3 files changed, 6 insertions, 3 deletions
diff --git a/src/main/scala/chisel3/util/Arbiter.scala b/src/main/scala/chisel3/util/Arbiter.scala
index 059bdd14..135700fa 100644
--- a/src/main/scala/chisel3/util/Arbiter.scala
+++ b/src/main/scala/chisel3/util/Arbiter.scala
@@ -47,7 +47,7 @@ abstract class LockingArbiterLike[T <: Data](gen: T, n: Int, count: Int, needsLo
     val locked = lockCount.value =/= 0.U
     val wantsLock = needsLock.map(_(io.out.bits)).getOrElse(true.B)
 
-    when (io.out.fire() && wantsLock) {
+    when (io.out.fire && wantsLock) {
       lockIdx := io.chosen
       lockCount.inc()
     }
@@ -63,7 +63,7 @@ abstract class LockingArbiterLike[T <: Data](gen: T, n: Int, count: Int, needsLo
 
 class LockingRRArbiter[T <: Data](gen: T, n: Int, count: Int, needsLock: Option[T => Bool] = None)
     extends LockingArbiterLike[T](gen, n, count, needsLock) {
-  lazy val lastGrant = RegEnable(io.chosen, io.out.fire())
+  lazy val lastGrant = RegEnable(io.chosen, io.out.fire)
   lazy val grantMask = (0 until n).map(_.asUInt > lastGrant)
   lazy val validMask = io.in zip grantMask map { case (in, g) => in.valid && g }
 
diff --git a/src/main/scala/chisel3/util/Valid.scala b/src/main/scala/chisel3/util/Valid.scala
index 838d43ca..4d348014 100644
--- a/src/main/scala/chisel3/util/Valid.scala
+++ b/src/main/scala/chisel3/util/Valid.scala
@@ -28,6 +28,9 @@ class Valid[+T <: Data](gen: T) extends Bundle {
   /** True when `valid` is asserted
     * @return a Chisel [[Bool]] true if `valid` is asserted
     */
+  def fire: Bool = valid
+
+  @deprecated("Calling this function with an empty argument list is invalid in Scala 3. Use the form without parentheses instead", "Chisel 3.5")
   def fire(dummy: Int = 0): Bool = valid
 }
 
diff --git a/src/main/scala/chisel3/util/random/PRNG.scala b/src/main/scala/chisel3/util/random/PRNG.scala
index d94b78e8..9b42acf1 100644
--- a/src/main/scala/chisel3/util/random/PRNG.scala
+++ b/src/main/scala/chisel3/util/random/PRNG.scala
@@ -62,7 +62,7 @@ abstract class PRNG(val width: Int, val seed: Option[BigInt], step: Int = 1, upd
     state := nextState(state)
   }
 
-  when (io.seed.fire()) {
+  when (io.seed.fire) {
     state := (if (updateSeed) { nextState(io.seed.bits) } else { io.seed.bits })
   }