Closes SI-5969.

Assumption that we enter tryTwice when inferring
the right alternative with an empty buffer is
wrong.
In this particular bug it manifested itself on
if/then/else which share the same context and 'else'
branch was simply flushing the buffer with an
error from the 'then' branch.

3 files changed, 19 insertions, 1 deletions

diff --git a/test/files/neg/t5969.check b/test/files/neg/t5969.check
new file mode 100644
index 0000000000..9d8ac9a3a5
--- /dev/null
+++ b/test/files/neg/t5969.check
@@ -0,0 +1,7 @@
+t5969.scala:9: error: overloaded method value g with alternatives:
+  (x: C2)String <and>
+  (x: C1)String
+ cannot be applied to (String)
+    if (false) List(g(x)) else List[C1]() map g
+                    ^
+one error found
diff --git a/test/files/neg/t5969.scala b/test/files/neg/t5969.scala
new file mode 100644
index 0000000000..62f87fd7ab
--- /dev/null
+++ b/test/files/neg/t5969.scala
@@ -0,0 +1,11 @@
+class C1
+class C2
+class A {
+  def f(x: Any) = x
+  def g(x: C1): String = "A"
+  def g(x: C2): String = "B"
+  
+  def crash() = f(List[String]() flatMap { x =>
+    if (false) List(g(x)) else List[C1]() map g
+  })
+}
diff --git a/test/files/neg/t649.check b/test/files/neg/t649.check
index a6670886b5..5a270d4751 100644
--- a/test/files/neg/t649.check
+++ b/test/files/neg/t649.check
@@ -1,4 +1,4 @@
 t649.scala:3: error: overloaded method foo needs result type
   def foo[A] = foo[A]
-      ^
+                  ^
 one error found