From cc4b45e238c92c64e473a4d71b0c3474f75fa6da Mon Sep 17 00:00:00 2001
From: Martin Odersky <odersky@gmail.com>
Date: Wed, 12 May 2021 10:26:39 +0200
Subject: [PATCH] Disallow attempts to instantiate packages

Fixes #12430
---
 compiler/src/dotty/tools/dotc/typer/Typer.scala | 3 +++
 tests/neg/i12430.scala                          | 4 ++++
 2 files changed, 7 insertions(+)
 create mode 100644 tests/neg/i12430.scala

diff --git a/compiler/src/dotty/tools/dotc/typer/Typer.scala b/compiler/src/dotty/tools/dotc/typer/Typer.scala
index 0c7867a03bdc..597afa096cce 100644
--- a/compiler/src/dotty/tools/dotc/typer/Typer.scala
+++ b/compiler/src/dotty/tools/dotc/typer/Typer.scala
@@ -778,6 +778,9 @@ class Typer extends Namer
         typed(cpy.Block(tree)(clsDef :: Nil, New(Ident(x), Nil)), pt)
       case _ =>
         var tpt1 = typedType(tree.tpt)
+        val tsym = tpt1.tpe.underlyingClassRef(refinementOK = false).typeSymbol
+        if tsym.is(Package) then
+          report error(em"$tsym cannot be instantiated", tpt1.srcPos)
         tpt1 = tpt1.withType(ensureAccessible(tpt1.tpe, superAccess = false, tpt1.srcPos))
         tpt1 match {
           case AppliedTypeTree(_, targs) =>
diff --git a/tests/neg/i12430.scala b/tests/neg/i12430.scala
new file mode 100644
index 000000000000..075c3bba4f90
--- /dev/null
+++ b/tests/neg/i12430.scala
@@ -0,0 +1,4 @@
+class i0 {
+  new collection // error
+  new io // error
+}
\ No newline at end of file