Don't try to unpickle RHS of deferred inline methods

Author: odersky

compiler/src/dotty/tools/dotc/core/SymDenotations.scala

@@ -939,7 +939,7 @@ object SymDenotations {
       isAllOf(InlineMethod, butNot = Accessor)
 
     def isInlineRetained: Ctx[Boolean] =
-      allOverriddenSymbols.exists(!_.is(Inline))
+      !is(Deferred) && allOverriddenSymbols.exists(!_.is(Inline))
 
     /** Is this a Scala 2 macro */
     final def isScala2Macro(implicit ctx: Context): Boolean = is(Macro) && symbol.owner.is(Scala2x)

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

@@ -580,7 +580,7 @@ class TreeUnpickler(reader: TastyReader,
         sym.completer.withDecls(newScope)
         forkAt(templateStart).indexTemplateParams()(localContext(sym))
       }
-      else if (sym.isInlineMethod)
+      else if sym.isInlineMethod && !sym.is(Deferred) then
         sym.addAnnotation(LazyBodyAnnotation { ctx0 =>
           val ctx1 = localContext(sym)(ctx0).addMode(Mode.ReadPositions)
           given Context = sourceChangeContext(Addr(0))(ctx1)