Ignore path liveness when collecting actual/expected permissions in b…

…oundary analysis.

crates/aquascope/src/analysis/boundaries/mod.rs

@@ -223,7 +223,8 @@ pub struct PermissionsBoundary {
   #[serde(skip)]
   byte_location: BytePos,
   pub expected: Permissions,
-  pub actual: PermissionsData,
+  pub actual: Permissions,
+  pub data: PermissionsData,
   #[serde(skip_serializing_if = "Option::is_none")]
   pub expecting_flow: Option<FlowBoundary>,
 }
@@ -232,7 +233,7 @@ impl PermissionsBoundary {
   pub fn is_violation(&self) -> bool {
     macro_rules! is_missing {
       ($this:ident, $perm:ident) => {
-        ($this.expected.$perm && !$this.actual.permissions.$perm)
+        ($this.expected.$perm && !$this.actual.$perm)
       };
     }
 
@@ -735,11 +736,11 @@ fn path_to_perm_boundary<'tcx>(
       &path_locations,
     )?;
 
-    log::debug!("Chosen place at location {place:#?} {loc:#?} other options: {path_locations:#?}");
-
     let point = ctxt.location_to_point(loc);
     let path = ctxt.place_to_path(&place);
 
+    log::debug!("Chosen place at location {place:#?} {loc:#?} ({point:?},{path:?})\nOther options: {path_locations:#?}");
+
     Some((point, path))
   };
 
@@ -755,8 +756,9 @@ fn path_to_perm_boundary<'tcx>(
       })
     })
     .map(|(point, path)| {
-      let actual = ctxt.permissions_data_at_point(path, point);
+      let data = ctxt.permissions_data_at_point(path, point);
       let expected = path_boundary.expected;
+      let actual = data.permissions_ignore_liveness();
 
       let expecting_flow =
         get_flow_permission(analysis, path_boundary.flow_context, hir_id);
@@ -781,6 +783,7 @@ fn path_to_perm_boundary<'tcx>(
         byte_location,
         expected: expected.into(),
         actual,
+        data,
         expecting_flow,
       }
     });

crates/aquascope/src/analysis/permissions/context.rs

@@ -300,11 +300,6 @@ impl<'tcx> PermissionsCtxt<'tcx> {
       loan_read_refined: None,
       loan_write_refined: None,
       loan_drop_refined: None,
-      permissions: Permissions {
-        read: true,
-        write: true,
-        drop: true,
-      },
     }
   }
 
@@ -349,6 +344,8 @@ impl<'tcx> PermissionsCtxt<'tcx> {
     path: Path,
     point: Point,
   ) -> PermissionsData {
+    log::trace!("permissions_data_at_point: {:?} at {:?}", path, point);
+
     let empty_hash_move = &HashMap::default();
     let empty_hash_loan = &HashMap::default();
     let empty_set = &HashSet::default();
@@ -384,36 +381,6 @@ impl<'tcx> PermissionsCtxt<'tcx> {
     let loan_drop_refined: Option<LoanKey> =
       loan_drop_refined.get(path).map(Into::<LoanKey>::into);
 
-    let mem_uninit = path_moved.is_some() || path_uninitialized;
-
-    // An English description of the previous Datalog rules:
-    //
-    // A path is readable IFF:
-    // - it is not moved.
-    // - there doesn't exist a read-refining loan at this point.
-    //
-    // A path is writeable IFF:
-    // - the path's declared type allows for mutability.
-    // - the path is readable (you can't write if you can't read)
-    //   this implies that the path isn't moved.
-    // - there doesn't exist a write-refining loan at this point.
-    //
-    // A path is droppable(without copy) IFF:
-    // - the path's declared type is droppable.
-    // - it isn't moved.
-    // - no drop-refining loan exists at this point.
-    let permissions = if !is_live {
-      Permissions::bottom()
-    } else {
-      let read = !mem_uninit && loan_read_refined.is_none();
-
-      let write = type_writeable && read && loan_write_refined.is_none();
-
-      let drop = type_droppable && read && loan_drop_refined.is_none();
-
-      Permissions { read, write, drop }
-    };
-
     PermissionsData {
       type_droppable,
       type_writeable,
@@ -424,7 +391,6 @@ impl<'tcx> PermissionsCtxt<'tcx> {
       loan_read_refined,
       loan_write_refined,
       loan_drop_refined,
-      permissions,
     }
   }
 
