Deprecate auto-application of empty argument lists to parameterless functions (#2124)

* Migrate nullary funcs to parameterless versions
* Make deprecation message and dummy arguments clear and consistent

Co-authored-by: Megan Wachs <megan@sifive.com>

1 files changed, 6 insertions, 2 deletions

diff --git a/core/src/main/scala/chisel3/Clock.scala b/core/src/main/scala/chisel3/Clock.scala
index edb07908..0400697d 100644
--- a/core/src/main/scala/chisel3/Clock.scala
+++ b/core/src/main/scala/chisel3/Clock.scala
@@ -32,8 +32,12 @@ sealed class Clock(private[chisel3] val width: Width = Width(1)) extends Element
   def toPrintable: Printable = PString("CLOCK")
 
   /** Returns the contents of the clock wire as a [[Bool]]. */
-  final def asBool(): Bool = macro SourceInfoTransform.noArg
-  def do_asBool(implicit sourceInfo: SourceInfo, compileOptions: CompileOptions): Bool = this.asUInt().asBool()
+  final def asBool: Bool = macro SourceInfoTransform.noArg
+
+  @deprecated("Calling this function with an empty argument list is invalid in Scala 3. Use the form without parentheses instead", "Chisel 3.5")
+  final def asBool(dummy: Int*): Bool = macro SourceInfoTransform.noArgDummy
+
+  def do_asBool(implicit sourceInfo: SourceInfo, compileOptions: CompileOptions): Bool = this.asUInt.asBool
 
   override def do_asUInt(implicit sourceInfo: SourceInfo, connectCompileOptions: CompileOptions): UInt = pushOp(DefPrim(sourceInfo, UInt(this.width), AsUIntOp, ref))
   private[chisel3] override def connectFromBits(that: Bits)(implicit sourceInfo: SourceInfo,