1 files changed, 68 insertions, 0 deletions
diff --git a/src/test/ui/coercion/coerce-unify.rs b/src/test/ui/coercion/coerce-unify.rs
new file mode 100644
index 000000000..f1818f9bb
--- /dev/null
+++ b/src/test/ui/coercion/coerce-unify.rs
@@ -0,0 +1,68 @@
+// run-pass
+// Check that coercions can unify if-else, match arms and array elements.
+
+// Try to construct if-else chains, matches and arrays out of given expressions.
+macro_rules! check {
+    ($last:expr $(, $rest:expr)+) => {
+        // Last expression comes first because of whacky ifs and matches.
+        let _ = $(if false { $rest })else+ else { $last };
+
+        let _ = match 0 { $(_ if false => $rest,)+ _ => $last };
+
+        let _ = [$($rest,)+ $last];
+    }
+}
+
+// Check all non-uniform cases of 2 and 3 expressions of 2 types.
+macro_rules! check2 {
+    ($a:expr, $b:expr) => {
+        check!($a, $b);
+        check!($b, $a);
+
+        check!($a, $a, $b);
+        check!($a, $b, $a);
+        check!($a, $b, $b);
+
+        check!($b, $a, $a);
+        check!($b, $a, $b);
+        check!($b, $b, $a);
+    }
+}
+
+// Check all non-uniform cases of 2 and 3 expressions of 3 types.
+macro_rules! check3 {
+    ($a:expr, $b:expr, $c:expr) => {
+        // Delegate to check2 for cases where a type repeats.
+        check2!($a, $b);
+        check2!($b, $c);
+        check2!($a, $c);
+
+        // Check the remaining cases, i.e., permutations of ($a, $b, $c).
+        check!($a, $b, $c);
+        check!($a, $c, $b);
+        check!($b, $a, $c);
+        check!($b, $c, $a);
+        check!($c, $a, $b);
+        check!($c, $b, $a);
+    }
+}
+
+use std::mem::size_of;
+
+fn foo() {}
+fn bar() {}
+
+pub fn main() {
+    check3!(foo, bar, foo as fn());
+    check3!(size_of::<u8>, size_of::<u16>, size_of::<usize> as fn() -> usize);
+
+    let s = String::from("bar");
+    check2!("foo", &s);
+
+    let a = [1, 2, 3];
+    let v = vec![1, 2, 3];
+    check2!(&a[..], &v);
+
+    // Make sure in-array coercion still works.
+    let _ = [("a", Default::default()), (Default::default(), "b"), (&s, &s)];
+}