Add some more tests

Author: oli-obk

tests/ui/traits/trait-upcasting/type-checking-test-4.rs

@@ -11,6 +11,10 @@ fn test_correct(x: &dyn Foo<'static>) {
     let _ = x as &dyn Bar<'static, 'static>;
 }
 
+fn test_correct2<'a>(x: &dyn Foo<'a>) {
+    let _ = x as &dyn Bar<'_, '_>;
+}
+
 fn test_wrong1<'a>(x: &dyn Foo<'static>, y: &'a u32) {
     let _ = x as &dyn Bar<'static, 'a>; // Error
                                         //~^ ERROR lifetime may not live long enough

tests/ui/traits/trait-upcasting/type-checking-test-4.stderr

@@ -1,21 +1,21 @@
 error: lifetime may not live long enough
-  --> $DIR/type-checking-test-4.rs:15:13
+  --> $DIR/type-checking-test-4.rs:19:13
    |
 LL | fn test_wrong1<'a>(x: &dyn Foo<'static>, y: &'a u32) {
    |                -- lifetime `'a` defined here
 LL |     let _ = x as &dyn Bar<'static, 'a>; // Error
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^ type annotation requires that `'a` must outlive `'static`
 
 error: lifetime may not live long enough
-  --> $DIR/type-checking-test-4.rs:20:13
+  --> $DIR/type-checking-test-4.rs:24:13
    |
 LL | fn test_wrong2<'a>(x: &dyn Foo<'static>, y: &'a u32) {
    |                -- lifetime `'a` defined here
 LL |     let _ = x as &dyn Bar<'a, 'static>; // Error
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^ type annotation requires that `'a` must outlive `'static`
 
 error: lifetime may not live long enough
-  --> $DIR/type-checking-test-4.rs:26:5
+  --> $DIR/type-checking-test-4.rs:30:5
    |
 LL | fn test_wrong3<'a>(x: &dyn Foo<'a>) -> Option<&'static u32> {
    |                -- lifetime `'a` defined here
@@ -24,23 +24,23 @@ LL |     y.get_b() // ERROR
    |     ^^^^^^^^^ returning this value requires that `'a` must outlive `'static`
 
 error: lifetime may not live long enough
-  --> $DIR/type-checking-test-4.rs:31:5
+  --> $DIR/type-checking-test-4.rs:35:5
    |
 LL | fn test_wrong4<'a>(x: &dyn Foo<'a>) -> Option<&'static u32> {
    |                -- lifetime `'a` defined here
 LL |     <_ as Bar>::get_b(x) // ERROR
    |     ^^^^^^^^^^^^^^^^^^^^ returning this value requires that `'a` must outlive `'static`
 
 error: lifetime may not live long enough
-  --> $DIR/type-checking-test-4.rs:36:5
+  --> $DIR/type-checking-test-4.rs:40:5
    |
 LL | fn test_wrong5<'a>(x: &dyn Foo<'a>) -> Option<&'static u32> {
    |                -- lifetime `'a` defined here
 LL |     <_ as Bar<'_, '_>>::get_b(x) // ERROR
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ returning this value requires that `'a` must outlive `'static`
 
 error: lifetime may not live long enough
-  --> $DIR/type-checking-test-4.rs:44:5
+  --> $DIR/type-checking-test-4.rs:48:5
    |
 LL | fn test_wrong6<'a>(x: &dyn Foo<'a>) -> Option<&'static u32> {
    |                -- lifetime `'a` defined here

tests/ui/traits/trait-upcasting/type-checking-test-opaques.rs

@@ -0,0 +1,21 @@
+#![feature(trait_upcasting, type_alias_impl_trait)]
+
+type Tait = impl Sized;
+
+trait Foo<'a>: Bar<'a, 'a, Tait> {}
+trait Bar<'a, 'b, T> {}
+
+fn test_correct(x: &dyn Foo<'static>) {
+    let _ = x as &dyn Bar<'static, 'static, Tait>;
+}
+
+fn test_correct2<'a>(x: &dyn Foo<'a>) {
+    let _ = x as &dyn Bar<'_, '_, Tait>;
+}
+
+fn test_correct3<'a>(x: &dyn Foo<'a>, _: Tait) {
+    let _ = x as &dyn Bar<'_, '_, ()>;
+    //~^ ERROR: non-primitive cast
+}
+
+fn main() {}

tests/ui/traits/trait-upcasting/type-checking-test-opaques.stderr

@@ -0,0 +1,9 @@
+error[E0605]: non-primitive cast: `&dyn Foo<'a>` as `&dyn Bar<'_, '_, ()>`
+  --> $DIR/type-checking-test-opaques.rs:17:13
+   |
+LL |     let _ = x as &dyn Bar<'_, '_, ()>;
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^ an `as` expression can only be used to convert between primitive types or to coerce to a specific trait object
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0605`.