C++: Also exclude unevaluated buffers in 'OverflowStatic'.

Author: MathiasVP

cpp/ql/src/Critical/OverflowStatic.ql

@@ -22,7 +22,8 @@ import LoopBounds
 private predicate staticBufferBase(VariableAccess access, Variable v) {
   v.getType().(ArrayType).getBaseType() instanceof CharType and
   access = v.getAnAccess() and
-  not memberMayBeVarSize(_, v)
+  not memberMayBeVarSize(_, v) and
+  not access.isUnevaluated()
 }
 
 predicate staticBuffer(VariableAccess access, Variable v, int size) {

cpp/ql/test/query-tests/Critical/OverflowStatic/OverflowStatic.expected

@@ -14,4 +14,3 @@
 | test.cpp:24:27:24:27 | 4 | Potential buffer-overflow: 'buffer1' has size 3 not 4. |
 | test.cpp:26:27:26:27 | 4 | Potential buffer-overflow: 'buffer2' has size 3 not 4. |
 | test.cpp:40:22:40:27 | amount | Potential buffer-overflow: 'buffer' has size 100 not 101. |
-| test.cpp:62:33:62:43 | access to array | Potential buffer-overflow: 'buffer' has size 100 but 'buffer[101]' may be accessed here. |

cpp/ql/test/query-tests/Critical/OverflowStatic/test.cpp

@@ -59,5 +59,5 @@ void f3() {
 
 int unevaluated_test() {
 	char buffer[100];
-	return sizeof(buffer) / sizeof(buffer[101]); // GOOD [FALSE POSITIVE]
+	return sizeof(buffer) / sizeof(buffer[101]); // GOOD
 }