Use inline val for inlined final vals

These `val`s are already inlined and do not generate a field, but they
still generate a getter that is never used. My marking these as `inline`
we can remove the getter and save a few bytes at runtime.

By making these fields `inline` we can also check that the RHS constant
folds to a value at compile time.

Author: nicolasstucki

compiler/src/dotty/tools/backend/ScalaPrimitivesOps.scala

@@ -19,17 +19,17 @@ object AsmUtils {
   /**
    * Print the bytecode of classes generated by GenBCode to the standard output.
    */
-  final val traceClassEnabled = false
-  final val traceClassPattern = ""
+  inline val traceClassEnabled = false
+  inline val traceClassPattern = ""
 
   /**
    * Print the bytedcode of classes as they are serialized by the ASM library. The serialization
    * performed by `asm.ClassWriter` can change the code generated by GenBCode. For example, it
    * introduces stack map frames, it computes the maximal stack sizes, and it replaces dead
    * code by NOPs (see also https://github.com/scala/scala/pull/3726#issuecomment-42861780).
    */
-  final val traceSerializedClassEnabled = false
-  final val traceSerializedClassPattern = ""
+  inline val traceSerializedClassEnabled = false
+  inline val traceSerializedClassPattern = ""
 
   def traceMethod(mnode: MethodNode1): Unit = {
     println(s"Bytecode for method ${mnode.name}")

compiler/src/dotty/tools/backend/jvm/AsmUtils.scala

@@ -70,7 +70,7 @@ trait BCodeSkelBuilder extends BCodeHelpers {
     with    BCJGenSigGen {
 
     // Strangely I can't find this in the asm code 255, but reserving 1 for "this"
-    final val MaximumJvmParameters = 254
+    inline val MaximumJvmParameters = 254
 
     // current class
     var cnode: ClassNode1          = null

compiler/src/dotty/tools/backend/jvm/BCodeSkelBuilder.scala

@@ -4369,7 +4369,7 @@ class JSCodeGen()(using genCtx: Context) {
     js.LoadJSConstructor(encodeClassName(sym))
   }
 
-  private final val GenericGlobalObjectInformationMsg = {
+  private inline val GenericGlobalObjectInformationMsg = {
     "\n  " +
     "See https://www.scala-js.org/doc/interoperability/global-scope.html " +
     "for further information."

compiler/src/dotty/tools/backend/sjs/JSCodeGen.scala

@@ -16,42 +16,42 @@ import scala.collection.mutable
 
 object JSPrimitives {
 
-  final val FirstJSPrimitiveCode = 300
+  inline val FirstJSPrimitiveCode = 300
 
-  final val DYNNEW = FirstJSPrimitiveCode + 1 // Instantiate a new JavaScript object
+  inline val DYNNEW = FirstJSPrimitiveCode + 1 // Instantiate a new JavaScript object
 
-  final val ARR_CREATE = DYNNEW + 1 // js.Array.apply (array literal syntax)
+  inline val ARR_CREATE = DYNNEW + 1 // js.Array.apply (array literal syntax)
 
-  final val TYPEOF = ARR_CREATE + 1 // typeof x
-  final val JS_NATIVE = TYPEOF + 1  // js.native. Marker method. Fails if tried to be emitted.
+  inline val TYPEOF = ARR_CREATE + 1 // typeof x
+  inline val JS_NATIVE = TYPEOF + 1  // js.native. Marker method. Fails if tried to be emitted.
 
-  final val UNITVAL = JS_NATIVE + 1 // () value, which is undefined
+  inline val UNITVAL = JS_NATIVE + 1 // () value, which is undefined
 
-  final val JS_IMPORT = UNITVAL + 1        // js.import.apply(specifier)
-  final val JS_IMPORT_META = JS_IMPORT + 1 // js.import.meta
+  inline val JS_IMPORT = UNITVAL + 1        // js.import.apply(specifier)
+  inline val JS_IMPORT_META = JS_IMPORT + 1 // js.import.meta
 
