middle: print `{Meta,Pointee}Sized` in opaques

When `sized_hierarchy` is enabled, rustc should print `MetaSized` or
`PointeeSized` instead of `?Sized` in opaques.

4 files changed, 119 insertions, 0 deletions

diff --git a/tests/ui/sized-hierarchy/pretty-print-opaque-no-feat.rs b/tests/ui/sized-hierarchy/pretty-print-opaque-no-feat.rs
new file mode 100644
index 00000000000..955108a2074
--- /dev/null
+++ b/tests/ui/sized-hierarchy/pretty-print-opaque-no-feat.rs
@@ -0,0 +1,13 @@
+//@ compile-flags: --crate-type=lib
+
+pub trait Tr {}
+impl Tr for u32 {}
+
+pub fn foo() -> Box<impl Tr + ?Sized> {
+    if true {
+        let x = foo();
+        let y: Box<dyn Tr> = x;
+//~^ ERROR: the size for values of type `impl Tr + ?Sized` cannot be known
+    }
+    Box::new(1u32)
+}
diff --git a/tests/ui/sized-hierarchy/pretty-print-opaque-no-feat.stderr b/tests/ui/sized-hierarchy/pretty-print-opaque-no-feat.stderr
new file mode 100644
index 00000000000..bbe19870937
--- /dev/null
+++ b/tests/ui/sized-hierarchy/pretty-print-opaque-no-feat.stderr
@@ -0,0 +1,12 @@
+error[E0277]: the size for values of type `impl Tr + ?Sized` cannot be known at compilation time
+  --> $DIR/pretty-print-opaque-no-feat.rs:9:30
+   |
+LL |         let y: Box<dyn Tr> = x;
+   |                              ^ doesn't have a size known at compile-time
+   |
+   = help: the trait `Sized` is not implemented for `impl Tr + ?Sized`
+   = note: required for the cast from `Box<impl Tr + ?Sized>` to `Box<dyn Tr>`
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/tests/ui/sized-hierarchy/pretty-print-opaque.rs b/tests/ui/sized-hierarchy/pretty-print-opaque.rs
new file mode 100644
index 00000000000..7fad93efbd2
--- /dev/null
+++ b/tests/ui/sized-hierarchy/pretty-print-opaque.rs
@@ -0,0 +1,44 @@
+//@ compile-flags: --crate-type=lib
+#![feature(sized_hierarchy)]
+
+use std::marker::{MetaSized, PointeeSized};
+
+pub trait Tr: PointeeSized {}
+impl Tr for u32 {}
+
+pub fn sized() -> Box<impl Tr + Sized> {
+    if true {
+        let x = sized();
+        let y: Box<dyn Tr> = x;
+    }
+    Box::new(1u32)
+}
+
+pub fn neg_sized() -> Box<impl Tr + ?Sized> {
+    if true {
+        let x = neg_sized();
+        let y: Box<dyn Tr> = x;
+//~^ ERROR: the size for values of type `impl Tr + MetaSized` cannot be known
+    }
+    Box::new(1u32)
+}
+
+pub fn metasized() -> Box<impl Tr + MetaSized> {
+    if true {
+        let x = metasized();
+        let y: Box<dyn Tr> = x;
+//~^ ERROR: the size for values of type `impl Tr + MetaSized` cannot be known
+    }
+    Box::new(1u32)
+}
+
+pub fn pointeesized() -> Box<impl Tr + PointeeSized> {
+//~^ ERROR: the size for values of type `impl Tr + PointeeSized` cannot be known
+    if true {
+        let x = pointeesized();
+//~^ ERROR: the size for values of type `impl Tr + PointeeSized` cannot be known
+        let y: Box<dyn Tr> = x;
+//~^ ERROR: the size for values of type `impl Tr + PointeeSized` cannot be known
+    }
+    Box::new(1u32)
+}
diff --git a/tests/ui/sized-hierarchy/pretty-print-opaque.stderr b/tests/ui/sized-hierarchy/pretty-print-opaque.stderr
new file mode 100644
index 00000000000..523f6e7dd83
--- /dev/null
+++ b/tests/ui/sized-hierarchy/pretty-print-opaque.stderr
@@ -0,0 +1,50 @@
+error[E0277]: the size for values of type `impl Tr + PointeeSized` cannot be known
+  --> $DIR/pretty-print-opaque.rs:35:26
+   |
+LL | pub fn pointeesized() -> Box<impl Tr + PointeeSized> {
+   |                          ^^^^^^^^^^^^^^^^^^^^^^^^^^^ doesn't have a known size
+   |
+   = help: the trait `MetaSized` is not implemented for `impl Tr + PointeeSized`
+note: required by a bound in `Box`
+  --> $SRC_DIR/alloc/src/boxed.rs:LL:COL
+
+error[E0277]: the size for values of type `impl Tr + MetaSized` cannot be known at compilation time
+  --> $DIR/pretty-print-opaque.rs:20:30
+   |
+LL |         let y: Box<dyn Tr> = x;
+   |                              ^ doesn't have a size known at compile-time
+   |
+   = help: the trait `Sized` is not implemented for `impl Tr + MetaSized`
+   = note: required for the cast from `Box<impl Tr + MetaSized>` to `Box<dyn Tr>`
+
+error[E0277]: the size for values of type `impl Tr + MetaSized` cannot be known at compilation time
+  --> $DIR/pretty-print-opaque.rs:29:30
+   |
+LL |         let y: Box<dyn Tr> = x;
+   |                              ^ doesn't have a size known at compile-time
+   |
+   = help: the trait `Sized` is not implemented for `impl Tr + MetaSized`
+   = note: required for the cast from `Box<impl Tr + MetaSized>` to `Box<dyn Tr>`
+
+error[E0277]: the size for values of type `impl Tr + PointeeSized` cannot be known
+  --> $DIR/pretty-print-opaque.rs:38:17
+   |
+LL |         let x = pointeesized();
+   |                 ^^^^^^^^^^^^^^ doesn't have a known size
+   |
+   = help: the trait `MetaSized` is not implemented for `impl Tr + PointeeSized`
+note: required by a bound in `Box`
+  --> $SRC_DIR/alloc/src/boxed.rs:LL:COL
+
+error[E0277]: the size for values of type `impl Tr + PointeeSized` cannot be known at compilation time
+  --> $DIR/pretty-print-opaque.rs:40:30
+   |
+LL |         let y: Box<dyn Tr> = x;
+   |                              ^ doesn't have a size known at compile-time
+   |
+   = help: the trait `Sized` is not implemented for `impl Tr + PointeeSized`
+   = note: required for the cast from `Box<impl Tr + PointeeSized>` to `Box<dyn Tr>`
+
+error: aborting due to 5 previous errors
+
+For more information about this error, try `rustc --explain E0277`.