Fix "Duplicate Local Variables in Object Scope"

sjsonnet/src/sjsonnet/Expr.scala

@@ -18,6 +18,8 @@ trait Expr{
     val n = getClass.getName
     if(n.startsWith("sjsonnet.Expr$")) n.substring(14) else n
   }
+
+  override def toString: String = s"$exprErrorString@$pos"
 }
 object Expr{
   private final def arrStr(a: Array[_]): String = {
@@ -165,7 +167,9 @@ object Expr{
 
   trait ObjBody extends Expr
   object ObjBody{
-    case class MemberList(pos: Position, binds: Array[Bind], fields: Array[Member.Field], asserts: Array[Member.AssertStmt]) extends ObjBody
+    case class MemberList(pos: Position, binds: Array[Bind], fields: Array[Member.Field], asserts: Array[Member.AssertStmt]) extends ObjBody {
+      override def toString: String = s"MemberList($pos, ${arrStr(binds)}, ${arrStr(fields)}, ${arrStr(asserts)})"
+    }
     case class ObjComp(pos: Position,
                        preLocals: Array[Bind],
                        key: Expr,

sjsonnet/src/sjsonnet/Parser.scala

@@ -328,6 +328,15 @@ class Parser(val currentFile: Path,
     case (pos, exprs, None) =>
       val binds = {
         val b = exprs.iterator.filter(_.isInstanceOf[Expr.Bind]).asInstanceOf[Iterator[Expr.Bind]].toArray
+        val seen = collection.mutable.Set.empty[String]
+        var overlap: String = null
+        b.foreach {
+          case Expr.Bind(_, n, _, _) =>
+            if (seen(n)) overlap = n
+            else seen.add(n)
+          case _ =>
+        }
+        if (overlap != null) Fail.opaque("no duplicate local: " + overlap)
         if(b.isEmpty) null else b
       }
       val fields = exprs.iterator.filter(_.isInstanceOf[Expr.Member.Field]).asInstanceOf[Iterator[Expr.Member.Field]].toArray

sjsonnet/test/src/sjsonnet/ParserTests.scala

@@ -4,7 +4,8 @@ import scala.collection.mutable
 import utest._
 import Expr._
 import fastparse.Parsed
-import Val.{True, Num}
+import Val.{Num, True}
+import sjsonnet.Expr.FieldName.Fixed
 object ParserTests extends TestSuite{
   def parse(s: String, strictImportSyntax: Boolean = false) = fastparse.parse(s, new Parser(null, strictImportSyntax, mutable.HashMap.empty, mutable.HashMap.empty).document(_)).get.value._1
   def parseErr(s: String, strictImportSyntax: Boolean = false) = fastparse.parse(s, new Parser(null, strictImportSyntax, mutable.HashMap.empty, mutable.HashMap.empty).document(_), verboseFailures = true).asInstanceOf[Parsed.Failure].msg
@@ -26,6 +27,18 @@ object ParserTests extends TestSuite{
     test("duplicateFields") {
       parseErr("{ a: 1, a: 2 }") ==> """Expected no duplicate field: a:1:14, found "}""""
     }
+    test("localInObj") {
+      parse("""{
+               |local x = 1,
+               |a: x,
+               |}""".stripMargin).toString ==> (ObjBody.MemberList(pos(2), Array(Bind(pos(8), "x", null, Num(pos(12), 1))),
+        Array(Member.Field(pos(15), Fixed("a"), false, null, Member.Visibility.Normal, Id(pos(18), "x"))), null)).toString
+      parseErr("""{
+                 |local x = 1,
+                 |local x = x + 1,
+                 |a: x,
+                 |}""".stripMargin) ==> """Expected no duplicate local: x:5:1, found "}""""
+    }
     test("givenDuplicateFieldsInListComprehension_expectError") {
       parseErr("""{ ["bar"]: x for x in [1, 2]}""") ==> """Expected no duplicate field: "bar" :1:29, found "}""""
     }