C++: Test for erroneous string types

Author: calumgrant

cpp/ql/test/query-tests/Likely Bugs/Format/WrongTypeFormatArguments/Buildless/WrongTypeFormatArguments.expected

@@ -1 +1,2 @@
 | tests.c:7:18:7:18 | 1 | This format specifier for type 'char *' does not match the argument type 'int'. |
+| tests.c:11:18:11:20 | str | This format specifier for type 'char *' does not match the argument type '<error-type> *'. |

cpp/ql/test/query-tests/Likely Bugs/Format/WrongTypeFormatArguments/Buildless/tests.c

@@ -3,9 +3,10 @@
 int printf(const char * format, ...);
 int fprintf();
 
-void f() {
+void f(UNKNOWN_CHAR * str) {
     printf("%s", 1); // BAD
     printf("%s", implicit_function()); // GOOD - we should ignore the type
     sprintf(0, "%s", ""); // GOOD
     fprintf(0, "%s", ""); // GOOD
+    printf("%s", str); // GOOD - erroneous type is ignored
 }