1 files changed, 39 insertions, 0 deletions
diff --git a/compiler/rustc_lint_defs/src/builtin.rs b/compiler/rustc_lint_defs/src/builtin.rs
index 3747e562cec..96c31a90da8 100644
--- a/compiler/rustc_lint_defs/src/builtin.rs
+++ b/compiler/rustc_lint_defs/src/builtin.rs
@@ -3366,6 +3366,7 @@ declare_lint_pass! {
         BYTE_SLICE_IN_PACKED_STRUCT_WITH_DERIVE,
         CENUM_IMPL_DROP_CAST,
         COHERENCE_LEAK_CHECK,
+        COINDUCTIVE_OVERLAP_IN_COHERENCE,
         CONFLICTING_REPR_HINTS,
         CONST_EVALUATABLE_UNCHECKED,
         CONST_ITEM_MUTATION,
@@ -4423,6 +4424,44 @@ declare_lint! {
 }
 
 declare_lint! {
+    /// The `coinductive_overlap_in_coherence` lint detects impls which are currently
+    /// considered not overlapping, but may be considered to overlap if support for
+    /// coinduction is added to the trait solver.
+    ///
+    /// ### Example
+    ///
+    /// ```rust,compile_fail
+    /// #![deny(coinductive_overlap_in_coherence)]
+    ///
+    /// trait CyclicTrait {}
+    /// impl<T: CyclicTrait> CyclicTrait for T {}
+    ///
+    /// trait Trait {}
+    /// impl<T: CyclicTrait> Trait for T {}
+    /// // conflicting impl with the above
+    /// impl Trait for u8 {}
+    /// ```
+    ///
+    /// {{produces}}
+    ///
+    /// ### Explanation
+    ///
+    /// We have two choices for impl which satisfy `u8: Trait`: the blanket impl
+    /// for generic `T`, and the direct impl for `u8`. These two impls nominally
+    /// overlap, since we can infer `T = u8` in the former impl, but since the where
+    /// clause `u8: CyclicTrait` would end up resulting in a cycle (since it depends
+    /// on itself), the blanket impl is not considered to hold for `u8`. This will
+    /// change in a future release.
+    pub COINDUCTIVE_OVERLAP_IN_COHERENCE,
+    Warn,
+    "impls that are not considered to overlap may be considered to \
+    overlap in the future",
+    @future_incompatible = FutureIncompatibleInfo {
+        reference: "issue #114040 <https://github.com/rust-lang/rust/issues/114040>",
+    };
+}
+
+declare_lint! {
     /// The `unknown_diagnostic_attributes` lint detects unrecognized diagnostic attributes.
     ///
     /// ### Example