diff --git a/luisa_compute/src/lang/control_flow.rs b/luisa_compute/src/lang/control_flow.rs
index 25f0b14..ca39dfd 100644
--- a/luisa_compute/src/lang/control_flow.rs
+++ b/luisa_compute/src/lang/control_flow.rs
@@ -95,8 +95,8 @@ pub fn return_() {
 
 pub fn if_then_else<R: Aggregate>(
     cond: Expr<bool>,
-    then: impl Fn() -> R,
-    else_: impl Fn() -> R,
+    then: impl FnOnce() -> R,
+    else_: impl FnOnce() -> R,
 ) -> R {
     let cond = cond.node().get();
     with_recorder(|r| {
@@ -199,11 +199,7 @@ pub fn select<A: Aggregate>(mask: Expr<bool>, a: A, b: A) -> A {
     A::from_vec_nodes(ret)
 }
 
-pub fn generic_loop(
-    mut cond: impl FnMut() -> Expr<bool>,
-    mut body: impl FnMut(),
-    mut update: impl FnMut(),
-) {
+pub fn generic_loop(cond: impl FnOnce() -> Expr<bool>, body: impl FnOnce(), update: impl FnOnce()) {
     with_recorder(|r| {
         let pools = r.pools.clone();
         let s = &mut r.scopes;
@@ -308,13 +304,13 @@ pub fn loop_(body: impl Fn()) {
     });
 }
 
-pub fn for_unrolled<I: IntoIterator>(iter: I, body: impl Fn(I::Item)) {
+pub fn for_unrolled<I: IntoIterator>(iter: I, mut body: impl FnMut(I::Item)) {
     for i in iter {
         body(i);
     }
 }
 
-pub fn for_range<R: ForLoopRange>(r: R, body: impl Fn(Expr<R::Element>)) {
+pub fn for_range<R: ForLoopRange>(r: R, body: impl FnMut(Expr<R::Element>)) {
     let start = r.start().get();
     let end = r.end().get();
     let inc = |v: NodeRef| {
diff --git a/luisa_compute/src/lang/ops/impls.rs b/luisa_compute/src/lang/ops/impls.rs
index 0d8fd89..de4c786 100644
--- a/luisa_compute/src/lang/ops/impls.rs
+++ b/luisa_compute/src/lang/ops/impls.rs
@@ -403,7 +403,7 @@ impl<V: Value, E: AsExpr<Value = V>> StoreMaybeExpr<E> for Var<V> {
 }
 
 impl<R> SelectMaybeExpr<R> for bool {
-    fn if_then_else(self, on: impl Fn() -> R, off: impl Fn() -> R) -> R {
+    fn if_then_else(self, on: impl FnOnce() -> R, off: impl FnOnce() -> R) -> R {
         if self {
             on()
         } else {
@@ -419,7 +419,7 @@ impl<R> SelectMaybeExpr<R> for bool {
     }
 }
 impl<R: Aggregate> SelectMaybeExpr<R> for Expr<bool> {
-    fn if_then_else(self, on: impl Fn() -> R, off: impl Fn() -> R) -> R {
+    fn if_then_else(self, on: impl FnOnce() -> R, off: impl FnOnce() -> R) -> R {
         crate::lang::control_flow::if_then_else(self, on, off)
     }
     fn select(self, on: R, off: R) -> R {
@@ -428,7 +428,7 @@ impl<R: Aggregate> SelectMaybeExpr<R> for Expr<bool> {
 }
 
 impl<R: Aggregate> SelectMaybeExpr<R> for Var<bool> {
-    fn if_then_else(self, on: impl Fn() -> R, off: impl Fn() -> R) -> R {
+    fn if_then_else(self, on: impl FnOnce() -> R, off: impl FnOnce() -> R) -> R {
         crate::lang::control_flow::if_then_else(**self, on, off)
     }
     fn select(self, on: R, off: R) -> R {
@@ -436,20 +436,20 @@ impl<R: Aggregate> SelectMaybeExpr<R> for Var<bool> {
     }
 }
 impl ActivateMaybeExpr for bool {
-    fn activate(self, then: impl Fn()) {
+    fn activate(self, then: impl FnOnce()) {
         if self {
             then()
         }
     }
 }
 impl ActivateMaybeExpr for Expr<bool> {
-    fn activate(self, then: impl Fn()) {
+    fn activate(self, then: impl FnOnce()) {
         crate::lang::control_flow::if_then_else(self, then, || {})
     }
 }
 
