C++: Fix named qualifier dataset check error with decltypes

cpp/downgrades/2121ffec11fac265524955fee1775217364d4ca4/upgrade.properties

@@ -0,0 +1,2 @@
+description: Fix decltype qualifier issue
+compatibility: full

cpp/ql/lib/semmle/code/cpp/NameQualifiers.qll

@@ -144,14 +144,14 @@ class NameQualifiableElement extends Element, @namequalifiableelement {
 class NameQualifyingElement extends Element, @namequalifyingelement {
   /**
    * Gets a name qualifier for which this is the qualifying namespace or
-   * user-defined type. For example: class `X` is the
+   * user-defined type, or decltype. For example: class `X` is the
    * `NameQualifyingElement` and `X::` is the `NameQualifier`.
    */
   NameQualifier getANameQualifier() {
     namequalifiers(unresolveElement(result), _, underlyingElement(this), _)
   }
 
-  /** Gets the name of this namespace or user-defined type. */
+  /** Gets the name of this namespace, user-defined type, or decltype. */
   string getName() { none() }
 }
 

cpp/ql/lib/semmle/code/cpp/Type.qll

@@ -1146,7 +1146,7 @@ class DerivedType extends Type, @derivedtype {
  * decltype(a) b;
  * ```
  */
-class Decltype extends Type {
+class Decltype extends Type, NameQualifyingElement {
   Decltype() { decltypes(underlyingElement(this), _, 0, _, _) }
 
   override string getAPrimaryQlClass() { result = "Decltype" }
@@ -1187,7 +1187,7 @@ class Decltype extends Type {
 
   override string toString() { result = "decltype(...)" }
 
-  override string getName() { none() }
+  override string getName() { result = "decltype(...)" }
 
   override int getSize() { result = this.getBaseType().getSize() }
 
@@ -1247,7 +1247,7 @@ class TypeofType extends Type {
 
   override string toString() { result = "typeof(...)" }
 
-  override string getName() { none() }
+  override string getName() { result = "typeof(...)" }
 
   override int getSize() { result = this.getBaseType().getSize() }
 
@@ -1311,8 +1311,6 @@ class TypeofTypeType extends TypeofType {
   Type getType() { type_operators(underlyingElement(this), unresolveElement(result), _, _) }
 
   override string getAPrimaryQlClass() { result = "TypeofTypeType" }
-
-  override string toString() { result = "typeof(...)" }
 }
 
 /**
@@ -1394,7 +1392,7 @@ class IntrinsicTransformedType extends Type {
 
   override Type resolveTypedefs() { result = this.getBaseType().resolveTypedefs() }
 
-  override string getName() { none() }
+  override string getName() { result = this.getIntrinsicName() + "(...)" }
 
   override int getSize() { result = this.getBaseType().getSize() }
 

cpp/ql/lib/semmlecode.cpp.dbscheme

@@ -1327,7 +1327,8 @@ specialnamequalifyingelements(
 @namequalifiableelement = @expr | @namequalifier;
 @namequalifyingelement = @namespace
                        | @specialnamequalifyingelement
-                       | @usertype;
+                       | @usertype
+                       | @decltype;
 
 namequalifiers(
     unique int id: @namequalifier,