diff --git a/Source/cmList.h b/Source/cmList.h
index 0f875e716e..1b94c2f2e0 100644
--- a/Source/cmList.h
+++ b/Source/cmList.h
@@ -747,8 +747,10 @@ public:
                        ExpandElements expandElements = ExpandElements::Yes,
                        EmptyElements emptyElements = EmptyElements::No)
   {
-    this->insert(this->begin() + this->ComputeInsertIndex(index), first, last,
-                 expandElements, emptyElements);
+    auto const offset =
+      static_cast<difference_type>(this->ComputeInsertIndex(index));
+    this->insert(this->begin() + offset, first, last, expandElements,
+                 emptyElements);
     return *this;
   }
   template <typename InputIterator>
@@ -1186,13 +1188,13 @@ private:
         auto size = container.size();
         insertPos = cmList::Insert(container, insertPos, *first,
                                    expandElements, emptyElements);
-        insertPos += container.size() - size;
+        insertPos += static_cast<decltype(delta)>(container.size() - size);
       }
     } else {
       for (; first != last; ++first) {
         if (!first->empty() || emptyElements == EmptyElements::Yes) {
           insertPos = container.insert(insertPos, *first);
-          insertPos++;
+          ++insertPos;
         }
       }
     }
diff --git a/Source/cmString.hxx b/Source/cmString.hxx
index 86b21c8ef7..1994c2ce10 100644
--- a/Source/cmString.hxx
+++ b/Source/cmString.hxx
@@ -493,8 +493,8 @@ public:
                   char ch)
   {
     std::string out;
-    out.reserve((first - this->view_.begin()) + count2 +
-                (this->view_.end() - last));
+    out.reserve(static_cast<size_type>(first - this->view_.begin()) + count2 +
+                static_cast<size_type>(this->view_.end() - last));
     out.append(this->view_.begin(), first);
     out.append(count2, ch);
     out.append(last, this->view_.end());