Warn on elided lifetimes in associated constants

4 files changed, 69 insertions, 1 deletions

diff --git a/tests/ui/associated-consts/infer-placeholder-in-non-suggestable-pos.rs b/tests/ui/associated-consts/infer-placeholder-in-non-suggestable-pos.rs
index 40896c32e11..1e0b77b0d3b 100644
--- a/tests/ui/associated-consts/infer-placeholder-in-non-suggestable-pos.rs
+++ b/tests/ui/associated-consts/infer-placeholder-in-non-suggestable-pos.rs
@@ -5,6 +5,8 @@ trait Trait {
 impl Trait for () {
     const ASSOC: &dyn Fn(_) = 1i32;
     //~^ ERROR the placeholder `_` is not allowed within types on item signatures for associated constants
+    //~| WARN `&` without an explicit lifetime name cannot be used here
+    //~| WARN this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
 }
 
 fn main() {}
diff --git a/tests/ui/associated-consts/infer-placeholder-in-non-suggestable-pos.stderr b/tests/ui/associated-consts/infer-placeholder-in-non-suggestable-pos.stderr
index 993a08faba9..f8c02420f96 100644
--- a/tests/ui/associated-consts/infer-placeholder-in-non-suggestable-pos.stderr
+++ b/tests/ui/associated-consts/infer-placeholder-in-non-suggestable-pos.stderr
@@ -1,9 +1,23 @@
+warning: `&` without an explicit lifetime name cannot be used here
+  --> $DIR/infer-placeholder-in-non-suggestable-pos.rs:6:18
+   |
+LL |     const ASSOC: &dyn Fn(_) = 1i32;
+   |                  ^
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #115010 <https://github.com/rust-lang/rust/issues/115010>
+   = note: `#[warn(elided_lifetimes_in_associated_constant)]` on by default
+help: use the `'static` lifetime
+   |
+LL |     const ASSOC: &'static dyn Fn(_) = 1i32;
+   |                   +++++++
+
 error[E0121]: the placeholder `_` is not allowed within types on item signatures for associated constants
   --> $DIR/infer-placeholder-in-non-suggestable-pos.rs:6:26
    |
 LL |     const ASSOC: &dyn Fn(_) = 1i32;
    |                          ^ not allowed in type signatures
 
-error: aborting due to previous error
+error: aborting due to previous error; 1 warning emitted
 
 For more information about this error, try `rustc --explain E0121`.
diff --git a/tests/ui/consts/assoc-const-elided-lifetime.rs b/tests/ui/consts/assoc-const-elided-lifetime.rs
new file mode 100644
index 00000000000..10cd33a8fed
--- /dev/null
+++ b/tests/ui/consts/assoc-const-elided-lifetime.rs
@@ -0,0 +1,19 @@
+#![deny(elided_lifetimes_in_associated_constant)]
+
+use std::marker::PhantomData;
+
+struct Foo<'a> {
+    x: PhantomData<&'a ()>,
+}
+
+impl<'a> Foo<'a> {
+    const FOO: Foo<'_> = Foo { x: PhantomData::<&()> };
+    //~^ ERROR `'_` cannot be used here
+    //~| WARN this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+
+    const BAR: &() = &();
+    //~^ ERROR `&` without an explicit lifetime name cannot be used here
+    //~| WARN this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+}
+
+fn main() {}
diff --git a/tests/ui/consts/assoc-const-elided-lifetime.stderr b/tests/ui/consts/assoc-const-elided-lifetime.stderr
new file mode 100644
index 00000000000..a1eeaff4ba8
--- /dev/null
+++ b/tests/ui/consts/assoc-const-elided-lifetime.stderr
@@ -0,0 +1,33 @@
+error: `'_` cannot be used here
+  --> $DIR/assoc-const-elided-lifetime.rs:10:20
+   |
+LL |     const FOO: Foo<'_> = Foo { x: PhantomData::<&()> };
+   |                    ^^
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #115010 <https://github.com/rust-lang/rust/issues/115010>
+note: the lint level is defined here
+  --> $DIR/assoc-const-elided-lifetime.rs:1:9
+   |
+LL | #![deny(elided_lifetimes_in_associated_constant)]
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+help: use the `'static` lifetime
+   |
+LL |     const FOO: Foo<'static> = Foo { x: PhantomData::<&()> };
+   |                    ~~~~~~~
+
+error: `&` without an explicit lifetime name cannot be used here
+  --> $DIR/assoc-const-elided-lifetime.rs:14:16
+   |
+LL |     const BAR: &() = &();
+   |                ^
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #115010 <https://github.com/rust-lang/rust/issues/115010>
+help: use the `'static` lifetime
+   |
+LL |     const BAR: &'static () = &();
+   |                 +++++++
+
+error: aborting due to 2 previous errors
+