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authorMartin Odersky <odersky@gmail.com>2017-04-10 16:35:01 +0200
committerMartin Odersky <odersky@gmail.com>2017-04-11 18:00:59 +0200
commit053cd236ee12f877cfd71affb9a62a417f917d3d (patch)
treec6e6a1c078e64e1719896f519a3cb95ebf7326d7
parent9917029becab32d56e786ac9309ee195737f6da0 (diff)
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Fix #2152: Instantiate dependent result type parameters
#2152 shows that dependent result type parameters can end up in the types of terms, so we have to eliminate them. If we don't we get orphan parameters in pickling. Fix method name and comment
-rw-r--r--compiler/src/dotty/tools/dotc/core/NameKinds.scala2
-rw-r--r--compiler/src/dotty/tools/dotc/core/TypeOps.scala4
-rw-r--r--compiler/src/dotty/tools/dotc/core/Types.scala2
-rw-r--r--compiler/src/dotty/tools/dotc/typer/ProtoTypes.scala17
-rw-r--r--tests/pos/i2152.scala7
5 files changed, 22 insertions, 10 deletions
diff --git a/compiler/src/dotty/tools/dotc/core/NameKinds.scala b/compiler/src/dotty/tools/dotc/core/NameKinds.scala
index 0f08e47..81ac3a0 100644
--- a/compiler/src/dotty/tools/dotc/core/NameKinds.scala
+++ b/compiler/src/dotty/tools/dotc/core/NameKinds.scala
@@ -209,7 +209,7 @@ object NameKinds {
val InlineAccessorName = new UniqueNameKind("$_inlineAccessor_$")
val TempResultName = new UniqueNameKind("ev$")
val EvidenceParamName = new UniqueNameKind("evidence$")
- val DepParamName = new UniqueNameKind("<param>")
+ val DepParamName = new UniqueNameKind("(param)")
val LazyImplicitName = new UniqueNameKind("$_lazy_implicit_$")
val LazyLocalName = new UniqueNameKind("$lzy")
val LazyLocalInitName = new UniqueNameKind("$lzyINIT")
diff --git a/compiler/src/dotty/tools/dotc/core/TypeOps.scala b/compiler/src/dotty/tools/dotc/core/TypeOps.scala
index 9593bfe..0de823e 100644
--- a/compiler/src/dotty/tools/dotc/core/TypeOps.scala
+++ b/compiler/src/dotty/tools/dotc/core/TypeOps.scala
@@ -7,6 +7,7 @@ import SymDenotations._, Denotations.SingleDenotation
import config.Printers.typr
import util.Positions._
import NameOps._
+import NameKinds.DepParamName
import Decorators._
import StdNames._
import Annotations._
@@ -169,6 +170,9 @@ trait TypeOps { this: Context => // TODO: Make standalone object.
simplify(l, theMap) & simplify(r, theMap)
case OrType(l, r) =>
simplify(l, theMap) | simplify(r, theMap)
+ case tp: TypeVar if tp.origin.paramName.is(DepParamName) =>
+ val effectiveVariance = if (theMap == null) 1 else theMap.variance
+ tp.instanceOpt orElse tp.instantiate(fromBelow = effectiveVariance != -1)
case _ =>
(if (theMap != null) theMap else new SimplifyMap).mapOver(tp)
}
diff --git a/compiler/src/dotty/tools/dotc/core/Types.scala b/compiler/src/dotty/tools/dotc/core/Types.scala
index c8c1886..955a5a1 100644
--- a/compiler/src/dotty/tools/dotc/core/Types.scala
+++ b/compiler/src/dotty/tools/dotc/core/Types.scala
@@ -3509,7 +3509,7 @@ object Types {
def apply(tp: Type): Type
- protected var variance = 1
+ protected[core] var variance = 1
protected def derivedSelect(tp: NamedType, pre: Type): Type =
tp.derivedSelect(pre)
diff --git a/compiler/src/dotty/tools/dotc/typer/ProtoTypes.scala b/compiler/src/dotty/tools/dotc/typer/ProtoTypes.scala
index 398a7a1..5d82403 100644
--- a/compiler/src/dotty/tools/dotc/typer/ProtoTypes.scala
+++ b/compiler/src/dotty/tools/dotc/typer/ProtoTypes.scala
@@ -377,9 +377,10 @@ object ProtoTypes {
* Also, if `owningTree` is non-empty, add a type variable for each parameter.
