Constraint hashcode equals fix

src/checkers/inference/ConstraintNormalizer.java

@@ -239,8 +239,8 @@ public Set<Constraint> toConstraints() {
                 return constraints;
             }
 
-            List<Constraint> ifExistsConstraints = new ArrayList<>();
-            List<Constraint> ifNotExistsConstraints = new ArrayList<>();
+            Set<Constraint> ifExistsConstraints = new HashSet<>();
+            Set<Constraint> ifNotExistsConstraints = new HashSet<>();
 
             ifExistsConstraints.addAll(constraints);
             for (final ExistentialNode existNode : ifExists.values()) {

src/checkers/inference/model/ArithmeticConstraint.java

@@ -104,7 +104,7 @@ public <S, T> T serialize(Serializer<S, T> serializer) {
     public int hashCode() {
         // We do not hash on annotation location as the result slot is unique for each annotation
         // location
-        return HashCodeUtils.hash(operation, leftOperand, rightOperand, result);
+        return HashCodeUtils.hash(3079, operation, leftOperand, rightOperand, result);
     }
 
     @Override

src/checkers/inference/model/CombineConstraint.java

@@ -1,6 +1,8 @@
 package checkers.inference.model;
 
 import java.util.Arrays;
+
+import org.checkerframework.dataflow.util.HashCodeUtils;
 import org.checkerframework.javacutil.BugInCF;
 
 /**
@@ -51,28 +53,19 @@ public Slot getResult() {
 
     @Override
     public int hashCode() {
-        int hc = 1;
-        hc += ((target == null) ? 0 : target.hashCode());
-        hc += ((decl == null) ? 0 : decl.hashCode());
-        hc += ((result == null) ? 0 : result.hashCode());
-        return hc;
+        return HashCodeUtils.hash(1543, target, decl, result);
     }
 
     @Override
     public boolean equals(Object obj) {
-        if (this == obj)
+        if (this == obj) {
             return true;
-        if (obj == null)
-            return false;
-        if (getClass() != obj.getClass())
-            return false;
-        CombineConstraint other = (CombineConstraint) obj;
-        if (target.equals(other.target) &&
-                decl.equals(other.decl) &&
-                result.equals(other.result)) {
-            return true;
-        } else {
+        }
+        if (obj == null || getClass() != obj.getClass()) {
             return false;
         }
+        CombineConstraint other = (CombineConstraint) obj;
+        return target.equals(other.target) && decl.equals(other.decl)
+                && result.equals(other.result);
     }
 }

src/checkers/inference/model/ComparableConstraint.java

@@ -2,6 +2,7 @@
 
 import java.util.Arrays;
 
+import org.checkerframework.dataflow.util.HashCodeUtils;
 import org.checkerframework.framework.type.QualifierHierarchy;
 import org.checkerframework.javacutil.BugInCF;
 
@@ -80,26 +81,20 @@ public Constraint make(Slot first, Slot second) {
 
     @Override
     public int hashCode() {
-        int result = 1;
-        result = result + ((first == null) ? 0 : first.hashCode());
-        result = result + ((second == null) ? 0 : second.hashCode());
-        return result;
+        // ComparableConstraint is insensitive to the order of the slots
+        return HashCodeUtils.hash(769, first.hashCode() + second.hashCode());
     }
 
     @Override
     public boolean equals(Object obj) {
-        if (this == obj)
+        if (this == obj) {
             return true;
-        if (obj == null)
-            return false;
-        if (getClass() != obj.getClass())
-            return false;
-        ComparableConstraint other = (ComparableConstraint) obj;
-        if ((first.equals(other.first) && second.equals(other.second))
-                || (first.equals(other.second) && (second.equals(other.first)))) {
-            return true;
-        } else {
+        }
+        if (obj == null || getClass() != obj.getClass()) {
             return false;
         }
+        ComparableConstraint other = (ComparableConstraint) obj;
+        return (first.equals(other.first) && second.equals(other.second))
+                || (first.equals(other.second) && second.equals(other.first));
     }
 }

src/checkers/inference/model/ConstraintManager.java

@@ -138,7 +138,7 @@ public PreferenceConstraint createPreferenceConstraint(VariableSlot variable, Co
      * Creates an {@link ExistentialConstraint} for the given slot and lists of constraints.
      */
     public ExistentialConstraint createExistentialConstraint(Slot slot,
-            List<Constraint> ifExistsConstraints, List<Constraint> ifNotExistsConstraints) {
+            Set<Constraint> ifExistsConstraints, Set<Constraint> ifNotExistsConstraints) {
         return ExistentialConstraint.create((VariableSlot) slot, ifExistsConstraints,
                 ifNotExistsConstraints, getCurrentLocation());
     }
@@ -261,14 +261,26 @@ public void addCombineConstraint(Slot target, Slot decl, Slot result) {
      * Creates and adds a {@link PreferenceConstraint} to the constraint set.
      */
     public void addPreferenceConstraint(VariableSlot variable, ConstantSlot goal, int weight) {
-        add(createPreferenceConstraint(variable, goal, weight));
+        PreferenceConstraint pc = createPreferenceConstraint(variable, goal, weight);
+        if (constraints.contains(pc)) {
+            PreferenceConstraint existingPC = (PreferenceConstraint) constraints.stream()
+                    .filter(c -> c.hashCode() == pc.hashCode()).findFirst().get();
+
+            if (existingPC.getWeight() != weight) {
+                throw new BugInCF(
+                        "Constraint " + pc + " already exists in the constraint set with weight "
+                                + existingPC.getWeight() + ".");
+            }
+        } else {
+            add(pc);
+        }
     }
 
