diff --git a/.clang-tidy b/.clang-tidy
index 231bf392..c8a0249d 100644
--- a/.clang-tidy
+++ b/.clang-tidy
@@ -16,6 +16,7 @@ Checks:          '*include*,
                   readability-convert-member-functions-to-static,
                   cppcoreguidelines-pro-type-member-init,
                   performance-unnecessary-value-param,
+                  google-runtime-int,
                   -altera-unroll-loops,
                   -altera-id-dependent-backward-branch,
                   -bugprone-easily-swappable-parameters,
diff --git a/src/interpreter/Interpreter.cpp b/src/interpreter/Interpreter.cpp
index 11cc8c92..4e0dfd64 100644
--- a/src/interpreter/Interpreter.cpp
+++ b/src/interpreter/Interpreter.cpp
@@ -165,7 +165,7 @@ void Interpreter::triggerDoesNotUnderstand(VMSymbol* signature) {
 
     // the receiver should not go into the argumentsArray
     // so, numberOfArgs - 2
-    for (long i = numberOfArgs - 2; i >= 0; --i) {
+    for (int64_t i = numberOfArgs - 2; i >= 0; --i) {
         vm_oop_t o = GetFrame()->Pop();
         argumentsArray->SetIndexableField(i, o);
     }
@@ -176,7 +176,7 @@ void Interpreter::triggerDoesNotUnderstand(VMSymbol* signature) {
     // check if current frame is big enough for this unplanned Send
     // doesNotUnderstand: needs 3 slots, one for this, one for method name, one
     // for args
-    long const additionalStackSlots = 3 - GetFrame()->RemainingStackSize();
+    int64_t const additionalStackSlots = 3 - GetFrame()->RemainingStackSize();
     if (additionalStackSlots > 0) {
         GetFrame()->SetBytecodeIndex(bytecodeIndexGlobal);
         // copy current frame into a bigger one and replace the current frame
@@ -288,7 +288,7 @@ void Interpreter::SendUnknownGlobal(VMSymbol* globalName) {
 
     // check if there is enough space on the stack for this unplanned Send
     // unknowGlobal: needs 2 slots, one for "this" and one for the argument
-    long const additionalStackSlots = 2 - GetFrame()->RemainingStackSize();
+    int64_t const additionalStackSlots = 2 - GetFrame()->RemainingStackSize();
     if (additionalStackSlots > 0) {
         GetFrame()->SetBytecodeIndex(bytecodeIndexGlobal);
         // copy current frame into a bigger one and replace the current
@@ -461,7 +461,8 @@ void Interpreter::doReturnNonLocal() {
 
         // check if current frame is big enough for this unplanned send
         // #escapedBlock: needs 2 slots, one for self, and one for the block
-        long const additionalStackSlots = 2 - GetFrame()->RemainingStackSize();
+        int64_t const additionalStackSlots =
+            2 - GetFrame()->RemainingStackSize();
         if (additionalStackSlots > 0) {
             GetFrame()->SetBytecodeIndex(bytecodeIndexGlobal);
             // copy current frame into a bigger one, and replace it
diff --git a/src/memory/DebugCopyingCollector.cpp b/src/memory/DebugCopyingCollector.cpp
index f1cad1f1..4a59914e 100644
--- a/src/memory/DebugCopyingCollector.cpp
+++ b/src/memory/DebugCopyingCollector.cpp
@@ -3,6 +3,7 @@
 
 #include <cassert>
 #include <cstddef>
+#include <cstdint>
 
 #include "../memory/Heap.h"
 #include "../misc/Timer.h"
diff --git a/src/vm/Universe.cpp b/src/vm/Universe.cpp
index 19ae1793..9190e662 100644
--- a/src/vm/Universe.cpp
+++ b/src/vm/Universe.cpp
@@ -343,8 +343,8 @@ void Universe::initialize(int32_t _argc, char** _argv) {
 
 #if CACHE_INTEGER
     // create prebuilt integers
-    for (long it = INT_CACHE_MIN_VALUE; it <= INT_CACHE_MAX_VALUE; ++it) {
-        prebuildInts[(unsigned long)(it - INT_CACHE_MIN_VALUE)] =
+    for (int64_t it = INT_CACHE_MIN_VALUE; it <= INT_CACHE_MAX_VALUE; ++it) {
+        prebuildInts[(size_t)(it - INT_CACHE_MIN_VALUE)] =
             store_root(new (GetHeap<HEAP_CLS>(), 0) VMInteger(it));
     }
 #endif