C++: Simplify deallocation check

Author: jketema

cpp/ql/src/Critical/MissingCheckScanf.ql

@@ -112,21 +112,11 @@ BasicBlock blockGuardedBy(int value, string op, ScanfFunctionCall call) {
   )
 }
 
-predicate isDeallocationAccess(Access access) {
-  exists(FunctionCall deallocCall, DeallocationFunction deallocFunc |
-    deallocCall.getTarget() = deallocFunc
-  |
-    deallocCall.getArgument(deallocFunc.getFreedArg()) = access
-  )
-  or
-  exists(DeallocationExpr deallocExpr | deallocExpr.getFreedExpr() = access)
-}
-
 from ScanfOutput output, ScanfFunctionCall call, Access access
 where
   output.getCall() = call and
   output.hasGuardedAccess(access, false) and
-  not isDeallocationAccess(access)
+  not exists(DeallocationExpr dealloc | dealloc.getFreedExpr() = access)
 select access,
   "This variable is read, but may not have been written. " +
     "It should be guarded by a check that the $@ returns at least " +