Replace SelfType with family of RecursiveTypes

3 files changed, 50 insertions, 17 deletions

diff --git a/core/src/main/kotlin/links/DRI.kt b/core/src/main/kotlin/links/DRI.kt
index e73c2faa..8dfac80c 100644
--- a/core/src/main/kotlin/links/DRI.kt
+++ b/core/src/main/kotlin/links/DRI.kt
@@ -68,8 +68,8 @@ data class TypeConstructor(
             (if (params.isNotEmpty()) "[${params.joinToString(",")}]" else "")
 }
 
-object SelfType : TypeReference() {
-    override fun toString() = "^"
+data class RecursiveType(val rank: Int): TypeReference() {
+    override fun toString() = "^".repeat(rank + 1)
 }
 
 data class Nullable(val wrapped: TypeReference) : TypeReference() {
diff --git a/kotlin-analysis/src/main/kotlin/org/jetbrains/dokka/analysis/TypeReferenceFactory.kt b/kotlin-analysis/src/main/kotlin/org/jetbrains/dokka/analysis/TypeReferenceFactory.kt
index e07672d4..aae1f189 100644
--- a/kotlin-analysis/src/main/kotlin/org/jetbrains/dokka/analysis/TypeReferenceFactory.kt
+++ b/kotlin-analysis/src/main/kotlin/org/jetbrains/dokka/analysis/TypeReferenceFactory.kt
@@ -12,7 +12,7 @@ import org.jetbrains.kotlin.types.TypeProjection
 
 fun TypeReference.Companion.from(d: ReceiverParameterDescriptor): TypeReference? =
     when (d.value) {
-        is ExtensionReceiver -> fromPossiblyNullable(d.type)
+        is ExtensionReceiver -> fromPossiblyNullable(d.type, emptyList())
         else -> run {
             println("Unknown value type for $d")
             null
@@ -20,31 +20,35 @@ fun TypeReference.Companion.from(d: ReceiverParameterDescriptor): TypeReference?
     }
 
 fun TypeReference.Companion.from(d: ValueParameterDescriptor): TypeReference? =
-    fromPossiblyNullable(d.type)
+    fromPossiblyNullable(d.type, emptyList())
 
 fun TypeReference.Companion.from(p: PsiClass) = TypeReference
 
-private fun TypeReference.Companion.fromPossiblyNullable(t: KotlinType, self: KotlinType? = null): TypeReference =
-    from(t, self).let { if (t.isMarkedNullable) Nullable(it) else it }
+private fun TypeReference.Companion.fromPossiblyNullable(t: KotlinType, paramTrace: List<KotlinType>): TypeReference =
+    fromPossiblyRecursive(t, paramTrace).let { if (t.isMarkedNullable) Nullable(it) else it }
 
-private fun TypeReference.Companion.from(t: KotlinType, self: KotlinType? = null): TypeReference =
-    if (self is KotlinType && self.constructor == t.constructor && self.arguments == t.arguments)
-        SelfType
-    else when (val d = t.constructor.declarationDescriptor) {
+private fun TypeReference.Companion.fromPossiblyRecursive(t: KotlinType, paramTrace: List<KotlinType>): TypeReference =
+    paramTrace.indexOfFirst { it.constructor == t.constructor && it.arguments == t.arguments }
+        .takeIf { it >= 0 }
+        ?.let(::RecursiveType)
+        ?: from(t, paramTrace)
+
+private fun TypeReference.Companion.from(t: KotlinType, paramTrace: List<KotlinType>): TypeReference =
+    when (val d = t.constructor.declarationDescriptor) {
         is TypeParameterDescriptor -> TypeParam(
-            d.upperBounds.map { fromPossiblyNullable(it, self ?: t) }
+            d.upperBounds.map { fromPossiblyNullable(it, paramTrace + t) }
         )
         else -> TypeConstructor(
             t.constructorName.orEmpty(),
-            t.arguments.map { fromProjection(it, self) }
+            t.arguments.map { fromProjection(it, paramTrace) }
         )
     }
 
