diff --git a/cpp/ql/test/library-tests/syntax-zoo/forstmt.cpp b/cpp/ql/test/library-tests/syntax-zoo/forstmt.cpp
index 917ccb0bbfd..61cb3ed59d7 100644
--- a/cpp/ql/test/library-tests/syntax-zoo/forstmt.cpp
+++ b/cpp/ql/test/library-tests/syntax-zoo/forstmt.cpp
@@ -1,21 +1,21 @@
-void f1() {
+static void f1() {
     for (int i = 0; i < 10; i++) {
         l1:
     }
     ;
 }
 
-void f2() {
+static void f2() {
     for (int i = 0; false; i++) { // true edge pruned
     }
 }
 
-void f3() {
+static void f3() {
     for (int i = 0; true; i++) { // false edge pruned
     }
 }
 
-void f4() {
+static void f4() {
     for (int i = 0; i < 0; i++) { // true edge pruned
     }
 }
\ No newline at end of file
diff --git a/cpp/ql/test/library-tests/syntax-zoo/lorexpr.c b/cpp/ql/test/library-tests/syntax-zoo/lorexpr.c
index d03d89760b6..f49446ff903 100644
--- a/cpp/ql/test/library-tests/syntax-zoo/lorexpr.c
+++ b/cpp/ql/test/library-tests/syntax-zoo/lorexpr.c
@@ -1,4 +1,4 @@
-void f() {
+static void f() {
 	int a, b;
 	if (a || b) {
 	}