Merge pull request #11000 from dotty-staging/fix-#10910

Fix #10910: Add missing position

Author: nicolasstucki

compiler/src-bootstrapped/scala/quoted/runtime/impl/QuotesImpl.scala

@@ -744,7 +744,7 @@ class QuotesImpl private (using val ctx: Context) extends Quotes, QuoteUnpickler
     object Lambda extends LambdaModule:
       def apply(owner: Symbol, tpe: MethodType, rhsFn: (Symbol, List[Tree]) => Tree): Block =
         val meth = dotc.core.Symbols.newSymbol(owner, nme.ANON_FUN, Synthetic | Method, tpe)
-        tpd.Closure(meth, tss => yCheckedOwners(rhsFn(meth, tss.head), meth))
+        tpd.Closure(meth, tss => yCheckedOwners(rhsFn(meth, tss.head.map(withDefaultPos)), meth))
 
       def unapply(tree: Block): Option[(List[ValDef], Term)] = tree match {
         case Block((ddef @ DefDef(_, _, params :: Nil, _, Some(body))) :: Nil, Closure(meth, _))

tests/pos-macros/i10910/Macro_1.scala

@@ -0,0 +1,86 @@
+package x
+
+import scala.quoted._
+
+trait CB[T]:
+ def map[S](f: T=>S): CB[S] = ???
+
+def await[T](x:CB[T]):T = ???
+
+object CBM:
+  def pure[T](t:T):CB[T] = ???
+
+object X:
+
+ inline def process[T](inline f:T) = ${
+   processImpl[T]('f)
+ }
+
+ def processImpl[T:Type](f:Expr[T])(using qctx: Quotes):Expr[CB[T]] =
+   import quotes.reflect._
+
+   def transform(term:Term): Either[Term, Term] =
+     term match
+        case ap@Apply(Select(obj,"foreach"),args) =>
+            //  println("handle-foreach")
+             val nArgs = args.map(x => shiftLambda(x).right.get)
+             val nSelect = Select.unique(obj, "foreach_async")
+             Right(Apply(nSelect,nArgs))
+        case ap@Apply(sel@Select(obj,"awrite"),args) =>
+            //  println("handle-awrite")
+             transform(args.head) match
+               case Left(unchanded) => Left(ap)
+               case Right(changed) =>
+                 val r = '{ ${changed.asExprOf[CB[?]]}.map(x => ${Apply(sel,List('x.asTerm)).asExpr}) }
+                 Right(r.asTerm)
+        case Apply(tap@TypeApply(Ident("await"),targs),args) =>
+            //  println("handle-await")
+             transform(args.head) match
+                case Left(unchanged) => Right(unchanged)
+                case Right(changed) =>
+                   val r = Apply(tap,List(changed))
+                   Right(r)
+        case Lambda(v, body) => ???
+        case Block(stats, last) => transform(last) match
+                                     case Left(unchanged) => Left(Block(stats, last))
+                                     case Right(changed) => Right(Block(stats, changed))
+        case Inlined(x,List(),body) => transform(body)
+        case Inlined(x,bindings,body) => transform(body) match
+                      case Left(unchanged) => Left(term)
+                      case Right(changed) => Right(Inlined(x,bindings,changed))
+        case Typed(arg,tp) => transform(arg)
+        case Ident(x) => Left(term)
+        case l@Literal(x) => Left(l)
+        case other =>
+             throw RuntimeException(s"Not supported $other")
+
+   def shiftLambda(term:Term): Either[Term,Term] =
+        term match
+          case lt@Lambda(params, body) =>
+            transform(body) match
+              case Left(unchanged) => Left(term)
+              case Right(nBody) =>
+                val paramTypes = params.map(_.tpt.tpe)
+                val paramNames = params.map(_.name+"Changed")
+                val mt = MethodType(paramNames)(_ => paramTypes, _ => TypeRepr.of[CB].appliedTo(body.tpe.widen) )
+                val r = Lambda(Symbol.spliceOwner, mt, (owner,args) => changeArgs(params,args,nBody).changeOwner(owner) )
+                Right(r)
+          case _ =>
+            throw RuntimeException("lambda expected")
+   def changeArgs(oldArgs:List[Tree], newArgs:List[Tree], body:Term):Term =
+        //  println(s"changeArgs: oldArgs=${oldArgs.map(_.symbol.hashCode)}, newArgs=${newArgs.map(_.symbol.hashCode)} ")
+         val association: Map[Symbol, Term] = (oldArgs zip newArgs).foldLeft(Map.empty){
+             case (m, (oldParam, newParam: Term)) => m.updated(oldParam.symbol, newParam)
+             case (m, (oldParam, newParam: Tree)) => throw RuntimeException("Term expected")
+         }
+         val changes = new TreeMap() {
+             override def transformTerm(tree:Term)(owner: Symbol): Term =
+               tree match
+                 case ident@Ident(name) => association.getOrElse(ident.symbol, super.transformTerm(tree)(owner))
+                 case _ => super.transformTerm(tree)(owner)
+         }
+         changes.transformTerm(body)(Symbol.spliceOwner)
+
+   transform(f.asTerm) match
+      case Left(unchanged) => '{ CBM.pure($f) }
+      case Right(changed) => changed.asExprOf[CB[T]]

tests/pos-macros/i10910/Test_2.scala

@@ -0,0 +1,31 @@
+import x._
+
+class Writer[A] {
+
+   def awrite(a:A): CB[Unit] = ???
+
+   inline def write(a:A):Unit =
+     await(awrite(a))
+
+}
+
+class Reader[A] {
+
+   def foreach_async(f: A=> CB[Unit]): CB[Unit] = ???
+
+   def foreach(f: A=>Unit): Unit =
+      foreach_async(v => CBM.pure(f(v)))
+
+}
+
+object Test {
+
+ def main(args:Array[String]):Unit =
+   val writer = new Writer[Int]()
+   val reader = new Reader[Int]()
+   val r = X.process{
+       reader.foreach( v => writer.write(v) )
+   }
+   println("r")
+
+}