Bugfix: Scala 3 generics (#353)

com-lihaoyi · Jan 3, 2022 · 1090cc5 · 1090cc5
1 parent 9655b81
commit 1090cc5
Show file tree

Hide file tree

Showing 2 changed files with 26 additions and 1 deletion.
diff --git a/implicits/src-3/upickle/implicits/macros.scala b/implicits/src-3/upickle/implicits/macros.scala
@@ -51,10 +51,11 @@ end extractKey
 inline def fieldLabels[T] = ${fieldLabelsImpl[T]}
 def fieldLabelsImpl0[T](using Quotes, Type[T]): List[String] =
   import quotes.reflect._
-  val fields: List[Symbol] = TypeTree.of[T].symbol
+  val fields: List[Symbol] = TypeRepr.of[T].typeSymbol
     .primaryConstructor
     .paramSymss
     .flatten
+    .filterNot(_.isType)
 
   fields.map{ sym =>
     extractKey(sym) match {

diff --git a/upickle/test/src/upickle/example/ExampleTests.scala b/upickle/test/src/upickle/example/ExampleTests.scala
@@ -78,6 +78,13 @@ object Custom2{
     )
   }
 }
+object Generic {
+  case class Container[T](a: T)
+  object Container{
+    implicit val intRW: RW[Container[Int]] = macroRW
+  }
+}
+
 
 import KeyedTag._
 import Keyed._
@@ -569,6 +576,23 @@ object ExampleTests extends TestSuite {
       writeBinary(Array[Byte](1, 2, 3, 4)) ==> Array(0xc4.toByte, 4, 1, 2, 3, 4)
       readBinary[Array[Byte]](Array[Byte](0xc4.toByte, 4, 1, 2, 3, 4)) ==> Array(1, 2, 3, 4)
     }
+    test("generic"){
+      import upickle.default._
+      import Generic._
+      test("read") - {
+        val containerJson = """{"a":3}"""
+        val parsed = read[Container[Int]](containerJson)
+        val expected = Container[Int](3)
+        assert(parsed == expected)
+      }
+
+      test("write") - {
+        val original = Container[Int](3)
+        val serialized = write(original)
+        val expected = """{"a":3}"""
+        assert(serialized == expected)
+      }
+    }
   }
 }