diff options
Diffstat (limited to 'src/dotty/tools/dotc/core/TypeErasure.scala')
| -rw-r--r-- | src/dotty/tools/dotc/core/TypeErasure.scala | 38 |
1 files changed, 30 insertions, 8 deletions
diff --git a/src/dotty/tools/dotc/core/TypeErasure.scala b/src/dotty/tools/dotc/core/TypeErasure.scala index 56b50c74a..1ea63465a 100644 --- a/src/dotty/tools/dotc/core/TypeErasure.scala +++ b/src/dotty/tools/dotc/core/TypeErasure.scala @@ -5,11 +5,13 @@ package core import Symbols._, Types._, Contexts._, Flags._, Names._, StdNames._, Decorators._, Flags.JavaDefined import Uniques.unique import dotc.transform.ExplicitOuter._ +import dotc.transform.ValueClasses._ import typer.Mode import util.DotClass /** Erased types are: * + * ErasedValueType * TypeRef(prefix is ignored, denot is ClassDenotation) * TermRef(prefix is ignored, denot is SymDenotation) * JavaArrayType @@ -30,8 +32,12 @@ object TypeErasure { /** A predicate that tests whether a type is a legal erased type. Only asInstanceOf and * isInstanceOf may have types that do not satisfy the predicate. + * ErasedValueType is considered an erased type because it is valid after Erasure (it is + * eliminated by ElimErasedValueType). */ def isErasedType(tp: Type)(implicit ctx: Context): Boolean = tp match { + case _: ErasedValueType => + true case tp: TypeRef => tp.symbol.isClass && tp.symbol != defn.AnyClass case _: TermRef => @@ -283,10 +289,12 @@ class TypeErasure(isJava: Boolean, semiEraseVCs: Boolean, isConstructor: Boolean * - For any other type, exception. */ private def apply(tp: Type)(implicit ctx: Context): Type = tp match { + case _: ErasedValueType => + tp case tp: TypeRef => val sym = tp.symbol if (!sym.isClass) this(tp.info) - else if (sym.isDerivedValueClass) eraseDerivedValueClassRef(tp) + else if (semiEraseVCs && isDerivedValueClass(sym)) eraseDerivedValueClassRef(tp) else eraseNormalClassRef(tp) case tp: RefinedType => val parent = tp.parent @@ -295,7 +303,9 @@ class TypeErasure(isJava: Boolean, semiEraseVCs: Boolean, isConstructor: Boolean case tp: TermRef => this(tp.widen) case tp: ThisType => - this(tp.cls.typeRef) + def thisTypeErasure(tpToErase: Type) = + erasureFn(isJava, semiEraseVCs = false, isConstructor, wildcardOK)(tpToErase) + thisTypeErasure(tp.cls.typeRef) case SuperType(thistpe, supertpe) => SuperType(this(thistpe), this(supertpe)) case ExprType(rt) => @@ -307,7 +317,8 @@ class TypeErasure(isJava: Boolean, semiEraseVCs: Boolean, isConstructor: Boolean case OrType(tp1, tp2) => ctx.typeComparer.orType(this(tp1), this(tp2), erased = true) case tp: MethodType => - val paramErasure = erasureFn(tp.isJava, semiEraseVCs, isConstructor, wildcardOK)(_) + def paramErasure(tpToErase: Type) = + erasureFn(tp.isJava, semiEraseVCs, isConstructor, wildcardOK)(tpToErase) val formals = tp.paramTypes.mapConserve(paramErasure) eraseResult(tp.resultType) match { case rt: MethodType => @@ -345,9 +356,11 @@ class TypeErasure(isJava: Boolean, semiEraseVCs: Boolean, isConstructor: Boolean private def eraseArray(tp: RefinedType)(implicit ctx: Context) = { val defn.ArrayType(elemtp) = tp + def arrayErasure(tpToErase: Type) = + erasureFn(isJava, semiEraseVCs = false, isConstructor, wildcardOK)(tpToErase) if (elemtp derivesFrom defn.NullClass) JavaArrayType(defn.ObjectType) else if (isUnboundedGeneric(elemtp)) defn.ObjectType - else JavaArrayType(this(elemtp)) + else JavaArrayType(arrayErasure(elemtp)) } /** The erasure of a symbol's info. This is different from `apply` in the way `ExprType`s are @@ -365,8 +378,12 @@ class TypeErasure(isJava: Boolean, semiEraseVCs: Boolean, isConstructor: Boolean case tp => this(tp) } - private def eraseDerivedValueClassRef(tref: TypeRef)(implicit ctx: Context): Type = - unsupported("eraseDerivedValueClass") + private def eraseDerivedValueClassRef(tref: TypeRef)(implicit ctx: Context): Type = { + val cls = tref.symbol.asClass + val underlying = underlyingOfValueClass(cls) + ErasedValueType(cls, erasure(underlying)) + } + private def eraseNormalClassRef(tref: TypeRef)(implicit ctx: Context): Type = { val cls = tref.symbol.asClass @@ -378,7 +395,10 @@ class TypeErasure(isJava: Boolean, semiEraseVCs: Boolean, isConstructor: Boolean case tp: TypeRef => val sym = tp.typeSymbol if (sym eq defn.UnitClass) sym.typeRef - else if (sym.isDerivedValueClass) eraseNormalClassRef(tp) + // For a value class V, "new V(x)" should have type V for type adaptation to work + // correctly (see SIP-15 and [[Erasure.Boxing.adaptToType]]), so the return type of a + // constructor method should not be semi-erased. + else if (isConstructor && isDerivedValueClass(sym)) eraseNormalClassRef(tp) else this(tp) case RefinedType(parent, _) if !(parent isRef defn.ArrayClass) => eraseResult(parent) @@ -400,10 +420,12 @@ class TypeErasure(isJava: Boolean, semiEraseVCs: Boolean, isConstructor: Boolean * Need to ensure correspondence with erasure! */ private def sigName(tp: Type)(implicit ctx: Context): TypeName = tp match { + case ErasedValueType(_, underlying) => + sigName(underlying) case tp: TypeRef => val sym = tp.symbol if (!sym.isClass) sigName(tp.info) - else if (sym.isDerivedValueClass) sigName(eraseDerivedValueClassRef(tp)) + else if (isDerivedValueClass(sym)) sigName(eraseDerivedValueClassRef(tp)) else normalizeClass(sym.asClass).fullName.asTypeName case defn.ArrayType(elem) => sigName(this(tp)) |