fix 2.12 issue with lazy decoder

jcouyang · Oct 15, 2020 · 7e69751 · 7e69751
1 parent 57a652a
commit 7e69751
Showing 1 changed file with 17 additions and 17 deletions.
diff --git a/src/main/scala/us/oyanglul/dhall/generic.scala b/src/main/scala/us/oyanglul/dhall/generic.scala
@@ -8,13 +8,27 @@ import shapeless.labelled.{FieldType, field}
 import shapeless._
 import cats.syntax.either._
 
-trait LowPriorityForScala212Binary {
+object generic {
+  implicit val decodeHNil: Decoder[HNil] = new Decoder[HNil] {
+    def decode(expr: Expr): Result[HNil] = HNil.asRight
+    def isValidType(typeExpr: Expr): Boolean = true
+    def isExactType(typeExpr: Expr): Boolean = true
+  }
+
+  implicit val decodeCNil: Decoder[CNil] = new Decoder[CNil] {
+    def decode(expr: Expr): Result[CNil] =
+      Left(new DecodingFailure("Inconceivable! Coproduct never be CNil", expr))
+    def isValidType(typeExpr: Expr): Boolean = true
+    def isExactType(typeExpr: Expr): Boolean = true
+  }
+
   implicit def decodeGeneric[A, ARepr](implicit
       gen: LabelledGeneric.Aux[A, ARepr],
-      decoder: Decoder[ARepr]
+      decoder: Lazy[Decoder[ARepr]]
   ): Decoder[A] =
     new Decoder[A] {
-      def decode(expr: Expr): Result[A] = decoder.decode(expr).map(gen.from)
+      def decode(expr: Expr): Result[A] =
+        decoder.value.decode(expr).map(gen.from)
       def isValidType(typeExpr: Expr): Boolean = true
       def isExactType(typeExpr: Expr): Boolean = true
     }
@@ -73,17 +87,3 @@ trait LowPriorityForScala212Binary {
       def isExactType(typeExpr: Expr): Boolean = true
     }
 }
-object generic extends LowPriorityForScala212Binary {
-  implicit val decodeHNil: Decoder[HNil] = new Decoder[HNil] {
-    def decode(expr: Expr): Result[HNil] = HNil.asRight
-    def isValidType(typeExpr: Expr): Boolean = true
-    def isExactType(typeExpr: Expr): Boolean = true
-  }
-
-  implicit val decodeCNil: Decoder[CNil] = new Decoder[CNil] {
-    def decode(expr: Expr): Result[CNil] =
-      Left(new DecodingFailure("Inconceivable! Coproduct never be CNil", expr))
-    def isValidType(typeExpr: Expr): Boolean = true
-    def isExactType(typeExpr: Expr): Boolean = true
-  }
-}