From 8448beb2ad6346d1d04a1feedb3de4d77f61024d Mon Sep 17 00:00:00 2001 From: Paul Phillips Date: Wed, 24 Apr 2013 12:22:44 -0700 Subject: SI-6943 warn on value class miscomparison. There's a very dangerous situation running around when you combine universal equality with value classes: // All over your code val x = "abc" if (x == "abc") ... // Hey let's make x a value class val x = new ValueClass("abc") // Uh-oh There was until now no warning when comparing a value class with something else. Now there is. --- test/files/neg/t5663-badwarneq.check | 34 ++++++++++++++++++++++++++-------- test/files/neg/t5663-badwarneq.scala | 18 ++++++++++++++++++ 2 files changed, 44 insertions(+), 8 deletions(-) (limited to 'test/files/neg') diff --git a/test/files/neg/t5663-badwarneq.check b/test/files/neg/t5663-badwarneq.check index 00c2234e9d..242be8de68 100644 --- a/test/files/neg/t5663-badwarneq.check +++ b/test/files/neg/t5663-badwarneq.check @@ -1,22 +1,40 @@ -t5663-badwarneq.scala:42: error: comparing case class values of types Some[Int] and None.type using `==' will always yield false +t5663-badwarneq.scala:47: error: comparing case class values of types Some[Int] and None.type using `==' will always yield false println(new Some(1) == None) // Should complain on type, was: spuriously complains on fresh object ^ -t5663-badwarneq.scala:43: error: comparing case class values of types Some[Int] and Thing using `==' will always yield false +t5663-badwarneq.scala:48: error: comparing case class values of types Some[Int] and Thing using `==' will always yield false println(Some(1) == new Thing(1)) // Should complain on type, was: spuriously complains on fresh object ^ -t5663-badwarneq.scala:51: error: ThingOne and Thingy are unrelated: they will most likely never compare equal +t5663-badwarneq.scala:56: error: ThingOne and Thingy are unrelated: they will most likely never compare equal println(t1 == t2) // true, but apparently unrelated, a compromise warning ^ -t5663-badwarneq.scala:52: error: ThingThree and Thingy are unrelated: they will most likely never compare equal +t5663-badwarneq.scala:57: error: ThingThree and Thingy are unrelated: they will most likely never compare equal println(t4 == t2) // true, complains because ThingThree is final and Thingy not a subclass, stronger claim than unrelated ^ -t5663-badwarneq.scala:55: error: comparing case class values of types ThingTwo and Some[Int] using `==' will always yield false +t5663-badwarneq.scala:60: error: comparing case class values of types ThingTwo and Some[Int] using `==' will always yield false println(t3 == Some(1)) // false, warn on different cases ^ -t5663-badwarneq.scala:56: error: comparing values of types ThingOne and Cousin using `==' will always yield false +t5663-badwarneq.scala:61: error: comparing values of types ThingOne and Cousin using `==' will always yield false println(t1 == c) // should warn ^ -t5663-badwarneq.scala:64: error: comparing case class values of types Simple and SimpleSibling.type using `==' will always yield false +t5663-badwarneq.scala:69: error: comparing case class values of types Simple and SimpleSibling.type using `==' will always yield false println(new Simple() == SimpleSibling) // like Some(1) == None, but needn't be final case ^ -7 errors found +t5663-badwarneq.scala:72: error: ValueClass1 and Int are unrelated: they will never compare equal + println(new ValueClass1(5) == 5) // bad + ^ +t5663-badwarneq.scala:74: error: comparing values of types Int and ValueClass1 using `==' will always yield false + println(5 == new ValueClass1(5)) // bad + ^ +t5663-badwarneq.scala:78: error: ValueClass2[String] and String are unrelated: they will never compare equal + println(new ValueClass2("abc") == "abc") // bad + ^ +t5663-badwarneq.scala:79: error: ValueClass2[Int] and ValueClass1 are unrelated: they will never compare equal + println(new ValueClass2(5) == new ValueClass1(5)) // bad - different value classes + ^ +t5663-badwarneq.scala:81: error: comparing values of types ValueClass3 and ValueClass2[Int] using `==' will always yield false + println(ValueClass3(5) == new ValueClass2(5)) // bad + ^ +t5663-badwarneq.scala:82: error: comparing values of types ValueClass3 and Int using `==' will always yield false + println(ValueClass3(5) == 5) // bad + ^ +13 errors found diff --git a/test/files/neg/t5663-badwarneq.scala b/test/files/neg/t5663-badwarneq.scala index 56ec389c03..3c0376914e 100644 --- a/test/files/neg/t5663-badwarneq.scala +++ b/test/files/neg/t5663-badwarneq.scala @@ -17,6 +17,11 @@ class SimpleParent case class Simple() extends SimpleParent case object SimpleSibling extends SimpleParent +// value classes +final class ValueClass1(val value: Int) extends AnyVal +final class ValueClass2[T](val value: T) extends AnyVal +final case class ValueClass3(val value: Int) extends AnyVal + /* It's not possible to run partest without -deprecation. * Since detecting the warnings requires a neg test with * -Xfatal-warnings, and deprecation terminates the compile, @@ -63,6 +68,19 @@ object Test { println(new Simple() == SimpleSibling) // like Some(1) == None, but needn't be final case + println(new ValueClass1(5) == new ValueClass1(5)) // ok + println(new ValueClass1(5) == 5) // bad + println(new ValueClass1(5) == (5: Any)) // ok, have to let it through + println(5 == new ValueClass1(5)) // bad + println((5: Any) == new ValueClass1(5) == (5: Any)) // ok + + println(new ValueClass2("abc") == new ValueClass2("abc")) // ok + println(new ValueClass2("abc") == "abc") // bad + println(new ValueClass2(5) == new ValueClass1(5)) // bad - different value classes + println(ValueClass3(5) == new ValueClass3(5)) // ok + println(ValueClass3(5) == new ValueClass2(5)) // bad + println(ValueClass3(5) == 5) // bad + /* val mine = new MyThing val some = new SomeThing -- cgit v1.2.3