SI-6120 Suppress extra warnings

This is a mere polish for the fix to allow multiple warnings.

Sensibility checks in refchecks were shown to be redundant.

This commit includes a mild refactor to reduce tabbage, and
uses a local var to flag that a warning has already been emitted.

It would be better to have the checks return true if warned,
to facilitate `nonSensically || unrelatedly`, etc., but that's
a lot of `else false`.

The check files that were updated with the redundant warnings
are reverted.

1 files changed, 1 insertions, 7 deletions

diff --git a/test/files/neg/t5426.check b/test/files/neg/t5426.check
index c042cdcec3..98f3ddaaae 100644
--- a/test/files/neg/t5426.check
+++ b/test/files/neg/t5426.check
@@ -4,18 +4,12 @@ t5426.scala:2: warning: comparing values of types Some[Int] and Int using `==' w
 t5426.scala:3: warning: comparing values of types Int and Some[Int] using `==' will always yield false
   def f2 = 5 == Some(5)
              ^
-t5426.scala:3: warning: Int and Some[Int] are unrelated: they will most likely never compare equal
-  def f2 = 5 == Some(5)
-             ^
 t5426.scala:8: warning: comparing values of types Int and Some[Int] using `==' will always yield false
   (x1 == x2)
       ^
-t5426.scala:8: warning: Int and Some[Int] are unrelated: they will most likely never compare equal
-  (x1 == x2)
-      ^
 t5426.scala:9: warning: comparing values of types Some[Int] and Int using `==' will always yield false
   (x2 == x1)
       ^
 error: No warnings can be incurred under -Xfatal-warnings.
-6 warnings found
+four warnings found
 one error found