Merge branch 'main' into cc-drop-outdated

.github/workflows/lts-backport.yaml

@@ -0,0 +1,24 @@
+name: Add to backporting project
+
+on:
+  pull_request:
+    types:
+      - closed
+
+jobs:
+  add-to-backporting-project:
+    if: "github.event.pull_request.merged == true
+         && github.event.pull_request.base.ref == 'main'
+         && !contains(github.event.pull_request.body, '[Next only]')"
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v3
+        with:
+          fetch-depth: 0
+      - uses: coursier/cache-action@v6
+      - uses: VirtusLab/scala-cli-setup@v1.0.5
+      - run: scala-cli ./project/scripts/addToBackportingProject.scala -- ${{ github.event.pull_request.number }}
+        env:
+          GRAPHQL_API_TOKEN: ${{ secrets.GRAPHQL_API_TOKEN }}
+

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

@@ -1684,7 +1684,7 @@ trait BCodeBodyBuilder extends BCodeSkelBuilder {
         val equalsMethod: Symbol = {
           if (l.tpe <:< defn.BoxedNumberClass.info) {
             if (r.tpe <:< defn.BoxedNumberClass.info) defn.BoxesRunTimeModule.requiredMethod(nme.equalsNumNum)
-            else if (r.tpe <:< defn.BoxedCharClass.info) NoSymbol // ctx.requiredMethod(BoxesRunTimeTypeRef, nme.equalsNumChar) // this method is private
+            else if (r.tpe <:< defn.BoxedCharClass.info) defn.BoxesRunTimeModule.requiredMethod(nme.equalsNumChar)
             else defn.BoxesRunTimeModule.requiredMethod(nme.equalsNumObject)
           } else defn.BoxesRunTimeModule_externalEquals
         }

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

@@ -2845,7 +2845,7 @@ class JSCodeGen()(using genCtx: Context) {
   private lazy val externalEqualsNumNum: Symbol =
     defn.BoxesRunTimeModule.requiredMethod(nme.equalsNumNum)
   private lazy val externalEqualsNumChar: Symbol =
-    NoSymbol // requiredMethod(BoxesRunTimeTypeRef, nme.equalsNumChar) // this method is private
+    defn.BoxesRunTimeModule.requiredMethod(nme.equalsNumChar)
   private lazy val externalEqualsNumObject: Symbol =
     defn.BoxesRunTimeModule.requiredMethod(nme.equalsNumObject)
   private lazy val externalEquals: Symbol =
@@ -2885,7 +2885,7 @@ class JSCodeGen()(using genCtx: Context) {
         val ptfm = ctx.platform
         if (lsym.derivesFrom(defn.BoxedNumberClass)) {
           if (rsym.derivesFrom(defn.BoxedNumberClass)) externalEqualsNumNum
-          else if (rsym.derivesFrom(defn.BoxedCharClass)) externalEqualsNumObject // will be externalEqualsNumChar in 2.12, SI-9030
+          else if (rsym.derivesFrom(defn.BoxedCharClass)) externalEqualsNumChar
           else externalEqualsNumObject
         } else externalEquals
       }

compiler/src/dotty/tools/dotc/ast/TreeInfo.scala

@@ -992,6 +992,8 @@ trait TypedTreeInfo extends TreeInfo[Type] { self: Trees.Instance[Type] =>
       def hasRefinement(qualtpe: Type): Boolean = qualtpe.dealias match
         case defn.PolyFunctionOf(_) =>
           false
+        case tp: MatchType =>
+          hasRefinement(tp.tryNormalize)
         case RefinedType(parent, rname, rinfo) =>
           rname == tree.name || hasRefinement(parent)
         case tp: TypeProxy =>

compiler/src/dotty/tools/dotc/ast/tpd.scala

@@ -45,21 +45,19 @@ object tpd extends Trees.Instance[Type] with TypedTreeInfo {
   def Apply(fn: Tree, args: List[Tree])(using Context): Apply = fn match
     case Block(Nil, expr) =>
       Apply(expr, args)
+    case _: RefTree | _: GenericApply | _: Inlined | _: Hole =>
+      ta.assignType(untpd.Apply(fn, args), fn, args)
     case _ =>
-      assert(
-        fn.isInstanceOf[RefTree | GenericApply | Inlined | Hole] || ctx.reporter.errorsReported,
-        s"Illegal Apply function prefix: $fn"
-      )
+      assert(ctx.reporter.errorsReported)
       ta.assignType(untpd.Apply(fn, args), fn, args)
 
