Improved warning for insensible comparisons.

Utilize knowledge of case class synthetic equals to rule out
some comparisons statically.  Closes SI-5426.

1 files changed, 13 insertions, 0 deletions

diff --git a/test/files/neg/t5426.check b/test/files/neg/t5426.check
new file mode 100644
index 0000000000..d9e192d3f0
--- /dev/null
+++ b/test/files/neg/t5426.check
@@ -0,0 +1,13 @@
+t5426.scala:2: error: comparing values of types Some[Int] and Int using `==' will always yield false
+  def f1 = Some(5) == 5
+                   ^
+t5426.scala:3: error: comparing values of types Int and Some[Int] using `==' will always yield false
+  def f2 = 5 == Some(5)
+             ^
+t5426.scala:8: error: comparing values of types Int and Some[Int] using `==' will always yield false
+  (x1 == x2)
+      ^
+t5426.scala:9: error: comparing values of types Some[Int] and Int using `==' will always yield false
+  (x2 == x1)
+      ^
+four errors found