prove both newly added tests are fixed by the changes

Author: jdonszelmann

tests/ui/dst/dst-object-from-unsized-type.stderr renamed to tests/ui/dst/dst-object-from-unsized-type.current.stderr

@@ -1,5 +1,5 @@
 error[E0277]: the size for values of type `T` cannot be known at compilation time
-  --> $DIR/dst-object-from-unsized-type.rs:8:23
+  --> $DIR/dst-object-from-unsized-type.rs:11:23
    |
 LL | fn test1<T: ?Sized + Foo>(t: &T) {
    |          - this type parameter needs to be `Sized`
@@ -14,7 +14,7 @@ LL + fn test1<T: Foo>(t: &T) {
    |
 
 error[E0277]: the size for values of type `T` cannot be known at compilation time
-  --> $DIR/dst-object-from-unsized-type.rs:13:23
+  --> $DIR/dst-object-from-unsized-type.rs:16:23
    |
 LL | fn test2<T: ?Sized + Foo>(t: &T) {
    |          - this type parameter needs to be `Sized`
@@ -29,7 +29,7 @@ LL + fn test2<T: Foo>(t: &T) {
    |
 
 error[E0277]: the size for values of type `str` cannot be known at compilation time
-  --> $DIR/dst-object-from-unsized-type.rs:18:28
+  --> $DIR/dst-object-from-unsized-type.rs:21:28
    |
 LL |     let _: &[&dyn Foo] = &["hi"];
    |                            ^^^^ doesn't have a size known at compile-time
@@ -38,7 +38,7 @@ LL |     let _: &[&dyn Foo] = &["hi"];
    = note: required for the cast from `&'static str` to `&dyn Foo`
 
 error[E0277]: the size for values of type `[u8]` cannot be known at compilation time
-  --> $DIR/dst-object-from-unsized-type.rs:23:23
+  --> $DIR/dst-object-from-unsized-type.rs:26:23
    |
 LL |     let _: &dyn Foo = x as &dyn Foo;
    |                       ^ doesn't have a size known at compile-time

tests/ui/dst/dst-object-from-unsized-type.next.stderr

@@ -0,0 +1,41 @@
+error[E0308]: mismatched types
+  --> $DIR/dst-object-from-unsized-type.rs:11:23
+   |
+LL | fn test1<T: ?Sized + Foo>(t: &T) {
+   |          - found this type parameter
+LL |     let u: &dyn Foo = t;
+   |            --------   ^ expected `&dyn Foo`, found `&T`
+   |            |
+   |            expected due to this
+   |
+   = note: expected reference `&dyn Foo`
+              found reference `&T`
+   = help: type parameters must be constrained to match other types
+   = note: for more information, visit https://doc.rust-lang.org/book/ch10-02-traits.html#traits-as-parameters
+
+error[E0605]: non-primitive cast: `&T` as `&dyn Foo`
+  --> $DIR/dst-object-from-unsized-type.rs:16:23
+   |
+LL |     let v: &dyn Foo = t as &dyn Foo;
+   |                       ^^^^^^^^^^^^^ an `as` expression can only be used to convert between primitive types or to coerce to a specific trait object
+
+error[E0308]: mismatched types
+  --> $DIR/dst-object-from-unsized-type.rs:21:28
+   |
+LL |     let _: &[&dyn Foo] = &["hi"];
+   |                            ^^^^ expected `&dyn Foo`, found `&str`
+   |
+   = note: expected reference `&dyn Foo`
+              found reference `&'static str`
+   = help: `str` implements `Foo` so you could box the found value and coerce it to the trait object `Box<dyn Foo>`, you will have to change the expected type as well
+
+error[E0605]: non-primitive cast: `&[u8]` as `&dyn Foo`
+  --> $DIR/dst-object-from-unsized-type.rs:26:23
+   |
+LL |     let _: &dyn Foo = x as &dyn Foo;
+   |                       ^^^^^^^^^^^^^ an `as` expression can only be used to convert between primitive types or to coerce to a specific trait object
+
+error: aborting due to 4 previous errors
+
+Some errors have detailed explanations: E0308, E0605.
+For more information about an error, try `rustc --explain E0308`.

tests/ui/traits/next-solver/unsize-goal-mismatch-2.next.stderr

@@ -0,0 +1,13 @@
+error[E0283]: type annotations needed: cannot satisfy `dyn Trait<&()>: Unsize<dyn Super<&()>>`
+  --> $DIR/unsize-goal-mismatch-2.rs:14:5
+   |
+LL |     x
+   |     ^
+   |
+   = note: cannot satisfy `dyn Trait<&()>: Unsize<dyn Super<&()>>`
+   = note: required for `Box<dyn Trait<&()>>` to implement `CoerceUnsized<Box<dyn Super<&()>>>`
+   = note: required for the cast from `Box<(dyn Trait<&'a ()> + 'static)>` to `Box<(dyn Super<&'a ()> + 'static)>`
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0283`.

