Remove Unused detection due to inconsistency

clippy_lints/src/borrow_pats/owned.rs

@@ -19,8 +19,6 @@ pub struct OwnedAnalysis<'a, 'tcx> {
     local_info: &'a VarInfo,
     /// This should be a `BTreeSet` to have it ordered and consistent.
     pats: BTreeSet<OwnedPat>,
-    /// Counts how many times a value was used. This starts at 1 for arguments otherwise 0.
-    use_count: u32,
 }
 
 impl<'a, 'tcx> OwnedAnalysis<'a, 'tcx> {
@@ -31,9 +29,6 @@ impl<'a, 'tcx> OwnedAnalysis<'a, 'tcx> {
         };
         let name = local_kind.name().unwrap();
 
-        // Arguments are assigned outside and therefore have at least a use of 1
-        let use_count = u32::from(local_kind.is_arg());
-
         let bbs_ctn = info.body.basic_blocks.len();
         let mut states = IndexVec::with_capacity(bbs_ctn);
         for bb in 0..bbs_ctn {
@@ -48,18 +43,13 @@ impl<'a, 'tcx> OwnedAnalysis<'a, 'tcx> {
             local_kind,
             local_info,
             pats: Default::default(),
-            use_count,
         }
     }
 
     pub fn run(info: &'a AnalysisInfo<'tcx>, local: Local) -> BTreeSet<OwnedPat> {
         let mut anly = Self::new(info, local);
         visit_body_with_state(&mut anly, info);
 
-        if anly.use_count == 1 {
-            anly.pats.insert(OwnedPat::Unused);
-        }
-
         anly.pats
     }
 
@@ -83,6 +73,7 @@ pub enum OwnedPat {
     #[expect(unused, reason = "Either this needs to be detected consistency or not at all")]
     Returned,
     /// The value is only assigned once and never read afterwards.
+    #[expect(unused, reason = "This can't be reliably detected with MIR")]
     Unused,
     /// The value is dynamically dropped, meaning if it's still valid at a given location.
     /// See RFC: #320
@@ -266,13 +257,6 @@ impl<'a, 'tcx> Visitor<'tcx> for OwnedAnalysis<'a, 'tcx> {
         self.visit_terminator_for_anons(term, loc.block);
         self.super_terminator(term, loc);
     }
-
-    fn visit_local(&mut self, local: Local, _context: mir::visit::PlaceContext, _loc: Location) {
-        // TODO: Check that this isn't called for StorageLife and StorageDead
-        if local == self.local {
-            self.use_count += 1;
-        }
-    }
 }
 
 impl<'a, 'tcx> OwnedAnalysis<'a, 'tcx> {

tests/ui/thesis/owned_field.rs

@@ -42,14 +42,14 @@ fn assign_drop_field() {
     ex.owned_1 = String::new();
 }
 
-#[forbid(clippy::borrow_pats)]
+#[warn(clippy::borrow_pats)]
 fn move_drop_field() {
     let ex = Example::default();
     // TODO: Chnage state to partially valid
     let _hey = ex.owned_1;
 }
 
-// #[forbid(clippy::borrow_pats)]
+#[warn(clippy::borrow_pats)]
 fn copy_field() {
     let ex = Example::default();
     let _hey = ex.copy_1;

tests/ui/thesis/owned_field.stdout

@@ -17,34 +17,12 @@
 - Body: Output(Unit)     , NotConst , Safe  , Sync , Free       {NoArguments}
 
 # "move_drop_field"
-=====
-Body for: DefId(0:7 ~ owned_field[df29]::move_drop_field)
-bb0:
-    StorageLive(_1)
-    _1 = <Example as std::default::Default>::default() -> [return: bb1, unwind continue]
-
-bb1:
-    StorageLive(_2)
-    _2 = move (_1.0: std::string::String)
-    _0 = const ()
-    drop(_2) -> [return: bb2, unwind: bb5]
-
-bb2:
-    StorageDead(_2)
-    drop((_1.1: std::string::String)) -> [return: bb4, unwind: bb3]
-
-bb3:
-    resume
-
-bb4:
-    StorageDead(_1)
-    return
-
-bb5:
-    drop((_1.1: std::string::String)) -> [return: bb3, unwind terminate(cleanup)]
-
-=====
 - ex             : (Immutable, Owned    , Local   , NonCopy, PartDrop, UserDef  ) {PartMovedToVar}
 - _hey           : (Immutable, Owned    , Local   , NonCopy, PartDrop, UserDef  ) {}
 - Body: Output(Unit)     , NotConst , Safe  , Sync , Free       {NoArguments}
 
