From 7787638737690ce3a7e61db6e2550d23b971aec1 Mon Sep 17 00:00:00 2001
From: pyos <pyos@google.com>
Date: Mon, 31 Oct 2022 12:53:47 +0100
Subject: [PATCH] FIR: fix substitution of anonymous type's supertype again

^KT-51418 Fixed
---
 .../jetbrains/kotlin/fir/types/TypeUtils.kt   | 42 ++-----------------
 ...ForReturnTypeOfSingleExpressionFunction.kt |  5 +++
 ...orReturnTypeOfSingleExpressionFunction.txt |  9 ++++
 3 files changed, 17 insertions(+), 39 deletions(-)

diff --git a/compiler/fir/providers/src/org/jetbrains/kotlin/fir/types/TypeUtils.kt b/compiler/fir/providers/src/org/jetbrains/kotlin/fir/types/TypeUtils.kt
index c3bb842df95..73409bd409c 100644
--- a/compiler/fir/providers/src/org/jetbrains/kotlin/fir/types/TypeUtils.kt
+++ b/compiler/fir/providers/src/org/jetbrains/kotlin/fir/types/TypeUtils.kt
@@ -416,46 +416,10 @@ private fun ConeKotlinType.approximateToOnlySupertype(session: FirSession): Cone
         return null
     }
     val result = superType.type.withNullability(nullability, session.typeContext)
-    if (typeArguments.isNotEmpty()) {
-        val substitution = mutableMapOf<FirTypeParameterSymbol, ConeKotlinType>()
-
-        var index = 0
-        fun addSubstitution(projection: ConeTypeProjection): Boolean {
-            when (projection) {
-                is ConeTypeParameterType -> {
-                    val symbol = projection.lookupTag.typeParameterSymbol
-                    if (!substitution.containsKey(symbol)) {
-                        substitution[symbol] = typeArguments[index].type!!
-                        index++
-                    }
-                }
-
-                is ConeErrorType -> {
-                    return false
-                }
-
-                is ConeClassLikeType -> {
-                    for (typeArgument in projection.typeArguments) {
-                        if (!addSubstitution(typeArgument)) {
-                            return false
-                        }
-                    }
-                }
-
-                is ConeKotlinTypeProjection -> {
-                    if (!addSubstitution(projection.type)) {
-                        return false
-                    }
-                }
-
-                is ConeStarProjection -> {
-                    index++
-                }
-            }
-            return true
+    if (typeArguments.isNotEmpty() && typeArguments.size == firClass.typeParameters.size) {
+        val substitution = firClass.typeParameters.zip(typeArguments).associate { (parameter, argument) ->
+            parameter.symbol to argument.type!!
         }
-
-        addSubstitution(result)
         return ConeSubstitutorByMap(substitution, session).substituteOrSelf(result)
     }
     return result
diff --git a/compiler/testData/diagnostics/tests/inference/substitutions/hideLocalTypeForReturnTypeOfSingleExpressionFunction.kt b/compiler/testData/diagnostics/tests/inference/substitutions/hideLocalTypeForReturnTypeOfSingleExpressionFunction.kt
index cda7d5ab8f7..3d0ca19789a 100644
--- a/compiler/testData/diagnostics/tests/inference/substitutions/hideLocalTypeForReturnTypeOfSingleExpressionFunction.kt
+++ b/compiler/testData/diagnostics/tests/inference/substitutions/hideLocalTypeForReturnTypeOfSingleExpressionFunction.kt
@@ -31,13 +31,18 @@ class FieldTest {
 
 interface I<T>
 interface I2<A, B>
+interface I3<T> { fun foo(x: T) }
 
 private fun <V> f(x: V) = object : I<I<V>> {}
 private fun <V> f1(x: V) = object : I<I<in V>> {}
 private fun <V> f2(x: V) = object : I2<V, V> {}
 private fun <V, W> f3(x: V, y: W) = object : I<I2<*, W>> {}
+private fun <V, W> I3<V>.f4(block: (W) -> V) = object : I3<W> {
+    override fun foo(x: W) = this@f4.foo(block(x))
+}
 
 fun g() = f("f")
 fun g1() = f("f1")
 fun g2() = f2("f2")
 fun g3() = f3("f3", 3)
+fun <V, W> I3<V>.g4(block: (W) -> V) = f4(block)
diff --git a/compiler/testData/diagnostics/tests/inference/substitutions/hideLocalTypeForReturnTypeOfSingleExpressionFunction.txt b/compiler/testData/diagnostics/tests/inference/substitutions/hideLocalTypeForReturnTypeOfSingleExpressionFunction.txt
index e928a799b63..643efd3eb5a 100644
--- a/compiler/testData/diagnostics/tests/inference/substitutions/hideLocalTypeForReturnTypeOfSingleExpressionFunction.txt
+++ b/compiler/testData/diagnostics/tests/inference/substitutions/hideLocalTypeForReturnTypeOfSingleExpressionFunction.txt
@@ -12,6 +12,8 @@ public fun g2(): I2<kotlin.String, kotlin.String>
 public fun g3(): I<I2<*, kotlin.Int>>
 public fun main(): kotlin.Unit
 private fun </*0*/ T> test(/*0*/ t: T): test.`<no name provided>`<T>
+private fun </*0*/ V, /*1*/ W> I3<V>.f4(/*0*/ block: (W) -> V): f4.`<no name provided>`<V, W>
+public fun </*0*/ V, /*1*/ W> I3<V>.g4(/*0*/ block: (W) -> V): I3<W>
 
 public abstract class A</*0*/ T> {
     public constructor A</*0*/ T>()
@@ -43,3 +45,10 @@ public interface I2</*0*/ A, /*1*/ B> {
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 }
 
+public interface I3</*0*/ T> {
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public abstract fun foo(/*0*/ x: T): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+