Mark AST value type nodes as Sendable

Why not.

Plugins/Libraries/LighterCodeGenAST/Nodes/Expression.swift

@@ -1,15 +1,15 @@
 //
 //  Created by Helge Heß.
-//  Copyright © 2022 ZeeZide GmbH.
+//  Copyright © 2022-2024 ZeeZide GmbH.
 //
 
 /**
  * An AST node for various Swift expressions.
  */
-public indirect enum Expression: Equatable {
+public indirect enum Expression: Equatable, Sendable {
 
   /// The operators for ``compare(lhs:operator:rhs:)`` expressions.
-  public enum Operator: String {
+  public enum Operator: String, Sendable {
     case equal              = "=="
     case notEqual           = "!="
     case greaterThanOrEqual = ">="
@@ -82,12 +82,12 @@ public indirect enum Expression: Equatable {
  *
  * Used as the value for ``Expression/functionCall(_:)``.
  */
-public struct FunctionCall: Equatable {
+public struct FunctionCall: Equatable, Sendable {
 
   /**
    * A parameter passed as part of the function call.
    */
-  public struct Parameter: Equatable {
+  public struct Parameter: Equatable, Sendable {
 
     /// The keyword/label of the parameter, can be `nil` if it is a wildcard
     /// (unlabled) parameter.
@@ -105,7 +105,7 @@ public struct FunctionCall: Equatable {
   /**
    * A trailing closure attached to a function call.
    */
-  public struct TrailingClosure: Equatable {
+  public struct TrailingClosure: Equatable, Sendable {
 
     /// The parameter list of the trailing closure (e.g. `( a, b ) in`).
     public let parameters: [ String    ]

Plugins/Libraries/LighterCodeGenAST/Nodes/FunctionComment.swift

@@ -1,17 +1,17 @@
 //
 //  Created by Helge Heß.
-//  Copyright © 2022 ZeeZide GmbH.
+//  Copyright © 2022-2024 ZeeZide GmbH.
 //
 
 /**
  * A comment for a function.
  *
  * Has all the function specific things, like parameters and such.
  */
-public struct FunctionComment: Equatable {
+public struct FunctionComment: Equatable, Sendable {
 
   /// A comment for a function parameter.
-  public struct Parameter: Equatable {
+  public struct Parameter: Equatable, Sendable {
 
     /// The name of the function parameter being documented.
     public var name : String

Plugins/Libraries/LighterCodeGenAST/Nodes/FunctionDeclaration.swift

@@ -1,6 +1,6 @@
 //
 //  Created by Helge Heß.
-//  Copyright © 2022 ZeeZide GmbH.
+//  Copyright © 2022-2024 ZeeZide GmbH.
 //
 
 /**
@@ -19,7 +19,7 @@
  * where C1: SQLColumn, C2: SQLColumn, T == C1.T, T == C2.T
  * ```
  */
-public struct FunctionDeclaration: Equatable {
+public struct FunctionDeclaration: Equatable, Sendable {
 
   /// Is the function public?
   public let `public`              : Bool

Plugins/Libraries/LighterCodeGenAST/Nodes/FunctionDefinition.swift

@@ -1,6 +1,6 @@
 //
 //  Created by Helge Heß.
-//  Copyright © 2022 ZeeZide GmbH.
+//  Copyright © 2022-2024 ZeeZide GmbH.
 //
 
 /**
@@ -9,7 +9,7 @@
  *
  * Plus extra annotations like ``inlinable`` and the ``comment``.
  */
-public struct FunctionDefinition: Equatable {
+public struct FunctionDefinition: Equatable, Sendable {
 
   /// Whether the definition is `@inlinable` (included in the module header).
   public var inlinable    : Bool

Plugins/Libraries/LighterCodeGenAST/Nodes/FunctionParameter.swift

@@ -1,13 +1,13 @@
 //
 //  Created by Helge Heß.
-//  Copyright © 2022 ZeeZide GmbH.
+//  Copyright © 2022-2024 ZeeZide GmbH.
 //
 
 public extension FunctionDeclaration {
 
   /// A parameter, like `from table: KeyPath<Self.RecordTypes, T.Type>`
   /// Or: `limit: Int? = nil`
-  struct Parameter: Equatable {
+  struct Parameter: Equatable, Sendable {
 
     /// The "label" of the parameter, e.g. the `from` in `select(from table:)`.
     /// Can be `nil` for a wildcard (`_`).

Plugins/Libraries/LighterCodeGenAST/Nodes/GenericConstraint.swift

@@ -1,13 +1,13 @@
 //
 //  Created by Helge Heß.
-//  Copyright © 2022 ZeeZide GmbH.
+//  Copyright © 2022-2024 ZeeZide GmbH.
 //
 
 /**
  * A generic constraint attached to a ``FunctionDeclaration`` generic parameter
  * or an ``Extension``.
  */
-public enum GenericConstraint: Equatable {
+public enum GenericConstraint: Equatable, Sendable {
 
   /// `C1: SQLColumn`
   case conformance(name: String, type: TypeReference)

Plugins/Libraries/LighterCodeGenAST/Nodes/Literal.swift

@@ -1,14 +1,14 @@
 //
 //  Created by Helge Heß.
-//  Copyright © 2022 ZeeZide GmbH.
+//  Copyright © 2022-2024 ZeeZide GmbH.
 //
 
 /**
  * A Swift literal
  *
  * E.g. as used in default values like: `limit: Int? = nil` (the `nil`).
  */
-public enum Literal: Equatable {
+public enum Literal: Equatable, Sendable {
 
   /// `nil`
   case `nil`

Plugins/Libraries/LighterCodeGenAST/Nodes/Statement.swift

@@ -1,18 +1,18 @@
 //
 //  Created by Helge Heß.
-//  Copyright © 2022 ZeeZide GmbH.
+//  Copyright © 2022-2024 ZeeZide GmbH.
 //
 
 /**
  * An AST node for a Swift statement.
  */
-public enum Statement: Equatable {
+public enum Statement: Equatable, Sendable {
 
   /**
    * A pair for an `if`, `else if` statement, consisting of a condition and the
    * associated ``Statement``s.
    */
-  public struct ConditionStatementPair: Equatable {
+  public struct ConditionStatementPair: Equatable, Sendable {
 
     /// The condition that must be true to have the ``statements`` executed.
     public var condition  : Expression

Plugins/Libraries/LighterCodeGenAST/Nodes/TypeReference.swift

@@ -1,12 +1,12 @@
 //
 //  Created by Helge Heß.
-//  Copyright © 2022 ZeeZide GmbH.
+//  Copyright © 2022-2024 ZeeZide GmbH.
 //
 
 /**
  * A reference to some type, e.g. `Void` or `Person` or `Int`.
  */
-public indirect enum TypeReference: Equatable {
+public indirect enum TypeReference: Equatable, Sendable {
 
   /// `Void`
   case void