From 65ff684589cb377a817c90ef9d4299b9afb45182 Mon Sep 17 00:00:00 2001
From: Kirill Rakhman <kirill.rakhman@jetbrains.com>
Date: Thu, 21 Sep 2023 16:29:29 +0200
Subject: [PATCH] [FIR] Don't discriminate generics in conflict resolution for
 callable references

#KT-59430 Fixed
---
 .../fir/resolve/calls/ConeOverloadConflictResolver.kt    | 9 ++++++++-
 .../diagnostics/tests/callableReference/kt49038.fir.kt   | 2 +-
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/ConeOverloadConflictResolver.kt b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/ConeOverloadConflictResolver.kt
index a9c5dc61d56..8360f7ae75d 100644
--- a/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/ConeOverloadConflictResolver.kt
+++ b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/ConeOverloadConflictResolver.kt
@@ -12,6 +12,7 @@ import org.jetbrains.kotlin.fir.declarations.getSingleExpectForActualOrNull
 import org.jetbrains.kotlin.fir.declarations.utils.isActual
 import org.jetbrains.kotlin.fir.declarations.utils.isExpect
 import org.jetbrains.kotlin.fir.declarations.utils.modality
+import org.jetbrains.kotlin.fir.expressions.FirCallableReferenceAccess
 import org.jetbrains.kotlin.fir.resolve.BodyResolveComponents
 import org.jetbrains.kotlin.fir.resolve.inference.ConeTypeParameterBasedTypeVariable
 import org.jetbrains.kotlin.fir.resolve.inference.InferenceComponents
@@ -53,7 +54,13 @@ class ConeOverloadConflictResolver(
     override fun chooseMaximallySpecificCandidates(
         candidates: Set<Candidate>,
         discriminateAbstracts: Boolean,
-    ): Set<Candidate> = chooseMaximallySpecificCandidates(candidates, discriminateAbstracts, discriminateGenerics = true)
+    ): Set<Candidate> = chooseMaximallySpecificCandidates(
+        candidates,
+        discriminateAbstracts,
+        // We don't discriminate against generics for callable references because, other than in regular calls,
+        // there is no syntax for specifying generic type arguments.
+        discriminateGenerics = candidates.first().callInfo.callSite !is FirCallableReferenceAccess
+    )
 
     /**
      * Partial mirror of [org.jetbrains.kotlin.resolve.calls.results.OverloadingConflictResolver.chooseMaximallySpecificCandidates]
diff --git a/compiler/testData/diagnostics/tests/callableReference/kt49038.fir.kt b/compiler/testData/diagnostics/tests/callableReference/kt49038.fir.kt
index 86f7f10ca61..5a13499e5a7 100644
--- a/compiler/testData/diagnostics/tests/callableReference/kt49038.fir.kt
+++ b/compiler/testData/diagnostics/tests/callableReference/kt49038.fir.kt
@@ -8,6 +8,6 @@ class A
 class B
 
 fun box(): String {
-    val ref1 = take(::foo) // error before 1.6.20; ok, resolved to (3) since 1.6.20
+    val ref1 = take(::<!OVERLOAD_RESOLUTION_AMBIGUITY!>foo<!>) // error before 1.6.20; ok, resolved to (3) since 1.6.20
     return "OK"
 }