Don't write side-effecting nullary methods.

Style says never write methods like this:

  def foo: Unit

If it is Unit, then it is side-effecting, and should be

  def foo(): Unit

Since -Xlint warns about this, we must adhere to its dictate.

6 files changed, 25 insertions, 26 deletions

diff --git a/src/actors-migration/scala/actors/migration/StashingActor.scala b/src/actors-migration/scala/actors/migration/StashingActor.scala
index 9c3917b65e..d0a1432e72 100644
--- a/src/actors-migration/scala/actors/migration/StashingActor.scala
+++ b/src/actors-migration/scala/actors/migration/StashingActor.scala
@@ -18,7 +18,7 @@ trait StashingActor extends InternalActor {
   type Receive = PartialFunction[Any, Unit]
 
   // checks if StashingActor is created within the actorOf block
-  creationCheck;
+  creationCheck()
 
   private[actors] val ref = new InternalActorRef(this)
 
@@ -112,8 +112,7 @@ trait StashingActor extends InternalActor {
   /*
    * Checks that StashingActor can be created only by MigrationSystem.actorOf method.
    */
-  private[this] def creationCheck = {
-
+  private[this] def creationCheck(): Unit = {
     // creation check (see ActorRef)
     val context = MigrationSystem.contextStack.get
     if (context.isEmpty)
diff --git a/src/compiler/scala/tools/nsc/ast/parser/Scanners.scala b/src/compiler/scala/tools/nsc/ast/parser/Scanners.scala
index a1785e5262..69091e4880 100644
--- a/src/compiler/scala/tools/nsc/ast/parser/Scanners.scala
+++ b/src/compiler/scala/tools/nsc/ast/parser/Scanners.scala
@@ -360,7 +360,7 @@ trait Scanners extends ScannersCommon {
           if (ch == '"' && token == IDENTIFIER)
             token = INTERPOLATIONID
         case '<' => // is XMLSTART?
-          def fetchLT = {
+          def fetchLT() = {
             val last = if (charOffset >= 2) buf(charOffset - 2) else ' '
             nextChar()
             last match {
@@ -389,7 +389,7 @@ trait Scanners extends ScannersCommon {
             getOperatorRest()
           }
         case '0' =>
-          def fetchZero = {
+          def fetchZero() = {
             putChar(ch)
             nextChar()
             if (ch == 'x' || ch == 'X') {
@@ -416,7 +416,7 @@ trait Scanners extends ScannersCommon {
         case '`' =>
           getBackquotedIdent()
         case '\"' =>
-          def fetchDoubleQuote = {
+          def fetchDoubleQuote() = {
             if (token == INTERPOLATIONID) {
               nextRawChar()
               if (ch == '\"') {
@@ -452,7 +452,7 @@ trait Scanners extends ScannersCommon {
           }
           fetchDoubleQuote
         case '\'' =>
-          def fetchSingleQuote = {
+          def fetchSingleQuote() = {
             nextChar()
             if (isIdentifierStart(ch))
               charLitOr(getIdentRest)
@@ -500,7 +500,7 @@ trait Scanners extends ScannersCommon {
             nextChar()
           }
         case _ =>
-          def fetchOther = {
+          def fetchOther() = {
             if (ch == '\u21D2') {
               nextChar(); token = ARROW
             } else if (ch == '\u2190') {
diff --git a/src/compiler/scala/tools/nsc/backend/jvm/GenASM.scala b/src/compiler/scala/tools/nsc/backend/jvm/GenASM.scala
index 5a5059d58c..4738ad8a38 100644
--- a/src/compiler/scala/tools/nsc/backend/jvm/GenASM.scala
+++ b/src/compiler/scala/tools/nsc/backend/jvm/GenASM.scala
@@ -2407,7 +2407,7 @@ abstract class GenASM extends SubComponent with BytecodeWriters {
         (instr.category: @scala.annotation.switch) match {
 
