@@ -93,7 +93,7 @@ class Copy extends @duplication_or_similarity
     }
 
     /** Gets a textual representation of this element. */
-    string toString() { none() }
+    string toString() { result = "Copy" }
 
     /**
      * Gets a block that extends this one, that is, its first token is also
 
@@ -419,7 +419,7 @@ abstract class Num extends Num_, ImmutableLiteral {
 
     /* We want to declare this abstract, but currently we cannot. */
     override string toString() {
-        none() 
+        result = "Num with missing toString"
     }
 
 }
 
@@ -60,7 +60,7 @@ abstract class DictUnpackingOrKeyword extends DictItem {
     abstract Expr getValue();
 
     override string toString() {
-        none() 
+        result = "DictUnpackingOrKeyword with missing toString"
     }
 
 }
@@ -70,7 +70,7 @@ abstract class DictDisplayItem extends DictItem {
     abstract Expr getValue();
 
     override string toString() {
-        none() 
+        result = "DictDisplayItem with missing toString"
     }
 
 }
 
@@ -13,7 +13,7 @@ library class CfgOrigin extends @py_object {
 
     string toString() {
         /* Not to be displayed */
-        none()
+        result = "CfgOrigin"
     }
 
     /** Get a `ControlFlowNode` from `this` or `here`.
@@ -68,7 +68,7 @@ module CfgOrigin {
 //
 //    string toString() {
 //        /* Not to be displayed */
-//        none()
+//        result = "CfgOrigin"
 //    }
 //
 //    /** Get a `ControlFlowNode` from `this` or `here`.
 
@@ -20,7 +20,7 @@ import semmle.python.objects.ObjectInternal
 
 abstract class PointsToExtension extends @py_flow_node {
 
-    string toString() { none() }
+    string toString() { result = "PointsToExtension with missing toString" }
 
     abstract predicate pointsTo(Context context, ObjectInternal value, ControlFlowNode origin);
 
@@ -36,7 +36,7 @@ abstract class PointsToExtension extends @py_flow_node {
 /** DEPRECATED -- Use PointsToExtension instead */
 deprecated abstract class CustomPointsToFact extends @py_flow_node {
 
-    string toString() { none() }
+    string toString() { result = "CustomPointsToFact with missing toString" }
 
     abstract predicate pointsTo(Context context, Object value, ClassObject cls, ControlFlowNode origin);
Original file line number	Diff line number	Diff line change
`@@ -93,7 +93,7 @@ class Copy extends @duplication_or_similarity`
`93`	`93`	`}`
`94`	`94`
`95`	`95`	`/** Gets a textual representation of this element. */`
`96`		`- string toString() { none() }`
	`96`	`+ string toString() { result = "Copy" }`
`97`	`97`
`98`	`98`	`/**`
`99`	`99`	`* Gets a block that extends this one, that is, its first token is also`
Original file line number	Diff line number	Diff line change
`@@ -419,7 +419,7 @@ abstract class Num extends Num_, ImmutableLiteral {`
`419`	`419`
`420`	`420`	`/* We want to declare this abstract, but currently we cannot. */`
`421`	`421`	`override string toString() {`
`422`		`- none()`
	`422`	`+ result = "Num with missing toString"`
`423`	`423`	`}`
`424`	`424`
`425`	`425`	`}`
Original file line number	Diff line number	Diff line change
`@@ -60,7 +60,7 @@ abstract class DictUnpackingOrKeyword extends DictItem {`
`60`	`60`	`abstract Expr getValue();`
`61`	`61`
`62`	`62`	`override string toString() {`
`63`		`- none()`
	`63`	`+ result = "DictUnpackingOrKeyword with missing toString"`
`64`	`64`	`}`
`65`	`65`
`66`	`66`	`}`
`@@ -70,7 +70,7 @@ abstract class DictDisplayItem extends DictItem {`
`70`	`70`	`abstract Expr getValue();`
`71`	`71`
`72`	`72`	`override string toString() {`
`73`		`- none()`
	`73`	`+ result = "DictDisplayItem with missing toString"`
`74`	`74`	`}`
`75`	`75`
`76`	`76`	`}`