diff --git a/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/Candidate.kt b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/Candidate.kt
index 1ebc1be02cd..f970ea5a745 100644
--- a/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/Candidate.kt
+++ b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/Candidate.kt
@@ -60,6 +60,9 @@ class Candidate(
     override val errors: List<ConstraintSystemError>
         get() = system.errors
 
+    /**
+     * Substitutor from declared type parameters to type variables created for that candidate
+     */
     lateinit var substitutor: ConeSubstitutor
     lateinit var freshVariables: List<ConeTypeVariable>
     var resultingTypeForCallableReference: ConeKotlinType? = null