Prepare to have both inlined and transparent methods

All necessary changes except for those in the Inliner itself.

Author: odersky

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

@@ -547,6 +547,7 @@ 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/ast/TreeTypeMap.scala

@@ -95,7 +95,9 @@ class TreeTypeMap(
           val (tmap2, vparamss1) = tmap1.transformVParamss(vparamss)
           val res = cpy.DefDef(ddef)(name, tparams1, vparamss1, tmap2.transform(tpt), tmap2.transform(ddef.rhs))
           res.symbol.transformAnnotations {
-            case ann: BodyAnnotation => ann.derivedAnnotation(res.rhs)
+            case ann: BodyAnnotation =>
+              if (res.symbol.isTransparentMethod) ann.derivedAnnotation(transform(ann.tree))
+              else ann.derivedAnnotation(res.rhs)
             case ann => ann
           }
           res
@@ -126,7 +128,7 @@ class TreeTypeMap(
   override def transformStats(trees: List[tpd.Tree])(implicit ctx: Context) =
     transformDefs(trees)._2
 
-  private def transformDefs[TT <: tpd.Tree](trees: List[TT])(implicit ctx: Context): (TreeTypeMap, List[TT]) = {
+  def transformDefs[TT <: tpd.Tree](trees: List[TT])(implicit ctx: Context): (TreeTypeMap, List[TT]) = {
     val tmap = withMappedSyms(tpd.localSyms(trees))
     (tmap, tmap.transformSub(trees))
   }

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

@@ -20,6 +20,8 @@ import scala.io.Codec
 /** Some creators for typed trees */
 object tpd extends Trees.Instance[Type] with TypedTreeInfo {
 
+  case class UntypedSplice(splice: untpd.Tree) extends Tree
+
   private def ta(implicit ctx: Context) = ctx.typeAssigner
 
   def Ident(tp: NamedType)(implicit ctx: Context): Ident =
@@ -471,8 +473,6 @@ object tpd extends Trees.Instance[Type] with TypedTreeInfo {
       } else foldOver(sym, tree)
   }
 
-  case class UntypedSplice(splice: untpd.Tree) extends Tree
-
   override val cpy: TypedTreeCopier = // Type ascription needed to pick up any new members in TreeCopier (currently there are none)
     new TypedTreeCopier
 

compiler/src/dotty/tools/dotc/core/tasty/TreePickler.scala

@@ -637,8 +637,8 @@ class TreePickler(pickler: TastyPickler) {
       // a different toplevel class, it is impossible to pickle a reference to it.
       // Such annotations will be reconstituted when unpickling the child class.
       // See tests/pickling/i3149.scala
-    case _ => ann.symbol == defn.BodyAnnot
-      // inline bodies are reconstituted automatically when unpickling
+    case _ => ann.symbol == defn.BodyAnnot && owner.isInlinedMethod
+      // bodies of inlined (but not transparent) methods are reconstituted automatically when unpickling
   }
 
   def pickleAnnotation(owner: Symbol, ann: Annotation)(implicit ctx: Context) =

compiler/src/dotty/tools/dotc/core/tasty/TreeUnpickler.scala

@@ -634,9 +634,12 @@ class TreeUnpickler(reader: TastyReader,
         val end = readEnd()
         val tp = readType()
         val lazyAnnotTree = readLater(end, rdr => ctx => rdr.readTerm()(ctx))
-        Annotation.deferredSymAndTree(
-          implicit ctx => tp.typeSymbol,
-          implicit ctx => lazyAnnotTree.complete)
+        if (tp.isRef(defn.BodyAnnot))
+          LazyBodyAnnotation(implicit ctx => lazyAnnotTree.complete)
+        else
+          Annotation.deferredSymAndTree(
+            implicit ctx => tp.typeSymbol,
+            implicit ctx => lazyAnnotTree.complete)
     }
 
