diff options
Diffstat (limited to 'compiler/src/dotty/tools/dotc/core/Types.scala')
| -rw-r--r-- | compiler/src/dotty/tools/dotc/core/Types.scala | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/compiler/src/dotty/tools/dotc/core/Types.scala b/compiler/src/dotty/tools/dotc/core/Types.scala index b8f81f1bb..639f5d142 100644 --- a/compiler/src/dotty/tools/dotc/core/Types.scala +++ b/compiler/src/dotty/tools/dotc/core/Types.scala @@ -3546,6 +3546,13 @@ object Types { def apply(tp: Type) = tp } + /** A type map that approximates NoTypes by upper or lower known bounds depending on + * variance. + * + * if variance > 0 : approximate by upper bound + * variance < 0 : approximate by lower bound + * variance = 0 : propagate NoType to next outer level + */ abstract class ApproximatingTypeMap(implicit ctx: Context) extends TypeMap { thisMap => def approx(lo: Type = defn.NothingType, hi: Type = defn.AnyType) = if (variance == 0) NoType |