C++: Rename union types to follow the naming convention of IPA types (and make them private)

Author: MathiasVP

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

@@ -289,7 +289,7 @@ class Declaration extends Locatable, @declaration {
   }
 }
 
-class DeclarationEntryDB = @var_decl or @type_decl or @fun_decl;
+private class TDeclarationEntry = @var_decl or @type_decl or @fun_decl;
 
 /**
  * A C/C++ declaration entry. For example the following code contains five
@@ -306,7 +306,7 @@ class DeclarationEntryDB = @var_decl or @type_decl or @fun_decl;
  * See the comment above `Declaration` for an explanation of the relationship
  * between `Declaration` and `DeclarationEntry`.
  */
-class DeclarationEntry extends Locatable, DeclarationEntryDB {
+class DeclarationEntry extends Locatable, TDeclarationEntry {
   /** Gets a specifier associated with this declaration entry. */
   string getASpecifier() { none() }
 
@@ -373,7 +373,7 @@ class DeclarationEntry extends Locatable, DeclarationEntryDB {
   }
 }
 
-class AccessHolderDB = @function or @usertype;
+private class TAccessHolder = @function or @usertype;
 
 /**
  * A declaration that can potentially have more C++ access rights than its
@@ -396,7 +396,7 @@ class AccessHolderDB = @function or @usertype;
  * the informal phrase "_R_ occurs in a member or friend of class C", where
  * `AccessHolder` corresponds to this _R_.
  */
-class AccessHolder extends Declaration, AccessHolderDB {
+class AccessHolder extends Declaration, TAccessHolder {
   /**
    * Holds if `this` can access private members of class `c`.
    *

cpp/ql/src/semmle/code/cpp/exprs/Call.qll

@@ -2,12 +2,12 @@ import semmle.code.cpp.exprs.Expr
 import semmle.code.cpp.Function
 private import semmle.code.cpp.dataflow.EscapesTree
 
-class CallDB = @funbindexpr or @callexpr;
+private class TCall = @funbindexpr or @callexpr;
 
 /**
  * A C/C++ call.
  */
-class Call extends Expr, NameQualifiableElement, CallDB {
+class Call extends Expr, NameQualifiableElement, TCall {
   // `@funbindexpr` (which is the dbscheme type for FunctionCall) is a union type that includes
   // `@routineexpr. This dbscheme type includes accesses to functions that are not necessarily calls to
   // that function. That's why the charpred for `FunctionCall` requires: