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author | Paul Phillips <paulp@improving.org> | 2012-09-27 06:41:17 -0700 |
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committer | Paul Phillips <paulp@improving.org> | 2012-09-27 09:24:04 -0700 |
commit | 96d4a8646b1962fac2f2fc443b56c6619221b43c (patch) | |
tree | bd39f411275452bb5db2335da966ac8042cd504f /test | |
parent | 17b409b7832f541e3d52d2776c8ff3c47574ae0f (diff) | |
download | scala-96d4a8646b1962fac2f2fc443b56c6619221b43c.tar.gz scala-96d4a8646b1962fac2f2fc443b56c6619221b43c.tar.bz2 scala-96d4a8646b1962fac2f2fc443b56c6619221b43c.zip |
Nailed down the "impossible match" logic.
I will again defer to a comment.
/** Given classes A and B, can it be shown that nothing which is
* an A will ever be a subclass of something which is a B? This
* entails not only showing that !(A isSubClass B) but that the
* same is true of all their subclasses. Restated for symmetry:
* the same value cannot be a member of both A and B.
*
* 1) A must not be a subclass of B, nor B of A (the trivial check)
* 2) One of A or B must be completely knowable (see isKnowable)
* 3) Assuming A is knowable, the proposition is true if
* !(A' isSubClass B) for all A', where A' is a subclass of A.
*
* Due to symmetry, the last condition applies as well in reverse.
*/
Diffstat (limited to 'test')
-rw-r--r-- | test/files/neg/patmat-type-check.check | 10 | ||||
-rw-r--r-- | test/files/neg/t1872.check | 4 | ||||
-rw-r--r-- | test/files/neg/unchecked-abstract.check | 25 | ||||
-rw-r--r-- | test/files/neg/unchecked-abstract.flags | 1 | ||||
-rw-r--r-- | test/files/neg/unchecked-abstract.scala | 93 | ||||
-rw-r--r-- | test/files/neg/unchecked-impossible.check | 4 | ||||
-rw-r--r-- | test/files/neg/unchecked-impossible.flags | 1 | ||||
-rw-r--r-- | test/files/neg/unchecked-impossible.scala | 16 | ||||
-rw-r--r-- | test/files/neg/unchecked-knowable.check | 4 | ||||
-rw-r--r-- | test/files/neg/unchecked-knowable.flags | 1 | ||||
-rw-r--r-- | test/files/neg/unchecked-knowable.scala | 20 | ||||
-rw-r--r-- | test/files/neg/unchecked2.check | 12 |
12 files changed, 185 insertions, 6 deletions
diff --git a/test/files/neg/patmat-type-check.check b/test/files/neg/patmat-type-check.check index e045841ce1..721217c314 100644 --- a/test/files/neg/patmat-type-check.check +++ b/test/files/neg/patmat-type-check.check @@ -1,3 +1,12 @@ +patmat-type-check.scala:11: warning: fruitless type test: a value of type Test.Bop4[T] cannot also be a Seq[A] + def s3[T](x: Bop4[T]) = x match { case Seq('b', 'o', 'b') => true } + ^ +patmat-type-check.scala:15: warning: fruitless type test: a value of type Test.Bop5[_$1,T1,T2] cannot also be a Seq[A] + def s4[T1, T2](x: Bop5[_, T1, T2]) = x match { case Seq('b', 'o', 'b') => true } + ^ +patmat-type-check.scala:19: warning: fruitless type test: a value of type Test.Bop3[T] cannot also be a Seq[A] + def f4[T](x: Bop3[T]) = x match { case Seq('b', 'o', 'b') => true } + ^ patmat-type-check.scala:22: error: scrutinee is incompatible with pattern type; found : Seq[A] required: String @@ -18,4 +27,5 @@ patmat-type-check.scala:30: error: scrutinee is incompatible with pattern type; required: Test.Bop3[Char] def f4[T](x: Bop3[Char]) = x match { case Seq('b', 'o', 'b') => true } // fail ^ +three warnings found four errors found diff --git a/test/files/neg/t1872.check b/test/files/neg/t1872.check index ef84ef79e0..c5dc2a8080 100644 --- a/test/files/neg/t1872.check +++ b/test/files/neg/t1872.check @@ -1,4 +1,8 @@ +t1872.scala:3: warning: fruitless type test: a value of type Int cannot also be a scala.util.Random + def f(x: Int) = x.isInstanceOf[util.Random] + ^ t1872.scala:3: error: isInstanceOf cannot test if value types are references. def f(x: Int) = x.isInstanceOf[util.Random] ^ +one warning found one error found diff --git a/test/files/neg/unchecked-abstract.check b/test/files/neg/unchecked-abstract.check new file mode 100644 index 0000000000..dc7a8d93d0 --- /dev/null +++ b/test/files/neg/unchecked-abstract.check @@ -0,0 +1,25 @@ +unchecked-abstract.scala:16: error: abstract type H in type Con[M.this.H] is unchecked since it is eliminated by erasure + /* warn */ println(x.isInstanceOf[Con[H]]) + ^ +unchecked-abstract.scala:21: error: abstract type H in type Con[M.this.H] is unchecked since it is eliminated by erasure + /* warn */ println(x.isInstanceOf[Con[H]]) + ^ +unchecked-abstract.scala:27: error: abstract type T in type Inv[M.this.T] is unchecked since it is eliminated by erasure + /* warn */ println(x.isInstanceOf[Inv[T]]) + ^ +unchecked-abstract.scala:28: error: abstract type L in type Inv[M.this.L] is unchecked since it is eliminated by erasure + /* warn */ println(x.isInstanceOf[Inv[L]]) + ^ +unchecked-abstract.scala:31: error: abstract type H in type Inv[M.this.H] is unchecked since it is eliminated by erasure + /* warn */ println(x.isInstanceOf[Inv[H]]) + ^ +unchecked-abstract.scala:33: error: abstract type L in type Inv[M.this.L] is unchecked since it is eliminated by erasure + /* warn */ println(x.isInstanceOf[Inv[L]]) + ^ +unchecked-abstract.scala:36: error: abstract type H in type Inv[M.this.H] is unchecked since it is eliminated by erasure + /* warn */ println(x.isInstanceOf[Inv[H]]) + ^ +unchecked-abstract.scala:37: error: abstract type T in type Inv[M.this.T] is unchecked since it is eliminated by erasure + /* warn */ println(x.isInstanceOf[Inv[T]]) + ^ +8 errors found diff --git a/test/files/neg/unchecked-abstract.flags b/test/files/neg/unchecked-abstract.flags new file mode 100644 index 0000000000..85d8eb2ba2 --- /dev/null +++ b/test/files/neg/unchecked-abstract.flags @@ -0,0 +1 @@ +-Xfatal-warnings diff --git a/test/files/neg/unchecked-abstract.scala b/test/files/neg/unchecked-abstract.scala new file mode 100644 index 0000000000..5b915755f4 --- /dev/null +++ b/test/files/neg/unchecked-abstract.scala @@ -0,0 +1,93 @@ +trait Con[-X] +trait Inv[X] +trait Cov[+X] + +abstract class M { + type H + type L <: H + type T >: L <: H + + def h1(x: Con[H]) = { + /* nowarn */ println(x.isInstanceOf[Con[H]]) + /* nowarn */ println(x.isInstanceOf[Con[T]]) + /* nowarn */ println(x.isInstanceOf[Con[L]]) + } + def h2(x: Con[T]) = { + /* warn */ println(x.isInstanceOf[Con[H]]) + /* nowarn */ println(x.isInstanceOf[Con[T]]) + /* nowarn */ println(x.isInstanceOf[Con[L]]) + } + def h3(x: Con[L]) = { + /* warn */ println(x.isInstanceOf[Con[H]]) + /* warn */ println(x.isInstanceOf[Con[T]]) + /* nowarn */ println(x.isInstanceOf[Con[L]]) + } + def h4(x: Inv[H]) = { + /* nowarn */ println(x.isInstanceOf[Inv[H]]) + /* warn */ println(x.isInstanceOf[Inv[T]]) + /* warn */ println(x.isInstanceOf[Inv[L]]) + } + def h5(x: Inv[T]) = { + /* warn */ println(x.isInstanceOf[Inv[H]]) + /* nowarn */ println(x.isInstanceOf[Inv[T]]) + /* warn */ println(x.isInstanceOf[Inv[L]]) + } + def h6(x: Inv[L]) = { + /* warn */ println(x.isInstanceOf[Inv[H]]) + /* warn */ println(x.isInstanceOf[Inv[T]]) + /* nowarn */ println(x.isInstanceOf[Inv[L]]) + } + def h7(x: Cov[H]) = { + /* nowarn */ println(x.isInstanceOf[Cov[H]]) + /* warn */ println(x.isInstanceOf[Cov[T]]) + /* warn */ println(x.isInstanceOf[Cov[L]]) + } + def h8(x: Cov[T]) = { + /* nowarn */ println(x.isInstanceOf[Cov[H]]) + /* nowarn */ println(x.isInstanceOf[Cov[T]]) + /* warn */ println(x.isInstanceOf[Cov[L]]) + } + def h9(x: Cov[L]) = { + /* nowarn */ println(x.isInstanceOf[Cov[H]]) + /* nowarn */ println(x.isInstanceOf[Cov[T]]) + /* nowarn */ println(x.isInstanceOf[Cov[L]]) + } +} + +object Test extends M { + type H = Any + type T = Int + type L = Nothing + + val conh = new Con[H] { } + val cont = new Con[T] { } + val conl = new Con[L] { } + + val invh = new Inv[H] { } + val invt = new Inv[T] { } + val invl = new Inv[L] { } + + val covh = new Cov[H] { } + val covt = new Cov[T] { } + val covl = new Cov[L] { } + + def main(args: Array[String]): Unit = { + h1(conh) + h2(conh) + h2(cont) + h3(conh) + h3(cont) + h3(conl) + + h4(invh) + h5(invt) + h6(invl) + + h7(covh) + h7(covt) + h7(covl) + h8(covt) + h8(covl) + h9(covl) + } +} diff --git a/test/files/neg/unchecked-impossible.check b/test/files/neg/unchecked-impossible.check new file mode 100644 index 0000000000..0ab371dbaa --- /dev/null +++ b/test/files/neg/unchecked-impossible.check @@ -0,0 +1,4 @@ +unchecked-impossible.scala:5: error: fruitless type test: a value of type T2[Int,Int] cannot also be a Seq[A] + case Seq(x) => + ^ +one error found diff --git a/test/files/neg/unchecked-impossible.flags b/test/files/neg/unchecked-impossible.flags new file mode 100644 index 0000000000..85d8eb2ba2 --- /dev/null +++ b/test/files/neg/unchecked-impossible.flags @@ -0,0 +1 @@ +-Xfatal-warnings diff --git a/test/files/neg/unchecked-impossible.scala b/test/files/neg/unchecked-impossible.scala new file mode 100644 index 0000000000..985a2d0b08 --- /dev/null +++ b/test/files/neg/unchecked-impossible.scala @@ -0,0 +1,16 @@ +final case class T2[+A, +B](a: A, b: B) + +class A { + def f1 = T2(1, 2) match { + case Seq(x) => + case _ => + } + def f2 = T2(1, 2) match { + case _: T2[Int, Int] => /* nowarn */ + case _ => + } + def f3 = T2(1, 2) match { + case _: T2[_, Int] => /* nowarn */ + case _ => + } +} diff --git a/test/files/neg/unchecked-knowable.check b/test/files/neg/unchecked-knowable.check new file mode 100644 index 0000000000..3a6ef994b5 --- /dev/null +++ b/test/files/neg/unchecked-knowable.check @@ -0,0 +1,4 @@ +unchecked-knowable.scala:17: error: fruitless type test: a value of type Bippy cannot also be a A1 + /* warn */ (new Bippy).isInstanceOf[A1] + ^ +one error found diff --git a/test/files/neg/unchecked-knowable.flags b/test/files/neg/unchecked-knowable.flags new file mode 100644 index 0000000000..85d8eb2ba2 --- /dev/null +++ b/test/files/neg/unchecked-knowable.flags @@ -0,0 +1 @@ +-Xfatal-warnings diff --git a/test/files/neg/unchecked-knowable.scala