1 files changed, 42 insertions, 0 deletions
diff --git a/src/test/ui/nll/match-cfg-fake-edges.rs b/src/test/ui/nll/match-cfg-fake-edges.rs
new file mode 100644
index 000000000..252f7f8ba
--- /dev/null
+++ b/src/test/ui/nll/match-cfg-fake-edges.rs
@@ -0,0 +1,42 @@
+// Test that we have enough false edges to avoid exposing the exact matching
+// algorithm in borrow checking.
+
+fn guard_always_precedes_arm(y: i32) {
+    let mut x;
+    // x should always be initialized, as the only way to reach the arm is
+    // through the guard.
+    match y {
+        0 | 2 if { x = 2; true } => x,
+        _ => 2,
+    };
+}
+
+fn guard_may_be_skipped(y: i32) {
+    let x;
+    // Even though x *is* always initialized, we don't want to have borrowck
+    // results be based on whether patterns are exhaustive.
+    match y {
+        _ if { x = 2; true } => 1,
+        _ if {
+            x; //~ ERROR E0381
+            false
+        } => 2,
+        _ => 3,
+    };
+}
+
+fn guard_may_be_taken(y: bool) {
+    let x = String::new();
+    // Even though x *is* never moved before the use, we don't want to have
+    // borrowck results be based on whether patterns are disjoint.
+    match y {
+        false if { drop(x); true } => 1,
+        true => {
+            x; //~ ERROR use of moved value: `x`
+            2
+        }
+        false => 3,
+    };
+}
+
+fn main() {}