Rust: Remove the workaround in rust/unused-variable.

rust/ql/src/queries/unusedentities/UnusedVariable.qll

@@ -10,6 +10,5 @@ predicate isUnused(Variable v) {
   not exists(v.getAnAccess()) and
   not exists(v.getInitializer()) and
   not v instanceof DiscardVariable and
-  not v.getPat().isInMacroExpansion() and
-  exists(File f | f.getBaseName() = "main.rs" | v.getLocation().getFile() = f) // temporarily severely limit results
+  not v.getPat().isInMacroExpansion()
 }

rust/ql/test/query-tests/unusedentities/UnusedValue.expected

@@ -14,7 +14,6 @@
 | main.rs:270:13:270:17 | total | Variable $@ is assigned a value that is never used. | main.rs:238:13:238:17 | total | total |
 | main.rs:363:9:363:9 | x | Variable $@ is assigned a value that is never used. | main.rs:363:9:363:9 | x | x |
 | main.rs:371:17:371:17 | x | Variable $@ is assigned a value that is never used. | main.rs:371:17:371:17 | x | x |
-| more.rs:24:9:24:11 | val | Variable $@ is assigned a value that is never used. | more.rs:24:9:24:11 | val | val |
 | more.rs:44:9:44:14 | a_ptr4 | Variable $@ is assigned a value that is never used. | more.rs:44:9:44:14 | a_ptr4 | a_ptr4 |
 | more.rs:59:9:59:13 | d_ptr | Variable $@ is assigned a value that is never used. | more.rs:59:9:59:13 | d_ptr | d_ptr |
 | more.rs:65:9:65:17 | f_ptr | Variable $@ is assigned a value that is never used. | more.rs:65:13:65:17 | f_ptr | f_ptr |

rust/ql/test/query-tests/unusedentities/UnusedVariable.expected

@@ -19,3 +19,4 @@
 | main.rs:417:26:417:28 | val | Variable 'val' is not used. |
 | main.rs:420:21:420:23 | acc | Variable 'acc' is not used. |
 | main.rs:441:9:441:14 | unused | Variable 'unused' is not used. |
+| more.rs:24:9:24:11 | val | Variable 'val' is not used. |

rust/ql/test/query-tests/unusedentities/more.rs

@@ -21,7 +21,7 @@ impl<T> MySettable<T> for MyContainer<T> {
 impl<T> MyGettable<T> for MyContainer<T> {
     fn get(
         &self,
-        val: T, // $ SPURIOUS: Alert[rust/unused-value] $ MISSING: Alert[rust/unused-variable]
+        val: T, // $ Alert[rust/unused-variable]
     ) -> &T {
         return &(self.val);
     }