diff --git a/src/openrct2/common.h b/src/openrct2/common.h
index 15ffd8f000..e0bdd02cdb 100644
--- a/src/openrct2/common.h
+++ b/src/openrct2/common.h
@@ -37,8 +37,6 @@
 #include <string.h>
 #include <stdbool.h>
 
-#include "diagnostic.h"
-
 typedef int8_t sint8;
 typedef int16_t sint16;
 typedef int32_t sint32;
@@ -48,6 +46,8 @@ typedef uint16_t uint16;
 typedef uint32_t uint32;
 typedef uint64_t uint64;
 
+#include "diagnostic.h"
+
 typedef char utf8;
 typedef utf8* utf8string;
 typedef const utf8* const_utf8string;
diff --git a/src/openrct2/diagnostic.c b/src/openrct2/diagnostic.c
index 0166235e23..ebb34b8029 100644
--- a/src/openrct2/diagnostic.c
+++ b/src/openrct2/diagnostic.c
@@ -19,8 +19,8 @@
 #include <stdio.h>
 #include "diagnostic.h"
 
-int _log_levels[DIAGNOSTIC_LEVEL_COUNT] = { 1, 1, 1, 0, 1 };
-int _log_location_enabled = 1;
+sint32 _log_levels[DIAGNOSTIC_LEVEL_COUNT] = { 1, 1, 1, 0, 1 };
+sint32 _log_location_enabled = 1;
 
 const char * _level_strings[] = {
 	"FATAL",
@@ -30,7 +30,7 @@ const char * _level_strings[] = {
 	"INFO"
 };
 
-void diagnostic_log(int diagnosticLevel, const char *format, ...)
+void diagnostic_log(sint32 diagnosticLevel, const char *format, ...)
 {
 	FILE *stream;
 	va_list args;
@@ -52,7 +52,7 @@ void diagnostic_log(int diagnosticLevel, const char *format, ...)
 	fprintf(stream, "\n");
 }
 
-void diagnostic_log_with_location(int diagnosticLevel, const char *file, const char *function, int line, const char *format, ...)
+void diagnostic_log_with_location(sint32 diagnosticLevel, const char *file, const char *function, sint32 line, const char *format, ...)
 {
 	FILE *stream;
 	va_list args;
diff --git a/src/openrct2/diagnostic.h b/src/openrct2/diagnostic.h
index f862a9a278..0368b6236e 100644
--- a/src/openrct2/diagnostic.h
+++ b/src/openrct2/diagnostic.h
@@ -48,6 +48,8 @@ enum {
  * only checking whether the define is present or not.
  */
 
+#include "common.h"
+
 #if defined(DEBUG)
 	#if DEBUG > 0
 		#define DEBUG_LEVEL_1 1
@@ -73,14 +75,14 @@ enum {
 	#define DEBUG_LEVEL_1 0
 #endif // defined(DEBUG)
 
-extern int _log_levels[DIAGNOSTIC_LEVEL_COUNT];
+extern sint32 _log_levels[DIAGNOSTIC_LEVEL_COUNT];
 
 #ifdef __cplusplus
 extern "C" {
 #endif // __cplusplus
 
-void diagnostic_log(int diagnosticLevel, const char *format, ...);
-void diagnostic_log_with_location(int diagnosticLevel, const char *file, const char *function, int line, const char *format, ...);
+void diagnostic_log(sint32 diagnosticLevel, const char *format, ...);
+void diagnostic_log_with_location(sint32 diagnosticLevel, const char *file, const char *function, sint32 line, const char *format, ...);
 
 #ifdef __cplusplus
 }