-  final val CONSTRUCTOROF = JS_IMPORT_META + 1                         // runtime.constructorOf(clazz)
-  final val CREATE_INNER_JS_CLASS = CONSTRUCTOROF + 1                  // runtime.createInnerJSClass
-  final val CREATE_LOCAL_JS_CLASS = CREATE_INNER_JS_CLASS + 1          // runtime.createLocalJSClass
-  final val WITH_CONTEXTUAL_JS_CLASS_VALUE = CREATE_LOCAL_JS_CLASS + 1 // runtime.withContextualJSClassValue
-  final val LINKING_INFO = WITH_CONTEXTUAL_JS_CLASS_VALUE + 1          // runtime.linkingInfo
+  inline val CONSTRUCTOROF = JS_IMPORT_META + 1                         // runtime.constructorOf(clazz)
+  inline val CREATE_INNER_JS_CLASS = CONSTRUCTOROF + 1                  // runtime.createInnerJSClass
+  inline val CREATE_LOCAL_JS_CLASS = CREATE_INNER_JS_CLASS + 1          // runtime.createLocalJSClass
+  inline val WITH_CONTEXTUAL_JS_CLASS_VALUE = CREATE_LOCAL_JS_CLASS + 1 // runtime.withContextualJSClassValue
+  inline val LINKING_INFO = WITH_CONTEXTUAL_JS_CLASS_VALUE + 1          // runtime.linkingInfo
 
-  final val STRICT_EQ = LINKING_INFO + 1 // js.special.strictEquals
-  final val IN = STRICT_EQ + 1           // js.special.in
-  final val INSTANCEOF = IN + 1          // js.special.instanceof
-  final val DELETE = INSTANCEOF + 1      // js.special.delete
-  final val FORIN = DELETE + 1           // js.special.forin
-  final val DEBUGGER = FORIN + 1         // js.special.debugger
+  inline val STRICT_EQ = LINKING_INFO + 1 // js.special.strictEquals
+  inline val IN = STRICT_EQ + 1           // js.special.in
+  inline val INSTANCEOF = IN + 1          // js.special.instanceof
+  inline val DELETE = INSTANCEOF + 1      // js.special.delete
+  inline val FORIN = DELETE + 1           // js.special.forin
+  inline val DEBUGGER = FORIN + 1         // js.special.debugger
 
-  final val THROW = DEBUGGER + 1
+  inline val THROW = DEBUGGER + 1
 
-  final val UNION_FROM = THROW + 1                       // js.|.from
-  final val UNION_FROM_TYPE_CONSTRUCTOR = UNION_FROM + 1 // js.|.fromTypeConstructor
+  inline val UNION_FROM = THROW + 1                       // js.|.from
+  inline val UNION_FROM_TYPE_CONSTRUCTOR = UNION_FROM + 1 // js.|.fromTypeConstructor
 
-  final val REFLECT_SELECTABLE_SELECTDYN = UNION_FROM_TYPE_CONSTRUCTOR + 1 // scala.reflect.Selectable.selectDynamic
-  final val REFLECT_SELECTABLE_APPLYDYN = REFLECT_SELECTABLE_SELECTDYN + 1 // scala.reflect.Selectable.applyDynamic
+  inline val REFLECT_SELECTABLE_SELECTDYN = UNION_FROM_TYPE_CONSTRUCTOR + 1 // scala.reflect.Selectable.selectDynamic
+  inline val REFLECT_SELECTABLE_APPLYDYN = REFLECT_SELECTABLE_SELECTDYN + 1 // scala.reflect.Selectable.applyDynamic
 
-  final val LastJSPrimitiveCode = REFLECT_SELECTABLE_APPLYDYN
+  inline val LastJSPrimitiveCode = REFLECT_SELECTABLE_APPLYDYN
 
   def isJSPrimitive(code: Int): Boolean =
     code >= FirstJSPrimitiveCode && code <= LastJSPrimitiveCode

compiler/src/dotty/tools/backend/sjs/JSPrimitives.scala

@@ -9,19 +9,19 @@ import Decorators._
 
 object Constants {
 
-  final val NoTag      = 0
-  final val UnitTag    = 1
-  final val BooleanTag = 2
-  final val ByteTag    = 3
-  final val ShortTag   = 4
-  final val CharTag    = 5
-  final val IntTag     = 6
-  final val LongTag    = 7
-  final val FloatTag   = 8
-  final val DoubleTag  = 9
-  final val StringTag  = 10
-  final val NullTag    = 11
-  final val ClazzTag   = 12
+  inline val NoTag      = 0
+  inline val UnitTag    = 1
+  inline val BooleanTag = 2
+  inline val ByteTag    = 3
+  inline val ShortTag   = 4
+  inline val CharTag    = 5
+  inline val IntTag     = 6
+  inline val LongTag    = 7
+  inline val FloatTag   = 8
+  inline val DoubleTag  = 9
+  inline val StringTag  = 10
+  inline val NullTag    = 11
+  inline val ClazzTag   = 12
 
   class Constant(val value: Any, val tag: Int) extends printing.Showable with Product1[Any] {
     import java.lang.Double.doubleToRawLongBits

compiler/src/dotty/tools/dotc/core/Constants.scala

@@ -74,7 +74,7 @@ object Decorators {
       NoSymbol
     }
 
-  final val MaxFilterRecursions = 10
+  inline val MaxFilterRecursions = 10
 
   /** Implements filterConserve, zipWithConserve methods
    *  on lists that avoid duplication of list nodes where feasible.

