From daa421189d9191f05b5006418580eb6c0e0b1ec7 Mon Sep 17 00:00:00 2001 From: Jason Zaugg Date: Mon, 31 Aug 2015 13:44:54 +1000 Subject: SI-8989 Better error message for invalid extractor pattern --- .../transform/patmat/ScalacPatternExpanders.scala | 11 ++++++++--- test/files/neg/t4425b.check | 22 +++++++++++++++++----- test/files/neg/t8127a.check | 4 ++++ test/files/neg/t8127a.scala | 12 ++++++++++++ test/files/neg/t8989.check | 4 ++++ test/files/neg/t8989.scala | 14 ++++++++++++++ 6 files changed, 59 insertions(+), 8 deletions(-) create mode 100644 test/files/neg/t8127a.check create mode 100644 test/files/neg/t8127a.scala create mode 100644 test/files/neg/t8989.check create mode 100644 test/files/neg/t8989.scala diff --git a/src/compiler/scala/tools/nsc/transform/patmat/ScalacPatternExpanders.scala b/src/compiler/scala/tools/nsc/transform/patmat/ScalacPatternExpanders.scala index 55d4366a46..5678c53e78 100644 --- a/src/compiler/scala/tools/nsc/transform/patmat/ScalacPatternExpanders.scala +++ b/src/compiler/scala/tools/nsc/transform/patmat/ScalacPatternExpanders.scala @@ -74,11 +74,16 @@ trait ScalacPatternExpanders { * Unfortunately the MethodType does not carry the information of whether * it was unapplySeq, so we have to funnel that information in separately. */ - def unapplyMethodTypes(whole: Type, result: Type, isSeq: Boolean): Extractor = { + def unapplyMethodTypes(context: Context, whole: Type, result: Type, isSeq: Boolean): Extractor = { if (result =:= BooleanTpe) newExtractor(whole, Nil, NoRepeated) else { val getResult = typeOfMemberNamedGet(result) + def noGetError() = { + val name = "unapply" + (if (isSeq) "Seq" else "") + context.error(context.tree.pos, s"The result type of an $name method must contain a member `get` to be used as an extractor pattern, no such member exists in ${result}") + } val expanded = getResult match { + case global.NoType => noGetError(); Nil case rawGet if !hasSelectors(rawGet) => rawGet :: Nil case rawGet => typesOfSelectors(rawGet) } @@ -131,8 +136,8 @@ trait ScalacPatternExpanders { val isUnapply = sel.symbol.name == nme.unapply val extractor = sel.symbol.name match { - case nme.unapply => unapplyMethodTypes(firstParamType(fn.tpe), sel.tpe, isSeq = false) - case nme.unapplySeq => unapplyMethodTypes(firstParamType(fn.tpe), sel.tpe, isSeq = true) + case nme.unapply => unapplyMethodTypes(context, firstParamType(fn.tpe), sel.tpe, isSeq = false) + case nme.unapplySeq => unapplyMethodTypes(context, firstParamType(fn.tpe), sel.tpe, isSeq = true) case _ => applyMethodTypes(fn.tpe) } diff --git a/test/files/neg/t4425b.check b/test/files/neg/t4425b.check index 8418b4fd12..a204467586 100644 --- a/test/files/neg/t4425b.check +++ b/test/files/neg/t4425b.check @@ -22,16 +22,28 @@ t4425b.scala:10: error: object X is not a case class, nor does it have an unappl Note: def unapply(x: String)(y: String): Nothing exists in object X, but it cannot be used as an extractor due to its second non-implicit parameter list println((X: Any) match { case X(_, _) => "ok" ; case _ => "fail" }) ^ -t4425b.scala:18: error: too many patterns for object X: expected 1, found 2 +t4425b.scala:18: error: The result type of an unapply method must contain a member `get` to be used as an extractor pattern, no such member exists in Nothing + println( "" match { case _ X _ => "ok" ; case _ => "fail" }) + ^ +t4425b.scala:18: error: too many patterns for object X offering Boolean: expected 0, found 2 println( "" match { case _ X _ => "ok" ; case _ => "fail" }) ^ -t4425b.scala:19: error: too many patterns for object X: expected 1, found 2 +t4425b.scala:19: error: