diff --git a/src/pages/ClientiPage.tsx b/src/pages/ClientiPage.tsx
index caf93cd..e4cc06d 100644
--- a/src/pages/ClientiPage.tsx
+++ b/src/pages/ClientiPage.tsx
@@ -124,7 +124,7 @@ export default function ClientiPage() {
     try {
       if (editing) {
         const validation = validateClienteUpdate(raw);
-        if (!validation.success) {
+        if (validation.success === false) {
           setFieldErrors(validation.errors);
           setSaving(false);
           return;
@@ -133,7 +133,7 @@ export default function ClientiPage() {
         toast.success("Cliente aggiornato");
       } else {
         const validation = validateClienteCreate(raw);
-        if (!validation.success) {
+        if (validation.success === false) {
           setFieldErrors(validation.errors);
           setSaving(false);
           return;
diff --git a/src/pages/ConsegnePage.tsx b/src/pages/ConsegnePage.tsx
index 8c17997..9d82e44 100644
--- a/src/pages/ConsegnePage.tsx
+++ b/src/pages/ConsegnePage.tsx
@@ -140,7 +140,7 @@ export default function ConsegnePage() {
     try {
       if (editing) {
         const validation = validateConsegnaUpdate(raw);
-        if (!validation.success) {
+        if (validation.success === false) {
           setFieldErrors(validation.errors);
           setSaving(false);
           return;
@@ -149,7 +149,7 @@ export default function ConsegnePage() {
         toast.success("Consegna aggiornata");
       } else {
         const validation = validateConsegnaCreate(raw);
-        if (!validation.success) {
+        if (validation.success === false) {
           setFieldErrors(validation.errors);
           setSaving(false);
           return;
diff --git a/src/pages/Login.tsx b/src/pages/Login.tsx
index 4759d38..dc47708 100644
--- a/src/pages/Login.tsx
+++ b/src/pages/Login.tsx
@@ -28,7 +28,7 @@ export default function Login() {
     setError(null);
 
     const validation = validateLoginInput({ email, password });
-    if (!validation.success) {
+    if (validation.success === false) {
       setError(Object.values(validation.errors)[0] ?? "Dati di accesso non validi");
       return;
     }
diff --git a/src/pages/UtentiPage.tsx b/src/pages/UtentiPage.tsx
index bae82f8..ad14e31 100644
--- a/src/pages/UtentiPage.tsx
+++ b/src/pages/UtentiPage.tsx
@@ -127,7 +127,7 @@ export default function UtentiPage() {
     try {
       if (editing) {
         const validation = validateUtenteUpdate(raw);
-        if (!validation.success) {
+        if (validation.success === false) {
           setFieldErrors(validation.errors);
           setSaving(false);
           return;
@@ -136,7 +136,7 @@ export default function UtentiPage() {
         toast.success("Utente aggiornato");
       } else {
         const validation = validateUtenteCreate(raw);
-        if (!validation.success) {
+        if (validation.success === false) {
           setFieldErrors(validation.errors);
           setSaving(false);
           return;
diff --git a/src/validation/primitives.ts b/src/validation/primitives.ts
index 7d8b6d5..412c8a9 100644
--- a/src/validation/primitives.ts
+++ b/src/validation/primitives.ts
@@ -192,7 +192,8 @@ export function validateDecimalPositive(
 }
 
 export function buildResult<T>(data: T, errors: FieldErrors): ValidationResult<T> {
-    return Object.keys(errors).length > 0
-        ? { success: false, errors }
-        : { success: true, data };
+  if (Object.keys(errors).length > 0) {
+    return { success: false as const, errors };
+  }
+  return { success: true as const, data };
 }