highlight the whole problem subpattern when pointing out the default binding mode

4 files changed, 161 insertions, 43 deletions

diff --git a/tests/ui/pattern/rfc-3627-match-ergonomics-2024/experimental/ref-binding-on-inh-ref-errors.classic2024.stderr b/tests/ui/pattern/rfc-3627-match-ergonomics-2024/experimental/ref-binding-on-inh-ref-errors.classic2024.stderr
index fbe1164c625..d4313f915df 100644
--- a/tests/ui/pattern/rfc-3627-match-ergonomics-2024/experimental/ref-binding-on-inh-ref-errors.classic2024.stderr
+++ b/tests/ui/pattern/rfc-3627-match-ergonomics-2024/experimental/ref-binding-on-inh-ref-errors.classic2024.stderr
@@ -14,7 +14,10 @@ error: binding modifiers may only be written when the default binding mode is `m
   --> $DIR/ref-binding-on-inh-ref-errors.rs:67:10
    |
 LL |     let [ref mut x] = &[0];
-   |          ^^^^^^^ default binding mode is `ref`
+   |          ^^^^^^^--
+   |          |
+   |          this binding modifier
+   |          default binding mode is `ref`
    |
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/match-ergonomics.html>
 help: make the implied reference pattern explicit
@@ -32,7 +35,10 @@ error: binding modifiers may only be written when the default binding mode is `m
   --> $DIR/ref-binding-on-inh-ref-errors.rs:75:10
    |
 LL |     let [ref x] = &[0];
-   |          ^^^ default binding mode is `ref`
+   |          ^^^--
+   |          |
+   |          this binding modifier
+   |          default binding mode is `ref`
    |
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/match-ergonomics.html>
 help: make the implied reference pattern explicit
@@ -44,7 +50,10 @@ error: binding modifiers may only be written when the default binding mode is `m
   --> $DIR/ref-binding-on-inh-ref-errors.rs:79:10
    |
 LL |     let [ref x] = &mut [0];
-   |          ^^^ default binding mode is `ref mut`
+   |          ^^^--
+   |          |
+   |          this binding modifier
+   |          default binding mode is `ref mut`
    |
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/match-ergonomics.html>
 help: make the implied reference pattern explicit
@@ -56,7 +65,10 @@ error: binding modifiers may only be written when the default binding mode is `m
   --> $DIR/ref-binding-on-inh-ref-errors.rs:83:10
    |
 LL |     let [ref mut x] = &mut [0];
-   |          ^^^^^^^ default binding mode is `ref mut`
+   |          ^^^^^^^--
+   |          |
+   |          this binding modifier
+   |          default binding mode is `ref mut`
    |
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/match-ergonomics.html>
 help: make the implied reference pattern explicit
diff --git a/tests/ui/pattern/rfc-3627-match-ergonomics-2024/experimental/ref-binding-on-inh-ref-errors.structural2024.stderr b/tests/ui/pattern/rfc-3627-match-ergonomics-2024/experimental/ref-binding-on-inh-ref-errors.structural2024.stderr
index f355b7c61a2..8edb6511f23 100644
--- a/tests/ui/pattern/rfc-3627-match-ergonomics-2024/experimental/ref-binding-on-inh-ref-errors.structural2024.stderr
+++ b/tests/ui/pattern/rfc-3627-match-ergonomics-2024/experimental/ref-binding-on-inh-ref-errors.structural2024.stderr
@@ -2,7 +2,10 @@ error: binding modifiers may only be written when the default binding mode is `m
   --> $DIR/ref-binding-on-inh-ref-errors.rs:15:11
    |
 LL |     let [&ref x] = &[&0];
-   |           ^^^ default binding mode is `ref`
+   |           ^^^--
+   |           |
+   |           this binding modifier
+   |           default binding mode is `ref`
    |
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/match-ergonomics.html>
 help: make the implied reference pattern explicit
@@ -14,7 +17,10 @@ error: binding modifiers may only be written when the default binding mode is `m
   --> $DIR/ref-binding-on-inh-ref-errors.rs:20:11
    |
 LL |     let [&ref x] = &mut [&0];
-   |           ^^^ default binding mode is `ref`
+   |           ^^^--
+   |           |
+   |           this binding modifier
+   |           default binding mode is `ref`
    |
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/match-ergonomics.html>
 help: make the implied reference pattern explicit
@@ -26,7 +32,10 @@ error: binding modifiers may only be written when the default binding mode is `m
   --> $DIR/ref-binding-on-inh-ref-errors.rs:25:15
    |
 LL |     let [&mut ref x] = &mut [&mut 0];
-   |               ^^^ default binding mode is `ref mut`
+   |               ^^^--
+   |               |
+   |               this binding modifier
+   |               default binding mode is `ref mut`
    |
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/match-ergonomics.html>
