C++: Make IRBlock final

Author: aschackmull

cpp/ql/lib/semmle/code/cpp/ir/implementation/aliased_ssa/IRBlock.qll

@@ -121,7 +121,7 @@ class IRBlockBase extends TIRBlock {
  * corresponds to the control flow between the last instruction of one block and the first
  * instruction of another block.
  */
-class IRBlock extends IRBlockBase {
+final class IRBlock extends IRBlockBase {
   /**
    * Gets a block to which control flows directly from this block.
    */

cpp/ql/lib/semmle/code/cpp/ir/implementation/raw/IRBlock.qll

@@ -121,7 +121,7 @@ class IRBlockBase extends TIRBlock {
  * corresponds to the control flow between the last instruction of one block and the first
  * instruction of another block.
  */
-class IRBlock extends IRBlockBase {
+final class IRBlock extends IRBlockBase {
   /**
    * Gets a block to which control flows directly from this block.
    */

cpp/ql/lib/semmle/code/cpp/ir/implementation/unaliased_ssa/IRBlock.qll

@@ -121,7 +121,7 @@ class IRBlockBase extends TIRBlock {
  * corresponds to the control flow between the last instruction of one block and the first
  * instruction of another block.
  */
-class IRBlock extends IRBlockBase {
+final class IRBlock extends IRBlockBase {
   /**
    * Gets a block to which control flows directly from this block.
    */