Merge pull request #4249 from dotty-staging/fix/4248

Fix #4248: intersection dominator of Arrays

Author: allanrenucci

compiler/src/dotty/tools/dotc/transform/GenericSignatures.scala

@@ -317,7 +317,7 @@ object GenericSignatures {
       val psyms = parents map (_.typeSymbol)
       if (psyms contains defn.ArrayClass) {
         // treat arrays specially
-        defn.ArrayType.appliedTo(intersectionDominator(parents.filter(_.typeSymbol == defn.ArrayClass).map(t => t.typeParams.head.paramInfo)))
+        defn.ArrayType.appliedTo(intersectionDominator(parents.filter(_.typeSymbol == defn.ArrayClass).map(t => t.argInfos.head)))
       } else {
         // implement new spec for erasure of refined types.
         def isUnshadowed(psym: Symbol) =

tests/generic-java-signatures/i4248.check

@@ -0,0 +1 @@
+public <U> void Foo$.foo(int[])

tests/generic-java-signatures/i4248.scala

@@ -0,0 +1,10 @@
+object Foo {
+  def foo[U](u: Array[Int] & Array[U]): Unit = ()
+}
+
+object Test {
+  def main(args: Array[String]): Unit = {
+    val f1 = Foo.getClass.getMethods.find(_.getName.endsWith("foo")).get
+    println(f1.toGenericString)
+  }
+}