* @return The added type lambda, and the list of created type variables.
*/
- def constrained(tl: TypeLambda, owningTree: untpd.Tree)(implicit ctx: Context): (TypeLambda, List[TypeTree]) = {
+ def constrained(tl: TypeLambda, owningTree: untpd.Tree, alwaysAddTypeVars: Boolean = false)(implicit ctx: Context): (TypeLambda, List[TypeTree]) = {
val state = ctx.typerState
- assert(!(ctx.typerState.isCommittable && owningTree.isEmpty),
+ val addTypeVars = alwaysAddTypeVars || !owningTree.isEmpty
+ assert(!(ctx.typerState.isCommittable && !addTypeVars),
s"inconsistent: no typevars were added to committable constraint ${state.constraint}")
def newTypeVars(tl: TypeLambda): List[TypeTree] =
@@ -392,7 +393,7 @@ object ProtoTypes {
val added =
if (state.constraint contains tl) tl.newLikeThis(tl.paramNames, tl.paramInfos, tl.resultType)
else tl
- val tvars = if (owningTree.isEmpty) Nil else newTypeVars(added)
+ val tvars = if (addTypeVars) newTypeVars(added) else Nil
ctx.typeComparer.addToConstraint(added, tvars.tpes.asInstanceOf[List[TypeVar]])
(added, tvars)
}
@@ -400,13 +401,13 @@ object ProtoTypes {
/** Same as `constrained(tl, EmptyTree)`, but returns just the created type lambda */
def constrained(tl: TypeLambda)(implicit ctx: Context): TypeLambda = constrained(tl, EmptyTree)._1
- /** Create a new TypeParamRef that represents a dependent method parameter singleton */
- def newDepTypeParamRef(tp: Type)(implicit ctx: Context): TypeParamRef = {
+ /** Create a new TypeVar that represents a dependent method parameter singleton */
+ def newDepTypeVar(tp: Type)(implicit ctx: Context): TypeVar = {
val poly = PolyType(DepParamName.fresh().toTypeName :: Nil)(
pt => TypeBounds.upper(AndType(tp, defn.SingletonType)) :: Nil,
pt => defn.AnyType)
- ctx.typeComparer.addToConstraint(poly, Nil)
- TypeParamRef(poly, 0)
+ constrained(poly, untpd.EmptyTree, alwaysAddTypeVars = true)
+ ._2.head.tpe.asInstanceOf[TypeVar]
}
/** The result type of `mt`, where all references to parameters of `mt` are
@@ -415,7 +416,7 @@ object ProtoTypes {
def resultTypeApprox(mt: MethodType)(implicit ctx: Context): Type =
if (mt.isDependent) {
def replacement(tp: Type) =
- if (ctx.mode.is(Mode.TypevarsMissContext)) WildcardType else newDepTypeParamRef(tp)
+ if (ctx.mode.is(Mode.TypevarsMissContext)) WildcardType else newDepTypeVar(tp)
mt.resultType.substParams(mt, mt.paramInfos.map(replacement))
}
else mt.resultType
diff --git a/tests/pos/i2152.scala b/tests/pos/i2152.scala
new file mode 100644
index 0000000..2171a48
--- /dev/null
+++ b/tests/pos/i2152.scala
@@ -0,0 +1,7 @@
+class Contra[-D](task: AnyRef)
+object Test {
+ def narrow(task: AnyRef): Contra[task.type] = new Contra(task)
+ def ident[Before](elems: Contra[Before]): Contra[Before] = elems
+ val foo = null
+ ident(narrow(foo))
+}