The result type of an unapply method must contain a member `get` to be used as an extractor pattern, no such member exists in Nothing + println((X: Any) match { case _ X _ => "ok" ; case _ => "fail" }) + ^ +t4425b.scala:19: error: too many patterns for object X offering Boolean: expected 0, found 2 println((X: Any) match { case _ X _ => "ok" ; case _ => "fail" }) ^ -t4425b.scala:22: error: too many patterns for object X: expected 1, found 2 +t4425b.scala:20: error: The result type of an unapply method must contain a member `get` to be used as an extractor pattern, no such member exists in Nothing + println( "" match { case X(_) => "ok" ; case _ => "fail" }) + ^ +t4425b.scala:21: error: The result type of an unapply method must contain a member `get` to be used as an extractor pattern, no such member exists in Nothing + println((X: Any) match { case X(_) => "ok" ; case _ => "fail" }) + ^ +t4425b.scala:22: error: The result type of an unapply method must contain a member `get` to be used as an extractor pattern, no such member exists in Nothing println( "" match { case X(_, _) => "ok" ; case _ => "fail" }) ^ -t4425b.scala:23: error: too many patterns for object X: expected 1, found 2 +t4425b.scala:23: error: The result type of an unapply method must contain a member `get` to be used as an extractor pattern, no such member exists in Nothing println((X: Any) match { case X(_, _) => "ok" ; case _ => "fail" }) ^ t4425b.scala:31: error: too many patterns for object X offering Nothing: expected 1, found 2 @@ -46,4 +58,4 @@ t4425b.scala:35: error: too many patterns for object X offering Nothing: expecte t4425b.scala:36: error: too many patterns for object X offering Nothing: expected 1, found 2 println((X: Any) match { case X(_, _) => "ok" ; case _ => "fail" }) ^ -14 errors found +18 errors found diff --git a/test/files/neg/t8127a.check b/test/files/neg/t8127a.check new file mode 100644 index 0000000000..5a30574861 --- /dev/null +++ b/test/files/neg/t8127a.check @@ -0,0 +1,4 @@ +t8127a.scala:7: error: The result type of an unapplySeq method must contain a member `get` to be used as an extractor pattern, no such member exists in Seq[_$1] + case H(v) => + ^ +one error found diff --git a/test/files/neg/t8127a.scala b/test/files/neg/t8127a.scala new file mode 100644 index 0000000000..c05facdac1 --- /dev/null +++ b/test/files/neg/t8127a.scala @@ -0,0 +1,12 @@ +object H { + def unapplySeq(m: Any): Seq[_] = List("") +} + +object Test { + def unapply(m: Any) = m match { + case H(v) => + case _ => + } + // now: too many patterns for object H offering Boolean: expected 0, found 1 + // was: result type Seq[_$2] of unapplySeq defined in method unapplySeq in object H does not conform to Option[_] +} diff --git a/test/files/neg/t8989.check b/test/files/neg/t8989.check new file mode 100644 index 0000000000..4e89b862bd --- /dev/null +++ b/test/files/neg/t8989.check @@ -0,0 +1,4 @@ +t8989.scala:11: error: The result type of an unapply method must contain a member `get` to be used as an extractor pattern, no such member exists in A + val f = p match {case d(1) => true; case _ => false} + ^ +one error found diff --git a/test/files/neg/t8989.scala b/test/files/neg/t8989.scala new file mode 100644 index 0000000000..8ed6a901cd --- /dev/null +++ b/test/files/neg/t8989.scala @@ -0,0 +1,14 @@ +class A extends Product1[Int] { + def _1 = 1 + def isEmpty = false // used by scalac + def isDefined = !isEmpty // used by dotty + def canEqual(a: Any) = true +} + +object d{ + def unapply(a: Any) = new A + val p: Any = ??? + val f = p match {case d(1) => true; case _ => false} +} + + -- cgit v1.2.3