diff --git a/compiler/rustc_lint/src/default_could_be_derived.rs b/compiler/rustc_lint/src/default_could_be_derived.rs
index 4028a038f36f..d0635c8f9067 100644
--- a/compiler/rustc_lint/src/default_could_be_derived.rs
+++ b/compiler/rustc_lint/src/default_could_be_derived.rs
@@ -54,7 +54,7 @@ declare_lint! {
     /// so the derive for `Default` for a struct is trivial, and for an enum
     /// variant with no fields, which can be annotated with `#[default]`.
     pub DEFAULT_COULD_BE_DERIVED,
-    Warn,
+    Deny,
     "detect `Default` impl that could be derived"
 }
 
diff --git a/src/tools/clippy/tests/ui/new_without_default.stderr b/src/tools/clippy/tests/ui/new_without_default.stderr
index 1ef62238982c..0c4a5f4f5df7 100644
--- a/src/tools/clippy/tests/ui/new_without_default.stderr
+++ b/src/tools/clippy/tests/ui/new_without_default.stderr
@@ -177,8 +177,7 @@ LL | |     }
 LL | | }
    | |_^
    |
-   = note: `-D default-could-be-derived` implied by `-D warnings`
-   = help: to override `-D warnings` add `#[allow(default_could_be_derived)]`
+   = note: `#[deny(default_could_be_derived)]` on by default
 help: you don't need to manually `impl Default`, you can derive it
    |
 LL ~ #[derive(Default)] pub struct Ok;
diff --git a/src/tools/clippy/tests/ui/or_fun_call.stderr b/src/tools/clippy/tests/ui/or_fun_call.stderr
index 1cd2afcc14dd..44f96a159231 100644
--- a/src/tools/clippy/tests/ui/or_fun_call.stderr
+++ b/src/tools/clippy/tests/ui/or_fun_call.stderr
@@ -255,8 +255,7 @@ LL | |         }
 LL | |     }
    | |_____^
    |
-   = note: `-D default-could-be-derived` implied by `-D warnings`
-   = help: to override `-D warnings` add `#[allow(default_could_be_derived)]`
+   = note: `#[deny(default_could_be_derived)]` on by default
 help: you don't need to manually `impl Default`, you can derive it
    |
 LL ~     #[derive(Default)] struct FakeDefault;
diff --git a/src/tools/clippy/tests/ui/unwrap_or_else_default.stderr b/src/tools/clippy/tests/ui/unwrap_or_else_default.stderr
index 50c3a6db8531..6e86aac95bbb 100644
--- a/src/tools/clippy/tests/ui/unwrap_or_else_default.stderr
+++ b/src/tools/clippy/tests/ui/unwrap_or_else_default.stderr
@@ -108,8 +108,7 @@ LL | |         }
 LL | |     }
    | |_____^
    |
-   = note: `-D default-could-be-derived` implied by `-D warnings`
-   = help: to override `-D warnings` add `#[allow(default_could_be_derived)]`
+   = note: `#[deny(default_could_be_derived)]` on by default
 help: you don't need to manually `impl Default`, you can derive it
    |
 LL ~     #[derive(Default)] struct HasDefaultAndDuplicate;