diff options
Diffstat (limited to 'src')
-rw-r--r-- | src/reflect/scala/reflect/internal/Types.scala | 17 |
1 files changed, 10 insertions, 7 deletions
diff --git a/src/reflect/scala/reflect/internal/Types.scala b/src/reflect/scala/reflect/internal/Types.scala index a2c9f1fadf..ee584bed2c 100644 --- a/src/reflect/scala/reflect/internal/Types.scala +++ b/src/reflect/scala/reflect/internal/Types.scala @@ -3076,12 +3076,14 @@ trait Types extends api.Types { self: SymbolTable => /** The variable's skolemization level */ val level = skolemizationLevel - /** Two occurrences of a higher-kinded typevar, e.g. `?CC[Int]` and `?CC[String]`, correspond to - * ''two instances'' of `TypeVar` that share the ''same'' `TypeConstraint`. + /** Applies this TypeVar to type arguments, if arity matches. * - * `constr` for `?CC` only tracks type constructors anyway, - * so when `?CC[Int] <:< List[Int]` and `?CC[String] <:< Iterable[String]` - * `?CC's` hibounds contains List and Iterable. + * Different applications of the same type constructor variable `?CC`, + * e.g. `?CC[Int]` and `?CC[String]`, are modeled as distinct instances of `TypeVar` + * that share a `TypeConstraint`, so that the comparisons `?CC[Int] <:< List[Int]` + * and `?CC[String] <:< Iterable[String]` result in `?CC` being upper-bounded by `List` and `Iterable`. + * + * Applying the wrong number of type args results in a TypeVar whose instance is set to `ErrorType`. */ def applyArgs(newArgs: List[Type]): TypeVar = ( if (newArgs.isEmpty && typeArgs.isEmpty) @@ -3091,7 +3093,7 @@ trait Types extends api.Types { self: SymbolTable => TypeVar.trace("applyArgs", "In " + originLocation + ", apply args " + newArgs.mkString(", ") + " to " + originName)(tv) } else - throw new Error("Invalid type application in TypeVar: " + params + ", " + newArgs) + TypeVar(typeSymbol).setInst(ErrorType) ) // newArgs.length may differ from args.length (could've been empty before) // @@ -3121,13 +3123,14 @@ trait Types extends api.Types { self: SymbolTable => // <region name="constraint mutators + undoLog"> // invariant: before mutating constr, save old state in undoLog // (undoLog is used to reset constraints to avoid piling up unrelated ones) - def setInst(tp: Type) { + def setInst(tp: Type): this.type = { // assert(!(tp containsTp this), this) undoLog record this // if we were compared against later typeskolems, repack the existential, // because skolems are only compatible if they were created at the same level val res = if (shouldRepackType) repackExistential(tp) else tp constr.inst = TypeVar.trace("setInst", "In " + originLocation + ", " + originName + "=" + res)(res) + this } def addLoBound(tp: Type, isNumericBound: Boolean = false) { |