add TastyVersion to ClassSymbol

Author: EugeneFlesselle

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

@@ -24,7 +24,8 @@ import ast.desugar
 
 import parsing.JavaParsers.OutlineJavaParser
 import parsing.Parsers.OutlineParser
-import dotty.tools.tasty.TastyHeaderUnpickler
+import dotty.tools.tasty.{TastyHeaderUnpickler, TastyHeader}
+import dotty.tools.tasty.TastyFormat.TastyVersion
 
 
 object SymbolLoaders {
@@ -430,6 +431,11 @@ class TastyLoader(val tastyFile: AbstractFile) extends SymbolLoader {
       moduleRoot.classSymbol.rootTreeOrProvider = unpickler
     checkTastyUUID(tastyFile, tastyBytes)
 
+    // TODO move
+    val TastyHeader(_, maj, min, exp, _) = new TastyHeaderUnpickler(tastyBytes).readFullHeader()
+    classRoot.classSymbol.tastyVersion = TastyVersion(maj, min, exp)
+    moduleRoot.classSymbol.tastyVersion = TastyVersion(maj, min, exp)
+
 
   private def checkTastyUUID(tastyFile: AbstractFile, tastyBytes: Array[Byte])(using Context): Unit =
     val classfile =

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

@@ -32,6 +32,7 @@ import util.{SourceFile, NoSource, Property, SourcePosition, SrcPos, EqHashMap}
 import scala.annotation.internal.sharable
 import config.Printers.typr
 import dotty.tools.dotc.classpath.FileUtils.isScalaBinary
+import dotty.tools.tasty.TastyFormat.TastyVersion
 
 object Symbols {
 
@@ -403,6 +404,9 @@ object Symbols {
 
     private var myTree: TreeOrProvider = tpd.EmptyTree
 
+    // TODO private and getter/setter
+    var tastyVersion: TastyVersion = TastyVersion() // overwritten when loading from Tasty
+
     /** If this is a top-level class and `-Yretain-trees` (or `-from-tasty`) is set.
       * Returns the TypeDef tree (possibly wrapped inside PackageDefs) for this class, otherwise EmptyTree.
       * This will force the info of the class.

compiler/src/dotty/tools/dotc/typer/Synthesizer.scala

@@ -22,6 +22,7 @@ import Synthesizer._
 import sbt.ExtractDependencies.*
 import sbt.ClassDependency
 import xsbti.api.DependencyContext._
+import dotty.tools.tasty.TastyFormat.TastyVersion
 
 /** Synthesize terms for special classes */
 class Synthesizer(typer: Typer)(using @constructorOnly c: Context):
@@ -415,7 +416,8 @@ class Synthesizer(typer: Typer)(using @constructorOnly c: Context):
       val elemLabels = accessors.map(acc => ConstantType(Constant(acc.name.toString)))
       val elemsLabels = TypeOps.nestedPairs(elemLabels)
 
-      val elemHasDefaults = accessors.map(acc => ConstantType(Constant(acc.is(HasDefault))))
+      val canSupportDefaults = cls.asClass.tastyVersion gteq TastyVersion(28, 4, 1) // TODO? cst
+      val elemHasDefaults = accessors.map(acc => ConstantType(Constant(canSupportDefaults && acc.is(HasDefault))))
       val elemsHasDefaults = TypeOps.nestedPairs(elemHasDefaults)
 
       val typeElems = tps.getOrElse(accessors.map(mirroredType.resultType.memberInfo(_).widenExpr))
@@ -474,7 +476,7 @@ class Synthesizer(typer: Typer)(using @constructorOnly c: Context):
               // case class `cls` changes. See `sbt-test/source-dependencies/mirror-product`.
               val rec = ctx.compilationUnit.depRecorder
               rec.addClassDependency(cls, DependencyByMemberRef)
-              rec.addUsedName(cls.primaryConstructor)
+              rec.addUsedName(cls.primaryConstructor) // TODO test when only adding default
             makeProductMirror(pre, cls, None)
           else withErrors(i"$cls is not a generic product because ${cls.whyNotGenericProduct}")
       case Left(msg) =>

tasty/src/dotty/tools/tasty/TastyFormat.scala

@@ -271,6 +271,19 @@ Standard Section: "Comments" Comment*
 
 object TastyFormat {
 
+  // TODO mv ?
+  case class TastyVersion(
+    majorVersion: Int = MajorVersion,
+    minorVersion: Int = MinorVersion,
+    experimentalVersion: Int = ExperimentalVersion
+  ) {
+    def gteq(that: TastyVersion): Boolean = summon[Ordering[(Int, Int, Int)]].gteq(
+      (this.majorVersion, this.minorVersion, this.experimentalVersion),
+      (that.majorVersion, that.minorVersion, that.experimentalVersion)
+    )
+  }
+
+
   /** The first four bytes of a TASTy file, followed by four values:
     * - `MajorVersion: Int` - see definition in `TastyFormat`
     * - `MinorVersion: Int` - see definition in `TastyFormat`