C++: Support mixed typedefs and usings

Author: jketema

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

@@ -13,7 +13,7 @@ private import semmle.code.cpp.internal.ResolveClass
  * ```
  */
 class TypedefType extends UserType {
-  TypedefType() { usertypes(underlyingElement(this), _, [5, 14]) }
+  TypedefType() { usertypes(underlyingElement(this), _, 18) }
 
   /**
    * Gets the base type of this typedef type.
@@ -54,7 +54,7 @@ class TypedefType extends UserType {
  * ```
  */
 class CTypedefType extends TypedefType {
-  CTypedefType() { usertypes(underlyingElement(this), _, 5) }
+  CTypedefType() { usertype_alias_kind(underlyingElement(this), 0) }
 
   override string getAPrimaryQlClass() { result = "CTypedefType" }
 
@@ -70,7 +70,7 @@ class CTypedefType extends TypedefType {
  * ```
  */
 class UsingAliasTypedefType extends TypedefType {
-  UsingAliasTypedefType() { usertypes(underlyingElement(this), _, 14) }
+  UsingAliasTypedefType() { usertype_alias_kind(underlyingElement(this), 1) }
 
   override string getAPrimaryQlClass() { result = "UsingAliasTypedefType" }
 

cpp/ql/lib/semmlecode.cpp.dbscheme

@@ -776,7 +776,7 @@ case @usertype.kind of
 |  2 = @class
 |  3 = @union
 |  4 = @enum
-|  5 = @typedef                       // classic C: typedef typedef type name
+// ... 5 = @typedef deprecated        // classic C: typedef typedef type name
 // ... 6 = @template deprecated
 |  7 = @template_parameter
 |  8 = @template_template_parameter
@@ -785,10 +785,11 @@ case @usertype.kind of
 // ... 11 objc_protocol deprecated
 // ... 12 objc_category deprecated
 | 13 = @scoped_enum
-| 14 = @using_alias                  // a using name = type style typedef
+// ... 14 = @using_alias deprecated   // a using name = type style typedef
 | 15 = @template_struct
 | 16 = @template_class
 | 17 = @template_union
+| 18 = @alias
 ;
 */
 
@@ -811,6 +812,17 @@ usertype_uuid(
     string uuid: string ref
 );
 
+/*
+case @usertype.alias_kind of
+| 0 = @typedef
+| 1 = @alias
+*/
+
+usertype_alias_kind(
+    int id: @usertype ref,
+    int alias_kind: int ref
+)
+
 nontype_template_parameters(
     int id: @expr ref
 );