Make sure messages are lazily evaluated until `report` in `Reporter`

1 files changed, 37 insertions, 0 deletions

diff --git a/test/dotty/tools/dotc/reporting/TestMessageLaziness.scala b/test/dotty/tools/dotc/reporting/TestMessageLaziness.scala
new file mode 100644
index 000000000..fe85edda6
--- /dev/null
+++ b/test/dotty/tools/dotc/reporting/TestMessageLaziness.scala
@@ -0,0 +1,37 @@
+package dotty.tools
+package dotc
+package reporting
+
+import org.junit.Assert._
+import org.junit.Test
+
+import core.Contexts._
+
+import test.DottyTest
+
+import diagnostic.{ Message, MessageContainer, ExtendMessage }
+
+class TestMessageLaziness extends DottyTest {
+  ctx = ctx.fresh.setReporter(new NonchalantReporter)
+
+  class NonchalantReporter(implicit ctx: Context) extends Reporter
+  with UniqueMessagePositions with HideNonSensicalMessages {
+    def doReport(d: MessageContainer)(implicit ctx: Context) = ???
+
+    override def report(d: => MessageContainer)(implicit ctx: Context) = ()
+  }
+
+  case class LazyError() extends Message(1000) {
+    throw new Error("Didn't stay lazy.")
+
+    val kind = "Test"
+    val msg = "Please don't blow up"
+    val explanation = ""
+  }
+
+  @Test def assureLazy =
+    ctx.error(LazyError())
+
+  @Test def assureLazyExtendMessage =
+    ctx.strictWarning(LazyError())
+}