tests/ui/traits/next-solver/unsize-goal-mismatch-2.rs

@@ -1,7 +1,7 @@
-//@ check-pass
 //@ revisions: current next
 //@ ignore-compare-mode-next-solver (explicit revisions)
 //@[next] compile-flags: -Znext-solver
+//@[current] check-pass
 // Test from trait-system-refactor-initiative#241:
 // Used to ICE in mir typeck because of ambiguity in the new solver.
 // The wrong (first) trait bound was selected.
@@ -12,6 +12,7 @@ trait Trait<T>: Super<T> + for<'hr> Super<&'hr ()> {}
 
 fn foo<'a>(x: Box<dyn Trait<&'a ()>>) -> Box<dyn Super<&'a ()>> {
     x
+    //[next]~^ ERROR type annotations needed: cannot satisfy `dyn Trait<&()>: Unsize<dyn Super<&()>>`
 }
 
 fn main() {}

tests/ui/traits/next-solver/unsize-goal-mismatch.current.stderr

@@ -0,0 +1,17 @@
+error[E0283]: type annotations needed: cannot satisfy `Self: Super<'a>`
+  --> $DIR/unsize-goal-mismatch.rs:10:18
+   |
+LL | trait Trait<'a>: Super<'a> + for<'hr> Super<'hr> {}
+   |                  ^^^^^^^^^
+   |
+note: multiple `impl`s or `where` clauses satisfying `Self: Super<'a>` found
+  --> $DIR/unsize-goal-mismatch.rs:9:1
+   |
+LL | trait Super<'a> {}
+   | ^^^^^^^^^^^^^^^
+LL | trait Trait<'a>: Super<'a> + for<'hr> Super<'hr> {}
+   |                              ^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0283`.

tests/ui/traits/next-solver/unsize-goal-mismatch.next.stderr

@@ -0,0 +1,13 @@
+error[E0283]: type annotations needed: cannot satisfy `dyn Trait<'_>: Unsize<dyn Super<'_>>`
+  --> $DIR/unsize-goal-mismatch.rs:14:5
+   |
+LL |     x
+   |     ^
+   |
+   = note: cannot satisfy `dyn Trait<'_>: Unsize<dyn Super<'_>>`
+   = note: required for `Box<dyn Trait<'_>>` to implement `CoerceUnsized<Box<dyn Super<'_>>>`
+   = note: required for the cast from `Box<(dyn Trait<'a> + 'static)>` to `Box<(dyn Super<'a> + 'static)>`
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0283`.

tests/ui/traits/next-solver/unsize-goal-mismatch.rs

@@ -1,4 +1,3 @@
-//@ check-pass
 //@ revisions: current next
 //@ ignore-compare-mode-next-solver (explicit revisions)
 //@[next] compile-flags: -Znext-solver
@@ -9,10 +8,11 @@
 
 trait Super<'a> {}
 trait Trait<'a>: Super<'a> + for<'hr> Super<'hr> {}
+//[current]~^ ERROR type annotations needed: cannot satisfy `Self: Super<'a>`
 
 fn foo<'a>(x: Box<dyn Trait<'a>>) -> Box<dyn Super<'a>> {
     x
-    //~^ ERROR type annotations needed: cannot satisfy `dyn Trait<'_>: Unsize<dyn Super<'_>>
+    //[next]~^ ERROR type annotations needed: cannot satisfy `dyn Trait<'_>: Unsize<dyn Super<'_>>
 }
 
 fn main() {}

tests/ui/traits/next-solver/unsize-overflow.stderr

@@ -0,0 +1,12 @@
+error[E0275]: overflow evaluating the requirement `Box<&&&&&&&i32>: CoerceUnsized<Box<dyn Send>>`
+  --> $DIR/unsize-overflow.rs:5:28
+   |
+LL |     let _: Box<dyn Send> = Box::new(&&&&&&&1);
+   |                            ^^^^^^^^^^^^^^^^^^
+   |
+   = help: consider increasing the recursion limit by adding a `#![recursion_limit = "16"]` attribute to your crate (`unsize_overflow`)
+   = note: required for the cast from `Box<&&&&&&&i32>` to `Box<dyn Send>`
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0275`.