From 070b863408cab1b5ce64b65a552a6bb243c74e63 Mon Sep 17 00:00:00 2001
From: Olivier Blanvillain <olivier.blanvillain@gmail.com>
Date: Wed, 19 May 2021 13:06:00 +0200
Subject: [PATCH] Fix #12249: don't export java defined modules

---
 compiler/src/dotty/tools/dotc/typer/Namer.scala | 2 ++
 tests/neg/12249.scala                           | 9 +++++++++
 2 files changed, 11 insertions(+)
 create mode 100644 tests/neg/12249.scala

diff --git a/compiler/src/dotty/tools/dotc/typer/Namer.scala b/compiler/src/dotty/tools/dotc/typer/Namer.scala
index 14e4aecd55c9..f421c75f9287 100644
--- a/compiler/src/dotty/tools/dotc/typer/Namer.scala
+++ b/compiler/src/dotty/tools/dotc/typer/Namer.scala
@@ -1000,6 +1000,8 @@ class Namer { typer: Typer =>
           ) match
               case Some(other) => No(i"overrides ${other.showLocated}, which is already a member of $cls")
               case None => Yes
+        else if sym.isAllOf(JavaModule) then
+          Skip
         else Yes
       }
 
diff --git a/tests/neg/12249.scala b/tests/neg/12249.scala
new file mode 100644
index 000000000000..81e8ce053584
--- /dev/null
+++ b/tests/neg/12249.scala
@@ -0,0 +1,9 @@
+
+export java.util.UUID
+
+def bar = println(new UUID(1, 2)) // OK
+
+def foo = println(UUID.randomUUID()) // error
+//                ^^^^
+//                Not found: UUID
+