Merge pull request #1931 from dotty-staging/fix-#1501

Fix #1501 - Check trait inheritance condition

2 files changed, 29 insertions, 1 deletions

diff --git a/tests/neg/i1501.scala b/tests/neg/i1501.scala
new file mode 100644
index 000000000..685566403
--- /dev/null
+++ b/tests/neg/i1501.scala
@@ -0,0 +1,28 @@
+class A {
+  def foo: Int = 1
+}
+
+trait B extends A
+
+abstract class D {
+  def foo: Int
+}
+
+class C extends D with B // error: illegal trait inheritance
+trait E extends D with B // error: illegal trait inheritance
+
+object Test {
+  def main(args: Array[String]): Unit = {
+    println(new C().foo)
+  }
+}
+
+object Test2 {
+  class A
+  class SubA(x: Int) extends A
+  trait TA extends A
+  trait TSubA extends SubA(2) // error: trait TSubA may not call constructor of class SubA
+
+
+  class Foo extends TA with TSubA // error: missing argument for parameter x of constructor SubA:
+}
diff --git a/tests/neg/i1653.scala b/tests/neg/i1653.scala
index ab5369e5f..f21fc7d54 100644
--- a/tests/neg/i1653.scala
+++ b/tests/neg/i1653.scala
@@ -1,3 +1,3 @@
 trait Foo {
-  def foo() = new Unit with Foo  // error
+  def foo() = new Unit with Foo  // error: cannot extend final class Unit  // error: illegal trait inheritance
 }