 help: make the implied reference pattern explicit
@@ -38,7 +47,10 @@ error: binding modifiers may only be written when the default binding mode is `m
   --> $DIR/ref-binding-on-inh-ref-errors.rs:30:15
    |
 LL |     let [&mut ref mut x] = &mut [&mut 0];
-   |               ^^^^^^^ default binding mode is `ref mut`
+   |               ^^^^^^^--
+   |               |
+   |               this binding modifier
+   |               default binding mode is `ref mut`
    |
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/match-ergonomics.html>
 help: make the implied reference pattern explicit
@@ -50,7 +62,10 @@ error: binding modifiers may only be written when the default binding mode is `m
   --> $DIR/ref-binding-on-inh-ref-errors.rs:39:11
    |
 LL |     let [&ref x] = &[&mut 0];
-   |           ^^^ default binding mode is `ref`
+   |           ^^^--
+   |           |
+   |           this binding modifier
+   |           default binding mode is `ref`
    |
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/match-ergonomics.html>
 help: make the implied reference pattern explicit
@@ -62,7 +77,10 @@ error: binding modifiers may only be written when the default binding mode is `m
   --> $DIR/ref-binding-on-inh-ref-errors.rs:45:11
    |
 LL |     let [&ref x] = &mut [&mut 0];
-   |           ^^^ default binding mode is `ref`
+   |           ^^^--
+   |           |
+   |           this binding modifier
+   |           default binding mode is `ref`
    |
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/match-ergonomics.html>
 help: make the implied reference pattern explicit
@@ -74,7 +92,10 @@ error: binding modifiers may only be written when the default binding mode is `m
   --> $DIR/ref-binding-on-inh-ref-errors.rs:54:15
    |
 LL |     let [&mut ref x] = &[&mut 0];
-   |               ^^^ default binding mode is `ref`
+   |               ^^^--
+   |               |
+   |               this binding modifier
+   |               default binding mode is `ref`
    |
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/match-ergonomics.html>
 help: make the implied reference pattern explicit
@@ -86,7 +107,10 @@ error: binding modifiers may only be written when the default binding mode is `m
   --> $DIR/ref-binding-on-inh-ref-errors.rs:67:10
    |
 LL |     let [ref mut x] = &[0];
-   |          ^^^^^^^ default binding mode is `ref`
+   |          ^^^^^^^--
+   |          |
+   |          this binding modifier
+   |          default binding mode is `ref`
    |
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/match-ergonomics.html>
 help: make the implied reference pattern explicit
@@ -104,7 +128,10 @@ error: binding modifiers may only be written when the default binding mode is `m
   --> $DIR/ref-binding-on-inh-ref-errors.rs:75:10
    |
 LL |     let [ref x] = &[0];
-   |          ^^^ default binding mode is `ref`
+   |          ^^^--
+   |          |
+   |          this binding modifier
+   |          default binding mode is `ref`
    |
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/match-ergonomics.html>
 help: make the implied reference pattern explicit
@@ -116,7 +143,10 @@ error: binding modifiers may only be written when the default binding mode is `m
   --> $DIR/ref-binding-on-inh-ref-errors.rs:79:10
    |
 LL |     let [ref x] = &mut [0];
-   |          ^^^ default binding mode is `ref mut`
+   |          ^^^--
+   |          |
+   |          this binding modifier
+   |          default binding mode is `ref mut`
    |
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/match-ergonomics.html>
 help: make the implied reference pattern explicit
@@ -128,7 +158,10 @@ error: binding modifiers may only be written when the default binding mode is `m
   --> $DIR/ref-binding-on-inh-ref-errors.rs:83:10
    |
 LL |     let [ref mut x] = &mut [0];
-   |          ^^^^^^^ default binding mode is `ref mut`
+   |          ^^^^^^^--
+   |          |
+   |          this binding modifier
+   |          default binding mode is `ref mut`
    |
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/match-ergonomics.html>
 help: make the implied reference pattern explicit
diff --git a/tests/ui/pattern/rfc-3627-match-ergonomics-2024/migration_lint.stderr b/tests/ui/pattern/rfc-3627-match-ergonomics-2024/migration_lint.stderr
index 0a9d2cf223a..cbb94a52878 100644
--- a/tests/ui/pattern/rfc-3627-match-ergonomics-2024/migration_lint.stderr
+++ b/tests/ui/pattern/rfc-3627-match-ergonomics-2024/migration_lint.stderr
@@ -2,7 +2,10 @@ error: binding modifiers may only be written when the default binding mode is `m
   --> $DIR/migration_lint.rs:25:13
    |