     /**
      * Creates and adds a {@link ExistentialConstraint} to the constraint set.
      */
-    public void addExistentialConstraint(Slot slot, List<Constraint> ifExistsConstraints,
-            List<Constraint> ifNotExistsConstraints) {
+    public void addExistentialConstraint(Slot slot, Set<Constraint> ifExistsConstraints,
+            Set<Constraint> ifNotExistsConstraints) {
         add(createExistentialConstraint(slot, ifExistsConstraints, ifNotExistsConstraints));
     }
 

src/checkers/inference/model/EqualityConstraint.java

@@ -2,6 +2,7 @@
 
 import java.util.Arrays;
 
+import org.checkerframework.dataflow.util.HashCodeUtils;
 import org.checkerframework.javacutil.BugInCF;
 
 /**
@@ -95,26 +96,20 @@ public Constraint make(Slot first, Slot second) {
 
     @Override
     public int hashCode() {
-        int result = 1;
-        result = result + ((first == null) ? 0 : first.hashCode());
-        result = result + ((second == null) ? 0 : second.hashCode());
-        return result;
+        // EqualityConstraint is insensitive to the order of the slots
+        return HashCodeUtils.hash(97, first.hashCode() + second.hashCode());
     }
 
     @Override
     public boolean equals(Object obj) {
-        if (this == obj)
+        if (this == obj) {
             return true;
-        if (obj == null)
-            return false;
-        if (getClass() != obj.getClass())
-            return false;
-        EqualityConstraint other = (EqualityConstraint) obj;
-        if ((first.equals(other.first) && second.equals(other.second))
-                || (first.equals(other.second) && (second.equals(other.first)))) {
-            return true;
-        } else {
+        }
+        if (obj == null || getClass() != obj.getClass()) {
             return false;
         }
+        EqualityConstraint other = (EqualityConstraint) obj;
+        return (first.equals(other.first) && second.equals(other.second))
+                || (first.equals(other.second) && second.equals(other.first));
     }
 }

src/checkers/inference/model/ExistentialConstraint.java

@@ -1,10 +1,12 @@
 package checkers.inference.model;
 
 import org.checkerframework.javacutil.PluginUtil;
+import org.checkerframework.dataflow.util.HashCodeUtils;
 import org.checkerframework.javacutil.BugInCF;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
+import java.util.Set;
 
 /**
  * An ExistentialConstraint indicates that solvers need to determine if a variable's annotation
@@ -27,22 +29,22 @@ public class ExistentialConstraint extends Constraint {
     private final VariableSlot potentialVariable;
 
     // The constraints to enforce if potentialVariable exists
-    private final List<Constraint> potentialConstraints;
+    private final Set<Constraint> potentialConstraints;
 
     // the constraints to enforce if potentialVariable DOES NOT exist
-    private final List<Constraint> alternateConstraints;
+    private final Set<Constraint> alternateConstraints;
 
     private ExistentialConstraint(VariableSlot potentialVariable,
-                                 List<Constraint> potentialConstraints,
-                                 List<Constraint> alternateConstraints, AnnotationLocation location) {
+            Set<Constraint> potentialConstraints,
+            Set<Constraint> alternateConstraints, AnnotationLocation location) {
         super(combineSlots(potentialVariable, potentialConstraints, alternateConstraints), location);
         this.potentialVariable = potentialVariable;
-        this.potentialConstraints = Collections.unmodifiableList(potentialConstraints);
-        this.alternateConstraints = Collections.unmodifiableList(alternateConstraints);
+        this.potentialConstraints = Collections.unmodifiableSet(potentialConstraints);
+        this.alternateConstraints = Collections.unmodifiableSet(alternateConstraints);
     }
 
     protected static ExistentialConstraint create(VariableSlot potentialVariable,
-            List<Constraint> potentialConstraints, List<Constraint> alternateConstraints,
+            Set<Constraint> potentialConstraints, Set<Constraint> alternateConstraints,
             AnnotationLocation location) {
         if (potentialVariable == null || potentialConstraints == null
                 || alternateConstraints == null) {
@@ -57,10 +59,10 @@ protected static ExistentialConstraint create(VariableSlot potentialVariable,
     }
 
