Test all the things

src/test/ui/existential_types/generic_duplicate_param_use.stderr

@@ -1,9 +0,0 @@
-error[E0091]: type parameter `U` is unused
-  --> $DIR/generic_duplicate_param_use.rs:5:25
-   |
-LL | existential type Two<T, U>: 'static; //~ ERROR type parameter `U` is unused
-   |                         ^ unused type parameter
-
-error: aborting due to previous error
-
-For more information about this error, try `rustc --explain E0091`.

src/test/ui/existential_types/generic_duplicate_param_use2.rs

@@ -0,0 +1,15 @@
+// compile-pass
+#![feature(existential_type)]
+
+fn main() {}
+
+// test that unused generic parameters are ok
+existential type Two<T, U>: 'static;
+
+fn one<T: 'static>(t: T) -> Two<T, T> {
+    t
+}
+
+fn two<T: 'static, U: 'static>(t: T, _: U) -> Two<T, U> {
+    t
+}

src/test/ui/existential_types/generic_duplicate_param_use3.rs

@@ -0,0 +1,19 @@
+#![feature(existential_type)]
+
+fn main() {}
+
+// test that unused generic parameters are ok
+existential type Two<T, U>: 'static;
+
+fn one<T: 'static>(t: T) -> Two<T, T> {
+    t
+}
+
+fn two<T: 'static, U: 'static>(t: T, _: U) -> Two<T, U> {
+    t
+}
+
+fn three<T: 'static, U: 'static>(_: T, u: U) -> Two<T, U> {
+    //~^ ERROR defining existential type use differs from previous
+    u
+}

src/test/ui/existential_types/generic_duplicate_param_use3.stderr

@@ -0,0 +1,19 @@
+error: defining existential type use differs from previous
+  --> $DIR/generic_duplicate_param_use3.rs:16:1
+   |
+LL | / fn three<T: 'static, U: 'static>(_: T, u: U) -> Two<T, U> {
+LL | |     //~^ ERROR defining existential type use differs from previous
+LL | |     u
+LL | | }
+   | |_^
+   |
+note: previous use here
+  --> $DIR/generic_duplicate_param_use3.rs:8:1
+   |
+LL | / fn one<T: 'static>(t: T) -> Two<T, T> {
+LL | |     t
+LL | | }
+   | |_^
+
+error: aborting due to previous error
+

src/test/ui/existential_types/generic_duplicate_param_use4.rs

@@ -0,0 +1,15 @@
+#![feature(existential_type)]
+
+fn main() {}
+
+// test that unused generic parameters are ok
+existential type Two<T, U>: 'static;
+
+fn one<T: 'static>(t: T) -> Two<T, T> {
+    t
+}
+
+fn three<T: 'static, U: 'static>(_: T, u: U) -> Two<T, U> {
+//~^ ERROR defining existential type use differs from previous
+    u
+}

src/test/ui/existential_types/generic_duplicate_param_use4.stderr

@@ -0,0 +1,19 @@
+error: defining existential type use differs from previous
+  --> $DIR/generic_duplicate_param_use4.rs:12:1
+   |
+LL | / fn three<T: 'static, U: 'static>(_: T, u: U) -> Two<T, U> {
+LL | | //~^ ERROR defining existential type use differs from previous
+LL | |     u
+LL | | }
+   | |_^
+   |
+note: previous use here
+  --> $DIR/generic_duplicate_param_use4.rs:8:1
+   |
+LL | / fn one<T: 'static>(t: T) -> Two<T, T> {
+LL | |     t
+LL | | }
+   | |_^
+
+error: aborting due to previous error
+

src/test/ui/existential_types/unused_generic_param.stderr

@@ -1,15 +0,0 @@
-error[E0091]: type parameter `T` is unused
-  --> $DIR/unused_generic_param.rs:6:35
-   |
-LL | existential type PartiallyDefined<T>: 'static; //~ `T` is unused
-   |                                   ^ unused type parameter
-
-error[E0091]: type parameter `T` is unused
-  --> $DIR/unused_generic_param.rs:12:36
-   |
-LL | existential type PartiallyDefined2<T>: 'static; //~ `T` is unused
-   |                                    ^ unused type parameter
-
-error: aborting due to 2 previous errors
-
-For more information about this error, try `rustc --explain E0091`.