 LL |     let Foo(mut x) = &Foo(0);
-   |             ^^^ default binding mode is `ref`
+   |             ^^^--
+   |             |
+   |             this binding modifier
+   |             default binding mode is `ref`
    |
    = warning: this changes meaning in Rust 2024
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/match-ergonomics.html>
@@ -20,7 +23,10 @@ error: binding modifiers may only be written when the default binding mode is `m
   --> $DIR/migration_lint.rs:30:13
    |
 LL |     let Foo(mut x) = &mut Foo(0);
-   |             ^^^ default binding mode is `ref mut`
+   |             ^^^--
+   |             |
+   |             this binding modifier
+   |             default binding mode is `ref mut`
    |
    = warning: this changes meaning in Rust 2024
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/match-ergonomics.html>
@@ -33,7 +39,10 @@ error: binding modifiers may only be written when the default binding mode is `m
   --> $DIR/migration_lint.rs:35:13
    |
 LL |     let Foo(ref x) = &Foo(0);
-   |             ^^^ default binding mode is `ref`
+   |             ^^^--
+   |             |
+   |             this binding modifier
+   |             default binding mode is `ref`
    |
    = warning: this changes meaning in Rust 2024
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/match-ergonomics.html>
@@ -46,7 +55,10 @@ error: binding modifiers may only be written when the default binding mode is `m
   --> $DIR/migration_lint.rs:40:13
    |
 LL |     let Foo(ref x) = &mut Foo(0);
-   |             ^^^ default binding mode is `ref mut`
+   |             ^^^--
+   |             |
+   |             this binding modifier
+   |             default binding mode is `ref mut`
    |
    = warning: this changes meaning in Rust 2024
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/match-ergonomics.html>
@@ -59,7 +71,10 @@ error: reference patterns may only be written when the default binding mode is `
   --> $DIR/migration_lint.rs:57:13
    |
 LL |     let Foo(&x) = &Foo(&0);
-   |             ^ default binding mode is `ref`
+   |             ^-
+   |             |
+   |             this reference pattern
+   |             default binding mode is `ref`
    |
    = warning: this changes meaning in Rust 2024
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/match-ergonomics.html>
@@ -72,7 +87,10 @@ error: reference patterns may only be written when the default binding mode is `
   --> $DIR/migration_lint.rs:62:13
    |
 LL |     let Foo(&mut x) = &Foo(&mut 0);
-   |             ^^^^ default binding mode is `ref`
+   |             ^^^^--
+   |             |
+   |             this reference pattern
+   |             default binding mode is `ref`
    |
    = warning: this changes meaning in Rust 2024
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/match-ergonomics.html>
@@ -85,7 +103,10 @@ error: reference patterns may only be written when the default binding mode is `
   --> $DIR/migration_lint.rs:67:13
    |
 LL |     let Foo(&x) = &mut Foo(&0);
-   |             ^ default binding mode is `ref mut`
+   |             ^-
+   |             |
+   |             this reference pattern
+   |             default binding mode is `ref mut`
    |
    = warning: this changes meaning in Rust 2024
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/match-ergonomics.html>
@@ -98,7 +119,10 @@ error: reference patterns may only be written when the default binding mode is `
   --> $DIR/migration_lint.rs:72:13
    |
 LL |     let Foo(&mut x) = &mut Foo(&mut 0);
-   |             ^^^^ default binding mode is `ref mut`
+   |             ^^^^--
+   |             |
+   |             this reference pattern
+   |             default binding mode is `ref mut`
    |
    = warning: this changes meaning in Rust 2024
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/match-ergonomics.html>
@@ -111,7 +135,10 @@ error: reference patterns may only be written when the default binding mode is `
   --> $DIR/migration_lint.rs:81:17
    |
 LL |     if let Some(&x) = &&&&&Some(&0u8) {
-   |                 ^ default binding mode is `ref`
+   |                 ^-
+   |                 |
+   |                 this reference pattern
+   |                 default binding mode is `ref`
    |
    = warning: this changes meaning in Rust 2024
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/match-ergonomics.html>
@@ -124,7 +151,10 @@ error: reference patterns may only be written when the default binding mode is `
   --> $DIR/migration_lint.rs:87:17
    |
 LL |     if let Some(&mut x) = &&&&&Some(&mut 0u8) {
-   |                 ^^^^ default binding mode is `ref`