           case icodes.localsCat =>
-          def genLocalInstr = (instr: @unchecked) match {
+          def genLocalInstr() = (instr: @unchecked) match {
             case THIS(_) => jmethod.visitVarInsn(Opcodes.ALOAD, 0)
             case LOAD_LOCAL(local) => jcode.load(indexOf(local), local.kind)
             case STORE_LOCAL(local) => jcode.store(indexOf(local), local.kind)
@@ -2440,7 +2440,7 @@ abstract class GenASM extends SubComponent with BytecodeWriters {
           genLocalInstr
 
           case icodes.stackCat =>
-          def genStackInstr = (instr: @unchecked) match {
+          def genStackInstr() = (instr: @unchecked) match {
 
             case LOAD_MODULE(module) =>
               // assert(module.isModule, "Expected module: " + module)
@@ -2468,7 +2468,7 @@ abstract class GenASM extends SubComponent with BytecodeWriters {
           case icodes.arilogCat => genPrimitive(instr.asInstanceOf[CALL_PRIMITIVE].primitive, instr.pos)
 
           case icodes.castsCat =>
-          def genCastInstr = (instr: @unchecked) match {
+          def genCastInstr() = (instr: @unchecked) match {
 
             case IS_INSTANCE(tpe) =>
               val jtyp: asm.Type =
@@ -2498,7 +2498,7 @@ abstract class GenASM extends SubComponent with BytecodeWriters {
           genCastInstr
 
           case icodes.objsCat =>
-          def genObjsInstr = (instr: @unchecked) match {
+          def genObjsInstr() = (instr: @unchecked) match {
 
             case BOX(kind) =>
               val MethodNameAndType(mname, mdesc) = jBoxTo(kind)
@@ -2518,7 +2518,7 @@ abstract class GenASM extends SubComponent with BytecodeWriters {
           genObjsInstr
 
           case icodes.fldsCat =>
-          def genFldsInstr = (instr: @unchecked) match {
+          def genFldsInstr() = (instr: @unchecked) match {
 
             case lf @ LOAD_FIELD(field, isStatic) =>
               var owner = javaName(lf.hostClass)
@@ -2539,7 +2539,7 @@ abstract class GenASM extends SubComponent with BytecodeWriters {
           genFldsInstr
 
           case icodes.mthdsCat =>
-          def genMethodsInstr = (instr: @unchecked) match {
+          def genMethodsInstr() = (instr: @unchecked) match {
 
             /** Special handling to access native Array.clone() */
             case call @ CALL_METHOD(definitions.Array_clone, Dynamic) =>
@@ -2552,7 +2552,7 @@ abstract class GenASM extends SubComponent with BytecodeWriters {
           genMethodsInstr
 
           case icodes.arraysCat =>
-          def genArraysInstr = (instr: @unchecked) match {
+          def genArraysInstr() = (instr: @unchecked) match {
             case LOAD_ARRAY_ITEM(kind) => jcode.aload(kind)
             case STORE_ARRAY_ITEM(kind) => jcode.astore(kind)
             case CREATE_ARRAY(elem, 1) => jcode newarray elem
@@ -2561,7 +2561,7 @@ abstract class GenASM extends SubComponent with BytecodeWriters {
           genArraysInstr
 
           case icodes.jumpsCat =>
-          def genJumpInstr = (instr: @unchecked) match {
+          def genJumpInstr() = (instr: @unchecked) match {
 
             case sw @ SWITCH(tagss, branches) =>
               assert(branches.length == tagss.length + 1, sw)
@@ -2691,7 +2691,7 @@ abstract class GenASM extends SubComponent with BytecodeWriters {
           genJumpInstr
 
           case icodes.retCat =>
-          def genRetInstr = (instr: @unchecked) match {
+          def genRetInstr() = (instr: @unchecked) match {
             case RETURN(kind) => jcode emitRETURN kind
             case THROW(_) => emit(Opcodes.ATHROW)
           }
@@ -2781,7 +2781,7 @@ abstract class GenASM extends SubComponent with BytecodeWriters {
           case Negation(kind) => jcode.neg(kind)
 
           case Arithmetic(op, kind) =>
-            def genArith = {
+            def genArith() = {
             op match {
 