-private fun TypeReference.Companion.fromProjection(t: TypeProjection, r: KotlinType? = null): TypeReference =
+private fun TypeReference.Companion.fromProjection(t: TypeProjection, paramTrace: List<KotlinType>): TypeReference =
     if (t.isStarProjection) {
         StarProjection
     } else {
-        fromPossiblyNullable(t.type, r)
+        fromPossiblyNullable(t.type, paramTrace)
     }
 
 private val KotlinType.constructorName
diff --git a/plugins/base/src/test/kotlin/basic/DRITest.kt b/plugins/base/src/test/kotlin/basic/DRITest.kt
index 7083609a..4e805f48 100644
--- a/plugins/base/src/test/kotlin/basic/DRITest.kt
+++ b/plugins/base/src/test/kotlin/basic/DRITest.kt
@@ -38,7 +38,7 @@ class DRITest : AbstractCoreTest() {
                 val expected = TypeConstructor(
                     "kotlin.Function1", listOf(
                         TypeParam(listOf(Nullable(TypeConstructor("kotlin.Any", emptyList())))),
-                        Nullable(TypeParam(listOf(TypeConstructor("kotlin.Comparable", listOf(SelfType)))))
+                        Nullable(TypeParam(listOf(TypeConstructor("kotlin.Comparable", listOf(RecursiveType(0))))))
                     )
                 )
                 val actual = module.packages.single()
@@ -70,7 +70,7 @@ class DRITest : AbstractCoreTest() {
             configuration
         ) {
             documentablesMergingStage = { module ->
-                val expected = Nullable(TypeParam(listOf(TypeConstructor("kotlin.Comparable", listOf(SelfType)))))
+                val expected = Nullable(TypeParam(listOf(TypeConstructor("kotlin.Comparable", listOf(RecursiveType(0))))))
                 val actual = module.packages.single()
                     .functions.single()
                     .dri.callable?.params?.single()
@@ -100,7 +100,7 @@ class DRITest : AbstractCoreTest() {
             configuration
         ) {
             documentablesMergingStage = { module ->
-                val expected = Nullable(TypeParam(listOf(TypeConstructor("kotlin.Comparable", listOf(SelfType)))))
+                val expected = Nullable(TypeParam(listOf(TypeConstructor("kotlin.Comparable", listOf(RecursiveType(0))))))
                 val actual = module.packages.single()
                     .functions.single()
                     .dri.callable?.receiver
@@ -314,4 +314,33 @@ class DRITest : AbstractCoreTest() {
             }
         }
     }
+
+    @Test
+    fun `deep recursive typebound #1342`() {
+        val configuration = dokkaConfiguration {
+            sourceSets {
+                sourceSet {
+                    sourceRoots = listOf("src/")
+                }
+            }
+        }
+        testInline(
+            """
+            |/src/main/kotlin/Test.kt
+            |package example
+            |
+            | fun <T, S, R> recursiveBound(t: T, s: S, r: R) where T: List<S>, S: List<R>, R: List<S> = Unit
+            |
+        """.trimMargin(),
+            configuration
+        ) {
+            documentablesMergingStage = { module ->
+                val function = module.dfs { it.name == "recursiveBound" }
+                assertEquals(
+                    "example//recursiveBound/#TypeParam(bounds=[kotlin.collections.List[TypeParam(bounds=[kotlin.collections.List[TypeParam(bounds=[kotlin.collections.List[^^]])]])]])#TypeParam(bounds=[kotlin.collections.List[TypeParam(bounds=[kotlin.collections.List[^]])]])#TypeParam(bounds=[kotlin.collections.List[TypeParam(bounds=[kotlin.collections.List[^]])]])/PointingToDeclaration/",
+                    function?.dri?.toString(),
+                )
+            }
+        }
+    }
 }