SI-8607 Generalize previous change to preErase

In the previous commit, we avoided an awkward chain of casts
by exploiting the knowledge that Scala defined classes will
by JVM accessible, and as such immune to `LinkageError`s when
used as the target of a cast.

This commit generalized this to the entire fix for SI-4283,
rather than just for derived value classes.

2 files changed, 11 insertions, 22 deletions

diff --git a/src/compiler/scala/tools/nsc/transform/Erasure.scala b/src/compiler/scala/tools/nsc/transform/Erasure.scala
index e31cb02033..2f2142027f 100644
--- a/src/compiler/scala/tools/nsc/transform/Erasure.scala
+++ b/src/compiler/scala/tools/nsc/transform/Erasure.scala
@@ -1050,29 +1050,21 @@ abstract class Erasure extends AddInterfaces
             }
           }
 
-          def isAccessible(sym: Symbol) = localTyper.context.isAccessible(sym, sym.owner.thisType)
-          if (!isAccessible(owner) && qual.tpe != null) {
+          def isJvmAccessible(sym: Symbol) = (sym.isClass && !sym.isJavaDefined) || localTyper.context.isAccessible(sym, sym.owner.thisType)
+          if (!isJvmAccessible(owner) && qual.tpe != null) {
             qual match {
               case Super(_, _) =>
-                // Insert a cast here at your peril -- see SI-5162. Bail out if the target method is defined in
-                // Java, otherwise, we'd get an IllegalAccessError at runtime. If the target method is defined in
-                // Scala, however, we should have access.
-                if (owner.isJavaDefined) unit.error(tree.pos, s"Unable to access ${tree.symbol.fullLocationString} with a super reference.")
+                // Insert a cast here at your peril -- see SI-5162.
+                unit.error(tree.pos, s"Unable to access ${tree.symbol.fullLocationString} with a super reference.")
                 tree
               case _ =>
                 // Todo: Figure out how qual.tpe could be null in the check above (it does appear in build where SwingWorker.this
                 // has a null type).
                 val qualSym = qual.tpe.widen.typeSymbol
-                if (isAccessible(qualSym) && !qualSym.isPackageClass && !qualSym.isPackageObjectClass) {
+                if (isJvmAccessible(qualSym) && !qualSym.isPackageClass && !qualSym.isPackageObjectClass) {
                   // insert cast to prevent illegal access error (see #4283)
                   // util.trace("insert erasure cast ") (*/
-                  if (qualSym.isDerivedValueClass) {
-                    assert(!owner.isJavaDefined, owner)
-                    // Safe, as derived value can't extend Java classes that would be JVM inaccessible
-                    devWarning("SI-8607 Not casting qualifier ${qual} to its widened type as it is a derived value class and this cast will trip up the rest of erasure/post erasure.")
-                    tree
-                  } else
-                    treeCopy.Select(tree, gen.mkAttributedCast(qual, qual.tpe.widen), name) //)
+                  treeCopy.Select(tree, gen.mkAttributedCast(qual, qual.tpe.widen), name) //)
                 } else tree
             }
           } else tree
diff --git a/test/files/run/analyzerPlugins.check b/test/files/run/analyzerPlugins.check
index e3ab554d4c..9803465ddc 100644
--- a/test/files/run/analyzerPlugins.check
+++ b/test/files/run/analyzerPlugins.check
@@ -19,7 +19,7 @@ canAdaptAnnotations(Trees$Typed, Any) [1]
 canAdaptAnnotations(Trees$Typed, Int) [1]
 lub(List(Int @testAnn, Int)) [1]
 pluginsPt(?, Trees$Annotated) [7]
-pluginsPt(?, Trees$Apply) [9]
+pluginsPt(?, Trees$Apply) [8]
 pluginsPt(?, Trees$ApplyImplicitView) [2]
 pluginsPt(?, Trees$Assign) [7]
 pluginsPt(?, Trees$Block) [4]
@@ -31,13 +31,13 @@ pluginsPt(?, Trees$Literal) [16]
 pluginsPt(?, Trees$New) [5]
 pluginsPt(?, Trees$PackageDef) [1]
 pluginsPt(?, Trees$Return) [1]
-pluginsPt(?, Trees$Select) [48]
+pluginsPt(?, Trees$Select) [47]
 pluginsPt(?, Trees$Super) [2]
 pluginsPt(?, Trees$This) [20]
-pluginsPt(?, Trees$TypeApply) [4]
+pluginsPt(?, Trees$TypeApply) [3]
 pluginsPt(?, Trees$TypeBoundsTree) [2]
 pluginsPt(?, Trees$TypeDef) [1]
-pluginsPt(?, Trees$TypeTree) [39]
+pluginsPt(?, Trees$TypeTree) [38]
 pluginsPt(?, Trees$Typed) [1]
 pluginsPt(?, Trees$ValDef) [21]
 pluginsPt(Any, Trees$Literal) [2]
@@ -98,7 +98,6 @@ pluginsTyped(()String, Trees$Ident) [1]
 pluginsTyped(()String, Trees$TypeApply) [1]
 pluginsTyped(()scala.annotation.Annotation, Trees$Select) [1]
 pluginsTyped(()testAnn, Trees$Select) [10]
-pluginsTyped(()type, Trees$TypeApply) [1]
 pluginsTyped((str: String)A <and> (param: Double)A, Trees$Select) [1]
 pluginsTyped((x$1: Any)Boolean <and> (x: Double)Boolean <and> (x: Float)Boolean <and> (x: Long)Boolean <and> (x: Int)Boolean <and> (x: Char)Boolean <and> (x: Short)Boolean <and> (x: Byte)Boolean, Trees$Select) [1]
 pluginsTyped((x$1: Int)Unit, Trees$Select) [1]
@@ -173,7 +172,7 @@ pluginsTyped(Unit, Trees$Literal) [5]
 pluginsTyped(Unit, Trees$TypeTree) [1]
 pluginsTyped([A](xs: A*)List[A], Trees$Select) [1]
 pluginsTyped([T <: Int]=> Int, Trees$Select) [1]
-pluginsTyped([T0]()T0, Trees$Select) [2]
+pluginsTyped([T0]()T0, Trees$Select) [1]
 pluginsTyped([T](xs: Array[T])scala.collection.mutable.WrappedArray[T], Trees$Select) [1]
 pluginsTyped(annotation.type, Trees$Select) [4]
 pluginsTyped(math.type, Trees$Select) [9]
@@ -190,7 +189,5 @@ pluginsTyped(testAnn, Trees$New) [5]
 pluginsTyped(testAnn, Trees$This) [1]
 pluginsTyped(testAnn, Trees$TypeTree) [2]
 pluginsTyped(testAnn.super.type, Trees$Super) [1]
-pluginsTyped(type, Trees$Apply) [1]
 pluginsTyped(type, Trees$Select) [1]
-pluginsTyped(type, Trees$TypeTree) [1]
 pluginsTypedReturn(return f, String) [1]