@@ -450,7 +416,6 @@ impl<'tcx> PermissionsCtxt<'tcx> {
           loan_read_refined: None,
           loan_write_refined: None,
           loan_drop_refined: None,
-          permissions: Permissions::bottom(),
         })
       })
       .collect::<HashMap<_, _>>()

crates/aquascope/src/analysis/permissions/mod.rs

@@ -113,9 +113,42 @@ pub struct PermissionsData {
   #[serde(skip_serializing_if = "Option::is_none")]
   /// Is a live loan removing `drop` permissions?
   pub loan_drop_refined: Option<LoanKey>,
+}
+
+impl PermissionsData {
+  /// If the place is not live, then the permissions are always the bottom type.
+  /// Otherwise, see `permissions_ignore_liveness`. (You may want to ignore liveness
+  /// when you know a variable is being used, and should therefore be live.)
+  pub fn permissions(&self) -> Permissions {
+    if !self.is_live {
+      Permissions::bottom()
+    } else {
+      self.permissions_ignore_liveness()
+    }
+  }
 
-  /// Computed permissions given the above information.
-  pub permissions: Permissions,
+  /// A path is readable IFF:
+  /// - it is not moved.
+  /// - there doesn't exist a read-refining loan at this point.
+  ///
+  /// A path is writeable IFF:
+  /// - the path's declared type allows for mutability.
+  /// - the path is readable (you can't write if you can't read)
+  ///   this implies that the path isn't moved.
+  /// - there doesn't exist a write-refining loan at this point.
+  ///
+  /// A path is droppable(without copy) IFF:
+  /// - the path's declared type is droppable.
+  /// - it isn't moved.
+  /// - no drop-refining loan exists at this point.
+  pub fn permissions_ignore_liveness(&self) -> Permissions {
+    let mem_uninit = self.path_moved.is_some() || self.path_uninitialized;
+    let read = !mem_uninit && self.loan_read_refined.is_none();
+    let write =
+      self.type_writeable && read && self.loan_write_refined.is_none();
+    let drop = self.type_droppable && read && self.loan_drop_refined.is_none();
+    Permissions { read, write, drop }
+  }
 }
 
 /// A permissions refiner. [`Loan`]s and moves can refine permissions.

crates/aquascope/src/analysis/permissions/utils.rs

@@ -28,6 +28,8 @@ pub(crate) fn dump_mir_debug(ctxt: &PermissionsCtxt) {
     },
   )
   .unwrap();
+
+  log::debug!("{:?}", ctxt.polonius_output);
 }
 
 // --------------------------------------------------
@@ -67,7 +69,7 @@ impl JoinSemiLattice for PermissionsDomain<'_> {
     for (place, perms) in other.0.iter() {
       match self.0.entry(*place) {
         Entry::Occupied(mut entry) => {
-          changed |= entry.get_mut().permissions.join(&perms.permissions);
+          changed |= entry.get_mut().permissions().join(&perms.permissions());
         }
         Entry::Vacant(entry) => {
           entry.insert(*perms);
@@ -119,7 +121,7 @@ impl<C> DebugWithContext<C> for PermissionsDomain<'_> {
       r#"<table border="0" cellborder="1" cellspacing="0" cellpadding="2">"#
     )?;
     for (place, perms) in self.iter() {
-      let perms = perms.permissions;
+      let perms = perms.permissions();
       write!(
         f,
         r#"<tr><td align="left">{place:?}</td><td align="left">{perms:?}</td></tr>"#
@@ -137,11 +139,11 @@ impl<C> DebugWithContext<C> for PermissionsDomain<'_> {
     f: &mut std::fmt::Formatter<'_>,
   ) -> std::fmt::Result {
     let no_perm_changes = self.0.iter().all(|(place, permsd)| {
-      let perms = permsd.permissions;
+      let perms = permsd.permissions();
       old
         .0
         .get(place)
-        .map_or(true, |permd| permd.permissions == perms)
+        .map_or(true, |permd| permd.permissions() == perms)
     });
 
