C++: Add getCanonicalQLClass overrides in Variable

cpp/ql/src/semmle/code/cpp/Field.qll

@@ -19,6 +19,8 @@ import semmle.code.cpp.exprs.Access
 class Field extends MemberVariable {
   Field() { fieldoffsets(underlyingElement(this), _, _) }
 
+  override string getCanonicalQLClass() { result = "Field" }
+
   /**
    * Gets the offset of this field in bytes from the start of its declaring
    * type (on the machine where facts were extracted).
@@ -84,6 +86,8 @@ class Field extends MemberVariable {
 class BitField extends Field {
   BitField() { bitfield(underlyingElement(this), _, _) }
 
+  override string getCanonicalQLClass() { result = "BitField" }
+
   /**
    * Gets the size of this bitfield in bits (on the machine where facts
    * were extracted).

cpp/ql/src/semmle/code/cpp/Variable.qll

@@ -28,6 +28,8 @@ private import semmle.code.cpp.internal.ResolveClass
  * can have multiple declarations.
  */
 class Variable extends Declaration, @variable {
+  override string getCanonicalQLClass() { result = "Variable" }
+
   /** Gets the initializer of this variable, if any. */
   Initializer getInitializer() { result.getDeclaration() = this }
 
@@ -351,6 +353,8 @@ class StackVariable extends LocalScopeVariable {
  * A local variable can be declared by a `DeclStmt` or a `ConditionDeclExpr`.
  */
 class LocalVariable extends LocalScopeVariable, @localvariable {
+  override string getCanonicalQLClass() { result = "LocalVariable" }
+
   override string getName() { localvariables(underlyingElement(this), _, result) }
 
   override Type getType() { localvariables(underlyingElement(this), unresolveElement(result), _) }
@@ -396,6 +400,8 @@ class NamespaceVariable extends GlobalOrNamespaceVariable {
   NamespaceVariable() {
     exists(Namespace n | namespacembrs(unresolveElement(n), underlyingElement(this)))
   }
+
+  override string getCanonicalQLClass() { result = "NamespaceVariable" }
 }
 
 /**
@@ -415,6 +421,8 @@ class NamespaceVariable extends GlobalOrNamespaceVariable {
  */
 class GlobalVariable extends GlobalOrNamespaceVariable {
   GlobalVariable() { not this instanceof NamespaceVariable }
+
+  override string getCanonicalQLClass() { result = "GlobalVariable" }
 }
 
 /**
@@ -434,6 +442,8 @@ class GlobalVariable extends GlobalOrNamespaceVariable {
 class MemberVariable extends Variable, @membervariable {
   MemberVariable() { this.isMember() }
 
+  override string getCanonicalQLClass() { result = "MemberVariable" }
+
   /** Holds if this member is private. */
   predicate isPrivate() { this.hasSpecifier("private") }