     @SafeVarargs
-    private static List<Slot> combineSlots(Slot potential, final List<Constraint> ... constraints) {
+    private static List<Slot> combineSlots(Slot potential, final Set<Constraint> ... constraints) {
         final List<Slot> slots = new ArrayList<>();
         slots.add(potential);
-        for (final List<Constraint> constraintList : constraints) {
+        for (final Set<Constraint> constraintList : constraints) {
             for (final Constraint constraint : constraintList) {
                 slots.addAll(constraint.getSlots());
             }
@@ -72,11 +74,11 @@ public VariableSlot getPotentialVariable() {
         return potentialVariable;
     }
 
-    public List<Constraint> potentialConstraints() {
+    public Set<Constraint> potentialConstraints() {
         return potentialConstraints;
     }
 
-    public List<Constraint> getAlternateConstraints() {
+    public Set<Constraint> getAlternateConstraints() {
         return alternateConstraints;
     }
 
@@ -85,6 +87,26 @@ public <S, T> T serialize(Serializer<S, T> serializer) {
         return serializer.serialize(this);
     }
 
+    @Override
+    public int hashCode() {
+        return HashCodeUtils.hash(389, potentialVariable, potentialConstraints,
+                alternateConstraints);
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) {
+            return true;
+        }
+        if (obj == null || getClass() != obj.getClass()) {
+            return false;
+        }
+        ExistentialConstraint other = (ExistentialConstraint) obj;
+        return potentialVariable.equals(other.potentialVariable)
+                && potentialConstraints.equals(other.potentialConstraints)
+                && alternateConstraints.equals(other.alternateConstraints);
+    }
+
     @Override
     public String toString() {
         String tab = "    ";

src/checkers/inference/model/ImplicationConstraint.java

@@ -145,7 +145,7 @@ public Constraint getConclusion() {
 
     @Override
     public int hashCode() {
-        return HashCodeUtils.hash(assumptions, conclusion);
+        return HashCodeUtils.hash(12289, assumptions, conclusion);
     }
 
     @Override

src/checkers/inference/model/InequalityConstraint.java

@@ -2,6 +2,7 @@
 
 import java.util.Arrays;
 
+import org.checkerframework.dataflow.util.HashCodeUtils;
 import org.checkerframework.javacutil.BugInCF;
 
 public class InequalityConstraint extends Constraint implements BinaryConstraint {
@@ -73,26 +74,20 @@ public Constraint make(Slot first, Slot second) {
 
     @Override
     public int hashCode() {
-        int result = 1;
-        result = result + ((first == null) ? 0 : first.hashCode());
-        result = result + ((second == null) ? 0 : second.hashCode());
-        return result;
+        // InequalityConstraint is insensitive to the order of the slots
+        return HashCodeUtils.hash(193, first.hashCode() + second.hashCode());
     }
 
     @Override
     public boolean equals(Object obj) {
-        if (this == obj)
+        if (this == obj) {
             return true;
-        if (obj == null)
-            return false;
-        if (getClass() != obj.getClass())
-            return false;
-        InequalityConstraint other = (InequalityConstraint) obj;
-        if ((first.equals(other.first) && second.equals(other.second))
-                || (first.equals(other.second) && (second.equals(other.first)))) {
-            return true;
-        } else {
+        }
+        if (obj == null || getClass() != obj.getClass()) {
             return false;
         }
+        InequalityConstraint other = (InequalityConstraint) obj;
+        return (first.equals(other.first) && second.equals(other.second))
+                || (first.equals(other.second) && second.equals(other.first));
     }
 }

src/checkers/inference/model/PreferenceConstraint.java

@@ -1,6 +1,8 @@
 package checkers.inference.model;
 
 import java.util.Arrays;
+
+import org.checkerframework.dataflow.util.HashCodeUtils;
 import org.checkerframework.javacutil.BugInCF;
 
 /**
@@ -49,40 +51,18 @@ public int getWeight() {
 
     @Override
     public int hashCode() {
-        final int prime = 31;
-        int result = 1;
-        result = prime * result + ((variable == null) ? 0 : variable.hashCode());
-        result = prime * result
-                + ((goal == null) ? 0 : goal.hashCode());
-        result = prime * result + weight;
-        return result;
+        return HashCodeUtils.hash(6151, variable, goal);
     }
 
     @Override
     public boolean equals(Object obj) {
-        if (this == obj)
+        if (this == obj) {
             return true;
-        if (obj == null)
-            return false;
-        if (getClass() != obj.getClass())
-            return false;
-        PreferenceConstraint other = (PreferenceConstraint) obj;
-        if (variable == null) {
-            if (other.variable != null) {
-                return false;
-            }
-        } else if (!variable.equals(other.variable)) {
-            return false;
         }
-
-        if (goal == null) {
-            if (other.goal != null) {
-                return false;
-            }
-        } else if (!goal.equals(other.goal)) {
+        if (obj == null || getClass() != obj.getClass()) {
             return false;
         }
-
-        return weight == other.weight;
+        PreferenceConstraint other = (PreferenceConstraint) obj;
+        return variable.equals(other.variable) && goal.equals(other.goal);
     }
 }