Fix for over enum

src/main/scala/millfork/compiler/AbstractStatementCompiler.scala

@@ -112,9 +112,34 @@ abstract class AbstractStatementCompiler[T <: AbstractCode] {
     // TODO: special faster cases
     val p = f.position
     val vex = VariableExpression(f.variable)
+    val indexType = ctx.env.get[Variable](f.variable).typ
+    val arithmetic = indexType.isArithmetic
+    if (!arithmetic && f.direction != ForDirection.ParallelUntil) {
+      ctx.log.error("Invalid direction for enum iteration", p)
+      compile(ctx, f.body)
+      return Nil -> Nil
+    }
     val one = LiteralExpression(1, 1).pos(p)
-    val increment = ExpressionStatement(FunctionCallExpression("+=", List(vex, one)).pos(p)).pos(p)
-    val decrement = ExpressionStatement(FunctionCallExpression("-=", List(vex, one)).pos(p)).pos(p)
+    val increment = if (arithmetic) {
+      ExpressionStatement(FunctionCallExpression("+=", List(vex, one)).pos(p)).pos(p)
+    } else {
+      Assignment(vex, FunctionCallExpression(indexType.name, List(
+        SumExpression(List(
+          false -> FunctionCallExpression("byte", List(vex)).pos(p),
+          false -> LiteralExpression(1,1).pos(p),
+        ), decimal = false).pos(p)
+      )).pos(p)).pos(p)
+    }
+    val decrement = if (arithmetic) {
+          ExpressionStatement(FunctionCallExpression("-=", List(vex, one)).pos(p)).pos(p)
+        } else {
+          Assignment(vex, FunctionCallExpression(indexType.name, List(
+            SumExpression(List(
+              false -> FunctionCallExpression("byte", List(vex)).pos(p),
+              true -> LiteralExpression(1,1).pos(p),
+            ), decimal = false).pos(p)
+          )).pos(p)).pos(p)
+        }
     val names = Set("", "for", f.variable)
 
     val startEvaluated = ctx.env.eval(f.start)

src/main/scala/millfork/node/Node.scala

@@ -432,7 +432,7 @@ case class ForStatement(variable: String, start: Expression, end: Expression, di
 }
 
 case class ForEachStatement(variable: String, values: Either[Expression, List[Expression]], body: List[ExecutableStatement]) extends CompoundStatement {
-  override def getAllExpressions: List[Expression] = VariableExpression(variable) :: (values.fold(List(_), identity) ++ body.flatMap(_.getAllExpressions))
+  override def getAllExpressions: List[Expression] = VariableExpression(variable) :: body.flatMap(_.getAllExpressions)
 
   override def getChildStatements: Seq[Statement] = body
   override def flatMap(f: ExecutableStatement => Option[ExecutableStatement]): Option[ExecutableStatement] = {

src/test/scala/millfork/test/EnumSuite.scala

@@ -66,6 +66,22 @@ class EnumSuite extends FunSuite with Matchers {
       """.stripMargin){_=>}
   }
 
+  test("Loops over enums") {
+    EmuCrossPlatformBenchmarkRun(Cpu.Mos, Cpu.Z80, Cpu.Intel8080, Cpu.Sharp)(
+      """
+        | enum ugly {
+        |   a
+        |   b,c,
+        |   d
+        | }
+        | void main() {
+        |   ugly u
+        |   for u:ugly {
+        |   }
+        | }
+      """.stripMargin){_=>}
+  }
+
   test("Enum-byte incompatibility test") {
     ShouldNotCompile(
       """
@@ -151,5 +167,15 @@ class EnumSuite extends FunSuite with Matchers {
         |     return a[0]
         | }
       """.stripMargin)
+
+    ShouldNotCompile(
+      """
+        | enum ugly { a }
+        | array arr[ugly]
+        | void main() {
+        |     byte x
+        |     for x: ugly {}
+        | }
+      """.stripMargin)
   }
 }