C++: Add failing test.

Author: MathiasVP

cpp/ql/test/library-tests/dataflow/taint-tests/localTaint.expected

@@ -6646,6 +6646,17 @@ WARNING: Module TaintTracking has been deprecated and may be removed in future (
 | taint.cpp:738:17:738:31 | call to indirect_source | taint.cpp:739:30:739:35 | source |  |
 | taint.cpp:739:22:739:28 | call to realloc | taint.cpp:740:7:740:10 | dest |  |
 | taint.cpp:739:30:739:35 | source | taint.cpp:739:22:739:28 | call to realloc | TAINT |
+| taint.cpp:743:40:743:45 | buffer | taint.cpp:744:5:744:10 | buffer |  |
+| taint.cpp:743:40:743:45 | buffer | taint.cpp:745:27:745:32 | buffer |  |
+| taint.cpp:744:4:744:10 | * ... | taint.cpp:744:3:744:10 | * ... | TAINT |
+| taint.cpp:744:5:744:10 | buffer | taint.cpp:744:4:744:10 | * ... | TAINT |
+| taint.cpp:744:14:744:19 | call to source | taint.cpp:744:3:744:21 | ... = ... |  |
+| taint.cpp:745:19:745:25 | call to realloc | taint.cpp:743:40:743:45 | buffer |  |
+| taint.cpp:745:19:745:25 | call to realloc | taint.cpp:745:3:745:36 | ... = ... |  |
+| taint.cpp:745:19:745:25 | call to realloc | taint.cpp:746:10:746:15 | buffer |  |
+| taint.cpp:745:27:745:32 | buffer | taint.cpp:745:19:745:25 | call to realloc | TAINT |
+| taint.cpp:746:9:746:15 | * ... | taint.cpp:746:8:746:15 | * ... | TAINT |
+| taint.cpp:746:10:746:15 | buffer | taint.cpp:746:9:746:15 | * ... | TAINT |
 | vector.cpp:16:43:16:49 | source1 | vector.cpp:17:26:17:32 | source1 |  |
 | vector.cpp:16:43:16:49 | source1 | vector.cpp:31:38:31:44 | source1 |  |
 | vector.cpp:17:21:17:33 | call to vector | vector.cpp:19:14:19:14 | v |  |

cpp/ql/test/library-tests/dataflow/taint-tests/taint.cpp

@@ -738,4 +738,10 @@ void test_realloc() {
 	char *source = indirect_source();
 	char *dest = (char*)realloc(source, 16);
 	sink(dest); // $ ir MISSING: ast
+}
+
+void test_realloc_2_indirections(int **buffer) {
+  **buffer = source();
+  buffer = (int**)realloc(buffer, 16);
+  sink(**buffer); // $ MISSING: ir,ast
 }