Detect when 'static obligation might come from an impl

Address #71341.

src/test/ui/suggestions/impl-on-dyn-trait-with-implicit-static-bound.rs

@@ -0,0 +1,37 @@
+// run-rustfix
+#![allow(dead_code)]
+
+mod foo {
+    trait OtherTrait<'a> {}
+    impl<'a> OtherTrait<'a> for &'a () {}
+
+    trait ObjectTrait {}
+    trait MyTrait {
+        fn use_self(&self) -> &();
+    }
+
+    impl MyTrait for dyn ObjectTrait {
+        fn use_self(&self) -> &() { panic!() }
+    }
+
+    fn use_it<'a>(val: &'a dyn ObjectTrait) -> impl OtherTrait<'a> + 'a {
+        val.use_self() //~ ERROR cannot infer an appropriate lifetime
+    }
+}
+
+mod bar {
+    trait ObjectTrait {}
+    trait MyTrait {
+        fn use_self(&self) -> &();
+    }
+
+    impl MyTrait for dyn ObjectTrait {
+        fn use_self(&self) -> &() { panic!() }
+    }
+
+    fn use_it<'a>(val: &'a dyn ObjectTrait) -> &'a () {
+        val.use_self() //~ ERROR cannot infer an appropriate lifetime
+    }
+}
+
+fn main() {}