Fix equality test; fixes #4806

Co-authored-by: Martin Kellogg <kelloggm@cs.washington.edu>

checker/tests/calledmethods/EnsuresCalledMethodsThisLub.java

@@ -0,0 +1,43 @@
+import org.checkerframework.checker.calledmethods.qual.CalledMethods;
+import org.checkerframework.checker.calledmethods.qual.EnsuresCalledMethods;
+
+class EnsuresCalledMethodsThisLub {
+
+  @EnsuresCalledMethods(
+      value = "#1",
+      methods = {"toString", "equals"})
+  void call1(Object obj) {
+    obj.toString();
+    obj.equals(null);
+  }
+
+  @EnsuresCalledMethods(
+      value = "#1",
+      methods = {"toString", "hashCode"})
+  void call2(Object obj) {
+    obj.toString();
+    obj.hashCode();
+  }
+
+  void test(boolean b) {
+    if (b) {
+      call1(this);
+    } else {
+      call2(this);
+    }
+    @CalledMethods("toString") Object obj1 = this;
+    // :: error: (assignment)
+    @CalledMethods({"toString", "equals"}) Object obj2 = this;
+  }
+
+  void test_arg(Object arg, boolean b) {
+    if (b) {
+      call1(arg);
+    } else {
+      call2(arg);
+    }
+    @CalledMethods("toString") Object obj1 = arg;
+    // :: error: (assignment)
+    @CalledMethods({"toString", "equals"}) Object obj2 = arg;
+  }
+}

framework/src/main/java/org/checkerframework/framework/flow/CFAbstractStore.java

@@ -4,6 +4,7 @@
 import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
 import java.util.StringJoiner;
 import java.util.concurrent.atomic.AtomicLong;
 import java.util.function.BinaryOperator;
@@ -1181,6 +1182,9 @@ protected boolean supersetOf(CFAbstractStore<V, S> other) {
         return false;
       }
     }
+    if (!Objects.equals(thisValue, other.thisValue)) {
+      return false;
+    }
     for (Map.Entry<FieldAccess, V> e : other.fieldValues.entrySet()) {
       FieldAccess key = e.getKey();
       V value = fieldValues.get(key);