Made -Xfatal-warnings less immediately fatal.

Instead of changing warnings to errors mid-stream, at the end of
a run I check for condition "no errors, some warnings, and fatal
warnings" and then generate an error at that point.  This is
necessary to test for some warnings which come from later stages.

1 files changed, 5 insertions, 3 deletions

diff --git a/test/files/neg/unit-returns-value.check b/test/files/neg/unit-returns-value.check
index ab458a350b..363946f94d 100644
--- a/test/files/neg/unit-returns-value.check
+++ b/test/files/neg/unit-returns-value.check
@@ -1,7 +1,9 @@
-unit-returns-value.scala:4: error: a pure expression does nothing in statement position; you may be omitting necessary parentheses
+unit-returns-value.scala:4: warning: a pure expression does nothing in statement position; you may be omitting necessary parentheses
     if (b) return 5
                   ^
-unit-returns-value.scala:4: error: enclosing method f has result type Unit: return value discarded
+unit-returns-value.scala:4: warning: enclosing method f has result type Unit: return value discarded
     if (b) return 5
            ^
-two errors found
+error: No warnings can be incurred under -Xfatal-warnings.
+two warnings found
+one error found