diff --git a/src/test/ui/issues/issue-58887.rs b/src/test/ui/existential-type/issue-58887.rs
similarity index 69%
rename from src/test/ui/issues/issue-58887.rs
rename to src/test/ui/existential-type/issue-58887.rs
index ca2374af7bdc1..f038648ec2149 100644
--- a/src/test/ui/issues/issue-58887.rs
+++ b/src/test/ui/existential-type/issue-58887.rs
@@ -1,8 +1,8 @@
 #![feature(existential_type)]
 
 trait UnwrapItemsExt {
-    type II;
-    fn unwrap_items(self) -> Self::II;
+    type Iter;
+    fn unwrap_items(self) -> Self::Iter;
 }
 
 impl<I, T, E> UnwrapItemsExt for I
@@ -10,12 +10,14 @@ where
     I: Iterator<Item = Result<T, E>>,
     E: std::fmt::Debug,
 {
-    existential type II: Iterator<Item = T>;
+    existential type Iter: Iterator<Item = T>;
     //~^ ERROR: could not find defining uses
 
-    fn unwrap_items(self) -> Self::II {
+    fn unwrap_items(self) -> Self::Iter {
     //~^ ERROR: type parameter `T` is part of concrete type
     //~| ERROR: type parameter `E` is part of concrete type
         self.map(|x| x.unwrap())
     }
 }
+
+fn main() {}
diff --git a/src/test/ui/existential-type/issue-58887.stderr b/src/test/ui/existential-type/issue-58887.stderr
new file mode 100644
index 0000000000000..800f4b7e059fb
--- /dev/null
+++ b/src/test/ui/existential-type/issue-58887.stderr
@@ -0,0 +1,30 @@
+error: type parameter `T` is part of concrete type but not used in parameter list for existential type
+  --> $DIR/issue-58887.rs:16:41
+   |
+LL |       fn unwrap_items(self) -> Self::Iter {
+   |  _________________________________________^
+LL | |
+LL | |
+LL | |         self.map(|x| x.unwrap())
+LL | |     }
+   | |_____^
+
+error: type parameter `E` is part of concrete type but not used in parameter list for existential type
+  --> $DIR/issue-58887.rs:16:41
+   |
+LL |       fn unwrap_items(self) -> Self::Iter {
+   |  _________________________________________^
+LL | |
+LL | |
+LL | |         self.map(|x| x.unwrap())
+LL | |     }
+   | |_____^
+
+error: could not find defining uses
+  --> $DIR/issue-58887.rs:13:5
+   |
+LL |     existential type Iter: Iterator<Item = T>;
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to 3 previous errors
+
diff --git a/src/test/ui/issues/issue-58887.stderr b/src/test/ui/issues/issue-58887.stderr
deleted file mode 100644
index 8cb25d84f54ad..0000000000000
--- a/src/test/ui/issues/issue-58887.stderr
+++ /dev/null
@@ -1,35 +0,0 @@
-error[E0601]: `main` function not found in crate `issue_58887`
-   |
-   = note: consider adding a `main` function to `$DIR/issue-58887.rs`
-
-error: type parameter `T` is part of concrete type but not used in parameter list for existential type
-  --> $DIR/issue-58887.rs:16:39
-   |
-LL |       fn unwrap_items(self) -> Self::II {
-   |  _______________________________________^
-LL | |
-LL | |
-LL | |         self.map(|x| x.unwrap())
-LL | |     }
-   | |_____^
-
-error: type parameter `E` is part of concrete type but not used in parameter list for existential type
-  --> $DIR/issue-58887.rs:16:39
-   |
-LL |       fn unwrap_items(self) -> Self::II {
-   |  _______________________________________^
-LL | |
-LL | |
-LL | |         self.map(|x| x.unwrap())
-LL | |     }
-   | |_____^
-
-error: could not find defining uses
-  --> $DIR/issue-58887.rs:13:5
-   |
-LL |     existential type II: Iterator<Item = T>;
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-
-error: aborting due to 4 previous errors
-
-For more information about this error, try `rustc --explain E0601`.