 impl ActivateMaybeExpr for Var<bool> {
-    fn activate(self, then: impl Fn()) {
+    fn activate(self, then: impl FnOnce()) {
         crate::lang::control_flow::if_then_else(self.load(), then, || {})
     }
 }
@@ -470,23 +470,23 @@ impl LoopMaybeExpr for Expr<bool> {
 
 impl LazyBoolMaybeExpr<bool, ValueType> for bool {
     type Bool = bool;
-    fn and(self, other: impl Fn() -> bool) -> bool {
+    fn and(self, other: impl FnOnce() -> bool) -> bool {
         self && other()
     }
-    fn or(self, other: impl Fn() -> bool) -> bool {
+    fn or(self, other: impl FnOnce() -> bool) -> bool {
         self || other()
     }
 }
 impl LazyBoolMaybeExpr<Expr<bool>, ExprType> for bool {
     type Bool = Expr<bool>;
-    fn and(self, other: impl Fn() -> Expr<bool>) -> Self::Bool {
+    fn and(self, other: impl FnOnce() -> Expr<bool>) -> Self::Bool {
         if self {
             other()
         } else {
             false.expr()
         }
     }
-    fn or(self, other: impl Fn() -> Expr<bool>) -> Self::Bool {
+    fn or(self, other: impl FnOnce() -> Expr<bool>) -> Self::Bool {
         if self {
             true.expr()
         } else {
@@ -496,21 +496,21 @@ impl LazyBoolMaybeExpr<Expr<bool>, ExprType> for bool {
 }
 impl LazyBoolMaybeExpr<bool, ExprType> for Expr<bool> {
     type Bool = Expr<bool>;
-    fn and(self, other: impl Fn() -> bool) -> Self::Bool {
+    fn and(self, other: impl FnOnce() -> bool) -> Self::Bool {
         let other = other().expr();
         select(self, other, false.expr())
     }
-    fn or(self, other: impl Fn() -> bool) -> Self::Bool {
+    fn or(self, other: impl FnOnce() -> bool) -> Self::Bool {
         let other = other().expr();
         select(self, true.expr(), other)
     }
 }
 impl LazyBoolMaybeExpr<Expr<bool>, ExprType> for Expr<bool> {
     type Bool = Expr<bool>;
-    fn and(self, other: impl Fn() -> Expr<bool>) -> Self::Bool {
+    fn and(self, other: impl FnOnce() -> Expr<bool>) -> Self::Bool {
         crate::lang::control_flow::if_then_else(self, other, || false.expr())
     }
-    fn or(self, other: impl Fn() -> Expr<bool>) -> Self::Bool {
+    fn or(self, other: impl FnOnce() -> Expr<bool>) -> Self::Bool {
         crate::lang::control_flow::if_then_else(self, || true.expr(), other)
     }
 }
diff --git a/luisa_compute/src/lang/ops/traits.rs b/luisa_compute/src/lang/ops/traits.rs
index 5bb5323..216ec6c 100644
--- a/luisa_compute/src/lang/ops/traits.rs
+++ b/luisa_compute/src/lang/ops/traits.rs
@@ -353,12 +353,12 @@ pub trait StoreMaybeExpr<V> {
 }
 
 pub trait SelectMaybeExpr<R> {
-    fn if_then_else(self, on: impl Fn() -> R, off: impl Fn() -> R) -> R;
+    fn if_then_else(self, on: impl FnOnce() -> R, off: impl FnOnce() -> R) -> R;
     fn select(self, on: R, off: R) -> R;
 }
 
 pub trait ActivateMaybeExpr {
-    fn activate(self, then: impl Fn());
+    fn activate(self, then: impl FnOnce());
 }
 
 pub trait LoopMaybeExpr {