More polishings and tests

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

@@ -551,6 +551,7 @@ trait TypedTreeInfo extends TreeInfo[Type] { self: Trees.Instance[Type] =>
   /** An extractor for def of a closure contained the block of the closure. */
   object closureDef {
     def unapply(tree: Tree): Option[DefDef] = tree match {
+      case Block(Nil, expr) => unapply(expr)
       case Block((meth @ DefDef(nme.ANON_FUN, _, _, _, _)) :: Nil, closure: Closure) =>
         Some(meth)
       case _ => None

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

@@ -53,23 +53,13 @@ object Inliner {
       // This is quite tricky, as such types can appear anywhere, including as parts
       // of types of other things. For the moment we do nothing and complain
       // at the implicit expansion site if there's a reference to an inaccessible type.
-      override def transform(tree: Tree)(implicit ctx: Context): Tree = tree match {
-        case tree: Assign =>
-          transform(tree.lhs) match {
-            case lhs1: RefTree =>
-              lhs1.name match {
-                case InlineAccessorName(name) =>
-                  cpy.Apply(tree)(useSetter(lhs1), transform(tree.rhs) :: Nil)
-                case _ =>
-                  super.transform(tree)
-              }
-            case _ =>
-              super.transform(tree)
-          }
-        case _ =>
-          super.transform(accessorIfNeeded(tree))
-      }
-
+      override def transform(tree: Tree)(implicit ctx: Context): Tree =
+        super.transform(accessorIfNeeded(tree)) match {
+          case tree1 @ Assign(lhs: RefTree, rhs) if lhs.symbol.name.is(InlineAccessorName) =>
+            cpy.Apply(tree1)(useSetter(lhs), rhs :: Nil)
+          case tree1 =>
+            tree1
+        }
     }
 
     /** Adds accessors for all non-public term members accessed
@@ -104,14 +94,14 @@ object Inliner {
    *                     to have the inlined method as owner.
    */
   def registerInlineInfo(
-      sym: SymDenotation, treeExpr: Context => Tree)(implicit ctx: Context): Unit = {
-    sym.unforcedAnnotation(defn.BodyAnnot) match {
+      inlined: Symbol, treeExpr: Context => Tree)(implicit ctx: Context): Unit = {
+    inlined.unforcedAnnotation(defn.BodyAnnot) match {
       case Some(ann: ConcreteBodyAnnotation) =>
       case Some(ann: LazyBodyAnnotation) if ann.isEvaluated =>
       case _ =>
         if (!ctx.isAfterTyper) {
           val inlineCtx = ctx
-          sym.updateAnnotation(LazyBodyAnnotation { _ =>
+          inlined.updateAnnotation(LazyBodyAnnotation { _ =>
             implicit val ctx = inlineCtx
             val body = treeExpr(ctx)
             if (ctx.reporter.hasErrors) body else ctx.compilationUnit.inlineAccessors.makeInlineable(body)
@@ -173,10 +163,10 @@ object Inliner {
 
 /** Produces an inlined version of `call` via its `inlined` method.
  *
- *  @param  call  The original call to a `@inline` method
- *  @param  rhs   The body of the inline method that replaces the call.
+ *  @param  call         the original call to a `@inline` method
+ *  @param  rhsToInline  the body of the inline method that replaces the call.
  */
-class Inliner(call: tpd.Tree, rhs: tpd.Tree)(implicit ctx: Context) {
+class Inliner(call: tpd.Tree, rhsToInline: tpd.Tree)(implicit ctx: Context) {
   import tpd._
   import Inliner._
 
@@ -200,7 +190,7 @@ class Inliner(call: tpd.Tree, rhs: tpd.Tree)(implicit ctx: Context) {
    */
   private val paramProxy = new mutable.HashMap[Type, Type]
 
-  /** A map from the classes of (direct and outer) this references in `rhs`
+  /** A map from the classes of (direct and outer) this references in `rhsToInline`
    *  to references of their proxies.
    *  Note that we can't index by the ThisType itself since there are several
    *  possible forms to express what is logicaly the same ThisType. E.g.
@@ -315,7 +305,7 @@ class Inliner(call: tpd.Tree, rhs: tpd.Tree)(implicit ctx: Context) {
     if (!isIdempotentExpr(prefix)) registerType(meth.owner.thisType)
 
     // Register types of all leaves of inlined body so that the `paramProxy` and `thisProxy` maps are defined.
-    rhs.foreachSubTree(registerLeaf)
+    rhsToInline.foreachSubTree(registerLeaf)
 
