Prevent ICE in case of a bound constraint on generic argument (rust-lang#13722)

Fix rust-lang#13706

changelog: [`trait_duplication_in_bounds`]: fix ICE on duplicate type or
constant bound

Author: llogiq

clippy_utils/src/hir_utils.rs

@@ -603,11 +603,7 @@ impl HirEqInterExpr<'_, '_, '_> {
     }
 
     fn eq_assoc_type_binding(&mut self, left: &AssocItemConstraint<'_>, right: &AssocItemConstraint<'_>) -> bool {
-        left.ident.name == right.ident.name
-            && self.eq_ty(
-                left.ty().expect("expected assoc type binding"),
-                right.ty().expect("expected assoc type binding"),
-            )
+        left.ident.name == right.ident.name && both_some_and(left.ty(), right.ty(), |l, r| self.eq_ty(l, r))
     }
 
     fn check_ctxt(&mut self, left: SyntaxContext, right: SyntaxContext) -> bool {
@@ -727,6 +723,11 @@ pub fn both<X>(l: Option<&X>, r: Option<&X>, mut eq_fn: impl FnMut(&X, &X) -> bo
         .map_or_else(|| r.is_none(), |x| r.as_ref().is_some_and(|y| eq_fn(x, y)))
 }
 
+/// Checks if the two `Option`s are both `Some` and pass the predicate function.
+pub fn both_some_and<X, Y>(l: Option<X>, r: Option<Y>, mut pred: impl FnMut(X, Y) -> bool) -> bool {
+    l.is_some_and(|l| r.is_some_and(|r| pred(l, r)))
+}
+
 /// Checks if two slices are equal as per `eq_fn`.
 pub fn over<X>(left: &[X], right: &[X], mut eq_fn: impl FnMut(&X, &X) -> bool) -> bool {
     left.len() == right.len() && left.iter().zip(right).all(|(x, y)| eq_fn(x, y))

tests/ui/trait_duplication_in_bounds.fixed

@@ -1,6 +1,6 @@
 #![deny(clippy::trait_duplication_in_bounds)]
 #![allow(unused)]
-#![feature(const_trait_impl)]
+#![feature(associated_const_equality, const_trait_impl)]
 
 use std::any::Any;
 
@@ -179,3 +179,18 @@ fn main() {
     let _x: fn(_) = f::<()>;
     let _x: fn(_) = f::<i32>;
 }
+
+// #13706
+fn assoc_tys_bounds<T>()
+where
+    T: Iterator<Item: Clone> + Iterator<Item: Clone>,
+{
+}
+trait AssocConstTrait {
+    const ASSOC: usize;
+}
+fn assoc_const_args<T>()
+where
+    T: AssocConstTrait<ASSOC = 0> + AssocConstTrait<ASSOC = 0>,
+{
+}

tests/ui/trait_duplication_in_bounds.rs

@@ -1,6 +1,6 @@
 #![deny(clippy::trait_duplication_in_bounds)]
 #![allow(unused)]
-#![feature(const_trait_impl)]
+#![feature(associated_const_equality, const_trait_impl)]
 
 use std::any::Any;
 
@@ -179,3 +179,18 @@ fn main() {
     let _x: fn(_) = f::<()>;
     let _x: fn(_) = f::<i32>;
 }
+
+// #13706
+fn assoc_tys_bounds<T>()
+where
+    T: Iterator<Item: Clone> + Iterator<Item: Clone>,
+{
+}
+trait AssocConstTrait {
+    const ASSOC: usize;
+}
+fn assoc_const_args<T>()
+where
+    T: AssocConstTrait<ASSOC = 0> + AssocConstTrait<ASSOC = 0>,
+{
+}