From 8b66af0cfe29ab6026215e44f4d4b148316c159d Mon Sep 17 00:00:00 2001
From: Adriaan Moors <adriaan.moors@epfl.ch>
Date: Wed, 15 Jun 2011 16:32:38 +0000
Subject: closes #4692: unification in type constructor i...

closes #4692: unification in type constructor inference now widens *and*
dealiases when necessary

in 2.8.1 implicit conversion search started with a widened type, so that
combo never came up

no review
---
 test/files/pos/t4692.scala | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)
 create mode 100644 test/files/pos/t4692.scala

(limited to 'test/files/pos')

diff --git a/test/files/pos/t4692.scala b/test/files/pos/t4692.scala
new file mode 100644
index 0000000000..409daf2257
--- /dev/null
+++ b/test/files/pos/t4692.scala
@@ -0,0 +1,27 @@
+class TypeAliasVsImplicitTest {
+
+    class For[m[_], a](x: m[a]) {
+       def map[b](y: a => b): m[b] = throw new Error
+    }
+    implicit def toFor[m[_], a](x: m[a]): For[m, a] = new For[m, a](x)
+
+    trait MyList[A]
+
+    def foo(xs: MyList[Int]) = xs.map(x => x) // compiles fine.
+
+    type MyListOfInt = MyList[Int]
+    def bar(xs: MyListOfInt) = xs.map(x => x) // doesn't compile: value map is not a member of TypeAliasVsImplicitTest.this.MyListOfInt
+}
+
+// minimal case -- the bug was in type constructor inference where `xs.type` needed to be widened *and* dealiased
+// in 2.8.1 implicit conversion search started with a widened type, so that combo never came up
+// object Test {
+//   class For[m[_], a](x: m[a])
+//   def toFor[m[_], a](x: m[a]): For[m, a] = new For[m, a](x)
+//
+//   trait MyList[A]
+//   type MyListOfInt = MyList[Int]
+//
+//   val xs: MyListOfInt = error("")
+//   toFor(xs : xs.type)
+// }
\ No newline at end of file
-- 
cgit v1.2.3