     /** Create symbols for the definitions in the statement sequence between

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

@@ -1103,19 +1103,24 @@ trait Implicits { self: Typer =>
       val eligible =
         if (contextual) ctx.implicits.eligible(wildProto)
         else implicitScope(wildProto).eligible
-      searchImplicits(eligible, contextual).recoverWith {
-        failure => failure.reason match {
-          case _: AmbiguousImplicits => failure
-          case reason =>
-            if (contextual)
-              bestImplicit(contextual = false).recoverWith {
-                failure2 => reason match {
-                  case (_: DivergingImplicit) | (_: ShadowedImplicit) => failure
-                  case _ => failure2
+      searchImplicits(eligible, contextual) match {
+        case result: SearchSuccess =>
+          if (contextual && ctx.mode.is(Mode.TransparentBody))
+            Inliner.markContextualImplicit(result.tree)
+          result
+        case failure: SearchFailure =>
+          failure.reason match {
+            case _: AmbiguousImplicits => failure
+            case reason =>
+              if (contextual)
+                bestImplicit(contextual = false).recoverWith {
+                  failure2 => reason match {
+                    case (_: DivergingImplicit) | (_: ShadowedImplicit) => failure
+                    case _ => failure2
+                  }
                 }
-              }
-            else failure
-        }
+              else failure
+          }
       }
     }
 

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

@@ -27,10 +27,20 @@ import collection.mutable
 import transform.TypeUtils._
 import reporting.trace
 import util.Positions.Position
+import util.Property
 
 object Inliner {
   import tpd._
 
+  /** Marks an implicit reference found in the context (as opposed to the implicit scope)
+   *  from an inlineable body. Such references will be carried along with the body to
+   *  the expansion site.
+   */
+  private val ContextualImplicit = new Property.StickyKey[Unit]
+
+  def markContextualImplicit(tree: Tree)(implicit ctx: Context): Unit =
+    methPart(tree).putAttachment(ContextualImplicit, ())
+
   class InlineAccessors extends AccessProxies {
 
     /** A tree map which inserts accessors for all non-public term members accessed
@@ -104,7 +114,7 @@ object Inliner {
    *                     to have the inlined method as owner.
    */
   def registerInlineInfo(
-      sym: SymDenotation, treeExpr: Context => Tree)(implicit ctx: Context): Unit = {
+      sym: SymDenotation, originalBody: untpd.Tree, treeExpr: Context => Tree)(implicit ctx: Context): Unit = {
     sym.unforcedAnnotation(defn.BodyAnnot) match {
       case Some(ann: ConcreteBodyAnnotation) =>
       case Some(ann: LazyBodyAnnotation) if ann.isEvaluated =>
@@ -173,10 +183,10 @@ 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 +210,7 @@ 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 +325,7 @@ 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 +397,7 @@ 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.

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

@@ -825,6 +825,7 @@ class Namer { typer: Typer =>
       case original: untpd.DefDef if denot.isInlineableMethod =>
         Inliner.registerInlineInfo(
             denot,
+            original.rhs,
             implicit ctx => typedAheadExpr(original).asInstanceOf[tpd.DefDef].rhs
           )(localContext(denot.symbol))
       case _ =>

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

@@ -1420,7 +1420,7 @@ class Typer extends Namer
     val rhs1 = normalizeErasedRhs(typedExpr(ddef.rhs, tpt1.tpe)(rhsCtx), sym)
 
     // Overwrite inline body to make sure it is not evaluated twice
-    if (sym.isInlineableMethod) Inliner.registerInlineInfo(sym, _ => rhs1)
+    if (sym.isInlineableMethod) Inliner.registerInlineInfo(sym, ddef.rhs, _ => rhs1)
 
     if (sym.isConstructor && !sym.isPrimaryConstructor)
       for (param <- tparams1 ::: vparamss1.flatten)
@@ -1885,7 +1885,17 @@ class Typer extends Namer
           case none =>
             typed(mdef) match {
               case mdef1: DefDef if Inliner.hasBodyToInline(mdef1.symbol) =>
-                buf += inlineExpansion(mdef1)
+                if (mdef1.symbol.isInlinedMethod) {
+                  buf += inlineExpansion(mdef1)
+                    // replace body with expansion, because it will be used as inlined body
+                    // from separately compiled files - the original BodyAnnotation is not kept.
+                }
+                else {
+                  assert(mdef.symbol.isTransparentMethod)
+                  Inliner.bodyToInline(mdef1.symbol) // just make sure accessors are computed,
+                  buf += mdef1                       // but keep original definition, since inline-expanded code
+                                                     // is pickled in this case.
+                }
               case mdef1 =>
                 import untpd.modsDeco
                 mdef match {