2 files changed, 78 insertions, 0 deletions
diff --git a/src/test/ui/nll/user-annotations/issue-57731-ascibed-coupled-types.rs b/src/test/ui/nll/user-annotations/issue-57731-ascibed-coupled-types.rs
new file mode 100644
index 00000000000..f4969bb4067
--- /dev/null
+++ b/src/test/ui/nll/user-annotations/issue-57731-ascibed-coupled-types.rs
@@ -0,0 +1,40 @@
+// Check that repeated type variables are correctly handled
+
+#![allow(unused)]
+#![feature(nll, type_ascription)]
+
+type PairUncoupled<'a, 'b, T> = (&'a T, &'b T);
+type PairCoupledTypes<T> = (T, T);
+type PairCoupledRegions<'a, T> = (&'a T, &'a T);
+
+fn uncoupled_wilds_rhs<'a>(_x: &'a u32, s: &'static u32) -> &'static u32 {
+    let ((y, _z),) = ((s, _x),): (PairUncoupled<_>,);
+    y // OK
+}
+
+fn coupled_wilds_rhs<'a>(_x: &'a u32, s: &'static u32) -> &'static u32 {
+    let ((y, _z),) = ((s, _x),): (PairCoupledTypes<_>,);
+    y //~ ERROR lifetime may not live long enough
+}
+
+fn coupled_regions_rhs<'a>(_x: &'a u32, s: &'static u32) -> &'static u32 {
+    let ((y, _z),) = ((s, _x),): (PairCoupledRegions<_>,);
+    y //~ ERROR lifetime may not live long enough
+}
+
+fn cast_uncoupled_wilds_rhs<'a>(_x: &'a u32, s: &'static u32) -> &'static u32 {
+    let ((y, _z),) = ((s, _x),) as (PairUncoupled<_>,);
+    y // OK
+}
+
+fn cast_coupled_wilds_rhs<'a>(_x: &'a u32, s: &'static u32) -> &'static u32 {
+    let ((y, _z),) = ((s, _x),) as (PairCoupledTypes<_>,);
+    y //~ ERROR lifetime may not live long enough
+}
+
+fn cast_coupled_regions_rhs<'a>(_x: &'a u32, s: &'static u32) -> &'static u32 {
+    let ((y, _z),) = ((s, _x),) as (PairCoupledRegions<_>,);
+    y //~ ERROR lifetime may not live long enough
+}
+
+fn main() {}
diff --git a/src/test/ui/nll/user-annotations/issue-57731-ascibed-coupled-types.stderr b/src/test/ui/nll/user-annotations/issue-57731-ascibed-coupled-types.stderr
new file mode 100644
index 00000000000..76be637220a
--- /dev/null
+++ b/src/test/ui/nll/user-annotations/issue-57731-ascibed-coupled-types.stderr
@@ -0,0 +1,38 @@
+error: lifetime may not live long enough
+  --> $DIR/issue-57731-ascibed-coupled-types.rs:17:5
+   |
+LL | fn coupled_wilds_rhs<'a>(_x: &'a u32, s: &'static u32) -> &'static u32 {
+   |                      -- lifetime `'a` defined here
+LL |     let ((y, _z),) = ((s, _x),): (PairCoupledTypes<_>,);
+LL |     y //~ ERROR lifetime may not live long enough
+   |     ^ returning this value requires that `'a` must outlive `'static`
+
+error: lifetime may not live long enough
+  --> $DIR/issue-57731-ascibed-coupled-types.rs:22:5
+   |
+LL | fn coupled_regions_rhs<'a>(_x: &'a u32, s: &'static u32) -> &'static u32 {
+   |                        -- lifetime `'a` defined here
+LL |     let ((y, _z),) = ((s, _x),): (PairCoupledRegions<_>,);
+LL |     y //~ ERROR lifetime may not live long enough
+   |     ^ returning this value requires that `'a` must outlive `'static`
+
+error: lifetime may not live long enough
+  --> $DIR/issue-57731-ascibed-coupled-types.rs:32:5
+   |
+LL | fn cast_coupled_wilds_rhs<'a>(_x: &'a u32, s: &'static u32) -> &'static u32 {
+   |                           -- lifetime `'a` defined here
+LL |     let ((y, _z),) = ((s, _x),) as (PairCoupledTypes<_>,);
+LL |     y //~ ERROR lifetime may not live long enough
+   |     ^ returning this value requires that `'a` must outlive `'static`
+
+error: lifetime may not live long enough
+  --> $DIR/issue-57731-ascibed-coupled-types.rs:37:5
+   |
+LL | fn cast_coupled_regions_rhs<'a>(_x: &'a u32, s: &'static u32) -> &'static u32 {
+   |                             -- lifetime `'a` defined here
+LL |     let ((y, _z),) = ((s, _x),) as (PairCoupledRegions<_>,);
+LL |     y //~ ERROR lifetime may not live long enough
+   |     ^ returning this value requires that `'a` must outlive `'static`
+
+error: aborting due to 4 previous errors
+