C++: Add LambdaExpression.getInitializer()

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

@@ -57,6 +57,14 @@ class LambdaExpression extends Expr, @lambdaexpr {
   Operator getLambdaFunction() {
     result = getType().(Closure).getLambdaFunction()
   }
+
+  /**
+   * Gets the initializer that initializes the captured variables in the closure, if any.
+   * A lambda that does not capture any variables will not have an initializer.
+   */
+  Expr getInitializer() {
+    result = getChild(0)
+  }
 }
 
 /**

cpp/ql/src/semmle/code/cpp/ir/implementation/raw/internal/TranslatedElement.qll

@@ -270,7 +270,7 @@ newtype TTranslatedElement =
         throw.getExpr().getFullyConverted() = expr
       ) or
       exists(LambdaExpression lambda |
-        lambda.getChild(0).getFullyConverted() = expr
+        lambda.getInitializer().getFullyConverted() = expr
       )
     )
   } or