Disable -Ydelambdafy:method for specialized FunctionN

The Delambdafy phase generates its `FunctionN` subclasses after
the specialization phase. As such, `((x: Int) => x).apply(42)` incurs
boxing.

This commit falls back to the `-Ydelambdafy:inline` in this case.

This is done by running the specialization type map over the
type of the function, and seeing if anything changes. To make this
work robustly, we first need to ensure that the specialization info
transformer has processed all the function types.

This is not a fundamental limitation; we could in principle generate
the specialized code.

A followup change will use `-Ydelambdafy:method` as the basis for
invokedymnamic lambdas. As part of that stream of
work, we will synthesize specialization-aware lambdas, and remove
the fallback to `-Ydelambdafy:inline`.

I have updated some tests that intend to test the delambdafy transform
to avoid use of specialized function types.

1 files changed, 5 insertions, 5 deletions

diff --git a/test/files/run/delambdafy_t6028.scala b/test/files/run/delambdafy_t6028.scala
index 0b7ef48c3d..ca39195310 100644
--- a/test/files/run/delambdafy_t6028.scala
+++ b/test/files/run/delambdafy_t6028.scala
@@ -5,11 +5,11 @@ object Test extends DirectTest {
 
   override def extraSettings: String = "-usejavacp -Ydelambdafy:method -Xprint:lambdalift -d " + testOutput.path
 
-  override def code = """class T(classParam: Int) {
-                        |  val field: Int = 0
-                        |  def foo(methodParam: Int) = {val methodLocal = 0 ; () => classParam + field + methodParam + methodLocal }
-                        |  def bar(barParam: Int) = { trait MethodLocalTrait { print(barParam) }; object MethodLocalObject extends MethodLocalTrait; MethodLocalObject }
-                        |  def tryy(tryyParam: Int) = { var tryyLocal = 0; () => try { tryyLocal = tryyParam } finally () }
+  override def code = """class T(classParam: String) {
+                        |  val field: String = ""
+                        |  def foo(methodParam: String) = {val methodLocal = "" ; () => classParam + field + methodParam + methodLocal }
+                        |  def bar(barParam: String) = { trait MethodLocalTrait { print(barParam) }; object MethodLocalObject extends MethodLocalTrait; MethodLocalObject }
+                        |  def tryy(tryyParam: String) = { var tryyLocal = ""; () => try { tryyLocal = tryyParam } finally () }
                         |}
                         |""".stripMargin.trim