Give MemberwiseInit support for @inlinable and @usableFromInline

Sources/MemberwiseInit/MemberwiseInit.swift

@@ -7,11 +7,17 @@ public enum AccessLevelConfig {
   case `open`
 }
 
+public enum InlinabilityConfig {
+  case usableFromInline
+  case inlinable
+}
+
 // MARK: @MemberwiseInit macro
 
 @attached(member, names: named(init))
 public macro MemberwiseInit(
   _ accessLevel: AccessLevelConfig,
+  _ inlinability: InlinabilityConfig? = nil,
   _deunderscoreParameters: Bool? = nil,
   _optionalsDefaultNil: Bool? = nil
 ) =
@@ -22,6 +28,7 @@ public macro MemberwiseInit(
 
 @attached(member, names: named(init))
 public macro MemberwiseInit(
+  _ inlinability: InlinabilityConfig? = nil,
   _deunderscoreParameters: Bool? = nil,
   _optionalsDefaultNil: Bool? = nil
 ) =
@@ -32,6 +39,7 @@ public macro MemberwiseInit(
 
 @attached(member, names: named(init))
 public macro _UncheckedMemberwiseInit(
+  _ inlinability: InlinabilityConfig? = nil,
   _deunderscoreParameters: Bool? = nil,
   _optionalsDefaultNil: Bool? = nil
 ) =
@@ -43,6 +51,7 @@ public macro _UncheckedMemberwiseInit(
 @attached(member, names: named(init))
 public macro _UncheckedMemberwiseInit(
   _ accessLevel: AccessLevelConfig,
+  _ inlinability: InlinabilityConfig? = nil,
   _deunderscoreParameters: Bool? = nil,
   _optionalsDefaultNil: Bool? = nil
 ) =

Sources/MemberwiseInitClient/main.swift

@@ -122,6 +122,43 @@ public struct InferType<T: CaseIterable> {
   var dictionaryAs = ["foo": 1, 3: "bar"] as [AnyHashable: Any]
 }
 
+@MemberwiseInit(.inlinable)
+public struct InlinableInit_Default {
+  public let foo: String
+
+  @Init(.ignore)
+  private var ignored: Int = 7
+}
+let _ = InlinableInit_Default(foo: "bar")
+
+@MemberwiseInit(.internal, .inlinable)
+public struct InlinableInit_Internal {
+  public let foo: String
+
+  @Init(.ignore)
+  private var ignored: Int = 7
+}
+let _ = InlinableInit_Internal(foo: "bar")
+
+//@MemberwiseInit(.fileprivate, .inlinable)
+//internal struct InlinableInit_FilePrivate {
+//  fileprivate let foo: String
+//  
+//  @Init(.ignore)
+//  private var ignored: Int = 7
+//}
+////let _ = InlinableInit_FilePrivate(foo: "bar")
+
+@MemberwiseInit(.package, .usableFromInline)
+public struct InlinableInit_Package {
+  public let foo: String
+
+  @Init(.ignore)
+  private var ignored: Int = 7
+}
+let _ = InlinableInit_Package(foo: "bar")
+
+
 // - MARK: Usage tour
 
 public typealias SimpleClosure = () -> Void

Sources/MemberwiseInitMacros/Macros/MemberwiseInitMacro.swift

@@ -2,9 +2,10 @@ import SwiftCompilerPlugin
 import SwiftDiagnostics
 import SwiftSyntax
 import SwiftSyntaxBuilder
-import SwiftSyntaxMacroExpansion
 import SwiftSyntaxMacros
 
+
+
 public struct InitMacro: PeerMacro {
   public static func expansion(
     of node: SwiftSyntax.AttributeSyntax,
@@ -30,11 +31,13 @@ public struct MemberwiseInitMacro: MemberMacro {
         """
       )
     }
-
+    
     deprecationDiagnostics(node: node, declaration: decl)
       .forEach(context.diagnose)
 
     let configuredAccessLevel: AccessLevelModifier? = extractConfiguredAccessLevel(from: node)
+    let inlinability: InlinabilityAttribute? = extractInlinabilityAttribute(from: node)
+
     let optionalsDefaultNil: Bool? =
       extractLabeledBoolArgument("_optionalsDefaultNil", from: node)
     let deunderscoreParameters: Bool =
@@ -46,37 +49,71 @@ public struct MemberwiseInitMacro: MemberMacro {
       targetAccessLevel: accessLevel
     )
     diagnostics.forEach { context.diagnose($0) }
+    if let incompatibilityDiagnostic = incompatibilityDiagnosticBetween(
+      accessLevel: accessLevel,
+      inlinability: inlinability,
+      in: node,
+      typeAccessLevel: decl.declAccessLevel
+    ) {
+      context.diagnose(incompatibilityDiagnostic)
+    }
 
     return [
       DeclSyntax(
         MemberwiseInitFormatter.formatInitializer(
           properties: properties,
           accessLevel: accessLevel,
+          inlinability: inlinability,
           deunderscoreParameters: deunderscoreParameters,
           optionalsDefaultNil: optionalsDefaultNil
         )
       )
     ]
   }
-
+  
   static func extractConfiguredAccessLevel(
     from node: AttributeSyntax
   ) -> AccessLevelModifier? {
-    guard let arguments = node.arguments?.as(LabeledExprListSyntax.self)
-    else { return nil }
-
-    // NB: Search for the first argument whose name matches an access level name
-    for labeledExprSyntax in arguments {
-      if let identifier = labeledExprSyntax.expression.as(MemberAccessExprSyntax.self)?.declName,
-        let accessLevel = AccessLevelModifier(rawValue: identifier.baseName.trimmedDescription)
-      {
-        return accessLevel
-      }
+    node.firstArgumentValue(interpretableAs: AccessLevelModifier.self)
+  }
+
+  static func extractInlinabilityAttribute(
+    from node: AttributeSyntax
+  ) -> InlinabilityAttribute? {
+    node.firstArgumentValue(interpretableAs: InlinabilityAttribute.self)
+  }
+
+  static func incompatibilityDiagnosticBetween(
+    accessLevel: AccessLevelModifier,
+    inlinability: InlinabilityAttribute?,
+    in node: AttributeSyntax,
+    typeAccessLevel: AccessLevelModifier
+  ) -> Diagnostic? {
+    guard let inlinability else { return nil }
+    switch (accessLevel, inlinability) {
+    case
+      (.public, .inlinable),
+      (.package, .inlinable),
+      (.package, .usableFromInline),
+      (.internal, .inlinable),
+      (.internal, .usableFromInline):
+      return nil
+    default:
+      // NOTE:
+      // the real issue with (.open, .inlinable) is specific
+      // to init: `init` can't be `open`.
+      return Diagnostic(
+        node: node,
+        message: MacroExpansionErrorMessage(
+          """
+          Inlinability '.\(inlinability.rawValue)' is incompatible-with access-level '.\(accessLevel)'!
+          """
+        ),
+        fixIts: node.allInlinabilityFixIts(typeAccessLevel: typeAccessLevel)
+      )
     }
-
-    return nil
   }
-
+  
   static func extractLabeledBoolArgument(
     _ label: String,
     from node: AttributeSyntax

Sources/MemberwiseInitMacros/Macros/Support/DeprecationDiagnostics.swift

@@ -1,6 +1,6 @@
 import SwiftDiagnostics
 import SwiftSyntax
-import SwiftSyntaxMacroExpansion
+import SwiftSyntaxMacros
 
 func deprecationDiagnostics(
   node: AttributeSyntax,