Merge pull request #181 from softwaremill/fix-i159

Extract focuses from nested `Inlined` trees when determining modification path in Scala 3 macro

Author: adamw

quicklens/src/main/scala-3/com/softwaremill/quicklens/QuicklensMacros.scala

@@ -326,19 +326,24 @@ object QuicklensMacros {
         accumulateToCopy(owner, mod, objTerm, children)
     }
 
-    val focusesTrees: Seq[Tree] = focuses.map(_.asTerm)
-    val paths: Seq[Seq[PathSymbol]] = focusesTrees.zip(focuses).map { (tree, focus) =>
-      tree match
-        /** Single inlined path */
-        case Inlined(_, _, Block(List(DefDef(_, _, _, Some(p))), _)) =>
-          toPath(p, focus)
-        /** One of paths from modifyAll */
-        case Block(List(DefDef(_, _, _, Some(p))), _) =>
-          toPath(p, focus)
-        case _ =>
-          report.errorAndAbort(unsupportedShapeInfo(tree))
+    def extractFocus(tree: Tree): Tree = tree match {
+      /** Single inlined path */
+      case Inlined(_, _, p) =>
+        extractFocus(p)
+      /** One of paths from modifyAll */
+      case Block(List(DefDef(_, _, _, Some(p))), _) =>
+        p
+      case _ =>
+        println(tree)
+        report.errorAndAbort(unsupportedShapeInfo(tree))
     }
 
+    val focusesTrees: Seq[Tree] = focuses.map(_.asTerm)
+    val paths: Seq[Seq[PathSymbol]] =
+      focusesTrees.zip(focuses).map { (tree, focus) =>
+        toPath(extractFocus(tree), focus)
+      }
+
     val pathTree: PathTree =
       paths.foldLeft(PathTree.empty) { (tree, path) => tree <> path }
 

quicklens/src/test/scala-3/com/softwaremill/quicklens/test/CustomModifyProxyTest.scala

@@ -0,0 +1,22 @@
+package com.softwaremill.quicklens.test
+
+import org.scalatest.flatspec.AnyFlatSpec
+import org.scalatest.matchers.should.Matchers
+import com.softwaremill.quicklens.*
+
+class CustomModifyProxyTest extends AnyFlatSpec with Matchers {
+
+  it should "correctly modify a class using a custom modify proxy method" in {
+    case class State(foo: Int)
+
+    inline def set[A](state: State, inline path: State => A, value: A): State = {
+      modify(state)(path).setTo(value)
+    }
+
+    val state = State(100)
+    val res = set(state, _.foo, 200)
+    val expected = State(200)
+    res.shouldBe(expected)
+  }
+
+}