Merge pull request #18200 from github/calumgrant/bmn/wrong-type-format-args2

C++: Fix more FPs with extraction errors on cpp/wrong-type-format-arguments

Author: calumgrant

cpp/ql/src/Likely Bugs/Format/WrongTypeFormatArguments.ql

@@ -170,7 +170,7 @@ where
   ) and
   not arg.isAffectedByMacro() and
   not arg.isFromUninstantiatedTemplate(_) and
-  not actual.getUnspecifiedType() instanceof ErroneousType and
+  not actual.stripType() instanceof ErroneousType and
   not arg.(Call).mayBeFromImplicitlyDeclaredFunction()
 select arg,
   "This format specifier for type '" + expected.getName() + "' does not match the argument type '" +

cpp/ql/src/change-notes/2024-12-05-wrong-type-format-args.md

@@ -0,0 +1,4 @@
+---
+category: minorAnalysis
+---
+* The "Wrong type of arguments to formatting function" query (`cpp/wrong-type-format-argument`) no longer produces results when an argument type has an extraction error.

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
 }