tests: adjust some `augmented-assignment*` tests

- `tests/ui/augmented-assignment-feature-gate-cross.rs`:
  - This was *originally* to feature-gate overloaded OpAssign
    cross-crate, but now let's keep it as a smoke test.
  - Renamed as `augmented-assignment-cross-crate.rs`.
  - Relocated under `tests/ui/binop/`.
-  `tests/ui/augmented-assignments.rs`:
  - Documented test intent.
  - Moved under `tests/ui/borrowck/`.
- `tests/ui/augmented-assignment-rpass.rs`:
  - Renamed to drop the `-rpass` suffix, since this was leftover from
    when `run-pass` test suite was a thing.
  - Moved under `tests/ui/binop/`.

5 files changed, 7 insertions, 2 deletions

diff --git a/tests/ui/augmented-assignments-rpass.rs b/tests/ui/binop/augmented-assignment.rs
index 755ecb466ce..755ecb466ce 100644
--- a/tests/ui/augmented-assignments-rpass.rs
+++ b/tests/ui/binop/augmented-assignment.rs
diff --git a/tests/ui/augmented-assignments-feature-gate-cross.rs b/tests/ui/binop/augmented-assignments-cross-crate.rs
index d402d200617..6dbb0350988 100644
--- a/tests/ui/augmented-assignments-feature-gate-cross.rs
+++ b/tests/ui/binop/augmented-assignments-cross-crate.rs
@@ -1,3 +1,5 @@
+//! Smoke test for overloaded compound assignments cross-crate.
+
 //@ run-pass
 //@ aux-build:augmented_assignments.rs
 
diff --git a/tests/ui/auxiliary/augmented_assignments.rs b/tests/ui/binop/auxiliary/augmented_assignments.rs
index d0d3f57459a..d0d3f57459a 100644
--- a/tests/ui/auxiliary/augmented_assignments.rs
+++ b/tests/ui/binop/auxiliary/augmented_assignments.rs
diff --git a/tests/ui/augmented-assignments.rs b/tests/ui/borrowck/augmented-assignments.rs
index 35ab2d454f7..d717dcc7935 100644
--- a/tests/ui/augmented-assignments.rs
+++ b/tests/ui/borrowck/augmented-assignments.rs
@@ -1,3 +1,6 @@
+//! Check that overloaded compound assignment operators respect usual borrowck rules and emit
+//! reasonable diagnostics.
+
 use std::ops::AddAssign;
 
 #[derive(Clone)]
diff --git a/tests/ui/augmented-assignments.stderr b/tests/ui/borrowck/augmented-assignments.stderr
index a4b75cbf6e8..4b945cd998a 100644
--- a/tests/ui/augmented-assignments.stderr
+++ b/tests/ui/borrowck/augmented-assignments.stderr
@@ -1,5 +1,5 @@
 error[E0505]: cannot move out of `x` because it is borrowed
-  --> $DIR/augmented-assignments.rs:17:5
+  --> $DIR/augmented-assignments.rs:20:5
    |
 LL |     let mut x = Int(1);
    |         ----- binding `x` declared here
@@ -10,7 +10,7 @@ LL |     x;
    |     ^ move out of `x` occurs here
 
 error[E0596]: cannot borrow `y` as mutable, as it is not declared as mutable
-  --> $DIR/augmented-assignments.rs:24:5
+  --> $DIR/augmented-assignments.rs:27:5
    |
 LL |     y
    |     ^ cannot borrow as mutable