compiler/src/dotty/tools/dotc/core/Decorators.scala

@@ -19,20 +19,20 @@ object Hashable {
   /** A hash value indicating that the underlying type is not
    *  cached in uniques.
    */
-  final val NotCached = 0
+  inline val NotCached = 0
 
   /** An alternative value returned from `hash` if the
    *  computed hashCode would be `NotCached`.
    */
-  private[core] final val NotCachedAlt = Int.MinValue
+  private[core] inline val NotCachedAlt = Int.MinValue
 
   /** A value that indicates that the hash code is unknown
    */
-  private[core] final val HashUnknown = 1234
+  private[core] inline val HashUnknown = 1234
 
   /** An alternative value if computeHash would otherwise yield HashUnknown
    */
-  private[core] final val HashUnknownAlt = 4321
+  private[core] inline val HashUnknownAlt = 4321
 }
 
 trait Hashable {

compiler/src/dotty/tools/dotc/core/Hashable.scala

@@ -17,7 +17,7 @@ object NameOps {
   object compactify {
     lazy val md5: MessageDigest = MessageDigest.getInstance("MD5")
 
-    final val CLASSFILE_NAME_CHAR_LIMIT = 240
+    inline val CLASSFILE_NAME_CHAR_LIMIT = 240
 
     /** COMPACTIFY
      *

compiler/src/dotty/tools/dotc/core/NameOps.scala

@@ -5,32 +5,32 @@ import dotty.tools.tasty.TastyFormat
 /** The possible tags of a NameKind */
 object NameTags extends TastyFormat.NameTags {
 
-  final val FLATTENED = 5       // A flat name, generated by Flatten
+  inline val FLATTENED = 5       // A flat name, generated by Flatten
 
-  final val TRAITSETTER = 6     // A Scala-2 trait setter, generated by AugmentScala2Traits
+  inline val TRAITSETTER = 6     // A Scala-2 trait setter, generated by AugmentScala2Traits
 
-  final val OUTERSELECT = 13    // A name `<num>_outer`, used by the inliner to indicate an
+  inline val OUTERSELECT = 13    // A name `<num>_outer`, used by the inliner to indicate an
                                 // outer accessor that will be filled in by ExplicitOuter.
                                 // <num> indicates the number of hops needed to select the outer field.
 
-  final val PROTECTEDACCESSOR = 24 // The name of a protected accesor `protected$<name>` created by ProtectedAccessors.
+  inline val PROTECTEDACCESSOR = 24 // The name of a protected accesor `protected$<name>` created by ProtectedAccessors.
 
-  final val INITIALIZER = 26    // A mixin initializer method
+  inline val INITIALIZER = 26    // A mixin initializer method
 
-  final val FIELD = 29          // Used by Memoize to tag the name of a class member field.
+  inline val FIELD = 29          // Used by Memoize to tag the name of a class member field.
 
-  final val EXTMETH = 30        // Used by ExtensionMethods for the name of an extension method
+  inline val EXTMETH = 30        // Used by ExtensionMethods for the name of an extension method
                                 // implementing a value class method.
 
-  final val ADAPTEDCLOSURE = 31 // Used in Erasure to adapt closures over primitive types.
+  inline val ADAPTEDCLOSURE = 31 // Used in Erasure to adapt closures over primitive types.
 
-  final val DIRECT = 32         // Used to define implementations of methods with
+  inline val DIRECT = 32         // Used to define implementations of methods with
                                 // erased context function results that can override some
                                 // other method.
 
-  final val PARAMACC = 33       // Used for a private parameter alias
+  inline val PARAMACC = 33       // Used for a private parameter alias
 
-  final val SETTER = 34         // A synthesized += suffix.
+  inline val SETTER = 34         // A synthesized += suffix.
 
   def nameTagToString(tag: Int): String = tag match {
     case UTF8 => "UTF8"