Merge pull request scala#4102 from retronym/ticket/8965

lrytz · lrytz · commit 60d59ee9f3ac · 2014-11-10T12:48:04.000+01:00
SI-8965 Account for corner case in "unrelated types" warning
diff --git a/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala b/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala
@@ -1095,7 +1095,7 @@ abstract class RefChecks extends InfoTransform with scala.reflect.internal.trans
         // better to have lubbed and lost
         def warnIfLubless(): Unit = {
           val common = global.lub(List(actual.tpe, receiver.tpe))
-          if (ObjectTpe <:< common)
+          if (ObjectTpe <:< common && !(ObjectTpe <:< actual.tpe && ObjectTpe <:< receiver.tpe))
             unrelatedTypes()
         }
         // warn if actual has a case parent that is not same as receiver's;
diff --git a/test/files/pos/t8965.flags b/test/files/pos/t8965.flags
@@ -0,0 +1 @@
+-Xfatal-warnings
diff --git a/test/files/pos/t8965.scala b/test/files/pos/t8965.scala
@@ -0,0 +1,7 @@
+class A {
+  def f(x: Any with AnyRef, y: Any with AnyRef) = x eq y
+  // a.scala:2: warning: Any and Any are unrelated: they will most likely never compare equal
+  //   def f(x: Any with AnyRef, y: Any with AnyRef) = x eq y
+  //                                                     ^
+  // one warning found
+}

Original file line number	Diff line number	Diff line change
`@@ -1095,7 +1095,7 @@ abstract class RefChecks extends InfoTransform with scala.reflect.internal.trans`
`1095`	`1095`	`// better to have lubbed and lost`
`1096`	`1096`	`def warnIfLubless(): Unit = {`
`1097`	`1097`	`val common = global.lub(List(actual.tpe, receiver.tpe))`
`1098`		`- if (ObjectTpe <:< common)`
	`1098`	`+ if (ObjectTpe <:< common && !(ObjectTpe <:< actual.tpe && ObjectTpe <:< receiver.tpe))`
`1099`	`1099`	`unrelatedTypes()`
`1100`	`1100`	`}`
`1101`	`1101`	`// warn if actual has a case parent that is not same as receiver's;`