1 files changed, 43 insertions, 0 deletions
diff --git a/src/test/ui/coercion/coerce-expect-unsized.rs b/src/test/ui/coercion/coerce-expect-unsized.rs
new file mode 100644
index 000000000..eeb8fe823
--- /dev/null
+++ b/src/test/ui/coercion/coerce-expect-unsized.rs
@@ -0,0 +1,43 @@
+// run-pass
+#![allow(unused_braces)]
+
+use std::cell::RefCell;
+use std::fmt::Debug;
+use std::rc::Rc;
+
+// Check that coercions apply at the pointer level and don't cause
+// rvalue expressions to be unsized. See #20169 for more information.
+
+pub fn main() {
+    let _: Box<[isize]> = Box::new({ [1, 2, 3] });
+    let _: Box<[isize]> = Box::new(if true { [1, 2, 3] } else { [1, 3, 4] });
+    let _: Box<[isize]> = Box::new(match true { true => [1, 2, 3], false => [1, 3, 4] });
+    let _: Box<dyn Fn(isize) -> _> = Box::new({ |x| (x as u8) });
+    let _: Box<dyn Debug> = Box::new(if true { false } else { true });
+    let _: Box<dyn Debug> = Box::new(match true { true => 'a', false => 'b' });
+
+    let _: &[isize] = &{ [1, 2, 3] };
+    let _: &[isize] = &if true { [1, 2, 3] } else { [1, 3, 4] };
+    let _: &[isize] = &match true { true => [1, 2, 3], false => [1, 3, 4] };
+    let _: &dyn Fn(isize) -> _ = &{ |x| (x as u8) };
+    let _: &dyn Debug = &if true { false } else { true };
+    let _: &dyn Debug = &match true { true => 'a', false => 'b' };
+
+    let _: &str = &{ String::new() };
+    let _: &str = &if true { String::from("...") } else { 5.to_string() };
+    let _: &str = &match true {
+        true => format!("{}", false),
+        false => ["x", "y"].join("+")
+    };
+
+    let _: Box<[isize]> = Box::new([1, 2, 3]);
+    let _: Box<dyn Fn(isize) -> _> = Box::new(|x| (x as u8));
+
+    let _: Rc<RefCell<[isize]>> = Rc::new(RefCell::new([1, 2, 3]));
+    let _: Rc<RefCell<dyn FnMut(isize) -> _>> = Rc::new(RefCell::new(|x| (x as u8)));
+
+    let _: Vec<Box<dyn Fn(isize) -> _>> = vec![
+        Box::new(|x| (x as u8)),
+        Box::new(|x| (x as i16 as u8)),
+    ];
+}