From 64ae23f6438054a08bebf1fa6af0f14d63cfc0ea Mon Sep 17 00:00:00 2001 From: Jason Zaugg Date: Thu, 27 Nov 2014 14:27:07 +1000 Subject: SI-9008 Fix regression with higher kinded existentials Allow a naked type constructor in an existential type if we are directly within a type application. Recently, 84d4671 changed nested context creation to avoid passing down the `TypeConstructorAllowed`, which led to missing kind errors in code like `type T[({type M = List})#M]`. However, when typechecking `T forSome { quantifiers }`, we create a nested context to represent the nested scope introduced for the quantifiers. But we need to propagate the `TypeConstructorAllowed` bit to the nested context to allow for higher kinded existentials. The enclosed tests show: - pos/t9008 well kinded application of an hk existential - neg/t9008 hk existential forbidden outside of type application - neg/t9008b kind error reported for hk existential Regressed in 84d4671. --- src/compiler/scala/tools/nsc/typechecker/Contexts.scala | 3 ++- src/compiler/scala/tools/nsc/typechecker/Typers.scala | 6 +++++- test/files/neg/t9008.check | 4 ++++ test/files/neg/t9008.scala | 3 +++ test/files/neg/t9008b.check | 4 ++++ test/files/neg/t9008b.scala | 3 +++ test/files/pos/t9008.scala | 5 +++++ 7 files changed, 26 insertions(+), 2 deletions(-) create mode 100644 test/files/neg/t9008.check create mode 100644 test/files/neg/t9008.scala create mode 100644 test/files/neg/t9008b.check create mode 100644 test/files/neg/t9008b.scala create mode 100644 test/files/pos/t9008.scala diff --git a/src/compiler/scala/tools/nsc/typechecker/Contexts.scala b/src/compiler/scala/tools/nsc/typechecker/Contexts.scala index b13f9e94cc..9a34e8dfed 100644 --- a/src/compiler/scala/tools/nsc/typechecker/Contexts.scala +++ b/src/compiler/scala/tools/nsc/typechecker/Contexts.scala @@ -480,7 +480,8 @@ trait Contexts { self: Analyzer => // SI-8245 `isLazy` need to skip lazy getters to ensure `return` binds to the right place c.enclMethod = if (isDefDef && !owner.isLazy) c else enclMethod - if (tree != outer.tree) c(TypeConstructorAllowed) = false + if (tree != outer.tree) + c(TypeConstructorAllowed) = false registerContext(c.asInstanceOf[analyzer.Context]) debuglog("[context] ++ " + c.unit + " / " + tree.summaryString) diff --git a/src/compiler/scala/tools/nsc/typechecker/Typers.scala b/src/compiler/scala/tools/nsc/typechecker/Typers.scala index 4d9a6a47ef..aaa75b5ee1 100644 --- a/src/compiler/scala/tools/nsc/typechecker/Typers.scala +++ b/src/compiler/scala/tools/nsc/typechecker/Typers.scala @@ -5207,7 +5207,11 @@ trait Typers extends Adaptations with Tags with TypersTracking with PatternTyper def typedExistentialTypeTree(tree: ExistentialTypeTree) = { val tree1 = typerWithLocalContext(context.makeNewScope(tree, context.owner)){ - _.typedExistentialTypeTree(tree, mode) + typer => + if (context.inTypeConstructorAllowed) + typer.context.withinTypeConstructorAllowed(typer.typedExistentialTypeTree(tree, mode)) + else + typer.typedExistentialTypeTree(tree, mode) } checkExistentialsFeature(tree1.pos, tree1.tpe, "the existential type") tree1 diff --git a/test/files/neg/t9008.check b/test/files/neg/t9008.check new file mode 100644 index 0000000000..c32bc41baf --- /dev/null +++ b/test/files/neg/t9008.check @@ -0,0 +1,4 @@ +t9008.scala:2: error: type M takes type parameters + def x: List[M forSome { type M[_] }] = ??? + ^ +one error found diff --git a/test/files/neg/t9008.scala b/test/files/neg/t9008.scala new file mode 100644 index 0000000000..c6a5389e42 --- /dev/null +++ b/test/files/neg/t9008.scala @@ -0,0 +1,3 @@ +object Test { + def x: List[M forSome { type M[_] }] = ??? +} diff --git a/test/files/neg/t9008b.check b/test/files/neg/t9008b.check new file mode 100644 index 0000000000..5e911fc138 --- /dev/null +++ b/test/files/neg/t9008b.check @@ -0,0 +1,4 @@ +t9008b.scala:2: error: type M takes type parameters + type T = M forSome { type M[_] } + ^ +one error found diff --git a/test/files/neg/t9008b.scala b/test/files/neg/t9008b.scala new file mode 100644 index 0000000000..58f9d0e8de --- /dev/null +++ b/test/files/neg/t9008b.scala @@ -0,0 +1,3 @@ +object Test { + type T = M forSome { type M[_] } +} diff --git a/test/files/pos/t9008.scala b/test/files/pos/t9008.scala new file mode 100644 index 0000000000..d11b8604f2 --- /dev/null +++ b/test/files/pos/t9008.scala @@ -0,0 +1,5 @@ +trait Monad[M[_]] + +object Test { + def x: Monad[M forSome { type M[_] }] = ??? +} -- cgit v1.2.3