macros/mod.rs b/src/tools/rustfmt/src/parse/macros/mod.rs
index 3728f3a19b4..d4dbf21f8ca 100644
--- a/src/tools/rustfmt/src/parse/macros/mod.rs
+++ b/src/tools/rustfmt/src/parse/macros/mod.rs
@@ -1,4 +1,4 @@
-use rustc_ast::token::{DelimToken, TokenKind};
+use rustc_ast::token::{Delimiter, TokenKind};
 use rustc_ast::tokenstream::TokenStream;
 use rustc_ast::{ast, ptr};
 use rustc_parse::parser::{ForceCollect, Parser};
@@ -81,7 +81,7 @@ fn check_keyword<'a, 'b: 'a>(parser: &'a mut Parser<'b>) -> Option<MacroArg> {
             && parser.look_ahead(1, |t| {
                 t.kind == TokenKind::Eof
                     || t.kind == TokenKind::Comma
-                    || t.kind == TokenKind::CloseDelim(DelimToken::NoDelim)
+                    || t.kind == TokenKind::CloseDelim(Delimiter::Invisible)
             })
         {
             parser.bump();
@@ -97,7 +97,7 @@ fn check_keyword<'a, 'b: 'a>(parser: &'a mut Parser<'b>) -> Option<MacroArg> {
 pub(crate) fn parse_macro_args(
     context: &RewriteContext<'_>,
     tokens: TokenStream,
-    style: DelimToken,
+    style: Delimiter,
     forced_bracket: bool,
 ) -> Option<ParsedMacroArgs> {
     let mut parser = build_parser(context, tokens);
@@ -105,7 +105,7 @@ pub(crate) fn parse_macro_args(
     let mut vec_with_semi = false;
     let mut trailing_comma = false;
 
-    if DelimToken::Brace != style {
+    if Delimiter::Brace != style {
         loop {
             if let Some(arg) = check_keyword(&mut parser) {
                 args.push(arg);
diff --git a/src/tools/rustfmt/src/visitor.rs b/src/tools/rustfmt/src/visitor.rs
index 1621eb406b1..f04fb2e0446 100644
--- a/src/tools/rustfmt/src/visitor.rs
+++ b/src/tools/rustfmt/src/visitor.rs
@@ -1,7 +1,7 @@
 use std::cell::{Cell, RefCell};
 use std::rc::Rc;
 
-use rustc_ast::{ast, token::DelimToken, visit, AstLike};
+use rustc_ast::{ast, token::Delimiter, visit, AstLike};
 use rustc_data_structures::sync::Lrc;
 use rustc_span::{symbol, BytePos, Pos, Span};
 
@@ -689,7 +689,7 @@ impl<'b, 'a: 'b> FmtVisitor<'a> {
         // with whitespace between the delimiters and trailing semi (i.e. `foo!(abc)     ;`)
         // are formatted correctly.
         let (span, rewrite) = match macro_style(mac, &self.get_context()) {
-            DelimToken::Bracket | DelimToken::Paren if MacroPosition::Item == pos => {
+            Delimiter::Bracket | Delimiter::Parenthesis if MacroPosition::Item == pos => {
                 let search_span = mk_sp(mac.span().hi(), self.snippet_provider.end_pos());
                 let hi = self.snippet_provider.span_before(search_span, ";");
                 let target_span = mk_sp(mac.span().lo(), hi + BytePos(1));