Removing left-over move inference from reference analysis

third_party/move/move-compiler-v2/src/pipeline/reference_safety_processor.rs

@@ -157,8 +157,6 @@ pub struct LifetimeState {
     temp_to_label_map: BTreeMap<TempIndex, LifetimeLabel>,
     /// A map from globals to labels. Represents root states of the active graph.
     global_to_label_map: BTreeMap<QualifiedInstId<StructId>, LifetimeLabel>,
-    /// Contains the set of variables whose values may have been moved to somewhere else.
-    moved: SetDomain<TempIndex>,
 }
 
 /// Represents a node of the borrow graph.
@@ -307,8 +305,6 @@ impl AbstractDomain for LifetimeState {
             change = JoinResult::Changed;
         }
         self.check_graph_consistency();
-
-        change = change.combine(self.moved.join(&other.moved));
         change
     }
 }
@@ -1369,11 +1365,6 @@ impl<'env, 'state> LifetimeAnalysisStep<'env, 'state> {
             self.check_read_local(src, mode);
             self.check_write_local(dest);
         }
-        // Track whether the variable content is moved
-        if kind == AssignKind::Move {
-            self.state.moved.insert(src);
-        }
-        self.state.moved.remove(&dest);
     }
 
     /// Process a borrow local instruction.
@@ -1398,7 +1389,6 @@ impl<'env, 'state> LifetimeAnalysisStep<'env, 'state> {
             label,
             BorrowEdge::new(BorrowEdgeKind::BorrowGlobal(is_mut), loc, child),
         );
-        self.state.moved.remove(&dest);
     }
 
     /// Process a borrow field instruction.
@@ -1419,7 +1409,6 @@ impl<'env, 'state> LifetimeAnalysisStep<'env, 'state> {
             label,
             BorrowEdge::new(BorrowEdgeKind::BorrowField(is_mut, field_id), loc, child),
         );
-        self.state.moved.remove(&dest);
     }
 
     /// Process a function call. For now we implement standard Move semantics, where every
@@ -1474,20 +1463,11 @@ impl<'env, 'state> LifetimeAnalysisStep<'env, 'state> {
                 }
             }
         }
-        // All sources are moved into a call
-        self.state.moved.extend(srcs.iter().cloned());
-        for dest in dests {
-            self.state.moved.remove(dest);
-        }
     }
 
     /// Process a FreezeRef instruction.
     fn freeze_ref(&mut self, code_offset: CodeOffset, dest: TempIndex, src: TempIndex) {
-        let label = self
-            .state
-            .label_for_temp(src)
-            .expect("label for reference")
-            .clone();
+        let label = *self.state.label_for_temp(src).expect("label for reference");
         let target = self.state.replace_ref(dest, code_offset, 0);
         self.state.add_edge(label, BorrowEdge {
             kind: BorrowEdgeKind::Freeze,
@@ -1511,7 +1491,6 @@ impl<'env, 'state> LifetimeAnalysisStep<'env, 'state> {
                 self.borrow_info(label, |_| true).into_iter(),
             )
         }
-        self.state.moved.remove(&dest);
     }
 
     /// Process a return instruction.
@@ -1553,15 +1532,13 @@ impl<'env, 'state> LifetimeAnalysisStep<'env, 'state> {
                 }
             }
         }
-        self.state.moved.extend(srcs.iter().cloned())
     }
 
     /// Process a ReadRef instruction.
     fn read_ref(&mut self, dest: TempIndex, src: TempIndex) {
         debug_assert!(self.is_ref(src));
         self.check_write_local(dest);
         self.check_read_local(src, ReadMode::Argument);
-        self.state.moved.remove(&dest);
     }
 
     /// Process a WriteRef instruction.
@@ -1733,11 +1710,6 @@ impl LifetimeInfoAtCodeOffset {
             .filter(|t| !self.after.temp_to_label_map.contains_key(t))
             .cloned()
     }
-
-    /// Returns true if the value in the variable has been moved at this program point.
-    pub fn is_moved(&self, temp: TempIndex) -> bool {
-        self.after.moved.contains(&temp)
-    }
 }
 
 impl FunctionTargetProcessor for ReferenceSafetyProcessor {
@@ -1912,7 +1884,6 @@ impl<'a> Display for LifetimeStateDisplay<'a> {
             graph,
             temp_to_label_map,
             global_to_label_map,
-            moved,
         } = &self.1;
         let pool = self.0.global_env().symbol_pool();
         writeln!(
@@ -1939,14 +1910,6 @@ impl<'a> Display for LifetimeStateDisplay<'a> {
                 .iter()
                 .map(|(str, label)| format!("{}={}", self.0.global_env().display(str), label))
                 .join(",")
-        )?;
-        writeln!(
-            f,
-            "moved: {{{}}}",
-            moved
-                .iter()
-                .map(|t| self.0.get_local_raw_name(*t).display(pool).to_string())
-                .join(",")
         )
     }
 }