add test for #106874 ICE BoundUniversalRegionError

Fixes #106874

Author: matthiaskrgr

tests/ui/nll/ice-106874.rs

@@ -0,0 +1,48 @@
+// issue: rust-lang/rust#106874
+// ICE BoundUniversalRegionError
+
+use std::marker::PhantomData;
+use std::rc::Rc;
+
+pub fn func<V, F: Fn(&mut V)>(f: F) -> A<impl X> {
+    A(B(C::new(D::new(move |st| f(st)))))
+    //~^ ERROR implementation of `FnOnce` is not general enough
+    //~^^ ERROR implementation of `Fn` is not general enough
+    //~^^^ ERROR implementation of `FnOnce` is not general enough
+    //~^^^^ ERROR implementation of `FnOnce` is not general enough
+    //~^^^^^ ERROR implementation of `Fn` is not general enough
+    //~^^^^^^ ERROR implementation of `FnOnce` is not general enough
+    //~^^^^^^^ ERROR implementation of `Fn` is not general enough
+    //~^^^^^^^^ ERROR implementation of `FnOnce` is not general enough
+    //~^^^^^^^^^ ERROR higher-ranked subtype error
+    //~^^^^^^^^^^ ERROR higher-ranked subtype error
+}
+
+trait X {}
+trait Y {
+    type V;
+}
+
+struct A<T>(T);
+
+struct B<T>(Rc<T>);
+impl<T> X for B<T> {}
+
+struct C<T: Y>(T::V);
+impl<T: Y> C<T> {
+    fn new(_: T) -> Rc<Self> {
+        todo!()
+    }
+}
+struct D<V, F>(F, PhantomData<fn(&mut V)>);
+
+impl<V, F> D<V, F> {
+    fn new(_: F) -> Self {
+        todo!()
+    }
+}
+impl<V, F: Fn(&mut V)> Y for D<V, F> {
+    type V = V;
+}
+
+pub fn main() {}

tests/ui/nll/ice-106874.stderr

@@ -0,0 +1,90 @@
+error: implementation of `FnOnce` is not general enough
+  --> $DIR/ice-106874.rs:8:5
+   |
+LL |     A(B(C::new(D::new(move |st| f(st)))))
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ implementation of `FnOnce` is not general enough
+   |
+   = note: closure with signature `fn(&'0 mut V)` must implement `FnOnce<(&mut V,)>`, for some specific lifetime `'0`...
+   = note: ...but it actually implements `FnOnce<(&'1 mut V,)>`, for some specific lifetime `'1`
+
+error: implementation of `FnOnce` is not general enough
+  --> $DIR/ice-106874.rs:8:5
+   |
+LL |     A(B(C::new(D::new(move |st| f(st)))))
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ implementation of `FnOnce` is not general enough
+   |
+   = note: closure with signature `fn(&'0 mut V)` must implement `FnOnce<(&mut V,)>`, for some specific lifetime `'0`...
+   = note: ...but it actually implements `FnOnce<(&'1 mut V,)>`, for some specific lifetime `'1`
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
+error: implementation of `Fn` is not general enough
+  --> $DIR/ice-106874.rs:8:7
+   |
+LL |     A(B(C::new(D::new(move |st| f(st)))))
+   |       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ implementation of `Fn` is not general enough
+   |
+   = note: closure with signature `fn(&'2 mut V)` must implement `Fn<(&'1 mut V,)>`, for any lifetime `'1`...
+   = note: ...but it actually implements `Fn<(&'2 mut V,)>`, for some specific lifetime `'2`
+
+error: implementation of `FnOnce` is not general enough
+  --> $DIR/ice-106874.rs:8:7
+   |
+LL |     A(B(C::new(D::new(move |st| f(st)))))
+   |       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ implementation of `FnOnce` is not general enough
+   |
+   = note: closure with signature `fn(&'2 mut V)` must implement `FnOnce<(&'1 mut V,)>`, for any lifetime `'1`...
+   = note: ...but it actually implements `FnOnce<(&'2 mut V,)>`, for some specific lifetime `'2`
+
+error: implementation of `Fn` is not general enough
+  --> $DIR/ice-106874.rs:8:7
+   |
+LL |     A(B(C::new(D::new(move |st| f(st)))))
+   |       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ implementation of `Fn` is not general enough
+   |
+   = note: closure with signature `fn(&'2 mut V)` must implement `Fn<(&'1 mut V,)>`, for any lifetime `'1`...
+   = note: ...but it actually implements `Fn<(&'2 mut V,)>`, for some specific lifetime `'2`
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
+error: implementation of `FnOnce` is not general enough
+  --> $DIR/ice-106874.rs:8:9
+   |
+LL |     A(B(C::new(D::new(move |st| f(st)))))
+   |         ^^^^^^ implementation of `FnOnce` is not general enough
+   |
+   = note: closure with signature `fn(&'2 mut V)` must implement `FnOnce<(&'1 mut V,)>`, for any lifetime `'1`...
+   = note: ...but it actually implements `FnOnce<(&'2 mut V,)>`, for some specific lifetime `'2`
+
+error: implementation of `Fn` is not general enough
+  --> $DIR/ice-106874.rs:8:9
+   |
+LL |     A(B(C::new(D::new(move |st| f(st)))))
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ implementation of `Fn` is not general enough
+   |
+   = note: closure with signature `fn(&'2 mut V)` must implement `Fn<(&'1 mut V,)>`, for any lifetime `'1`...
+   = note: ...but it actually implements `Fn<(&'2 mut V,)>`, for some specific lifetime `'2`
+
+error: implementation of `FnOnce` is not general enough
+  --> $DIR/ice-106874.rs:8:9
+   |
+LL |     A(B(C::new(D::new(move |st| f(st)))))
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ implementation of `FnOnce` is not general enough
+   |
+   = note: closure with signature `fn(&'2 mut V)` must implement `FnOnce<(&'1 mut V,)>`, for any lifetime `'1`...
+   = note: ...but it actually implements `FnOnce<(&'2 mut V,)>`, for some specific lifetime `'2`
+
+error: higher-ranked subtype error
+  --> $DIR/ice-106874.rs:8:41
+   |
+LL |     A(B(C::new(D::new(move |st| f(st)))))
+   |                                         ^
+
+error: higher-ranked subtype error
+  --> $DIR/ice-106874.rs:8:41
+   |
+LL |     A(B(C::new(D::new(move |st| f(st)))))
+   |                                         ^
+   |
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
+error: aborting due to 10 previous errors
+