Merge pull request #394 from github/lcartey/m8-5-2-aggregate-variadic

`M8-5-2`: recognise aggregate literals initialized with parameters from variadic templates.

Author: lcartey

change_notes/2023-10-04-aggregate-literals-from-variadic-templates.md

@@ -0,0 +1,2 @@
+ `M8-5-2` - `AggregateLiteralEnhancements.qll`:
+   - recognise aggregate literals initialized with parameters from variadic templates.

cpp/autosar/test/rules/M8-5-2/test.cpp

@@ -55,4 +55,13 @@ void test() {
   Bar b2{{0}};      // NON_COMPLIANT - missing explicit init, nested zero init
   StructNested n{}; // COMPLIANT
   StructNested n1 = {}; // COMPLIANT
-}
+}
+
+#include <initializer_list>
+template <class T> bool all_of(std::initializer_list<T>);
+
+template <typename... Args> constexpr bool all_of(Args... args) noexcept {
+  return all_of({args...}); // COMPLIANT - explicitly initialized via varargs
+}
+
+void test_all_of() { all_of(true, false, false); }

cpp/common/src/codingstandards/cpp/enhancements/AggregateLiteralEnhancements.qll

@@ -85,6 +85,9 @@ module ArrayAggregateLiterals {
         // The aggregate itself not be compiler generated, or in a macro expansion, otherwise our line numbers will be off
         not cal.isCompilerGenerated() and
         not cal.isInMacroExpansion() and
+        // Ignore cases where the compilerGenerated value is a variable access targeting
+        // a parameter, as these are generated from variadic templates
+        not compilerGeneratedVal.(VariableAccess).getTarget() instanceof Parameter and
         exists(string filepath, int startline, int startcolumn, int endline, int endcolumn |
           compilerGeneratedVal.getLocation().hasLocationInfo(filepath, _, _, endline, endcolumn) and
           previousExpr