b/test/files/neg/unchecked-knowable.scala new file mode 100644 index 0000000000..667b47f504 --- /dev/null +++ b/test/files/neg/unchecked-knowable.scala @@ -0,0 +1,20 @@ +/** Knowable - only final leaves */ +sealed abstract class A1 +sealed abstract class A2 extends A1 +final class A3 extends A1 +final class A4 extends A2 + +/** Unknowable */ +sealed abstract class B1 +sealed abstract class B2 extends B1 +final class B3 extends B1 +trait B4 extends B2 + +class Bippy +trait Dingus + +class A { + /* warn */ (new Bippy).isInstanceOf[A1] + /* nowarn */ (new Bippy).isInstanceOf[B1] + /* nowarn */ ((new Bippy): Any).isInstanceOf[A1] +} diff --git a/test/files/neg/unchecked2.check b/test/files/neg/unchecked2.check index b4a14358c7..68fdfa82ac 100644 --- a/test/files/neg/unchecked2.check +++ b/test/files/neg/unchecked2.check @@ -1,22 +1,22 @@ -unchecked2.scala:4: error: fruitless type test: a Some[List[Int]] can never be a Option[List[String]] (but still might match its erasure) +unchecked2.scala:4: error: fruitless type test: a value of type Some[List[Int]] cannot also be a Option[List[String]] (but still might match its erasure) /* warn */ Some(List(1)).isInstanceOf[Option[List[String]]] ^ unchecked2.scala:5: error: non-variable type argument Option[_] in type Option[Option[_]] is unchecked since it is eliminated by erasure /* warn */ Some(123).isInstanceOf[Option[Option[_]]] ^ -unchecked2.scala:6: error: fruitless type test: a Some[Int] can never be a Option[String] (but still might match its erasure) +unchecked2.scala:6: error: fruitless type test: a value of type Some[Int] cannot also be a Option[String] (but still might match its erasure) /* warn */ Some(123).isInstanceOf[Option[String]] ^ -unchecked2.scala:7: error: fruitless type test: a Some[Int] can never be a Option[List[String]] (but still might match its erasure) +unchecked2.scala:7: error: fruitless type test: a value of type Some[Int] cannot also be a Option[List[String]] (but still might match its erasure) /* warn */ Some(123).isInstanceOf[Option[List[String]]] ^ -unchecked2.scala:8: error: fruitless type test: a Some[Int] can never be a Option[List[Int => String]] (but still might match its erasure) +unchecked2.scala:8: error: fruitless type test: a value of type Some[Int] cannot also be a Option[List[Int => String]] (but still might match its erasure) /* warn */ Some(123).isInstanceOf[Option[List[Int => String]]] ^ -unchecked2.scala:9: error: fruitless type test: a Some[Int] can never be a Option[(String, Double)] (but still might match its erasure) +unchecked2.scala:9: error: fruitless type test: a value of type Some[Int] cannot also be a Option[(String, Double)] (but still might match its erasure) /* warn */ Some(123).isInstanceOf[Option[(String, Double)]] ^ -unchecked2.scala:10: error: fruitless type test: a Some[Int] can never be a Option[String => Double] (but still might match its erasure) +unchecked2.scala:10: error: fruitless type test: a value of type Some[Int] cannot also be a Option[String => Double] (but still might match its erasure) /* warn */ Some(123).isInstanceOf[Option[String => Double]] ^ unchecked2.scala:14: error: non-variable type argument List[String] in type Option[List[String]] is unchecked since it is eliminated by erasure |