...

src/compiler/NubLang/Generation/QBE/QBEGenerator.cs

@@ -378,7 +378,8 @@ public partial class QBEGenerator
 
         EmitBlock(body, scope);
 
-        if (body.Statements.LastOrDefault() is not BoundReturn)
+        // Implicit return for void functions if no explicit return has been set
+        if (returnType is NubVoidType && body.Statements is [.., not BoundReturn])
         {
             if (returnType is NubVoidType)
             {