diff --git a/drd/tests/unit_bitmap.c b/drd/tests/unit_bitmap.c
index 6de61acdb..29892e47c 100644
--- a/drd/tests/unit_bitmap.c
+++ b/drd/tests/unit_bitmap.c
@@ -28,8 +28,8 @@ void* VG_(malloc)(HChar* cc, SizeT nbytes)
 { return malloc(nbytes); }
 void  VG_(free)(void* p)
 { return free(p); }
-void  VG_(assert_fail)(Bool isCore, const Char* assertion, const Char* file,
-                       Int line, const Char* function, const HChar* format,
+void  VG_(assert_fail)(Bool isCore, const HChar* assertion, const HChar* file,
+                       Int line, const HChar* function, const HChar* format,
                        ...)
 {
   fprintf(stderr,
diff --git a/drd/tests/unit_vc.c b/drd/tests/unit_vc.c
index 353ce4b3a..d9d9bb5dd 100644
--- a/drd/tests/unit_vc.c
+++ b/drd/tests/unit_vc.c
@@ -16,8 +16,8 @@ void* VG_(realloc)(HChar* cc, void* p, SizeT size)
 { return realloc(p, size); }
 void  VG_(free)(void* p)
 { return free(p); }
-void  VG_(assert_fail)(Bool isCore, const Char* assertion, const Char* file,
-                       Int line, const Char* function, const HChar* format,
+void  VG_(assert_fail)(Bool isCore, const HChar* assertion, const HChar* file,
+                       Int line, const HChar* function, const HChar* format,
                        ...)
 {
   fprintf(stderr,
diff --git a/none/tests/valgrind_cpp_test.cpp b/none/tests/valgrind_cpp_test.cpp
index 41a522b5e..5328829fb 100644
--- a/none/tests/valgrind_cpp_test.cpp
+++ b/none/tests/valgrind_cpp_test.cpp
@@ -40,8 +40,8 @@ int main(int argc, char** argv)
   return 0;
 }
 
-void VG_(assert_fail)(Bool isCore, const Char* expr, const Char* file,
-                      Int line, const Char* fn, const HChar* format, ... )
+void VG_(assert_fail)(Bool isCore, const HChar* expr, const HChar* file,
+                      Int line, const HChar* fn, const HChar* format, ... )
 {
   abort();
 }