+   |                 ^^^^--
+   |                 |
+   |                 this reference pattern
+   |                 default binding mode is `ref`
    |
    = warning: this changes meaning in Rust 2024
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/match-ergonomics.html>
@@ -137,7 +167,10 @@ error: reference patterns may only be written when the default binding mode is `
   --> $DIR/migration_lint.rs:93:17
    |
 LL |     if let Some(&x) = &&&&&mut Some(&0u8) {
-   |                 ^ default binding mode is `ref`
+   |                 ^-
+   |                 |
+   |                 this reference pattern
+   |                 default binding mode is `ref`
    |
    = warning: this changes meaning in Rust 2024
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/match-ergonomics.html>
@@ -150,7 +183,10 @@ error: reference patterns may only be written when the default binding mode is `
   --> $DIR/migration_lint.rs:99:17
    |
 LL |     if let Some(&mut Some(Some(x))) = &mut Some(&mut Some(&mut Some(0u8))) {
-   |                 ^^^^ default binding mode is `ref mut`
+   |                 ^^^^--------------
+   |                 |
+   |                 this reference pattern
+   |                 default binding mode is `ref mut`
    |
    = warning: this changes meaning in Rust 2024
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/match-ergonomics.html>
@@ -163,7 +199,10 @@ error: binding modifiers may only be written when the default binding mode is `m
   --> $DIR/migration_lint.rs:111:21
    |
 LL |     let Struct { a, mut b, c } = &Struct { a: 0, b: 0, c: 0 };
-   |                     ^^^ default binding mode is `ref`
+   |                     ^^^--
+   |                     |
+   |                     this binding modifier
+   |                     default binding mode is `ref`
    |
    = warning: this changes meaning in Rust 2024
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/match-ergonomics.html>
@@ -176,8 +215,11 @@ error: binding modifiers and reference patterns may only be written when the def
   --> $DIR/migration_lint.rs:117:21
    |
 LL |     let Struct { a: &a, b, ref c } = &Struct { a: &0, b: &0, c: &0 };
-   |                     ^      ^^^ default binding mode is `ref`
-   |                     |
+   |                     ^-     ^^^--
+   |                     |      |
+   |                     |      this binding modifier
+   |                     |      default binding mode is `ref`
+   |                     this reference pattern
    |                     default binding mode is `ref`
    |
    = warning: this changes meaning in Rust 2024
@@ -191,8 +233,11 @@ error: reference patterns may only be written when the default binding mode is `
   --> $DIR/migration_lint.rs:124:24
    |
 LL |     if let Struct { a: &Some(a), b: Some(&b), c: Some(c) } =
-   |                        ^                 ^ default binding mode is `ref`
-   |                        |
+   |                        ^-------          ^-
+   |                        |                 |
+   |                        |                 this reference pattern
+   |                        |                 default binding mode is `ref`
+   |                        this reference pattern
    |                        default binding mode is `ref`
    |
    = warning: this changes meaning in Rust 2024
@@ -206,8 +251,9 @@ error: binding modifiers may only be written when the default binding mode is `m
   --> $DIR/migration_lint.rs:137:15
    |
 LL |         (Some(mut x), migration_lint_macros::mixed_edition_pat!(y)) => {
-   |               ^^^     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ occurs within macro expansion
+   |               ^^^--   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ occurs within macro expansion
    |               |
+   |               this binding modifier
    |               default binding mode is `ref`
    |
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/match-ergonomics.html>
@@ -221,8 +267,11 @@ error: binding modifiers and reference patterns may only be written when the def
   --> $DIR/migration_lint.rs:145:10
    |
 LL |     let [&mut [ref a]] = &mut [&mut &[0]];
-   |          ^^^^  ^^^ default binding mode is `ref`
-   |          |
+   |          ^^^^--^^^---
+   |          |     |
+   |          |     this binding modifier
+   |          |     default binding mode is `ref`
+   |          this reference pattern
    |          default binding mode is `ref mut`
    |
    = warning: this changes meaning in Rust 2024
@@ -236,7 +285,10 @@ error: reference patterns may only be written when the default binding mode is `
