Don't ICE when RPITIT captures more method args than trait definition

2 files changed, 58 insertions, 0 deletions

diff --git a/tests/ui/impl-trait/precise-capturing/rpitit-captures-more-method-lifetimes.rs b/tests/ui/impl-trait/precise-capturing/rpitit-captures-more-method-lifetimes.rs
new file mode 100644
index 00000000000..71a91fe319e
--- /dev/null
+++ b/tests/ui/impl-trait/precise-capturing/rpitit-captures-more-method-lifetimes.rs
@@ -0,0 +1,16 @@
+// Make sure we don't ICE when an RPITIT captures more method args than the
+// trait definition, which is not allowed. Due to the default lifetime capture
+// rules of RPITITs, this is only doable if we use precise capturing.
+
+pub trait Foo {
+    fn bar<'tr: 'tr>(&'tr mut self) -> impl Sized + use<Self>;
+    //~^ ERROR `use<...>` precise capturing syntax is currently not allowed in return-position `impl Trait` in traits
+}
+
+impl Foo for () {
+    fn bar<'im: 'im>(&'im mut self) -> impl Sized + 'im {}
+    //~^ ERROR return type captures more lifetimes than trait definition
+    //~| WARN impl trait in impl method signature does not match trait method signature
+}
+
+fn main() {}
diff --git a/tests/ui/impl-trait/precise-capturing/rpitit-captures-more-method-lifetimes.stderr b/tests/ui/impl-trait/precise-capturing/rpitit-captures-more-method-lifetimes.stderr
new file mode 100644
index 00000000000..339e2e6335e
--- /dev/null
+++ b/tests/ui/impl-trait/precise-capturing/rpitit-captures-more-method-lifetimes.stderr
@@ -0,0 +1,42 @@
+error: `use<...>` precise capturing syntax is currently not allowed in return-position `impl Trait` in traits
+  --> $DIR/rpitit-captures-more-method-lifetimes.rs:6:53
+   |
+LL |     fn bar<'tr: 'tr>(&'tr mut self) -> impl Sized + use<Self>;
+   |                                                     ^^^^^^^^^
+   |
+   = note: currently, return-position `impl Trait` in traits and trait implementations capture all lifetimes in scope
+
+error: return type captures more lifetimes than trait definition
+  --> $DIR/rpitit-captures-more-method-lifetimes.rs:11:40
+   |
+LL |     fn bar<'im: 'im>(&'im mut self) -> impl Sized + 'im {}
+   |            ---                         ^^^^^^^^^^^^^^^^
+   |            |
+   |            this lifetime was captured
+   |
+note: hidden type must only reference lifetimes captured by this impl trait
+  --> $DIR/rpitit-captures-more-method-lifetimes.rs:6:40
+   |
+LL |     fn bar<'tr: 'tr>(&'tr mut self) -> impl Sized + use<Self>;
+   |                                        ^^^^^^^^^^^^^^^^^^^^^^
+   = note: hidden type inferred to be `impl Sized + 'im`
+
+warning: impl trait in impl method signature does not match trait method signature
+  --> $DIR/rpitit-captures-more-method-lifetimes.rs:11:40
+   |
+LL |     fn bar<'tr: 'tr>(&'tr mut self) -> impl Sized + use<Self>;
+   |                                        ---------------------- return type from trait method defined here
+...
+LL |     fn bar<'im: 'im>(&'im mut self) -> impl Sized + 'im {}
+   |                                        ^^^^^^^^^^^^^^^^
+   |
+   = note: add `#[allow(refining_impl_trait)]` if it is intended for this to be part of the public API of this crate
+   = note: we are soliciting feedback, see issue #121718 <https://github.com/rust-lang/rust/issues/121718> for more information
+   = note: `#[warn(refining_impl_trait_reachable)]` on by default
+help: replace the return type so that it matches the trait
+   |
+LL |     fn bar<'im: 'im>(&'im mut self) -> impl Sized {}
+   |                                        ~~~~~~~~~~
+
+error: aborting due to 2 previous errors; 1 warning emitted
+