diff --git a/src/test/ui/existential_type.rs b/src/test/ui/existential_types/existential_type-pass.rs
similarity index 100%
rename from src/test/ui/existential_type.rs
rename to src/test/ui/existential_types/existential_type-pass.rs
diff --git a/src/test/ui/existential_types/issue-53678-generator-and-const-fn.rs b/src/test/ui/existential_types/issue-53678-generator-and-const-fn.rs
new file mode 100644
index 0000000000000..d964f2b74ff69
--- /dev/null
+++ b/src/test/ui/existential_types/issue-53678-generator-and-const-fn.rs
@@ -0,0 +1,19 @@
+// check-pass
+
+#![feature(const_fn, generators, generator_trait, existential_type)]
+
+use std::ops::Generator;
+
+existential type GenOnce<Y, R>: Generator<Yield = Y, Return = R>;
+
+const fn const_generator<Y, R>(yielding: Y, returning: R) -> GenOnce<Y, R> {
+    move || {
+        yield yielding;
+
+        return returning;
+    }
+}
+
+const FOO: GenOnce<usize, usize> = const_generator(10, 100);
+
+fn main() {}
diff --git a/src/test/ui/existential-type/issue-58887.rs b/src/test/ui/existential_types/issue-58887.rs
similarity index 100%
rename from src/test/ui/existential-type/issue-58887.rs
rename to src/test/ui/existential_types/issue-58887.rs
diff --git a/src/test/ui/existential-type/issue-58887.stderr b/src/test/ui/existential_types/issue-58887.stderr
similarity index 100%
rename from src/test/ui/existential-type/issue-58887.stderr
rename to src/test/ui/existential_types/issue-58887.stderr
diff --git a/src/test/ui/existential-type/issue-60371.rs b/src/test/ui/existential_types/issue-60371.rs
similarity index 100%
rename from src/test/ui/existential-type/issue-60371.rs
rename to src/test/ui/existential_types/issue-60371.rs
diff --git a/src/test/ui/existential-type/issue-60371.stderr b/src/test/ui/existential_types/issue-60371.stderr
similarity index 100%
rename from src/test/ui/existential-type/issue-60371.stderr
rename to src/test/ui/existential_types/issue-60371.stderr
diff --git a/src/test/ui/existential_types/issue-60407.rs b/src/test/ui/existential_types/issue-60407.rs
new file mode 100644
index 0000000000000..52162c491b5c8
--- /dev/null
+++ b/src/test/ui/existential_types/issue-60407.rs
@@ -0,0 +1,15 @@
+// check-pass
+
+#![feature(existential_type)]
+
+existential type Debuggable: core::fmt::Debug;
+
+static mut TEST: Option<Debuggable> = None;
+
+fn main() {
+    unsafe { TEST = Some(foo()) }
+}
+
+fn foo() -> Debuggable {
+    0u32
+}
diff --git a/src/test/ui/existential_types/issue-60564.rs b/src/test/ui/existential_types/issue-60564.rs
new file mode 100644
index 0000000000000..cb3914ddd1deb
--- /dev/null
+++ b/src/test/ui/existential_types/issue-60564.rs
@@ -0,0 +1,26 @@
+#![feature(existential_type)]
+
+trait IterBits {
+    type BitsIter: Iterator<Item = u8>;
+    fn iter_bits(self, n: u8) -> Self::BitsIter;
+}
+
+existential type IterBitsIter<T, E, I>: std::iter::Iterator<Item = I>;
+//~^ ERROR could not find defining uses
+
+impl<T, E> IterBits for T
+where
+    T: std::ops::Shr<Output = T>
+        + std::ops::BitAnd<T, Output = T>
+        + std::convert::From<u8>
+        + std::convert::TryInto<u8, Error = E>,
+    E: std::fmt::Debug,
+{
+    type BitsIter = IterBitsIter<T, E, u8>;
+    fn iter_bits(self, n: u8) -> Self::BitsIter {
+    //~^ ERROR type parameter `E` is part of concrete type but not used
+        (0u8..n)
+            .rev()
+            .map(move |shift| ((self >> T::from(shift)) & T::from(1)).try_into().unwrap())
+    }
+}
diff --git a/src/test/ui/existential_types/issue-60564.stderr b/src/test/ui/existential_types/issue-60564.stderr
new file mode 100644
index 0000000000000..d8480b521570a
--- /dev/null
+++ b/src/test/ui/existential_types/issue-60564.stderr
@@ -0,0 +1,25 @@
+error[E0601]: `main` function not found in crate `issue_60564`
+   |
+   = note: consider adding a `main` function to `$DIR/issue-60564.rs`
+
+error: type parameter `E` is part of concrete type but not used in parameter list for existential type
+  --> $DIR/issue-60564.rs:20:49
+   |
+LL |       fn iter_bits(self, n: u8) -> Self::BitsIter {
+   |  _________________________________________________^
+LL | |
+LL | |         (0u8..n)
+LL | |             .rev()
+LL | |             .map(move |shift| ((self >> T::from(shift)) & T::from(1)).try_into().unwrap())
+LL | |     }
+   | |_____^
+
+error: could not find defining uses
+  --> $DIR/issue-60564.rs:8:1
+   |
+LL | existential type IterBitsIter<T, E, I>: std::iter::Iterator<Item = I>;
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to 3 previous errors
+
+For more information about this error, try `rustc --explain E0601`.