Step 21: union mismatch bytecode throw

lynglib/src/commonMain/kotlin/net/sergeych/lyng/Compiler.kt

@@ -4341,15 +4341,6 @@ class Compiler(
         }
     }
 
-    private class UnionTypeMismatchStatement(
-        private val message: String,
-        override val pos: Pos
-    ) : Statement() {
-        override suspend fun execute(scope: Scope): Obj {
-            throw ScriptError(pos, message)
-        }
-    }
-
     private fun resolveMemberHostForUnion(typeDecl: TypeDecl, memberName: String, pos: Pos): ObjClass {
         val receiverClass = when (typeDecl) {
             TypeDecl.TypeAny, TypeDecl.TypeNullableAny -> Obj.rootObjectType
@@ -4392,8 +4383,10 @@ class Compiler(
             resolveMemberHostForUnion(option, memberName, pos)
         }
         val unionName = typeDeclName(union)
-        val failStmt = UnionTypeMismatchStatement("value is not $unionName", pos)
-        var current: ObjRef = net.sergeych.lyng.obj.StatementRef(failStmt)
+        val errorMessage = ObjString("value is not $unionName").asReadonly
+        val throwExpr = ExpressionStatement(ConstRef(errorMessage), pos)
+        val throwStmt = ThrowStatement(throwExpr, pos)
+        var current: ObjRef = net.sergeych.lyng.obj.StatementRef(throwStmt)
         for (option in options.asReversed()) {
             val typeRef = net.sergeych.lyng.obj.TypeDeclRef(option, pos)
             val cond = BinaryOpRef(BinOp.IS, left, typeRef)

lynglib/src/commonTest/kotlin/BytecodeRecentOpsTest.kt

@@ -17,6 +17,7 @@
 
 import kotlinx.coroutines.test.runTest
 import net.sergeych.lyng.Compiler
+import net.sergeych.lyng.ExecutionError
 import net.sergeych.lyng.Script
 import net.sergeych.lyng.ScriptError
 import net.sergeych.lyng.Source
@@ -24,6 +25,7 @@ import net.sergeych.lyng.eval
 import net.sergeych.lyng.obj.toInt
 import kotlin.test.Test
 import kotlin.test.assertEquals
+import kotlin.test.assertFailsWith
 import kotlin.test.assertTrue
 
 class BytecodeRecentOpsTest {
@@ -221,6 +223,21 @@ class BytecodeRecentOpsTest {
         )
     }
 
+    @Test
+    fun unionMemberDispatchMismatch() = runTest {
+        val err = assertFailsWith<ExecutionError> {
+            eval(
+                """
+                class A { fun who() = "A" }
+                class B { fun who() = "B" }
+                val x: A | B = 1
+                x.who()
+                """.trimIndent()
+            )
+        }
+        assertTrue(err.message?.contains("value is not A | B") == true)
+    }
+
     @Test
     fun objectReceiverMemberError() = runTest {
         val failed = try {