Add a note to duplicate diagnostics

6 files changed, 26 insertions, 29 deletions

diff --git a/tests/rustdoc-ui/custom_code_classes_in_docs-warning3.stderr b/tests/rustdoc-ui/custom_code_classes_in_docs-warning3.stderr
index 4f2ded78c29..ad049804213 100644
--- a/tests/rustdoc-ui/custom_code_classes_in_docs-warning3.stderr
+++ b/tests/rustdoc-ui/custom_code_classes_in_docs-warning3.stderr
@@ -28,6 +28,8 @@ LL | |
 LL | | /// main;
 LL | | /// ```
    | |_______^
+   |
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
 error: aborting due to 2 previous errors
 
diff --git a/tests/rustdoc-ui/intra-doc/broken-link-in-unused-doc-string.stderr b/tests/rustdoc-ui/intra-doc/broken-link-in-unused-doc-string.stderr
index 83e0d3962ca..b25849f25b4 100644
--- a/tests/rustdoc-ui/intra-doc/broken-link-in-unused-doc-string.stderr
+++ b/tests/rustdoc-ui/intra-doc/broken-link-in-unused-doc-string.stderr
@@ -22,6 +22,7 @@ LL | /// [1]
    |      ^ no item named `1` in scope
    |
    = help: to escape `[` and `]` characters, add '\' before them like `\[` or `\]`
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
 warning: 3 warnings emitted
 
diff --git a/tests/rustdoc-ui/issues/issue-105742.stderr b/tests/rustdoc-ui/issues/issue-105742.stderr
index b63176c9149..4d3f9f5bced 100644
--- a/tests/rustdoc-ui/issues/issue-105742.stderr
+++ b/tests/rustdoc-ui/issues/issue-105742.stderr
@@ -169,6 +169,7 @@ note: associated type defined here, with 1 lifetime parameter: `'a`
    |
 LL |     type Item<'a, T>;
    |          ^^^^ --
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 help: add missing lifetime argument
    |
 LL |     <Self as SVec>::Item<'a>,
@@ -185,6 +186,7 @@ note: associated type defined here, with 1 generic parameter: `T`
    |
 LL |     type Item<'a, T>;
    |          ^^^^     -
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 help: add missing generic argument
    |
 LL |     <Self as SVec>::Item<T>,
@@ -201,6 +203,7 @@ note: associated type defined here, with 1 lifetime parameter: `'a`
    |
 LL |     type Item<'a, T>;
    |          ^^^^ --
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 help: add missing lifetime argument
    |
 LL |     Output = <Index<<Self as SVec>::Item<'a>,
@@ -217,6 +220,7 @@ note: associated type defined here, with 1 generic parameter: `T`
    |
 LL |     type Item<'a, T>;
    |          ^^^^     -
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 help: add missing generic argument
    |
 LL |     Output = <Index<<Self as SVec>::Item<T>,
@@ -233,6 +237,7 @@ note: associated type defined here, with 1 lifetime parameter: `'a`
    |
 LL |     type Item<'a, T>;
    |          ^^^^ --
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 help: add missing lifetime argument
    |
 LL |     Output = <Self as SVec>::Item<'a>> as SVec>::Item,
@@ -249,6 +254,7 @@ note: associated type defined here, with 1 generic parameter: `T`
    |
 LL |     type Item<'a, T>;
    |          ^^^^     -
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 help: add missing generic argument
    |
 LL |     Output = <Self as SVec>::Item<T>> as SVec>::Item,
@@ -265,6 +271,7 @@ note: associated type defined here, with 1 lifetime parameter: `'a`
    |
 LL |     type Item<'a, T>;
    |          ^^^^ --
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 help: add missing lifetime argument
    |
 LL |     Output = <Self as SVec>::Item> as SVec>::Item<'a>,
@@ -281,6 +288,7 @@ note: associated type defined here, with 1 generic parameter: `T`
    |
 LL |     type Item<'a, T>;
    |          ^^^^     -
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 help: add missing generic argument
    |
 LL |     Output = <Self as SVec>::Item> as SVec>::Item<T>,
@@ -327,6 +335,7 @@ note: associated type defined here, with 1 lifetime parameter: `'a`
    |
 LL |     type Item<'a, T>;
    |          ^^^^ --
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 help: add missing lifetime argument
    |
 LL |     <Self as SVec>::Item<'a>,
@@ -343,6 +352,7 @@ note: associated type defined here, with 1 generic parameter: `T`
    |
 LL |     type Item<'a, T>;
    |          ^^^^     -
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 help: add missing generic argument
    |
 LL |     <Self as SVec>::Item<T>,
@@ -359,6 +369,7 @@ note: associated type defined here, with 1 lifetime parameter: `'a`
    |
 LL |     type Item<'a, T>;
    |          ^^^^ --
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 help: add missing lifetime argument
    |
 LL |     Output = <Index<<Self as SVec>::Item<'a>,
@@ -375,6 +386,7 @@ note: associated type defined here, with 1 generic parameter: `T`
    |
 LL |     type Item<'a, T>;
    |          ^^^^     -
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 help: add missing generic argument
    |
 LL |     Output = <Index<<Self as SVec>::Item<T>,
@@ -391,6 +403,7 @@ note: associated type defined here, with 1 lifetime parameter: `'a`
    |
 LL |     type Item<'a, T>;
    |          ^^^^ --
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 help: add missing lifetime argument
    |
 LL |     Output = <Self as SVec>::Item<'a>> as SVec>::Item,
@@ -407,6 +420,7 @@ note: associated type defined here, with 1 generic parameter: `T`
    |
 LL |     type Item<'a, T>;
    |          ^^^^     -
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 help: add missing generic argument
    |
 LL |     Output = <Self as SVec>::Item<T>> as SVec>::Item,
@@ -423,6 +437,7 @@ note: associated type defined here, with 1 lifetime parameter: `'a`
    |
 LL |     type Item<'a, T>;
    |          ^^^^ --
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 help: add missing lifetime argument
    |
 LL |     Output = <Self as SVec>::Item> as SVec>::Item<'a>,
@@ -439,6 +454,7 @@ note: associated type defined here, with 1 generic parameter: `T`
    |
 LL |     type Item<'a, T>;
    |          ^^^^     -
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 help: add missing generic argument
    |
 LL |     Output = <Self as SVec>::Item> as SVec>::Item<T>,
diff --git a/tests/rustdoc-ui/lints/feature-gate-rustdoc_missing_doc_code_examples.rs b/tests/rustdoc-ui/lints/feature-gate-rustdoc_missing_doc_code_examples.rs
index c34ea0567a9..ce94a06c39e 100644
--- a/tests/rustdoc-ui/lints/feature-gate-rustdoc_missing_doc_code_examples.rs
+++ b/tests/rustdoc-ui/lints/feature-gate-rustdoc_missing_doc_code_examples.rs
@@ -1,12 +1,7 @@
+// compile-flags: -Zdeduplicate-diagnostics=yes
 #![deny(unknown_lints)]
 //~^ NOTE defined here
 #![allow(rustdoc::missing_doc_code_examples)]
 //~^ ERROR unknown lint
-//~| ERROR unknown lint
-//~| ERROR unknown lint
 //~| NOTE lint is unstable
-//~| NOTE lint is unstable
-//~| NOTE lint is unstable
-//~| NOTE see issue
-//~| NOTE see issue
 //~| NOTE see issue
diff --git a/tests/rustdoc-ui/lints/feature-gate-rustdoc_missing_doc_code_examples.stderr b/tests/rustdoc-ui/lints/feature-gate-rustdoc_missing_doc_code_examples.stderr
index 326dcfe3bde..b8a08e94312 100644
--- a/tests/rustdoc-ui/lints/feature-gate-rustdoc_missing_doc_code_examples.stderr
+++ b/tests/rustdoc-ui/lints/feature-gate-rustdoc_missing_doc_code_examples.stderr
@@ -1,5 +1,5 @@
 error: unknown lint: `rustdoc::missing_doc_code_examples`
-  --> $DIR/feature-gate-rustdoc_missing_doc_code_examples.rs:3:1
+  --> $DIR/feature-gate-rustdoc_missing_doc_code_examples.rs:4:1
    |
 LL | #![allow(rustdoc::missing_doc_code_examples)]
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -8,30 +8,10 @@ LL | #![allow(rustdoc::missing_doc_code_examples)]
    = note: see issue #101730 <https://github.com/rust-lang/rust/issues/101730> for more information
    = help: add `#![feature(rustdoc_missing_doc_code_examples)]` to the crate attributes to enable
 note: the lint level is defined here
-  --> $DIR/feature-gate-rustdoc_missing_doc_code_examples.rs:1:9
+  --> $DIR/feature-gate-rustdoc_missing_doc_code_examples.rs:2:9
    |
 LL | #![deny(unknown_lints)]
    |         ^^^^^^^^^^^^^
 
