Disambiguate owners of fields in output

dataflow/src/main/java/org/checkerframework/dataflow/cfg/node/ExplicitThisNode.java

@@ -32,6 +32,10 @@ public <R, P> R accept(NodeVisitor<R, P> visitor, P p) {
 
   @Override
   public String toString() {
-    return "this";
+    if (Node.disambiguateOwner) {
+      return "this{owner=" + type + "}";
+    } else {
+      return "this";
+    }
   }
 }

dataflow/src/main/java/org/checkerframework/dataflow/cfg/node/FieldAccessNode.java

@@ -3,6 +3,7 @@
 import com.sun.source.tree.IdentifierTree;
 import com.sun.source.tree.MemberSelectTree;
 import com.sun.source.tree.Tree;
+import com.sun.tools.javac.code.Symbol;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.Objects;
@@ -91,7 +92,11 @@ public <R, P> R accept(NodeVisitor<R, P> visitor, P p) {
 
   @Override
   public String toString() {
-    return getReceiver() + "." + field;
+    if (Node.disambiguateOwner) {
+      return getReceiver() + "." + field + "{owner=" + ((Symbol) element).owner + "}";
+    } else {
+      return getReceiver() + "." + field;
+    }
   }
 
   /**

dataflow/src/main/java/org/checkerframework/dataflow/cfg/node/ImplicitThisNode.java

@@ -26,6 +26,10 @@ public <R, P> R accept(NodeVisitor<R, P> visitor, P p) {
   // used in an inner class context.
   @Override
   public String toString() {
-    return "(this)";
+    if (Node.disambiguateOwner) {
+      return "(this{owner=" + type + "})";
+    } else {
+      return "(this)";
+    }
   }
 }

dataflow/src/main/java/org/checkerframework/dataflow/cfg/node/Node.java

@@ -35,6 +35,12 @@
  */
 public abstract class Node implements UniqueId {
 
+  /**
+   * If true, print the owner of each field and {@code this}, to disambiguate shadowing. This field
+   * is intended for debugging.
+   */
+  public static final boolean disambiguateOwner = false;
+
   /**
    * The basic block this node belongs to. If null, this object represents a method formal
    * parameter.

dataflow/src/main/java/org/checkerframework/dataflow/cfg/node/SuperNode.java

@@ -13,6 +13,9 @@
  * <pre>
  *   <em>super</em>
  * </pre>
+ *
+ * Its {@link #type} field is the type of the class in which "super" appears, <em>not</em> the type
+ * to which the "super" identifier resolves.
  */
 public class SuperNode extends Node {
 
@@ -36,7 +39,11 @@ public <R, P> R accept(NodeVisitor<R, P> visitor, P p) {
 
   @Override
   public String toString() {
-    return "super";
+    if (Node.disambiguateOwner) {
+      return "super{owner=" + type + "}";
+    } else {
+      return "super";
+    }
   }
 
   @Override

dataflow/src/main/java/org/checkerframework/dataflow/expression/FieldAccess.java

@@ -7,6 +7,7 @@
 import org.checkerframework.checker.nullness.qual.Nullable;
 import org.checkerframework.dataflow.analysis.Store;
 import org.checkerframework.dataflow.cfg.node.FieldAccessNode;
+import org.checkerframework.dataflow.cfg.node.Node;
 import org.checkerframework.javacutil.AnnotationProvider;
 import org.checkerframework.javacutil.BugInCF;
 import org.checkerframework.javacutil.ElementUtils;
@@ -139,8 +140,10 @@ public boolean containsModifiableAliasOf(Store<?> store, JavaExpression other) {
 
   @Override
   public String toString() {
-    if (receiver instanceof ClassName) {
-      return receiver.getType() + "." + field;
+    String receiverString =
+        (receiver instanceof ClassName) ? receiver.getType().toString() : receiver.toString();
+    if (Node.disambiguateOwner) {
+      return receiverString + "." + field + "{owner=" + ((Symbol) field).owner + "}";
     } else {
       return receiver + "." + field;
     }

dataflow/src/main/java/org/checkerframework/dataflow/expression/ThisReference.java

@@ -3,6 +3,7 @@
 import javax.lang.model.type.TypeMirror;
 import org.checkerframework.checker.nullness.qual.Nullable;
 import org.checkerframework.dataflow.analysis.Store;
+import org.checkerframework.dataflow.cfg.node.Node;
 import org.checkerframework.javacutil.AnnotationProvider;
 import org.checkerframework.javacutil.TypesUtils;
 
@@ -29,7 +30,11 @@ public int hashCode() {
 
   @Override
   public String toString() {
-    return "this";
+    if (Node.disambiguateOwner) {
+      return "this{" + type + "}";
+    } else {
+      return "this";
+    }
   }
 
   @SuppressWarnings("unchecked") // generic cast

dataflow/src/main/java/org/checkerframework/dataflow/expression/ViewpointAdaptJavaExpression.java

@@ -62,7 +62,7 @@ public static JavaExpression viewpointAdapt(
   /** List of arguments used to replace occurrences {@link FormalParameter}s. */
   private final @Nullable List<JavaExpression> args;
 
-  /** The expression to replace occurrences of {@link ThisReference}s. */
+  /** The expression to replace occurrences of {@link ThisReference}. */
   private final @Nullable JavaExpression thisReference;
 
   // Instance methods

javacutil/src/main/java/org/checkerframework/javacutil/TreeUtils.java

@@ -1844,6 +1844,9 @@ public static boolean isLocalVariable(Tree tree) {
    * Returns the type as a TypeMirror of {@code tree}. To obtain {@code tree}'s AnnotatedTypeMirror,
    * call {@code AnnotatedTypeFactory.getAnnotatedType()}.
    *
+   * <p>Note that for the expression "super", this method returns the type of "this", not "this"'s
+   * superclass.
+   *
    * @return the type as a TypeMirror of {@code tree}
    */
   public static TypeMirror typeOf(Tree tree) {