Merge pull request #1938 from dotty-staging/named-based-patmat

Change case class desugaring and decouple Products and name-based-pattern-matching

6 files changed, 111 insertions, 0 deletions

diff --git a/tests/pending/pos/t7296.scala b/tests/pos/t7296.scala
index fcba17c08..fcba17c08 100644
--- a/tests/pending/pos/t7296.scala
+++ b/tests/pos/t7296.scala
diff --git a/tests/run/1938.scala b/tests/run/1938.scala
new file mode 100644
index 000000000..95e94678d
--- /dev/null
+++ b/tests/run/1938.scala
@@ -0,0 +1,45 @@
+case class Large(
+  e1: Int,
+  e2: Int,
+  e3: Int,
+  e4: Int,
+  e5: Int,
+  e6: Int,
+  e7: Int,
+  e8: Int,
+  e9: Int,
+  e10: Int,
+  e11: Int,
+  e12: Int,
+  e13: Int,
+  e14: Int,
+  e15: Int,
+  e16: Int,
+  e17: Int,
+  e18: Int,
+  e19: Int,
+  e20: Int,
+  e21: Int,
+  e22: Int,
+  e23: Int
+)
+
+object Test {
+  def main(args: Array[String]): Unit = {
+    val l = Large(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
+
+    assert(l.productArity == 23)
+
+    assert(l.productElement(0) == 1)
+    assert(l.productElement(1) == 2)
+    assert(l.productElement(21) == 22)
+    assert(l.productElement(22) == 23)
+
+    try {
+      l.productElement(23)
+      ???
+    } catch {
+      case e: IndexOutOfBoundsException => assert(e.getMessage == "23")
+    }
+  }
+}
diff --git a/tests/pending/run/case-class-23.check b/tests/run/case-class-23.check
index 888ed2c9e..888ed2c9e 100644
--- a/tests/pending/run/case-class-23.check
+++ b/tests/run/case-class-23.check
diff --git a/tests/pending/run/case-class-23.scala b/tests/run/case-class-23.scala
index a6d78763c..a6d78763c 100644
--- a/tests/pending/run/case-class-23.scala
+++ b/tests/run/case-class-23.scala
diff --git a/tests/run/double-pattern-type.scala b/tests/run/double-pattern-type.scala
new file mode 100644
index 000000000..8045d173b
--- /dev/null
+++ b/tests/run/double-pattern-type.scala
@@ -0,0 +1,40 @@
+case class C1(i: String, s: Int) { def isEmpty = false; def get = ("EMPTY", -1) }
+case class C2(i: String, s: String) { def isEmpty = false; def get = (-1, -2, -3) }
+
+object Test {
+  def main(args: Array[String]): Unit = {
+    // When both Product and name based patterns with same arity are available,
+    // we follow scalac and silently use the Product one:
+
+    val c1 = C1("s", 0)
+    c1 match {
+      case C1(a, b) =>
+        assert(a == "s")
+        assert(b == 0)
+    }
+
+    // When the size differ, both are patterns become usable:
+
+    val c2 = C2("a", "b")
+    c2 match {
+      case C2(a, b) =>
+        assert(a == "a")
+        assert(b == "b")
+    }
+
+    c2 match {
+      case C2(a, b, c) =>
+        assert(a == -1)
+        assert(b == -2)
+        assert(c == -3)
+    }
+
+    // Interestingly things also compile with a single pattern, in which case
+    // the tuple returned by get is binded to `a`:
+
+    c2 match {
+      case C2(a) =>
+        assert(a == (-1, -2, -3))
+    }
+  }
+}
diff --git a/tests/run/zero-arity-case-class.scala b/tests/run/zero-arity-case-class.scala
new file mode 100644
index 000000000..de0ba4fe1
--- /dev/null
+++ b/tests/run/zero-arity-case-class.scala
@@ -0,0 +1,26 @@
+case class Foo()
+
+object Test {
+  def main(args: Array[String]): Unit = {
+    assert(Foo.unapply(Foo()) == true)
+
+    // unapply generate by scalac are `_ != null`,
+    // dotty returns true in all cases
+    assert(Foo.unapply(null) == true)
+
+    Foo() match {
+      case Foo() => ()
+      case _     => ???
+    }
+
+    Foo() match {
+      case _: Foo => ()
+      case _      => ???
+    }
+
+    (Foo(): Any) match {
+      case Foo() => ()
+      case _     => ???
+    }
+  }
+}