Keep SyntaxData instead of Syntax alive in syntax node initializers

Author: ahoppen

CodeGeneration/Sources/generate-swift-syntax/templates/swiftsyntax/SyntaxNodesFile.swift

@@ -84,9 +84,13 @@ func syntaxNode(nodesStartingWith: [Character]) -> SourceFileSyntax {
           \(node.generateInitializerDeclHeader())
           """
         ) {
-          let parameters = ClosureParameterListSyntax {
+          let parameters = TupleExprSyntax {
             for child in node.children {
-              ClosureParameterSyntax(firstName: child.varOrCaseName.backtickedIfNeeded)
+              if child.isOptional {
+                LabeledExprSyntax(expression: ExprSyntax("\(child.varOrCaseName.backtickedIfNeeded)?.data"))
+              } else {
+                LabeledExprSyntax(expression: ExprSyntax("\(child.varOrCaseName.backtickedIfNeeded).data"))
+              }
             }
           }
 
@@ -116,7 +120,7 @@ func syntaxNode(nodesStartingWith: [Character]) -> SourceFileSyntax {
             calledExpression: ExprSyntax("withExtendedLifetime"),
             leftParen: .leftParenToken(),
             arguments: LabeledExprListSyntax {
-              LabeledExprSyntax(expression: ExprSyntax("(SyntaxArena(), (\(parameters)))"))
+              LabeledExprSyntax(expression: ExprSyntax("(SyntaxArena(), \(parameters))"))
             },
             rightParen: .rightParenToken(),
             trailingClosure: ClosureExprSyntax(signature: closureSignature) {