[implied_bounds_in_impls]: move to nursery and fix ICEs

tests/ui/crashes/ice-11422.fixed

@@ -0,0 +1,25 @@
+#![warn(clippy::implied_bounds_in_impls)]
+
+use std::fmt::Debug;
+use std::ops::*;
+
+fn gen() -> impl PartialOrd + Debug {}
+
+struct Bar {}
+trait Foo<T = Self> {}
+trait FooNested<T = Option<Self>> {}
+impl Foo for Bar {}
+impl FooNested for Bar {}
+
+fn foo() -> impl Foo + FooNested {
+    Bar {}
+}
+
+fn test_impl_ops() -> impl Add + Sub + Mul + Div {
+    1
+}
+fn test_impl_assign_ops() -> impl AddAssign + SubAssign + MulAssign + DivAssign {
+    1
+}
+
+fn main() {}

tests/ui/crashes/ice-11422.rs

@@ -0,0 +1,25 @@
+#![warn(clippy::implied_bounds_in_impls)]
+
+use std::fmt::Debug;
+use std::ops::*;
+
+fn gen() -> impl PartialOrd + PartialEq + Debug {}
+
+struct Bar {}
+trait Foo<T = Self> {}
+trait FooNested<T = Option<Self>> {}
+impl Foo for Bar {}
+impl FooNested for Bar {}
+
+fn foo() -> impl Foo + FooNested {
+    Bar {}
+}
+
+fn test_impl_ops() -> impl Add + Sub + Mul + Div {
+    1
+}
+fn test_impl_assign_ops() -> impl AddAssign + SubAssign + MulAssign + DivAssign {
+    1
+}
+
+fn main() {}

tests/ui/crashes/ice-11422.stderr

@@ -0,0 +1,15 @@
+error: this bound is already specified as the supertrait of `PartialOrd`
+  --> $DIR/ice-11422.rs:6:31
+   |
+LL | fn gen() -> impl PartialOrd + PartialEq + Debug {}
+   |                               ^^^^^^^^^
+   |
+   = note: `-D clippy::implied-bounds-in-impls` implied by `-D warnings`
+help: try removing this bound
+   |
+LL - fn gen() -> impl PartialOrd + PartialEq + Debug {}
+LL + fn gen() -> impl PartialOrd + Debug {}
+   |
+
+error: aborting due to previous error
+

tests/ui/implied_bounds_in_impls.fixed

@@ -65,4 +65,22 @@ impl SomeTrait for SomeStruct {
     }
 }
 
+mod issue11422 {
+    use core::fmt::Debug;
+    // Some additional tests that would cause ICEs:
+
+    // `PartialOrd` has a default generic parameter and does not need to be explicitly specified.
+    // This needs special handling.
+    fn default_generic_param1() -> impl PartialOrd + Debug {}
+    fn default_generic_param2() -> impl PartialOrd + Debug {}
+
+    // Referring to `Self` in the supertrait clause needs special handling.
+    trait Trait1<X: ?Sized> {}
+    trait Trait2: Trait1<Self> {}
+    impl Trait1<()> for () {}
+    impl Trait2 for () {}
+
+    fn f() -> impl Trait1<()> + Trait2 {}
+}
+
 fn main() {}

tests/ui/implied_bounds_in_impls.rs

@@ -65,4 +65,22 @@ impl SomeTrait for SomeStruct {
     }
 }
 
+mod issue11422 {
+    use core::fmt::Debug;
+    // Some additional tests that would cause ICEs:
+
+    // `PartialOrd` has a default generic parameter and does not need to be explicitly specified.
+    // This needs special handling.
+    fn default_generic_param1() -> impl PartialEq + PartialOrd + Debug {}
+    fn default_generic_param2() -> impl PartialOrd + PartialEq + Debug {}
+
+    // Referring to `Self` in the supertrait clause needs special handling.
+    trait Trait1<X: ?Sized> {}
+    trait Trait2: Trait1<Self> {}
+    impl Trait1<()> for () {}
+    impl Trait2 for () {}
+
+    fn f() -> impl Trait1<()> + Trait2 {}
+}
+
 fn main() {}

tests/ui/implied_bounds_in_impls.stderr

@@ -119,5 +119,29 @@ LL -     fn f() -> impl Deref + DerefMut<Target = u8> {
 LL +     fn f() -> impl DerefMut<Target = u8> {
    |
 
-error: aborting due to 10 previous errors
+error: this bound is already specified as the supertrait of `PartialOrd`
+  --> $DIR/implied_bounds_in_impls.rs:74:41
+   |
+LL |     fn default_generic_param1() -> impl PartialEq + PartialOrd + Debug {}
+   |                                         ^^^^^^^^^
+   |
+help: try removing this bound
+   |
+LL -     fn default_generic_param1() -> impl PartialEq + PartialOrd + Debug {}
+LL +     fn default_generic_param1() -> impl PartialOrd + Debug {}
+   |
+
+error: this bound is already specified as the supertrait of `PartialOrd`
+  --> $DIR/implied_bounds_in_impls.rs:75:54
+   |
+LL |     fn default_generic_param2() -> impl PartialOrd + PartialEq + Debug {}
+   |                                                      ^^^^^^^^^
+   |
+help: try removing this bound
+   |
+LL -     fn default_generic_param2() -> impl PartialOrd + PartialEq + Debug {}
+LL +     fn default_generic_param2() -> impl PartialOrd + Debug {}
+   |
+
+error: aborting due to 12 previous errors