     if old == self || no_perm_changes {
@@ -153,10 +155,10 @@ impl<C> DebugWithContext<C> for PermissionsDomain<'_> {
       r#"<table border="0" cellborder="1" cellspacing="0" cellpadding="2" sides="rb">"#
     )?;
     for (place, perms) in self.0.iter() {
-      let perms = perms.permissions;
+      let perms = perms.permissions();
       match old.0.get(place) {
         Some(old_perms) => {
-          let old_perms = old_perms.permissions;
+          let old_perms = old_perms.permissions();
           if perms != old_perms {
             write!(
               f,
@@ -214,8 +216,6 @@ impl<'tcx> Analysis<'tcx> for PAnalysis<'_, 'tcx> {
       .domain_places()
       .into_iter()
       .map(|place| {
-        let path = self.ctxt.place_to_path(&place);
-        let mp = self.ctxt.max_permissions(path);
         // NOTE: I'm currently just ignoring the permissions data
         // for this utility just so we can see the permissions changes.
         (place, PermissionsData {
@@ -228,7 +228,6 @@ impl<'tcx> Analysis<'tcx> for PAnalysis<'_, 'tcx> {
           loan_read_refined: None,
           loan_write_refined: None,
           loan_drop_refined: None,
-          permissions: mp,
         })
       })
       .collect::<HashMap<_, _>>()

crates/aquascope/src/analysis/stepper/mod.rs

@@ -266,7 +266,7 @@ impl Difference for PermissionsData {
       loan_drop_refined: self.loan_drop_refined.diff(rhs.loan_drop_refined),
       path_moved: self.path_moved.diff(rhs.path_moved),
       path_uninitialized: self.path_uninitialized.diff(rhs.path_uninitialized),
-      permissions: self.permissions.diff(rhs.permissions),
+      permissions: self.permissions().diff(rhs.permissions()),
     }
   }
 }

crates/aquascope/src/test_utils.rs

@@ -272,8 +272,9 @@ pub fn test_refinements_in_file(path: &Path) {
 
           let path = ctxt.place_to_path(&place);
           let point = ctxt.location_to_point(loc);
-          let computed_perms =
-            ctxt.permissions_data_at_point(path, point).permissions;
+          let computed_perms = ctxt
+            .permissions_data_at_point(path, point)
+            .permissions_ignore_liveness();
 
           assert!(
             (*expected_perms == computed_perms),

crates/aquascope/tests/snapshots/boundaries__bar@coerced_0.test.snap

@@ -10,15 +10,15 @@ description: bar@coerced_0.test
     write: true
     drop: false
   actual:
+    read: true
+    write: true
+    drop: true
+  data:
     type_droppable: true
     type_writeable: true
     type_copyable: false
     is_live: true
     path_uninitialized: false
-    permissions:
-      read: true
-      write: true
-      drop: true
 - location:
     line: 3
     column: 29
@@ -27,15 +27,15 @@ description: bar@coerced_0.test
     write: true
     drop: false
   actual:
+    read: true
+    write: true
+    drop: false
+  data:
     type_droppable: false
     type_writeable: true
     type_copyable: false
     is_live: true
     path_uninitialized: false
-    permissions:
-      read: true
-      write: true
-      drop: false
 - location:
     line: 4
     column: 9
@@ -44,15 +44,15 @@ description: bar@coerced_0.test
     write: true
     drop: false
   actual:
+    read: true
+    write: true
+    drop: false
+  data:
     type_droppable: false
     type_writeable: true
     type_copyable: false
     is_live: true
     path_uninitialized: false
-    permissions:
-      read: true
-      write: true
-      drop: false
 - location:
     line: 5
     column: 3
@@ -61,13 +61,12 @@ description: bar@coerced_0.test
     write: true
     drop: false
   actual:
+    read: true
+    write: true
+    drop: false
+  data:
     type_droppable: false
     type_writeable: true
     type_copyable: false
     is_live: true
     path_uninitialized: false
-    permissions:
-      read: true
-      write: true
-      drop: false
-

crates/aquascope/tests/snapshots/boundaries__foo@mut_assign.test.snap

@@ -10,13 +10,12 @@ description: foo@mut_assign.test
     write: true
     drop: false
   actual:
+    read: true
+    write: true
+    drop: false
+  data:
     type_droppable: false
     type_writeable: true
     type_copyable: false
     is_live: true
     path_uninitialized: false
-    permissions:
-      read: true
-      write: true
-      drop: false
-