From 0bfe55cd67f096631cb9adfea4442836825dcd8e Mon Sep 17 00:00:00 2001
From: Alejandro Serrano <trupill@gmail.com>
Date: Fri, 14 Jul 2023 13:04:11 +0200
Subject: [PATCH] Fix problem with optics and <*> generics (#3097)

---
 .../arrow/optics/plugin/internals/processor.kt  |  7 ++++++-
 .../kotlin/arrow/optics/plugin/LensTests.kt     | 17 +++++++++++++++++
 2 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/arrow-libs/optics/arrow-optics-ksp-plugin/src/main/kotlin/arrow/optics/plugin/internals/processor.kt b/arrow-libs/optics/arrow-optics-ksp-plugin/src/main/kotlin/arrow/optics/plugin/internals/processor.kt
index 6725c87842c..5a699b4f383 100644
--- a/arrow-libs/optics/arrow-optics-ksp-plugin/src/main/kotlin/arrow/optics/plugin/internals/processor.kt
+++ b/arrow-libs/optics/arrow-optics-ksp-plugin/src/main/kotlin/arrow/optics/plugin/internals/processor.kt
@@ -10,6 +10,7 @@ import com.google.devtools.ksp.symbol.KSType
 import com.google.devtools.ksp.symbol.KSTypeArgument
 import com.google.devtools.ksp.symbol.KSTypeParameter
 import com.google.devtools.ksp.symbol.Variance.INVARIANT
+import com.google.devtools.ksp.symbol.Variance.STAR
 import java.util.Locale
 
 internal fun adt(c: KSClassDeclaration, logger: KSPLogger): ADT =
@@ -180,7 +181,11 @@ internal fun KSType.qualifiedString(prefix: String = ""): String = when (declara
 
 internal fun KSTypeArgument.qualifiedString(): String = when (val ty = type?.resolve()) {
   null -> toString()
-  else -> ty.qualifiedString(prefix = "${variance.label} ".takeIf { variance != INVARIANT }.orEmpty())
+  else -> when (variance) {
+    STAR -> "*"
+    INVARIANT -> ty.qualifiedString()
+    else -> ty.qualifiedString(prefix = "${variance.label} ")
+  }
 }
 
 internal fun KSClassDeclaration.getConstructorParamNames(): List<String> =
diff --git a/arrow-libs/optics/arrow-optics-ksp-plugin/src/test/kotlin/arrow/optics/plugin/LensTests.kt b/arrow-libs/optics/arrow-optics-ksp-plugin/src/test/kotlin/arrow/optics/plugin/LensTests.kt
index 3bc1e13ee91..4eb45199c16 100755
--- a/arrow-libs/optics/arrow-optics-ksp-plugin/src/test/kotlin/arrow/optics/plugin/LensTests.kt
+++ b/arrow-libs/optics/arrow-optics-ksp-plugin/src/test/kotlin/arrow/optics/plugin/LensTests.kt
@@ -113,4 +113,21 @@ class LensTests {
       |val r = i != null && j != null
       """.evals("r" to true)
   }
+
+  @Test
+  fun `Lenses for STAR arguments`() {
+    """
+      |$`package`
+      |$imports
+      |@optics
+      |data class GenericType<A>(
+      |  val field1: A
+      |) { companion object }
+      |
+      |@optics
+      |data class IsoData(val genericType: GenericType<*>) {
+      |  companion object
+      |}
+      """.compilationSucceeds()
+  }
 }