diff --git a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/FirConflictsHelpers.kt b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/FirConflictsHelpers.kt
index 5ab049ef4a9..9bb087763b3 100644
--- a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/FirConflictsHelpers.kt
+++ b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/FirConflictsHelpers.kt
@@ -63,7 +63,7 @@ private fun FirBasedSymbol<*>.isCollectable(): Boolean {
     return when (this) {
         // - see tests with `fun () {}`.
         // you can't redeclare something that has no name.
-        is FirNamedFunctionSymbol -> source?.kind !is KtFakeSourceElementKind && name != SpecialNames.NO_NAME_PROVIDED
+        is FirNamedFunctionSymbol -> isCollectableAccordingToSource && name != SpecialNames.NO_NAME_PROVIDED
         is FirRegularClassSymbol -> name != SpecialNames.NO_NAME_PROVIDED
         // - see testEnumValuesValueOf.
         // it generates a static function that has
@@ -76,6 +76,9 @@ private fun FirBasedSymbol<*>.isCollectable(): Boolean {
     }
 }
 
+private val FirNamedFunctionSymbol.isCollectableAccordingToSource: Boolean
+    get() = source?.kind !is KtFakeSourceElementKind || source?.kind == KtFakeSourceElementKind.DataClassGeneratedMembers
+
 private val FirBasedSymbol<*>.resolvedStatus
     get() = when (this) {
         is FirCallableSymbol<*> -> resolvedStatus
diff --git a/compiler/testData/diagnostics/tests/annotations/rendering/conflictingOverloads.fir.kt b/compiler/testData/diagnostics/tests/annotations/rendering/conflictingOverloads.fir.kt
index fdd2776bba6..ca520443b2a 100644
--- a/compiler/testData/diagnostics/tests/annotations/rendering/conflictingOverloads.fir.kt
+++ b/compiler/testData/diagnostics/tests/annotations/rendering/conflictingOverloads.fir.kt
@@ -4,7 +4,7 @@
 annotation class An
 
 @An
-data class A(@An val x: @An Int) {
-    @An
-    fun copy(@An x: @An Int) = x
+data class <!CONFLICTING_OVERLOADS("[@An() fun copy(@An() x: @R|An|()  Int): @R|An|()  Int]")!>A(@An val x: @An Int)<!> {
+    <!CONFLICTING_OVERLOADS("[fun copy(@An() x: @R|An|()  Int = ...): A]")!>@An
+    fun copy(@An x: @An Int)<!> = x
 }
\ No newline at end of file
diff --git a/compiler/testData/diagnostics/tests/dataClasses/conflictingCopyOverloads.fir.kt b/compiler/testData/diagnostics/tests/dataClasses/conflictingCopyOverloads.fir.kt
index 6433094e08a..0d0be4598da 100644
--- a/compiler/testData/diagnostics/tests/dataClasses/conflictingCopyOverloads.fir.kt
+++ b/compiler/testData/diagnostics/tests/dataClasses/conflictingCopyOverloads.fir.kt
@@ -1,6 +1,6 @@
 // !DIAGNOSTICS: -UNUSED_PARAMETER
 
-data class A(val x: Int, val y: String) {
+data class <!CONFLICTING_OVERLOADS!>A(val x: Int, val y: String)<!> {
     <!CONFLICTING_OVERLOADS!>fun copy(x: Int, y: String)<!> = x
     <!CONFLICTING_OVERLOADS!>fun copy(x: Int, y: String)<!> = A(x, y)
 }
\ No newline at end of file
diff --git a/compiler/testData/diagnostics/tests/dataClasses/dataClassExplicitlyOverridingCopyNoDefaults.fir.kt b/compiler/testData/diagnostics/tests/dataClasses/dataClassExplicitlyOverridingCopyNoDefaults.fir.kt
index 67177e2ebe9..0ee96f139d9 100644
--- a/compiler/testData/diagnostics/tests/dataClasses/dataClassExplicitlyOverridingCopyNoDefaults.fir.kt
+++ b/compiler/testData/diagnostics/tests/dataClasses/dataClassExplicitlyOverridingCopyNoDefaults.fir.kt
@@ -4,6 +4,6 @@ interface WithCopy<T> {
     fun copy(str: T): WithCopy<T>
 }
 
-<!DATA_CLASS_OVERRIDE_DEFAULT_VALUES!>data<!> class Test(val str: String) : WithCopy<String> {
-    override fun copy(str: String) = Test(str)
+<!DATA_CLASS_OVERRIDE_DEFAULT_VALUES!>data<!> class <!CONFLICTING_OVERLOADS!>Test(val str: String)<!> : WithCopy<String> {
+    <!CONFLICTING_OVERLOADS!>override fun copy(str: String)<!> = Test(str)
 }
diff --git a/compiler/testData/diagnostics/tests/dataClasses/dataClassExplicitlyOverridingCopyWithDefaults.fir.kt b/compiler/testData/diagnostics/tests/dataClasses/dataClassExplicitlyOverridingCopyWithDefaults.fir.kt
index b41114558c9..a0bad25ba65 100644
--- a/compiler/testData/diagnostics/tests/dataClasses/dataClassExplicitlyOverridingCopyWithDefaults.fir.kt
+++ b/compiler/testData/diagnostics/tests/dataClasses/dataClassExplicitlyOverridingCopyWithDefaults.fir.kt
@@ -4,6 +4,6 @@ interface WithCopy<T> {
     fun copy(str: T): WithCopy<T>
 }
 
-<!DATA_CLASS_OVERRIDE_DEFAULT_VALUES!>data<!> class Test(val str: String) : WithCopy<String> {
-    override fun copy(str: String = <!DEFAULT_VALUE_NOT_ALLOWED_IN_OVERRIDE!>this.str<!>) = Test(str)
+<!DATA_CLASS_OVERRIDE_DEFAULT_VALUES!>data<!> class <!CONFLICTING_OVERLOADS!>Test(val str: String)<!> : WithCopy<String> {
+    <!CONFLICTING_OVERLOADS!>override fun copy(str: String = <!DEFAULT_VALUE_NOT_ALLOWED_IN_OVERRIDE!>this.str<!>)<!> = Test(str)
 }