   --> $DIR/migration_lint.rs:150:10
    |
 LL |     let [&(_)] = &[&0];
-   |          ^^ default binding mode is `ref`
+   |          ^^--
+   |          |
+   |          this reference pattern
+   |          default binding mode is `ref`
    |
    = warning: this changes meaning in Rust 2024
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/match-ergonomics.html>
diff --git a/tests/ui/pattern/rfc-3627-match-ergonomics-2024/min_match_ergonomics_fail.stderr b/tests/ui/pattern/rfc-3627-match-ergonomics-2024/min_match_ergonomics_fail.stderr
index 89868a1f333..ce93199b186 100644
--- a/tests/ui/pattern/rfc-3627-match-ergonomics-2024/min_match_ergonomics_fail.stderr
+++ b/tests/ui/pattern/rfc-3627-match-ergonomics-2024/min_match_ergonomics_fail.stderr
@@ -103,7 +103,10 @@ error: reference patterns may only be written when the default binding mode is `
   --> $DIR/min_match_ergonomics_fail.rs:24:20
    |
 LL | test_pat_on_type![(&x,): &(&T,)];
-   |                    ^ default binding mode is `ref`
+   |                    ^-
+   |                    |
+   |                    this reference pattern
+   |                    default binding mode is `ref`
    |
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/match-ergonomics.html>
 help: make the implied reference pattern explicit
@@ -115,7 +118,10 @@ error: reference patterns may only be written when the default binding mode is `
   --> $DIR/min_match_ergonomics_fail.rs:27:20
    |
 LL | test_pat_on_type![(&mut x,): &(&mut T,)];
-   |                    ^^^^ default binding mode is `ref`
+   |                    ^^^^--
+   |                    |
+   |                    this reference pattern
+   |                    default binding mode is `ref`
    |
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/match-ergonomics.html>
 help: make the implied reference pattern explicit
@@ -127,7 +133,10 @@ error: reference patterns may only be written when the default binding mode is `
   --> $DIR/min_match_ergonomics_fail.rs:31:28
    |
 LL | test_pat_on_type![Foo { f: &(x,) }: &Foo];
-   |                            ^ default binding mode is `ref`
+   |                            ^----
+   |                            |
+   |                            this reference pattern
+   |                            default binding mode is `ref`
    |
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/match-ergonomics.html>
 help: make the implied reference pattern explicit
@@ -139,7 +148,10 @@ error: binding modifiers may only be written when the default binding mode is `m
   --> $DIR/min_match_ergonomics_fail.rs:32:20
    |
 LL | test_pat_on_type![(mut x,): &(T,)];
-   |                    ^^^ default binding mode is `ref`
+   |                    ^^^--
+   |                    |
+   |                    this binding modifier
+   |                    default binding mode is `ref`
    |
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/match-ergonomics.html>
 help: make the implied reference pattern explicit
@@ -151,7 +163,10 @@ error: binding modifiers may only be written when the default binding mode is `m
   --> $DIR/min_match_ergonomics_fail.rs:33:20
    |
 LL | test_pat_on_type![(ref x,): &(T,)];
-   |                    ^^^ default binding mode is `ref`
+   |                    ^^^--
+   |                    |
+   |                    this binding modifier
+   |                    default binding mode is `ref`
    |
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/match-ergonomics.html>
 help: make the implied reference pattern explicit
@@ -163,7 +178,10 @@ error: binding modifiers may only be written when the default binding mode is `m
   --> $DIR/min_match_ergonomics_fail.rs:34:20
    |
 LL | test_pat_on_type![(ref mut x,): &mut (T,)];
-   |                    ^^^^^^^ default binding mode is `ref mut`
+   |                    ^^^^^^^--
+   |                    |
+   |                    this binding modifier
+   |                    default binding mode is `ref mut`
    |
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/match-ergonomics.html>
 help: make the implied reference pattern explicit
@@ -175,7 +193,10 @@ error: reference patterns may only be written when the default binding mode is `
   --> $DIR/min_match_ergonomics_fail.rs:43:10
    |
 LL |         (&x,) => x,
-   |          ^ default binding mode is `ref`
+   |          ^-
+   |          |
+   |          this reference pattern
+   |          default binding mode is `ref`
    |
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/match-ergonomics.html>
 help: make the implied reference pattern explicit