1 files changed, 100 insertions, 0 deletions
diff --git a/src/test/ui/never_type/diverging-fallback-control-flow.rs b/src/test/ui/never_type/diverging-fallback-control-flow.rs
new file mode 100644
index 000000000..45a3362fa
--- /dev/null
+++ b/src/test/ui/never_type/diverging-fallback-control-flow.rs
@@ -0,0 +1,100 @@
+// revisions: nofallback fallback
+// run-pass
+
+#![allow(dead_code)]
+#![allow(unused_assignments)]
+#![allow(unused_variables)]
+#![allow(unreachable_code)]
+// Test various cases where we permit an unconstrained variable
+// to fallback based on control-flow. In all of these cases,
+// the type variable winds up being the target of both a `!` coercion
+// and a coercion from a non-`!` variable, and hence falls back to `()`.
+#![cfg_attr(fallback, feature(never_type, never_type_fallback))]
+
+trait UnitDefault {
+    fn default() -> Self;
+}
+
+impl UnitDefault for u32 {
+    fn default() -> Self {
+        0
+    }
+}
+
+impl UnitDefault for () {
+    fn default() -> () {
+        panic!()
+    }
+}
+
+fn assignment() {
+    let x;
+
+    if true {
+        x = UnitDefault::default();
+    } else {
+        x = return;
+    }
+}
+
+fn assignment_rev() {
+    let x;
+
+    if true {
+        x = return;
+    } else {
+        x = UnitDefault::default();
+    }
+}
+
+fn if_then_else() {
+    let _x = if true {
+        UnitDefault::default()
+    } else {
+        return;
+    };
+}
+
+fn if_then_else_rev() {
+    let _x = if true {
+        return;
+    } else {
+        UnitDefault::default()
+    };
+}
+
+fn match_arm() {
+    let _x = match Ok(UnitDefault::default()) {
+        Ok(v) => v,
+        Err(()) => return,
+    };
+}
+
+fn match_arm_rev() {
+    let _x = match Ok(UnitDefault::default()) {
+        Err(()) => return,
+        Ok(v) => v,
+    };
+}
+
+fn loop_break() {
+    let _x = loop {
+        if false {
+            break return;
+        } else {
+            break UnitDefault::default();
+        }
+    };
+}
+
+fn loop_break_rev() {
+    let _x = loop {
+        if false {
+            break return;
+        } else {
+            break UnitDefault::default();
+        }
+    };
+}
+
+fn main() {}