Check that the referenced enum member exists

It detects problems such as the following:
- kaitai-io/kaitai_struct_formats#349 (comment)
- kaitai-io/kaitai_struct_formats#591 (comment)

Author: generalmimon

shared/src/main/scala/io/kaitai/struct/format/EnumSpec.scala

@@ -4,7 +4,7 @@ import io.kaitai.struct.problems.KSYParseError
 
 import scala.collection.mutable
 
-case class EnumSpec(map: Map[Long, EnumValueSpec]) {
+case class EnumSpec(path: List[String], map: Map[Long, EnumValueSpec]) extends YAMLPath {
   var name = List[String]()
 
   /**
@@ -24,7 +24,7 @@ object EnumSpec {
   def fromYaml(src: Any, path: List[String]): EnumSpec = {
     val srcMap = ParseUtils.asMap(src, path)
     val memberNameMap = mutable.Map[String, Long]()
-    EnumSpec(srcMap.map { case (id, desc) =>
+    EnumSpec(path, srcMap.map { case (id, desc) =>
       val idLong = ParseUtils.asLong(id, path)
       val value = EnumValueSpec.fromYaml(desc, path ++ List(idLong.toString))
 

shared/src/main/scala/io/kaitai/struct/precompile/Exceptions.scala

@@ -18,6 +18,8 @@ class FieldNotFoundError(val name: String, val curClass: ClassSpec)
   extends NotFoundError(s"unable to access '$name' in ${curClass.nameAsStr} context")
 class EnumNotFoundError(val name: String, val curClass: ClassSpec)
   extends NotFoundError(s"unable to find enum '$name', searching from ${curClass.nameAsStr}")
+class EnumMemberNotFoundError(val label: String, val enum: String, val enumDefPath: String)
+  extends NotFoundError(s"unable to find enum member '$enum::$label' (enum '$enum' defined at /$enumDefPath)")
 class MethodNotFoundError(val name: String, val dataType: DataType)
   extends NotFoundError(s"don't know how to call method '$name' of object type '$dataType'")
 

shared/src/main/scala/io/kaitai/struct/translators/ExpressionValidator.scala

@@ -3,6 +3,7 @@ package io.kaitai.struct.translators
 import io.kaitai.struct.datatype.DataType
 import io.kaitai.struct.exprlang.Ast
 import io.kaitai.struct.format.Identifier
+import io.kaitai.struct.precompile.EnumMemberNotFoundError
 
 /**
   * Validates expressions usage of types (in typecasting operator,
@@ -33,8 +34,10 @@ class ExpressionValidator(val provider: TypeProvider)
         provider.resolveEnum(inType, enumType.name)
         validate(id)
       case Ast.expr.EnumByLabel(enumType, label, inType) =>
-        provider.resolveEnum(inType, enumType.name)
-        // TODO: check that label belongs to that enum
+        val enumSpec = provider.resolveEnum(inType, enumType.name)
+        if (!enumSpec.map.values.exists(_.name == label.name)) {
+          throw new EnumMemberNotFoundError(label.name, enumType.name, enumSpec.path.mkString("/"))
+        }
       case Ast.expr.Name(name: Ast.identifier) =>
         if (name.name == Identifier.SIZEOF) {
           CommonSizeOf.getByteSizeOfClassSpec(provider.nowClass)