Improve failure message of enum fromOrdinal/valueOf (scala#19182)

Fixes scala#19178
dwijnand · Dec 15, 2023 · 1f7aa24 · 1f7aa24
2 parents 08572ee + 2dcd64a
commit 1f7aa24
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Showing 6 changed files with 24 additions and 5 deletions.
diff --git a/compiler/src/dotty/tools/dotc/ast/DesugarEnums.scala b/compiler/src/dotty/tools/dotc/ast/DesugarEnums.scala
@@ -126,7 +126,7 @@ object DesugarEnums {
 
     val valuesOfBody: Tree =
       val defaultCase =
-        val msg = Apply(Select(Literal(Constant("enum case not found: ")), nme.PLUS), Ident(nme.nameDollar))
+        val msg = Apply(Select(Literal(Constant(s"enum ${enumClass.fullName} has no case with name: ")), nme.PLUS), Ident(nme.nameDollar))
         CaseDef(Ident(nme.WILDCARD), EmptyTree,
           Throw(New(TypeTree(defn.IllegalArgumentExceptionType), List(msg :: Nil))))
       val stringCases = enumValues.map(enumValue =>
@@ -148,7 +148,8 @@ object DesugarEnums {
     def valueCtor: List[Tree] = if constraints.requiresCreator then enumValueCreator :: Nil else Nil
     def fromOrdinal: Tree =
       def throwArg(ordinal: Tree) =
-        Throw(New(TypeTree(defn.NoSuchElementExceptionType), List(Select(ordinal, nme.toString_) :: Nil)))
+        val msg = Apply(Select(Literal(Constant(s"enum ${enumClass.fullName} has no case with ordinal: ")), nme.PLUS), Select(ordinal, nme.toString_))
+        Throw(New(TypeTree(defn.NoSuchElementExceptionType), List(msg :: Nil)))
       if !constraints.cached then
         fromOrdinalMeth(throwArg)
       else

diff --git a/tests/run/enum-java.check b/tests/run/enum-java.check
@@ -26,7 +26,7 @@ MONDAY : 0
 TUESDAY : 1
 SATURDAY : 2
 By-name value: MONDAY
-Correctly failed to retrieve illegal name, message: enum case not found: stuff
+Correctly failed to retrieve illegal name, message: enum A has no case with name: stuff
 
 Collections Test
 Retrieving Monday: workday

diff --git a/tests/run/enum-values.scala b/tests/run/enum-values.scala
@@ -61,7 +61,7 @@ enum ClassOnly: // this should still generate the `ordinal` and `fromOrdinal` co
     catch
       case e: java.lang.reflect.InvocationTargetException => // TODO: maybe reflect.Selectable should catch this?
         assert(e.getCause.isInstanceOf[java.util.NoSuchElementException]
-          && e.getCause.getMessage == ordinal.toString)
+          && e.getCause.getMessage == s"enum ${companion.getClass.getName.stripSuffix("$")} has no case with ordinal: $ordinal")
 
   fetchFromOrdinal(companion = Color,       compare = Red, Green, Blue)
   fetchFromOrdinal(companion = Suits,       compare = Clubs, Spades, Diamonds, Hearts)

diff --git a/tests/run/enums-java-compat.check b/tests/run/enums-java-compat.check
@@ -6,4 +6,4 @@ TUESDAY : 1
 SATURDAY : 2
 Stuff : 3
 By-name value: MONDAY
-Correctly failed to retrieve illegal name, message: enum case not found: stuff
+Correctly failed to retrieve illegal name, message: enum A has no case with name: stuff
diff --git a/tests/run/i19178.check b/tests/run/i19178.check
@@ -0,0 +1,4 @@
+Failure(java.util.NoSuchElementException: enum Foo has no case with ordinal: 3)
+Failure(java.lang.IllegalArgumentException: enum Foo has no case with name: Bar)
+Failure(java.util.NoSuchElementException: enum bar.Bar has no case with ordinal: 4)
+Failure(java.lang.IllegalArgumentException: enum bar.Bar has no case with name: Baz)
diff --git a/tests/run/i19178.scala b/tests/run/i19178.scala
@@ -0,0 +1,14 @@
+enum Foo:
+  case A
+
+package bar {
+  enum Bar:
+    case B
+}
+
+@main def Test =
+  import scala.util.Try
+  println(Try(Foo.fromOrdinal(3)))
+  println(Try(Foo.valueOf("Bar")))
+  println(Try(bar.Bar.fromOrdinal(4)))
+  println(Try(bar.Bar.valueOf("Baz")))