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-rw-r--r--tests/ui/higher-rank-trait-bounds/hrtb-identity-fn-borrows.rs26
1 files changed, 26 insertions, 0 deletions
diff --git a/tests/ui/higher-rank-trait-bounds/hrtb-identity-fn-borrows.rs b/tests/ui/higher-rank-trait-bounds/hrtb-identity-fn-borrows.rs
new file mode 100644
index 000000000..89fc4705a
--- /dev/null
+++ b/tests/ui/higher-rank-trait-bounds/hrtb-identity-fn-borrows.rs
@@ -0,0 +1,26 @@
+// Test that the `'a` in the where clause correctly links the region
+// of the output to the region of the input.
+
+trait FnLike<A,R> {
+ fn call(&self, arg: A) -> R;
+}
+
+fn call_repeatedly<F>(f: F)
+ where F : for<'a> FnLike<&'a isize, &'a isize>
+{
+ // Result is stored: cannot re-assign `x`
+ let mut x = 3;
+ let y = f.call(&x);
+ x = 5; //~ ERROR cannot assign to `x` because it is borrowed
+
+ // Result is not stored: can re-assign `x`
+ let mut x = 3;
+ f.call(&x);
+ f.call(&x);
+ f.call(&x);
+ x = 5;
+ drop(y);
+}
+
+fn main() {
+}