merge duplicate issue-46589 tests

also add explicit revisions for -Zpolonius=next

src/tools/tidy/src/issues.txt

@@ -3146,7 +3146,6 @@ ui/nll/issue-97997.rs
 ui/nll/issue-98170.rs
 ui/nll/issue-98589-closures-relate-named-regions.rs
 ui/nll/issue-98693.rs
-ui/nll/polonius/issue-46589.rs
 ui/nll/relate_tys/issue-48071.rs
 ui/nll/ty-outlives/issue-53789-1.rs
 ui/nll/ty-outlives/issue-53789-2.rs

tests/ui/nll/issue-46589.nll.stderr

@@ -1,5 +1,5 @@
 error[E0499]: cannot borrow `**other` as mutable more than once at a time
-  --> $DIR/issue-46589.rs:23:21
+  --> $DIR/issue-46589.rs:24:21
    |
 LL |         *other = match (*other).get_self() {
    |                        -------- first mutable borrow occurs here

tests/ui/nll/issue-46589.rs

@@ -1,8 +1,9 @@
-// This tests passes in Polonius mode, so is skipped in the automated compare-mode.
-// We will manually check it passes in Polonius tests, as we can't have a test here
-// which conditionally passes depending on a test revision/compile-flags.
-
-//@ ignore-compare-mode-polonius
+//@ ignore-compare-mode-polonius (explicit revisions)
+//@ revisions: nll polonius_next polonius
+//@ [polonius_next] check-pass
+//@ [polonius_next] compile-flags: -Zpolonius=next
+//@ [polonius] check-pass
+//@ [polonius] compile-flags: -Zpolonius
 
 struct Foo;
 
@@ -21,7 +22,7 @@ impl Foo {
         *other = match (*other).get_self() {
             Some(s) => s,
             None => (*other).new_self()
-            //~^ ERROR cannot borrow `**other` as mutable more than once at a time [E0499]
+            //[nll]~^ ERROR cannot borrow `**other` as mutable more than once at a time [E0499]
         };
 
         let c = other;

tests/ui/nll/polonius/issue-46589.rs

@@ -1,31 +0,0 @@
-// This test is a copy of `ui/nll/issue-46589.rs` which fails in NLL but succeeds in Polonius.
-// As we can't have a test here which conditionally passes depending on a test
-// revision/compile-flags. We ensure here that it passes in Polonius mode.
-
-//@ check-pass
-//@ compile-flags: -Z polonius
-
-struct Foo;
-
-impl Foo {
-    fn get_self(&mut self) -> Option<&mut Self> {
-        Some(self)
-    }
-
-    fn new_self(&mut self) -> &mut Self {
-        self
-    }
-
-    fn trigger_bug(&mut self) {
-        let other = &mut (&mut *self);
-
-        *other = match (*other).get_self() {
-            Some(s) => s,
-            None => (*other).new_self()
-        };
-
-        let c = other;
-    }
-}
-
-fn main() {}