Inline argument closures to inline methods

If an argumnet to an inline method refers to a closure
that is the result of eta-expanding another inline method
inline the argument method.

1 files changed, 8 insertions, 2 deletions

diff --git a/src/dotty/tools/dotc/ast/Desugar.scala b/src/dotty/tools/dotc/ast/Desugar.scala
index 4e27da2ca..ecb6a3212 100644
--- a/src/dotty/tools/dotc/ast/Desugar.scala
+++ b/src/dotty/tools/dotc/ast/Desugar.scala
@@ -607,11 +607,17 @@ object desugar {
    *  ==>
    *      def $anonfun(params) = body
    *      Closure($anonfun)
+   *
+   *  If `inlineable` is true, tag $anonfun with an @inline annotation.
    */
-  def makeClosure(params: List[ValDef], body: Tree, tpt: Tree = TypeTree()) =
+  def makeClosure(params: List[ValDef], body: Tree, tpt: Tree = TypeTree(), inlineable: Boolean)(implicit ctx: Context) = {
+    var mods = synthetic
+    if (inlineable)
+      mods = mods.withAddedAnnotation(New(ref(defn.InlineAnnotType), Nil).withPos(body.pos))
     Block(
-      DefDef(nme.ANON_FUN, Nil, params :: Nil, tpt, body).withMods(synthetic),
+      DefDef(nme.ANON_FUN, Nil, params :: Nil, tpt, body).withMods(mods),
       Closure(Nil, Ident(nme.ANON_FUN), EmptyTree))
+  }
 
   /** If `nparams` == 1, expand partial function
    *