-error: unknown lint: `rustdoc::missing_doc_code_examples`
-  --> $DIR/feature-gate-rustdoc_missing_doc_code_examples.rs:3:1
-   |
-LL | #![allow(rustdoc::missing_doc_code_examples)]
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = note: the `rustdoc::missing_doc_code_examples` lint is unstable
-   = note: see issue #101730 <https://github.com/rust-lang/rust/issues/101730> for more information
-   = help: add `#![feature(rustdoc_missing_doc_code_examples)]` to the crate attributes to enable
-
-error: unknown lint: `rustdoc::missing_doc_code_examples`
-  --> $DIR/feature-gate-rustdoc_missing_doc_code_examples.rs:3:1
-   |
-LL | #![allow(rustdoc::missing_doc_code_examples)]
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = note: the `rustdoc::missing_doc_code_examples` lint is unstable
-   = note: see issue #101730 <https://github.com/rust-lang/rust/issues/101730> for more information
-   = help: add `#![feature(rustdoc_missing_doc_code_examples)]` to the crate attributes to enable
-
-error: aborting due to 3 previous errors
+error: aborting due to previous error
 
diff --git a/tests/rustdoc-ui/unescaped_backticks.stderr b/tests/rustdoc-ui/unescaped_backticks.stderr
index 83822f778d0..2b4e491b1fe 100644
--- a/tests/rustdoc-ui/unescaped_backticks.stderr
+++ b/tests/rustdoc-ui/unescaped_backticks.stderr
@@ -302,6 +302,7 @@ LL | |     /// level changes.
    = help: if you meant to use a literal backtick, escape it
             change: or `None` if it isn't.
            to this: or `None\` if it isn't.
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
 error: unescaped backtick
   --> $DIR/unescaped_backticks.rs:323:5
@@ -321,6 +322,7 @@ LL | |     /// level changes.
    = help: if you meant to use a literal backtick, escape it
             change: `on_event` should be called.
            to this: `on_event\` should be called.
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
 error: unescaped backtick
   --> $DIR/unescaped_backticks.rs:323:5
@@ -340,6 +342,7 @@ LL | |     /// level changes.
    = help: if you meant to use a literal backtick, escape it
             change: [`rebuild_interest_cache`][rebuild] is called after the value of the max
            to this: [`rebuild_interest_cache\`][rebuild] is called after the value of the max
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
 error: unescaped backtick
   --> $DIR/unescaped_backticks.rs:349:56