Fix checkInlineConformant check for inlined trees

We where considering an `Inlined` tree as not conformant even if its contents are conformat.
Now we check if the exapnsion is conformant.

Author: nicolasstucki

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

@@ -710,6 +710,8 @@ trait Checking {
         tree match {
           case Typed(expr, _) =>
             checkInlineConformant(expr, isFinal, what)
+          case Inlined(_, Nil, expr) =>
+            checkInlineConformant(expr, isFinal, what)
           case SeqLiteral(elems, _) =>
             elems.foreach(elem => checkInlineConformant(elem, isFinal, what))
           case Apply(fn, List(arg)) if defn.WrapArrayMethods().contains(fn.symbol) =>

tests/pos/inlined-inline-param.scala

@@ -0,0 +1,4 @@
+class Foo {
+  inline def foo(inline x: Int): Int = x
+  def bar: Int = foo(foo(4))
+}