               case ADD => jcode.add(kind)
@@ -2811,7 +2811,7 @@ abstract class GenASM extends SubComponent with BytecodeWriters {
           // TODO GenICode uses `toTypeKind` to define that elem, `toValueTypeKind` would be needed instead.
           // TODO How about adding some asserts to Logical and similar ones to capture the remaining constraint (UNIT not allowed).
           case Logical(op, kind) =>
-            def genLogical = op match {
+            def genLogical() = op match {
               case AND =>
                 kind match {
                   case LONG => emit(Opcodes.LAND)
@@ -2840,7 +2840,7 @@ abstract class GenASM extends SubComponent with BytecodeWriters {
             genLogical
 
           case Shift(op, kind) =>
-            def genShift = op match {
+            def genShift() = op match {
               case LSL =>
                 kind match {
                   case LONG => emit(Opcodes.LSHL)
@@ -2869,7 +2869,7 @@ abstract class GenASM extends SubComponent with BytecodeWriters {
             genShift
 
           case Comparison(op, kind) =>
-            def genCompare = op match {
+            def genCompare() = op match {
               case CMP =>
                 (kind: @unchecked) match {
                   case LONG =>  emit(Opcodes.LCMP)
diff --git a/src/compiler/scala/tools/nsc/doc/model/ModelFactory.scala b/src/compiler/scala/tools/nsc/doc/model/ModelFactory.scala
index 07526a5608..86bf1f1efd 100644
--- a/src/compiler/scala/tools/nsc/doc/model/ModelFactory.scala
+++ b/src/compiler/scala/tools/nsc/doc/model/ModelFactory.scala
@@ -403,7 +403,7 @@ class ModelFactory(val global: Global, val settings: doc.Settings) {
      * This is the final point in the core model creation: no DocTemplates are created after the model has finished, but
      * inherited templates and implicit members are added to the members at this point.
      */
-    def completeModel: Unit = {
+    def completeModel(): Unit = {
       // DFS completion
       // since alias types and abstract types have no own members, there's no reason for them to call completeModel
       if (!sym.isAliasType && !sym.isAbstractType)
diff --git a/src/compiler/scala/tools/nsc/typechecker/PatternMatching.scala b/src/compiler/scala/tools/nsc/typechecker/PatternMatching.scala
index c413448b57..2282f62152 100644
--- a/src/compiler/scala/tools/nsc/typechecker/PatternMatching.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/PatternMatching.scala
@@ -1864,7 +1864,7 @@ trait PatternMatching extends Transform with TypingTransformers with ast.TreeDSL
       def registerEquality(c: Const): Unit
 
       // call this to indicate null is part of the domain
-      def registerNull: Unit
+      def registerNull(): Unit
 
       // can this variable be null?
       def mayBeNull: Boolean
@@ -2279,7 +2279,7 @@ trait PatternMatching extends Transform with TypingTransformers with ast.TreeDSL
       val staticTpCheckable: Type = checkableType(staticTp)
 
       private[this] var _mayBeNull = false
-      def registerNull: Unit = { ensureCanModify; if (NullTp <:< staticTpCheckable) _mayBeNull = true }
+      def registerNull(): Unit = { ensureCanModify; if (NullTp <:< staticTpCheckable) _mayBeNull = true }
       def mayBeNull: Boolean = _mayBeNull
 
       // case None => domain is unknown,
diff --git a/src/library/scala/concurrent/impl/Promise.scala b/src/library/scala/concurrent/impl/Promise.scala
index a1a3305db0..ff268d850c 100644
--- a/src/library/scala/concurrent/impl/Promise.scala
+++ b/src/library/scala/concurrent/impl/Promise.scala
@@ -107,7 +107,7 @@ private[concurrent] object Promise {
       case _ => None
     }
 
-    override def isCompleted(): Boolean = getState match { // Cheaper than boxing result into Option due to "def value"
+    override def isCompleted: Boolean = getState match { // Cheaper than boxing result into Option due to "def value"
       case _: Try[_] => true
       case _ => false
     }
@@ -156,7 +156,7 @@ private[concurrent] object Promise {
 
     val value = Some(resolveTry(suppliedValue))
 
-    override def isCompleted(): Boolean = true
+    override def isCompleted: Boolean = true
 
     def tryComplete(value: Try[T]): Boolean = false