diff options
Diffstat (limited to 'src/compiler/scala/reflect/internal/Types.scala')
| -rw-r--r-- | src/compiler/scala/reflect/internal/Types.scala | 39 |
1 files changed, 23 insertions, 16 deletions
diff --git a/src/compiler/scala/reflect/internal/Types.scala b/src/compiler/scala/reflect/internal/Types.scala index 73a8f5c55c..8bb1d5e2fa 100644 --- a/src/compiler/scala/reflect/internal/Types.scala +++ b/src/compiler/scala/reflect/internal/Types.scala @@ -917,8 +917,8 @@ trait Types extends api.Types { self: SymbolTable => /** A test whether a type contains any unification type variables. */ def isGround: Boolean = this match { - case TypeVar(_, constr) => - constr.instValid && constr.inst.isGround + case tv@TypeVar(_, _) => + tv.untouchable || (tv.instValid && tv.constr.inst.isGround) case TypeRef(pre, sym, args) => sym.isPackageClass || pre.isGround && (args forall (_.isGround)) case SingleType(pre, sym) => @@ -2677,14 +2677,15 @@ trait Types extends api.Types { self: SymbolTable => def unapply(tv: TypeVar): Some[(Type, TypeConstraint)] = Some((tv.origin, tv.constr)) def apply(origin: Type, constr: TypeConstraint): TypeVar = apply(origin, constr, Nil, Nil) def apply(tparam: Symbol): TypeVar = apply(tparam.tpeHK, deriveConstraint(tparam), Nil, tparam.typeParams) + def apply(tparam: Symbol, untouchable: Boolean): TypeVar = apply(tparam.tpeHK, deriveConstraint(tparam), Nil, tparam.typeParams, untouchable) /** This is the only place TypeVars should be instantiated. */ - def apply(origin: Type, constr: TypeConstraint, args: List[Type], params: List[Symbol]): TypeVar = { + def apply(origin: Type, constr: TypeConstraint, args: List[Type], params: List[Symbol], untouchable: Boolean = false): TypeVar = { val tv = ( - if (args.isEmpty && params.isEmpty) new TypeVar(origin, constr) - else if (args.size == params.size) new AppliedTypeVar(origin, constr, params zip args) - else if (args.isEmpty) new HKTypeVar(origin, constr, params) + if (args.isEmpty && params.isEmpty) new TypeVar(origin, constr, untouchable) + else if (args.size == params.size) new AppliedTypeVar(origin, constr, untouchable, params zip args) + else if (args.isEmpty) new HKTypeVar(origin, constr, untouchable, params) else throw new Error("Invalid TypeVar construction: " + ((origin, constr, args, params))) ) @@ -2712,8 +2713,9 @@ trait Types extends api.Types { self: SymbolTable => class HKTypeVar( _origin: Type, _constr: TypeConstraint, + _untouchable: Boolean, override val params: List[Symbol] - ) extends TypeVar(_origin, _constr) { + ) extends TypeVar(_origin, _constr, _untouchable) { require(params.nonEmpty, this) override def isHigherKinded = true @@ -2725,8 +2727,9 @@ trait Types extends api.Types { self: SymbolTable => class AppliedTypeVar( _origin: Type, _constr: TypeConstraint, + _untouchable: Boolean, zippedArgs: List[(Symbol, Type)] - ) extends TypeVar(_origin, _constr) { + ) extends TypeVar(_origin, _constr, _untouchable) { require(zippedArgs.nonEmpty, this) @@ -2749,7 +2752,8 @@ trait Types extends api.Types { self: SymbolTable => */ class TypeVar( val origin: Type, - val constr0: TypeConstraint + val constr0: TypeConstraint, + val untouchable: Boolean = false // by other typevars ) extends Type { override def params: List[Symbol] = Nil override def typeArgs: List[Type] = Nil @@ -2931,14 +2935,15 @@ trait Types extends api.Types { self: SymbolTable => // would be pointless. In this case, each check we perform causes us to lose specificity: in // the end the best we'll do is the least specific type we tested against, since the typevar // does not see these checks as "probes" but as requirements to fulfill. - // TODO: the `suspended` flag can be used to poke around with leaving a trace + // TODO: can the `suspended` flag be used to poke around without leaving a trace? // // So the strategy used here is to test first the type, then the direct parents, and finally // to fall back on the individual base types. This warrants eventual re-examination. // AM: I think we could use the `suspended` flag to avoid side-effecting during unification - if (suspended) // constraint accumulation is disabled + if (tp.isInstanceOf[TypeVar] && untouchable && !tp.asInstanceOf[TypeVar].untouchable) tp.asInstanceOf[TypeVar].registerBound(this, !isLowerBound, isNumericBound) + else if (suspended) // constraint accumulation is disabled checkSubtype(tp, origin) else if (constr.instValid) // type var is already set checkSubtype(tp, constr.inst) @@ -2962,7 +2967,8 @@ trait Types extends api.Types { self: SymbolTable => if(typeVarLHS) constr.inst =:= tp else tp =:= constr.inst - if (suspended) tp =:= origin + if (tp.isInstanceOf[TypeVar] && untouchable && !tp.asInstanceOf[TypeVar].untouchable) tp.asInstanceOf[TypeVar].registerTypeEquality(this, !typeVarLHS) + else if (suspended) tp =:= origin else if (constr.instValid) checkIsSameType(tp) else isRelatable(tp) && { val newInst = wildcardToTypeVarMap(tp) @@ -3036,7 +3042,7 @@ trait Types extends api.Types { self: SymbolTable => override def safeToString = ( if ((constr eq null) || (constr.inst eq null)) "TVar<" + originName + "=null>" else if (constr.inst ne NoType) "" + constr.inst - else "?" + levelString + originName + else (if(untouchable) "!?" else "?") + levelString + originName ) override def kind = "TypeVar" @@ -4733,7 +4739,7 @@ trait Types extends api.Types { self: SymbolTable => val sym1 = adaptToNewRun(sym.owner.thisType, sym) if (sym1 == sym) tp else ThisType(sym1) } catch { - case ex: MissingTypeControl => + case ex: MissingTypeControl => tp } case SingleType(pre, sym) => @@ -6044,8 +6050,9 @@ trait Types extends api.Types { self: SymbolTable => def stripType(tp: Type) = tp match { case ExistentialType(_, res) => res - case TypeVar(_, constr) => - if (constr.instValid) constr.inst + case tv@TypeVar(_, constr) => + if (tv.instValid) constr.inst + else if (tv.untouchable) tv else abort("trying to do lub/glb of typevar "+tp) case t => t } |