SI-7584 Test and spurious warning fix for by-name closures

The enclosed test case exercises by-name closures, which were
the subject of the previous commit. In the process, a spurious
warning was eliminated.

3 files changed, 21 insertions, 0 deletions

diff --git a/test/files/run/t7584.check b/test/files/run/t7584.check
new file mode 100644
index 0000000000..9f53e5dde5
--- /dev/null
+++ b/test/files/run/t7584.check
@@ -0,0 +1,6 @@
+no calls
+call A
+a
+call B twice
+b
+b
diff --git a/test/files/run/t7584.flags b/test/files/run/t7584.flags
new file mode 100644
index 0000000000..e8fb65d50c
--- /dev/null
+++ b/test/files/run/t7584.flags
@@ -0,0 +1 @@
+-Xfatal-warnings
\ No newline at end of file
diff --git a/test/files/run/t7584.scala b/test/files/run/t7584.scala
new file mode 100644
index 0000000000..6d7f4f7ebb
--- /dev/null
+++ b/test/files/run/t7584.scala
@@ -0,0 +1,14 @@
+// Test case added to show the behaviour of functions with
+// by-name parameters.  The evaluation behaviour was already correct.
+//
+// We did flush out a spurious "pure expression does nothing in statement position"
+// warning, hence -Xfatal-warnings in the flags file.
+object Test extends App {
+  def foo(f: (=> Int, => Int) => Unit) = f({println("a"); 0}, {println("b"); 1})
+  println("no calls")
+  foo((a, b) => ())
+  println("call A")
+  foo((a, b) => a)
+  println("call B twice")
+  foo((a, b) => {b; b})
+}