Add IMPLIED_BOUNDS_ENTAILMENT lint

4 files changed, 85 insertions, 0 deletions

diff --git a/src/test/ui/implied-bounds/impl-implied-bounds-compatibility-unnormalized.rs b/src/test/ui/implied-bounds/impl-implied-bounds-compatibility-unnormalized.rs
new file mode 100644
index 00000000000..cb5d83abfb6
--- /dev/null
+++ b/src/test/ui/implied-bounds/impl-implied-bounds-compatibility-unnormalized.rs
@@ -0,0 +1,20 @@
+trait Project {
+    type Ty;
+}
+impl Project for &'_ &'_ () {
+    type Ty = ();
+}
+trait Trait {
+    fn get<'s>(s: &'s str, _: ()) -> &'static str;
+}
+impl Trait for () {
+    fn get<'s>(s: &'s str, _: <&'static &'s () as Project>::Ty) -> &'static str {
+        //~^ ERROR impl method assumes more implied bounds than the corresponding trait method
+        //~| WARN this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+        s
+    }
+}
+fn main() {
+    let val = <() as Trait>::get(&String::from("blah blah blah"), ());
+    println!("{}", val);
+}
diff --git a/src/test/ui/implied-bounds/impl-implied-bounds-compatibility-unnormalized.stderr b/src/test/ui/implied-bounds/impl-implied-bounds-compatibility-unnormalized.stderr
new file mode 100644
index 00000000000..5a757901777
--- /dev/null
+++ b/src/test/ui/implied-bounds/impl-implied-bounds-compatibility-unnormalized.stderr
@@ -0,0 +1,23 @@
+error: impl method assumes more implied bounds than the corresponding trait method
+  --> $DIR/impl-implied-bounds-compatibility-unnormalized.rs:11:5
+   |
+LL |     fn get<'s>(s: &'s str, _: <&'static &'s () as Project>::Ty) -> &'static str {
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = 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 #105572 <https://github.com/rust-lang/rust/issues/105572>
+   = note: `#[deny(implied_bounds_entailment)]` on by default
+
+error: aborting due to previous error
+
+Future incompatibility report: Future breakage diagnostic:
+error: impl method assumes more implied bounds than the corresponding trait method
+  --> $DIR/impl-implied-bounds-compatibility-unnormalized.rs:11:5
+   |
+LL |     fn get<'s>(s: &'s str, _: <&'static &'s () as Project>::Ty) -> &'static str {
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = 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 #105572 <https://github.com/rust-lang/rust/issues/105572>
+   = note: `#[deny(implied_bounds_entailment)]` on by default
+
diff --git a/src/test/ui/implied-bounds/impl-implied-bounds-compatibility.rs b/src/test/ui/implied-bounds/impl-implied-bounds-compatibility.rs
new file mode 100644
index 00000000000..2d7cc38d263
--- /dev/null
+++ b/src/test/ui/implied-bounds/impl-implied-bounds-compatibility.rs
@@ -0,0 +1,19 @@
+use std::cell::RefCell;
+
+pub struct MessageListeners<'a> {
+    listeners: RefCell<Vec<Box<dyn FnMut(()) + 'a>>>,
+}
+
+pub trait MessageListenersInterface {
+    fn listeners<'c>(&'c self) -> &'c MessageListeners<'c>;
+}
+
+impl<'a> MessageListenersInterface for MessageListeners<'a> {
+    fn listeners<'b>(&'b self) -> &'a MessageListeners<'b> {
+        //~^ ERROR impl method assumes more implied bounds than the corresponding trait method
+        //~| WARN this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+        self
+    }
+}
+
+fn main() {}
diff --git a/src/test/ui/implied-bounds/impl-implied-bounds-compatibility.stderr b/src/test/ui/implied-bounds/impl-implied-bounds-compatibility.stderr
new file mode 100644
index 00000000000..b7dbfc8ab8c
--- /dev/null
+++ b/src/test/ui/implied-bounds/impl-implied-bounds-compatibility.stderr
@@ -0,0 +1,23 @@
+error: impl method assumes more implied bounds than the corresponding trait method
+  --> $DIR/impl-implied-bounds-compatibility.rs:12:5
+   |
+LL |     fn listeners<'b>(&'b self) -> &'a MessageListeners<'b> {
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = 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 #105572 <https://github.com/rust-lang/rust/issues/105572>
+   = note: `#[deny(implied_bounds_entailment)]` on by default
+
+error: aborting due to previous error
+
+Future incompatibility report: Future breakage diagnostic:
+error: impl method assumes more implied bounds than the corresponding trait method
+  --> $DIR/impl-implied-bounds-compatibility.rs:12:5
+   |
+LL |     fn listeners<'b>(&'b self) -> &'a MessageListeners<'b> {
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = 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 #105572 <https://github.com/rust-lang/rust/issues/105572>
+   = note: `#[deny(implied_bounds_entailment)]` on by default
+