+# "copy_field"
+- ex             : (Immutable, Owned    , Local   , NonCopy, PartDrop, UserDef  ) {CopiedToVar}
+- _hey           : (Immutable, Owned    , Local   , Copy   , NonDrop , Primitive) {}
+- Body: Output(Unit)     , NotConst , Safe  , Sync , Free       {NoArguments}
+

tests/ui/thesis/pass/owned.rs

@@ -1,11 +1,11 @@
 //@rustc-env: CLIPPY_PETS_PRINT=1
 
 struct Dropper {
-    duck: u32
+    duck: u32,
 }
 
 impl Drop for Dropper {
-    fn drop(&mut self) {  }
+    fn drop(&mut self) {}
 }
 
 struct Animal {
@@ -79,13 +79,13 @@ fn conditional_overwrite(mut animal: String, cond: bool) {
     if cond {
         animal = "Ducks".to_string();
     }
-    
+
     magic()
 }
 
 fn magic() {}
 
 #[warn(clippy::borrow_pats)]
 fn main() {
-    let dropper = Dropper {duck : 17};
+    let dropper = Dropper { duck: 17 };
 }

tests/ui/thesis/pass/owned.stdout

@@ -1,10 +1,10 @@
 # "take_one"
-- _animal        : (Immutable, Owned    , Argument, NonCopy, NonDrop , UserDef  ) {Unused}
+- _animal        : (Immutable, Owned    , Argument, NonCopy, NonDrop , UserDef  ) {}
 - Body: Output(Unit)     , NotConst , Safe  , Sync , Free       {}
 
 # "take_two"
-- _animal_1      : (Immutable, Owned    , Argument, NonCopy, NonDrop , UserDef  ) {Unused}
-- _animal_2      : (Immutable, Owned    , Argument, NonCopy, NonDrop , UserDef  ) {Unused}
+- _animal_1      : (Immutable, Owned    , Argument, NonCopy, NonDrop , UserDef  ) {}
+- _animal_2      : (Immutable, Owned    , Argument, NonCopy, NonDrop , UserDef  ) {}
 - Body: Output(Unit)     , NotConst , Safe  , Sync , Free       {}
 
 # "pat_return_owned_arg"

tests/ui/thesis/pass/owned_mut_to_unmut.rs

@@ -52,7 +52,7 @@ fn mut_copy_to_immut_and_use_after() {
     let _ = snapshot + counter;
 }
 
-#[forbid(clippy::borrow_pats)]
+#[warn(clippy::borrow_pats)]
 fn main() {
     let mut s = String::new();
     s += "Hey";

tests/ui/thesis/pass/owned_mut_to_unmut.stdout

@@ -24,41 +24,6 @@
 - Body: Output(Unit)     , NotConst , Safe  , Sync , Free       {NoArguments}
 
 # "main"
-=====
-Body for: DefId(0:8 ~ owned_mut_to_unmut[4ffe]::main)
-bb0:
-    StorageLive(_1)
-    _1 = std::string::String::new() -> [return: bb1, unwind continue]
-
-bb1:
-    StorageLive(_2)
-    StorageLive(_3)
-    _3 = &mut _1
-    StorageLive(_4)
-    StorageLive(_5)
-    _5 = const "Hey"
-    _4 = &(*_5)
-    _2 = <std::string::String as std::ops::AddAssign<&str>>::add_assign(move _3, move _4) -> [return: bb2, unwind: bb4]
-
-bb2:
-    StorageDead(_4)
-    StorageDead(_3)
-    StorageDead(_5)
-    StorageDead(_2)
-    _0 = const ()
-    drop(_1) -> [return: bb3, unwind: bb5]
-
-bb3:
-    StorageDead(_1)
-    return
-
-bb4:
-    drop(_1) -> [return: bb5, unwind terminate(cleanup)]
-
-bb5:
-    resume
-
-=====
 - s              : (Mutable  , Owned    , Local   , NonCopy, PartDrop, UserDef  ) {TempBorrowMut}
 - Body: Output(Unit)     , NotConst , Safe  , Sync , Free       {NoArguments, HasTempBorrowMut}