SI-5886 Remove check for packed type conformance.

Nothing breaks. Why did by-name arguments have this
extra check? What's the difference to a () => T?

The check was added originally in 8414eba.

2 files changed, 19 insertions, 22 deletions

diff --git a/src/compiler/scala/tools/nsc/typechecker/SuperAccessors.scala b/src/compiler/scala/tools/nsc/typechecker/SuperAccessors.scala
index fa72ad64bf..bad49385aa 100644
--- a/src/compiler/scala/tools/nsc/typechecker/SuperAccessors.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/SuperAccessors.scala
@@ -80,32 +80,11 @@ abstract class SuperAccessors extends transform.Transform with transform.TypingT
     private def transformArgs(params: List[Symbol], args: List[Tree]) = {
       treeInfo.mapMethodParamsAndArgs(params, args) { (param, arg) =>
         if (isByNameParamType(param.tpe))
-          withInvalidOwner { checkPackedConforms(transform(arg), param.tpe.typeArgs.head) }
+          withInvalidOwner(transform(arg))
         else transform(arg)
       }
     }
 
-    private def checkPackedConforms(tree: Tree, pt: Type): Tree = {
-      def typeError(typer: analyzer.Typer, pos: Position, found: Type, req: Type) {
-        if (!found.isErroneous && !req.isErroneous) {
-          val msg = analyzer.ErrorUtils.typeErrorMsg(found, req, typer.infer.isPossiblyMissingArgs(found, req))
-          typer.context.error(pos, analyzer.withAddendum(pos)(msg))
-          if (settings.explaintypes.value)
-            explainTypes(found, req)
-        }
-      }
-
-      if (tree.tpe exists (_.typeSymbol.isExistentialSkolem)) {
-        val packed = localTyper.packedType(tree, NoSymbol)
-        if (!(packed <:< pt)) {
-          val errorContext = localTyper.context.make(localTyper.context.tree)
-          errorContext.setReportErrors()
-          typeError(analyzer.newTyper(errorContext), tree.pos, packed, pt)
-        }
-      }
-      tree
-    }
-
     /** Check that a class and its companion object to not both define
      *  a class or module with same name
      */
diff --git a/test/files/pos/t5886.scala b/test/files/pos/t5886.scala
new file mode 100644
index 0000000000..066187322d
--- /dev/null
+++ b/test/files/pos/t5886.scala
@@ -0,0 +1,18 @@
+object A {
+  def f0[T](x: T): T = x
+  def f1[T](x: => T): T = x
+  def f2[T](x: () => T): T = x()
+
+  f0(this.getClass)  // ok
+  f1(this.getClass)
+  f2(this.getClass)  // ok
+
+  // a.scala:7: error: type mismatch;
+  //  found   : Class[_ <: A.type]
+  //  required: Class[?0(in value x1)] where type ?0(in value x1) <: A.type
+  // Note: A.type >: ?0, but Java-defined class Class is invariant in type T.
+  // You may wish to investigate a wildcard type such as `_ >: ?0`. (SLS 3.2.10)
+  //   val x1 = f1(this.getClass)
+  //                    ^
+  // one error found
+}