   def TypeApply(fn: Tree, args: List[Tree])(using Context): TypeApply = fn match
     case Block(Nil, expr) =>
       TypeApply(expr, args)
+    case _: RefTree | _: GenericApply =>
+      ta.assignType(untpd.TypeApply(fn, args), fn, args)
     case _ =>
-      assert(
-        fn.isInstanceOf[RefTree | GenericApply] || ctx.reporter.errorsReported,
-        s"Illegal TypeApply function prefix: $fn"
-      )
+      assert(ctx.reporter.errorsReported, s"unexpected tree for type application: $fn")
       ta.assignType(untpd.TypeApply(fn, args), fn, args)
 
   def Literal(const: Constant)(using Context): Literal =

compiler/src/dotty/tools/dotc/cc/CheckCaptures.scala

@@ -826,12 +826,16 @@ class CheckCaptures extends Recheck, SymTransformer:
      */
     def adaptUniversal(actual: Type, expected: Type, tree: Tree)(using Context): Type =
       if expected.captureSet.disallowsUniversal && actual.captureSet.isUniversal then
-        val localRoot = impliedRoot(tree)
-        CapturingType(
-            actual.stripCapturing,
-            localRoot.termRef.singletonCaptureSet,
-            actual.isBoxedCapturing)
-          .showing(i"adapt universal $actual vs $expected = $result", capt)
+        if actual.isInstanceOf[SingletonType] then
+          // capture set is only exposed when widening
+          adaptUniversal(actual.widen, expected, tree)
+        else
+          val localRoot = impliedRoot(tree)
+          CapturingType(
+              actual.stripCapturing,
+              localRoot.termRef.singletonCaptureSet,
+              actual.isBoxedCapturing)
+            .showing(i"adapt universal $actual vs $expected = $result", capt)
       else actual
 
     private inline val debugSuccesses = false

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

@@ -253,7 +253,7 @@ class TypeComparer(@constructorOnly initctx: Context) extends ConstraintHandling
         //}
         assert(!ctx.settings.YnoDeepSubtypes.value)
         if (Config.traceDeepSubTypeRecursions && !this.isInstanceOf[ExplainingTypeComparer])
-          report.log(explained(_.isSubType(tp1, tp2, approx)))
+          report.log(explained(_.isSubType(tp1, tp2, approx), short = false))
       }
       // Eliminate LazyRefs before checking whether we have seen a type before
       val normalize = new TypeMap with CaptureSet.IdempotentCaptRefMap {
@@ -2959,7 +2959,7 @@ class TypeComparer(@constructorOnly initctx: Context) extends ConstraintHandling
     }
   }
 
-  protected def explainingTypeComparer = ExplainingTypeComparer(comparerContext)
+  protected def explainingTypeComparer(short: Boolean) = ExplainingTypeComparer(comparerContext, short)
   protected def trackingTypeComparer = TrackingTypeComparer(comparerContext)
 
   private def inSubComparer[T, Cmp <: TypeComparer](comparer: Cmp)(op: Cmp => T): T =
@@ -2969,8 +2969,8 @@ class TypeComparer(@constructorOnly initctx: Context) extends ConstraintHandling
     finally myInstance = saved
 
   /** The trace of comparison operations when performing `op` */
-  def explained[T](op: ExplainingTypeComparer => T, header: String = "Subtype trace:")(using Context): String =
-    val cmp = explainingTypeComparer
+  def explained[T](op: ExplainingTypeComparer => T, header: String = "Subtype trace:", short: Boolean)(using Context): String =
+    val cmp = explainingTypeComparer(short)
     inSubComparer(cmp)(op)
     cmp.lastTrace(header)
 
@@ -3139,8 +3139,8 @@ object TypeComparer {
   def constrainPatternType(pat: Type, scrut: Type, forceInvariantRefinement: Boolean = false)(using Context): Boolean =
     comparing(_.constrainPatternType(pat, scrut, forceInvariantRefinement))
 
