Change INDEX property default value to -2.

domainClasses/src/main/generated/io/shiftleft/codepropertygraph/generated/Properties.scala

@@ -152,7 +152,7 @@ object Properties {
   /** Specifies an index, e.g., for a parameter or argument. Explicit parameters are numbered from 1 to N, while index 0
     * is reserved for implicit self / this parameter.
     */
-  val Index = flatgraph.SinglePropertyKey[Int](kind = 26, name = "INDEX", default = -1: Int)
+  val Index = flatgraph.SinglePropertyKey[Int](kind = 26, name = "INDEX", default = -2: Int)
 
   /** The static types a TYPE_DECL inherits from. This property is matched against the FULL_NAME of TYPE nodes and thus
     * it is required to have at least one TYPE node for each TYPE_FULL_NAME

domainClasses/src/main/generated/io/shiftleft/codepropertygraph/generated/PropertyDefaults.scala

@@ -14,7 +14,7 @@ object PropertyDefaults {
   val Filename             = "<empty>"
   val FullName             = "<empty>"
   val GenericSignature     = "<empty>"
-  val Index                = -1: Int
+  val Index                = -2: Int
   val IsExternal           = false
   val IsVariadic           = false
   val Key                  = "<empty>"

domainClasses/src/main/generated/io/shiftleft/codepropertygraph/generated/accessors/Accessors.scala

@@ -182,7 +182,7 @@ object Accessors {
       nodeKind = node.nodeKind,
       propertyKind = 26,
       seq = node.seq(),
-      default = -1: Int
+      default = -2: Int
     )
   }
   final class AccessPropertyInheritsFromTypeFullName(val node: nodes.StoredNode) extends AnyVal {

domainClasses/src/main/generated/io/shiftleft/codepropertygraph/generated/nodes/MethodParameterIn.scala

@@ -34,7 +34,7 @@ trait MethodParameterInBase
     val tmpDynamicTypeHintFullName = this.dynamicTypeHintFullName;
     if (tmpDynamicTypeHintFullName.nonEmpty) res.put("DYNAMIC_TYPE_HINT_FULL_NAME", tmpDynamicTypeHintFullName)
     if (("<empty>": String) != this.evaluationStrategy) res.put("EVALUATION_STRATEGY", this.evaluationStrategy)
-    if ((-1: Int) != this.index) res.put("INDEX", this.index)
+    if ((-2: Int) != this.index) res.put("INDEX", this.index)
     if ((false: Boolean) != this.isVariadic) res.put("IS_VARIADIC", this.isVariadic)
     this.lineNumber.foreach { p => res.put("LINE_NUMBER", p) }
     if (("<empty>": String) != this.name) res.put("NAME", this.name)
@@ -72,7 +72,7 @@ object MethodParameterIn {
   * passed by value, that is, a copy is made, 3) `BY_SHARING` the parameter is a pointer/reference and it is shared with
   * the caller/callee. While a copy of the pointer is made, a copy of the object that it points to is not made.
   *
-  * ▸ Index (Int); Cardinality `one` (mandatory with default value `-1`); Specifies an index, e.g., for a parameter or
+  * ▸ Index (Int); Cardinality `one` (mandatory with default value `-2`); Specifies an index, e.g., for a parameter or
   * argument. Explicit parameters are numbered from 1 to N, while index 0 is reserved for implicit self / this
   * parameter.
   *

domainClasses/src/main/generated/io/shiftleft/codepropertygraph/generated/nodes/MethodParameterOut.scala

@@ -28,7 +28,7 @@ trait MethodParameterOutBase
     if (("<empty>": String) != this.code) res.put("CODE", this.code)
     this.columnNumber.foreach { p => res.put("COLUMN_NUMBER", p) }
     if (("<empty>": String) != this.evaluationStrategy) res.put("EVALUATION_STRATEGY", this.evaluationStrategy)
-    if ((-1: Int) != this.index) res.put("INDEX", this.index)
+    if ((-2: Int) != this.index) res.put("INDEX", this.index)
     if ((false: Boolean) != this.isVariadic) res.put("IS_VARIADIC", this.isVariadic)
     this.lineNumber.foreach { p => res.put("LINE_NUMBER", p) }
     if (("<empty>": String) != this.name) res.put("NAME", this.name)
@@ -58,7 +58,7 @@ object MethodParameterOut {
   * passed by value, that is, a copy is made, 3) `BY_SHARING` the parameter is a pointer/reference and it is shared with
   * the caller/callee. While a copy of the pointer is made, a copy of the object that it points to is not made.
   *
-  * ▸ Index (Int); Cardinality `one` (mandatory with default value `-1`); Specifies an index, e.g., for a parameter or
+  * ▸ Index (Int); Cardinality `one` (mandatory with default value `-2`); Specifies an index, e.g., for a parameter or
   * argument. Explicit parameters are numbered from 1 to N, while index 0 is reserved for implicit self / this
   * parameter.
   *

domainClasses/src/main/generated/io/shiftleft/codepropertygraph/generated/nodes/NewMethodParameterIn.scala

@@ -2399,7 +2399,7 @@ class NewMethodParameterIn
   var columnNumber: Option[Int]                          = None
   var dynamicTypeHintFullName: IndexedSeq[String]        = ArraySeq.empty
   var evaluationStrategy: String                         = "<empty>": String
-  var index: Int                                         = -1: Int
+  var index: Int                                         = -2: Int
   var isVariadic: Boolean                                = false: Boolean
   var lineNumber: Option[Int]                            = None
   var name: String                                       = "<empty>": String

domainClasses/src/main/generated/io/shiftleft/codepropertygraph/generated/nodes/NewMethodParameterOut.scala

@@ -2314,7 +2314,7 @@ class NewMethodParameterOut
   var code: String                                 = "<empty>": String
   var columnNumber: Option[Int]                    = None
   var evaluationStrategy: String                   = "<empty>": String
-  var index: Int                                   = -1: Int
+  var index: Int                                   = -2: Int
   var isVariadic: Boolean                          = false: Boolean
   var lineNumber: Option[Int]                      = None
   var name: String                                 = "<empty>": String

schema/src/main/scala/io/shiftleft/codepropertygraph/schema/Base.scala

@@ -73,7 +73,10 @@ object Base extends SchemaBase {
                     | self / this parameter.
                     |""".stripMargin
       )
-      .mandatory(PropertyDefaults.Int)
+      // We use a default value that is different from -1 because some code working with parameters and return
+      // values represent them in a single number plane where -1 encodes the return value and we do not want
+      // the "value unset" default value to collide with that.
+      .mandatory(-2)
       .protoId(ProtoIds.Index)
 
     val name = builder