     // The class that the this-proxy `selfSym` represents
     def classOf(selfSym: Symbol) = selfSym.info.widen.classSymbol
@@ -387,7 +377,7 @@ class Inliner(call: tpd.Tree, rhs: tpd.Tree)(implicit ctx: Context) {
     // the owner from the inlined method to the current owner.
     val inliner = new TreeTypeMap(typeMap, treeMap, meth :: Nil, ctx.owner :: Nil)(inlineCtx)
 
-    val expansion = inliner(rhs.withPos(call.pos))
+    val expansion = inliner(rhsToInline.withPos(call.pos))
     trace(i"inlining $call\n, BINDINGS =\n${bindingsBuf.toList}%\n%\nEXPANSION =\n$expansion", inlining, show = true) {
 
       // The final expansion runs a typing pass over the inlined tree. See InlineTyper for details.
@@ -426,7 +416,7 @@ class Inliner(call: tpd.Tree, rhs: tpd.Tree)(implicit ctx: Context) {
   /** A typer for inlined code. Its purpose is:
    *  1. Implement constant folding over inlined code
    *  2. Selectively expand ifs with constant conditions
-   *  3. Inline arguments that are inlineable closures
+   *  3. Inline arguments that are by-name closures
    *  4. Make sure inlined code is type-correct.
    *  5. Make sure that the tree's typing is idempotent (so that future -Ycheck passes succeed)
    */

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

@@ -821,12 +821,12 @@ class Namer { typer: Typer =>
       else completeInCreationContext(denot)
     }
 
-    private def addInlineInfo(denot: SymDenotation) = original match {
-      case original: untpd.DefDef if denot.isInlineableMethod =>
+    private def addInlineInfo(sym: Symbol) = original match {
+      case original: untpd.DefDef if sym.isInlineableMethod =>
         Inliner.registerInlineInfo(
-            denot,
+            sym,
             implicit ctx => typedAheadExpr(original).asInstanceOf[tpd.DefDef].rhs
-          )(localContext(denot.symbol))
+          )(localContext(sym))
       case _ =>
     }
 
@@ -839,7 +839,7 @@ class Namer { typer: Typer =>
         case original: MemberDef => addAnnotations(sym, original)
         case _ =>
       }
-      addInlineInfo(denot)
+      addInlineInfo(sym)
       denot.info = typeSig(sym)
       Checking.checkWellFormed(sym)
       denot.info = avoidPrivateLeaks(sym, sym.pos)

tests/run/inline-implicits.check

@@ -0,0 +1 @@
+(X(),Y())

tests/run/inline-implicits.scala

@@ -0,0 +1,26 @@
+case class X()
+case class Y()
+
+object impl {
+  implicit val y: Y = new Y()
+}
+
+object inlines {
+  import impl._
+
+  class C {
+    implicit val x: X = new X()
+
+    inline
+    def f(): (X, Y) =
+      (implicitly[X], implicitly[Y])
+  }
+}
+
+object Test {
+  def main(args: Array[String]) = {
+    val c = new inlines.C
+    val xy = c.f()
+    println(xy)
+  }
+}

tests/run/typelevel.check

@@ -0,0 +1,3 @@
+ToNat(Z)
+ToNat(S(Z))
+ToNat(S(S(Z)))

tests/run/typelevel.scala

@@ -0,0 +1,31 @@
+object Test extends App {
+
+  trait Nat
+
+  case object Z extends Nat
+  type Z = Z.type
+  case class S[N <: Nat](n: Nat) extends Nat
+
+  abstract class HasResult[T] { type Result = T }
+  case class ToNat[+T](val value: T) extends HasResult[T]
+
+  transparent def ToNat(inline n: Int): ToNat[Nat] =
+    if n == 0 then new ToNat(Z)
+    else {
+      val n1 = ToNat(n - 1)
+      new ToNat[S[n1.Result]](S(n1.value))
+    }
+
+  val x0 = ToNat(0)
+  //val y0: Z = x0.value
+  //val z0: x0.Result = y0
+  val x1 = ToNat(1)
+  //val y1: S[Z] = x1.value
+  //val z1: x1.Result = y1
+  val x2 = ToNat(2)
+  //val y2: S[S[Z]] = x2.value
+  //val z2: x2.Result = y2
+  println(x0)
+  println(x1)
+  println(x2)
+}