Merging upstream version 1.68.2+dfsg1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 40 insertions, 0 deletions

diff --git a/tests/ui/regions/regions-infer-bound-from-trait.rs b/tests/ui/regions/regions-infer-bound-from-trait.rs
new file mode 100644
index 000000000..610452182
--- /dev/null
+++ b/tests/ui/regions/regions-infer-bound-from-trait.rs
@@ -0,0 +1,40 @@
+// Test that we can derive lifetime bounds on type parameters
+// from trait inheritance.
+
+trait Static : 'static { }
+
+trait Is<'a> : 'a { }
+
+struct Inv<'a> {
+    x: Option<&'a mut &'a isize>
+}
+
+fn check_bound<'a,A:'a>(x: Inv<'a>, a: A) { }
+
+// In all of these cases, we can derive a bound for A that is longer
+// than 'a based on the trait bound of A:
+
+fn foo1<'a,A:Static>(x: Inv<'a>, a: A) {
+    check_bound(x, a)
+}
+
+fn foo2<'a,A:Static>(x: Inv<'static>, a: A) {
+    check_bound(x, a)
+}
+
+fn foo3<'a,A:Is<'a>>(x: Inv<'a>, a: A) {
+    check_bound(x, a)
+}
+
+// In these cases, there is no trait bound, so we cannot derive any
+// bound for A and we get an error:
+
+fn bar1<'a,A>(x: Inv<'a>, a: A) {
+    check_bound(x, a) //~ ERROR parameter type `A` may not live long enough
+}
+
+fn bar2<'a,'b,A:Is<'b>>(x: Inv<'a>, y: Inv<'b>, a: A) {
+    check_bound(x, a) //~ ERROR parameter type `A` may not live long enough
+}
+
+fn main() { }