diff options
Diffstat (limited to 'src/dotty/tools/dotc/core/Types.scala')
| -rw-r--r-- | src/dotty/tools/dotc/core/Types.scala | 31 |
1 files changed, 17 insertions, 14 deletions
diff --git a/src/dotty/tools/dotc/core/Types.scala b/src/dotty/tools/dotc/core/Types.scala index f65633595..596d1ba24 100644 --- a/src/dotty/tools/dotc/core/Types.scala +++ b/src/dotty/tools/dotc/core/Types.scala @@ -141,20 +141,23 @@ object Types { } /** Is this type an instance of a non-bottom subclass of the given class `cls`? */ - final def derivesFrom(cls: Symbol)(implicit ctx: Context): Boolean = this match { - case tp: TypeRef => - val sym = tp.symbol - if (sym.isClass) sym.derivesFrom(cls) else tp.underlying.derivesFrom(cls) - case tp: TypeProxy => - tp.underlying.derivesFrom(cls) - case tp: AndType => - tp.tp1.derivesFrom(cls) || tp.tp2.derivesFrom(cls) - case tp: OrType => - tp.tp1.derivesFrom(cls) && tp.tp2.derivesFrom(cls) - case tp: JavaArrayType => - cls == defn.ObjectClass - case _ => - false + final def derivesFrom(cls: Symbol)(implicit ctx: Context): Boolean = { + def loop(tp: Type) = tp match { + case tp: TypeRef => + val sym = tp.symbol + if (sym.isClass) sym.derivesFrom(cls) else tp.underlying.derivesFrom(cls) + case tp: TypeProxy => + tp.underlying.derivesFrom(cls) + case tp: AndType => + tp.tp1.derivesFrom(cls) || tp.tp2.derivesFrom(cls) + case tp: OrType => + tp.tp1.derivesFrom(cls) && tp.tp2.derivesFrom(cls) + case tp: JavaArrayType => + cls == defn.ObjectClass + case _ => + false + } + cls == defn.AnyClass || loop(this) } /** Is this type guaranteed not to have `null` as a value? |