C++: Add a predicate for getting the 0'th child of a 'ConditionDeclExpr' without casting it to a 'VariableAccess' and use it in IR generation.

Author: MathiasVP

cpp/ql/lib/semmle/code/cpp/exprs/Assignment.qll

@@ -244,9 +244,15 @@ class ConditionDeclExpr extends Expr, @condition_decl {
 
   /**
    * Gets the compiler-generated variable access that conceptually occurs after
-   * the initialization of the declared variable.
+   * the initialization of the declared variable, if any.
    */
-  VariableAccess getVariableAccess() { result = this.getChild(0) }
+  VariableAccess getVariableAccess() { result = this.getExpr() }
+
+  /**
+   * Gets the expression that is evaluated after the initialization of the declared
+   * variable.
+   */
+  Expr getExpr() { result = this.getChild(0) }
 
   /**
    * Gets the expression that initializes the declared variable. This predicate

cpp/ql/lib/semmle/code/cpp/ir/implementation/raw/internal/TranslatedExpr.qll

@@ -3173,7 +3173,7 @@ class TranslatedConditionDeclExpr extends TranslatedNonConstantExpr {
   private TranslatedConditionDecl getDecl() { result = getTranslatedConditionDecl(expr) }
 
   private TranslatedExpr getConditionExpr() {
-    result = getTranslatedExpr(expr.getVariableAccess().getFullyConverted())
+    result = getTranslatedExpr(expr.getExpr().getFullyConverted())
   }
 }