Merge pull request #824 from adriaanm/ticket-4691_6008

[SI-4691, SI-6008] improve patmat analyses: irrefutable user-defined extractors, no-op type tests

6 files changed, 61 insertions, 1 deletions

diff --git a/test/files/neg/exhausting.check b/test/files/neg/exhausting.check
index 7140b99428..0f0d13cb33 100644
--- a/test/files/neg/exhausting.check
+++ b/test/files/neg/exhausting.check
@@ -7,7 +7,7 @@ It would fail on the following input: Nil
   def fail2[T](xs: List[T]) = xs match {
                               ^
 exhausting.scala:32: error: match may not be exhaustive.
-It would fail on the following input: List(<not in (1, 2)>)
+It would fail on the following input: List((x: Int forSome x not in (1, 2)))
   def fail3a(xs: List[Int]) = xs match {
                               ^
 exhausting.scala:39: error: match may not be exhaustive.
diff --git a/test/files/neg/t4691_exhaust_extractor.check b/test/files/neg/t4691_exhaust_extractor.check
new file mode 100644
index 0000000000..cd12e56f86
--- /dev/null
+++ b/test/files/neg/t4691_exhaust_extractor.check
@@ -0,0 +1,13 @@
+t4691_exhaust_extractor.scala:17: error: match may not be exhaustive.
+It would fail on the following input: Bar3()
+  def f1(x: Foo) = x match {
+                   ^
+t4691_exhaust_extractor.scala:23: error: match may not be exhaustive.
+It would fail on the following input: Bar3()
+  def f2(x: Foo) = x match {
+                   ^
+t4691_exhaust_extractor.scala:29: error: match may not be exhaustive.
+It would fail on the following input: Bar3()
+  def f3(x: Foo) = x match {
+                   ^
+three errors found
diff --git a/test/files/neg/t4691_exhaust_extractor.flags b/test/files/neg/t4691_exhaust_extractor.flags
new file mode 100644
index 0000000000..e8fb65d50c
--- /dev/null
+++ b/test/files/neg/t4691_exhaust_extractor.flags
@@ -0,0 +1 @@
+-Xfatal-warnings
\ No newline at end of file
diff --git a/test/files/neg/t4691_exhaust_extractor.scala b/test/files/neg/t4691_exhaust_extractor.scala
new file mode 100644
index 0000000000..c68c33d654
--- /dev/null
+++ b/test/files/neg/t4691_exhaust_extractor.scala
@@ -0,0 +1,33 @@
+sealed trait Foo
+class Bar1 extends Foo
+class Bar2 extends Foo
+class Bar3 extends Foo
+
+// these extractors are known to always succeed as they return a Some
+object Baz1 {
+  def unapply(x: Bar1): Some[Int] = Some(1)
+}
+object Baz2 {
+  def unapply(x: Bar2): Some[Int] = Some(2)
+}
+
+
+object Test {
+  // warning: missing Bar3
+  def f1(x: Foo) = x match {
+    case _: Bar1 => 1
+    case _: Bar2 => 2
+  }
+
+  // warning: missing Bar3
+  def f2(x: Foo) = x match {
+    case _: Bar1 => 1
+    case Baz2(x) => x
+  }
+
+  // warning: missing Bar3
+  def f3(x: Foo) = x match {
+    case Baz1(x) => x
+    case Baz2(x) => x
+  }
+}
\ No newline at end of file
diff --git a/test/files/pos/t6008.flags b/test/files/pos/t6008.flags
new file mode 100644
index 0000000000..e8fb65d50c
--- /dev/null
+++ b/test/files/pos/t6008.flags
@@ -0,0 +1 @@
+-Xfatal-warnings
\ No newline at end of file
diff --git a/test/files/pos/t6008.scala b/test/files/pos/t6008.scala
new file mode 100644
index 0000000000..84ae19b211
--- /dev/null
+++ b/test/files/pos/t6008.scala
@@ -0,0 +1,12 @@
+// none of these should complain about exhaustivity
+class Test {
+  // It would fail on the following inputs: (_, false), (_, true)
+  def x(in: (Int, Boolean)) = in match { case (i: Int, b: Boolean) => 3 }
+
+  // There is no warning if the Int is ignored or bound without an explicit type:
+  def y(in: (Int, Boolean)) = in match { case (_, b: Boolean) => 3 }
+
+  // Keeping the explicit type for the Int but dropping the one for Boolean presents a spurious warning again:
+  // It would fail on the following input: (_, _)
+  def z(in: (Int, Boolean)) = in match { case (i: Int, b) => 3 }
+}
\ No newline at end of file