From 7458177b5113c8bc6c9889388fffb9e3ce8659bd Mon Sep 17 00:00:00 2001
From: Alexis Schultz <Alex293@users.noreply.github.com>
Date: Wed, 29 Nov 2023 19:00:47 +0100
Subject: [PATCH] Add support for inout parameters to @DependencyEndpointMacro

---
 .../DependencyEndpointMacro.swift             | 10 ++++-
 .../DependencyEndpointMacroTests.swift        | 41 +++++++++++++++++++
 2 files changed, 50 insertions(+), 1 deletion(-)

diff --git a/Sources/DependenciesMacrosPlugin/DependencyEndpointMacro.swift b/Sources/DependenciesMacrosPlugin/DependencyEndpointMacro.swift
index 7eb49add..332d997d 100644
--- a/Sources/DependenciesMacrosPlugin/DependencyEndpointMacro.swift
+++ b/Sources/DependenciesMacrosPlugin/DependencyEndpointMacro.swift
@@ -160,7 +160,15 @@ public enum DependencyEndpointMacro: AccessorMacro, PeerMacro {
         parameters[i].secondName = TokenSyntax(stringLiteral: "p\(offset)")
         parameters[i].colon = parameters[i].colon ?? .colonToken(trailingTrivia: .space)
       }
-      let appliedParameters = (0..<parameters.count).map { "p\($0)" }.joined(separator: ", ")
+      let appliedParameters = parameters
+        .map {
+          guard let typed = $0.type.as(AttributedTypeSyntax.self), typed.specifier?.tokenKind == .keyword(.inout)
+          else { return false }
+          return true
+        }
+        .enumerated()
+        .map { $1 ? "&p\($0)" : "p\($0)" }
+        .joined(separator: ", ")
       decls.append(
         """
         \(raw: attributes.map { "@\($0) " }.joined())\
diff --git a/Tests/DependenciesMacrosPluginTests/DependencyEndpointMacroTests.swift b/Tests/DependenciesMacrosPluginTests/DependencyEndpointMacroTests.swift
index ef7bb6e7..5333027f 100644
--- a/Tests/DependenciesMacrosPluginTests/DependencyEndpointMacroTests.swift
+++ b/Tests/DependenciesMacrosPluginTests/DependencyEndpointMacroTests.swift
@@ -755,4 +755,45 @@ final class DependencyEndpointMacroTests: BaseTestCase {
       """
     }
   }
+
+  func testInout() {
+    assertMacro {
+    """
+    struct Blah {
+      @DependencyEndpoint
+      public var doAThing: (_ a: inout Int, _ b: Int, _ c: inout Bool) -> String = { _ in
+        "Hello, world"
+      }
+    }
+    """
+    } expansion: {
+    """
+    struct Blah {
+      public var doAThing: (_ a: inout Int, _ b: Int, _ c: inout Bool) -> String = { _ in
+        "Hello, world"
+      } {
+        @storageRestrictions(initializes: _doAThing)
+        init(initialValue) {
+          _doAThing = initialValue
+        }
+        get {
+          _doAThing
+        }
+        set {
+          _doAThing = newValue
+        }
+      }
+
+      public func doAThing(a p0: inout Int, b p1: Int, c p2: inout Bool) -> String {
+        self.doAThing(&p0, p1, &p2)
+      }
+
+      private var _doAThing: (_ a: inout Int, _ b: Int, _ c: inout Bool) -> String = { _ in
+        XCTestDynamicOverlay.XCTFail("Unimplemented: 'doAThing'")
+        return "Hello, world"
+        }
+    }
+    """
+    }
+  }
 }