-  def explained[T](op: ExplainingTypeComparer => T, header: String = "Subtype trace:")(using Context): String =
-    comparing(_.explained(op, header))
+  def explained[T](op: ExplainingTypeComparer => T, header: String = "Subtype trace:", short: Boolean = false)(using Context): String =
+    comparing(_.explained(op, header, short))
 
   def tracked[T](op: TrackingTypeComparer => T)(using Context): T =
     comparing(_.tracked(op))
@@ -3337,30 +3337,47 @@ class TrackingTypeComparer(initctx: Context) extends TypeComparer(initctx) {
   }
 }
 
-/** A type comparer that can record traces of subtype operations */
-class ExplainingTypeComparer(initctx: Context) extends TypeComparer(initctx) {
+/** A type comparer that can record traces of subtype operations
+ *  @param short  if true print only failing forward traces; never print succesful
+ *                subtraces; never print backtraces starting with `<==`.
+ */
+class ExplainingTypeComparer(initctx: Context, short: Boolean) extends TypeComparer(initctx) {
   import TypeComparer._
 
   init(initctx)
 
-  override def explainingTypeComparer = this
+  override def explainingTypeComparer(short: Boolean) =
+    if short == this.short then this
+    else ExplainingTypeComparer(comparerContext, short)
 
   private var indent = 0
   private val b = new StringBuilder
-
-  private var skipped = false
+  private var lastForwardGoal: String | Null = null
 
   override def traceIndented[T](str: String)(op: => T): T =
-    if (skipped) op
-    else {
+    val str1 = str.replace('\n', ' ')
+    if short && str1 == lastForwardGoal then
+      op // repeated goal, skip for clarity
+    else
+      lastForwardGoal = str1
+      val curLength = b.length
       indent += 2
-      val str1 = str.replace('\n', ' ')
       b.append("\n").append(" " * indent).append("==> ").append(str1)
       val res = op
-      b.append("\n").append(" " * indent).append("<== ").append(str1).append(" = ").append(show(res))
+      if short then
+        if res == false then
+          if lastForwardGoal != null then  // last was deepest goal that failed
+            b.append("  = false")
+            lastForwardGoal = null
+        else
+          b.length = curLength // don't show successful subtraces
+      else
+        b.append("\n").append(" " * indent).append("<== ").append(str1).append(" = ").append(show(res))
       indent -= 2
       res
-    }
+
+  private def traceIndentedIfNotShort[T](str: String)(op: => T): T =
+    if short then op else traceIndented(str)(op)
 
   private def frozenNotice: String =
     if frozenConstraint then " in frozen constraint" else ""
@@ -3371,7 +3388,8 @@ class ExplainingTypeComparer(initctx: Context) extends TypeComparer(initctx) {
       then s" ${tp1.getClass} ${tp2.getClass}"
       else ""
     val approx = approxState
-    traceIndented(s"${show(tp1)}  <:  ${show(tp2)}$moreInfo${approx.show}$frozenNotice") {
+    def approxStr = if short then "" else approx.show
+    traceIndented(s"${show(tp1)}  <:  ${show(tp2)}$moreInfo${approxStr}$frozenNotice") {
       super.recur(tp1, tp2)
     }
 
@@ -3381,12 +3399,12 @@ class ExplainingTypeComparer(initctx: Context) extends TypeComparer(initctx) {
     }
 
   override def lub(tp1: Type, tp2: Type, canConstrain: Boolean, isSoft: Boolean): Type =
-    traceIndented(s"lub(${show(tp1)}, ${show(tp2)}, canConstrain=$canConstrain, isSoft=$isSoft)") {
+    traceIndentedIfNotShort(s"lub(${show(tp1)}, ${show(tp2)}, canConstrain=$canConstrain, isSoft=$isSoft)") {
       super.lub(tp1, tp2, canConstrain, isSoft)
     }
 
   override def glb(tp1: Type, tp2: Type): Type =
-    traceIndented(s"glb(${show(tp1)}, ${show(tp2)})") {
+    traceIndentedIfNotShort(s"glb(${show(tp1)}, ${show(tp2)})") {
       super.glb(tp1, tp2)
     }