FirNestedClassifierScope: don't give empty map substitutor to a processor

Optimization related to KT-58008 (hides the issue in some cases)

compiler/fir/analysis-tests/testData/resolve/references/referenceToExtension.fir.txt

@@ -16,22 +16,22 @@ FILE: referenceToExtension.kt
                 super<R|kotlin/Any|>()
             }
 
-            public final val memberVal: R|GenericTest.A<T>| = R|SubstitutionOverride</GenericTest.A.A>|<R|T|>()
+            public final val memberVal: R|GenericTest.A<T>| = R|/GenericTest.A.A|<R|T|>()
                 public get(): R|GenericTest.A<T>|
 
             public final fun memberFun(): R|GenericTest.A<T>| {
-                ^memberFun R|SubstitutionOverride</GenericTest.A.A>|<R|T|>()
+                ^memberFun R|/GenericTest.A.A|<R|T|>()
             }
 
         }
 
         public final val <T> R|GenericTest.B<T>|.extensionVal: R|GenericTest.A<T>|
             public get(): R|GenericTest.A<T>| {
-                ^ R|SubstitutionOverride</GenericTest.A.A>|<R|T|>()
+                ^ R|/GenericTest.A.A|<R|T|>()
             }
 
         public final fun <T> R|GenericTest.B<T>|.extensionFun(): R|GenericTest.A<T>| {
-            ^extensionFun R|SubstitutionOverride</GenericTest.A.A>|<R|T|>()
+            ^extensionFun R|/GenericTest.A.A|<R|T|>()
         }
 
         public final fun test_1(): R|kotlin/Unit| {

compiler/fir/providers/src/org/jetbrains/kotlin/fir/scopes/impl/FirNestedClassifierScope.kt

@@ -31,10 +31,15 @@ abstract class FirNestedClassifierScope(val klass: FirClass, val useSiteSession:
         processor: (FirClassifierSymbol<*>, ConeSubstitutor) -> Unit
     ) {
         val matchedClass = getNestedClassSymbol(name) ?: return
-        val substitution = klass.typeParameters.associate {
-            it.symbol to it.toConeType()
+        val substitutor = if (klass.typeParameters.isEmpty()) {
+            ConeSubstitutor.Empty
+        } else {
+            val substitution = klass.typeParameters.associate {
+                it.symbol to it.toConeType()
+            }
+            ConeSubstitutorByMap(substitution, useSiteSession)
         }
-        processor(matchedClass, ConeSubstitutorByMap(substitution, useSiteSession))
+        processor(matchedClass, substitutor)
     }
 
     abstract fun isEmpty(): Boolean

compiler/testData/codegen/box/fir/TypeParameterInNestedClass.kt

@@ -1,7 +1,6 @@
 // WITH_STDLIB
 // WITH_COROUTINES
 // TARGET_BACKEND: JVM_IR
-// IGNORE_BACKEND_K2: JVM_IR
 // ISSUE: KT-58008
 
 import kotlin.coroutines.*

compiler/testData/ir/irText/firProblems/TypeParameterInNestedClass.fir.ir.txt

@@ -0,0 +1,69 @@
+FILE fqName:<root> fileName:/TypeParameterInNestedClass.kt
+  CLASS OBJECT name:Retry modality:FINAL visibility:public superTypes:[kotlin.Any]
+    $this: VALUE_PARAMETER INSTANCE_RECEIVER name:<this> type:<root>.Retry
+    CONSTRUCTOR visibility:private <> () returnType:<root>.Retry [primary]
+      BLOCK_BODY
+        DELEGATING_CONSTRUCTOR_CALL 'public constructor <init> () [primary] declared in kotlin.Any'
+        INSTANCE_INITIALIZER_CALL classDescriptor='CLASS OBJECT name:Retry modality:FINAL visibility:public superTypes:[kotlin.Any]'
+    CLASS CLASS name:Builder modality:FINAL visibility:public superTypes:[kotlin.Any]
+      $this: VALUE_PARAMETER INSTANCE_RECEIVER name:<this> type:<root>.Retry.Builder<B of <root>.Retry.Builder>
+      TYPE_PARAMETER name:B index:0 variance: superTypes:[kotlin.Any?] reified:false
+      CONSTRUCTOR visibility:public <> (action:kotlin.coroutines.SuspendFunction0<B of <root>.Retry.Builder>) returnType:<root>.Retry.Builder<B of <root>.Retry.Builder> [primary]
+        VALUE_PARAMETER name:action index:0 type:kotlin.coroutines.SuspendFunction0<B of <root>.Retry.Builder>
+        BLOCK_BODY
+          DELEGATING_CONSTRUCTOR_CALL 'public constructor <init> () [primary] declared in kotlin.Any'
+          INSTANCE_INITIALIZER_CALL classDescriptor='CLASS CLASS name:Builder modality:FINAL visibility:public superTypes:[kotlin.Any]'
+      PROPERTY name:action visibility:private modality:FINAL [val]
+        FIELD PROPERTY_BACKING_FIELD name:action type:kotlin.coroutines.SuspendFunction0<B of <root>.Retry.Builder> visibility:private [final]
+          EXPRESSION_BODY
+            GET_VAR 'action: kotlin.coroutines.SuspendFunction0<B of <root>.Retry.Builder> declared in <root>.Retry.Builder.<init>' type=kotlin.coroutines.SuspendFunction0<B of <root>.Retry.Builder> origin=INITIALIZE_PROPERTY_FROM_PARAMETER
+        FUN DEFAULT_PROPERTY_ACCESSOR name:<get-action> visibility:private modality:FINAL <> ($this:<root>.Retry.Builder<B of <root>.Retry.Builder>) returnType:kotlin.coroutines.SuspendFunction0<B of <root>.Retry.Builder>
+          correspondingProperty: PROPERTY name:action visibility:private modality:FINAL [val]
+          $this: VALUE_PARAMETER name:<this> type:<root>.Retry.Builder<B of <root>.Retry.Builder>
+          BLOCK_BODY
+            RETURN type=kotlin.Nothing from='private final fun <get-action> (): kotlin.coroutines.SuspendFunction0<B of <root>.Retry.Builder> declared in <root>.Retry.Builder'
+              GET_FIELD 'FIELD PROPERTY_BACKING_FIELD name:action type:kotlin.coroutines.SuspendFunction0<B of <root>.Retry.Builder> visibility:private [final]' type=kotlin.coroutines.SuspendFunction0<B of <root>.Retry.Builder> origin=null
+                receiver: GET_VAR '<this>: <root>.Retry.Builder<B of <root>.Retry.Builder> declared in <root>.Retry.Builder.<get-action>' type=<root>.Retry.Builder<B of <root>.Retry.Builder> origin=null
+      FUN FAKE_OVERRIDE name:equals visibility:public modality:OPEN <> ($this:kotlin.Any, other:kotlin.Any?) returnType:kotlin.Boolean [fake_override,operator]
+        overridden:
+          public open fun equals (other: kotlin.Any?): kotlin.Boolean [operator] declared in kotlin.Any
+        $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+        VALUE_PARAMETER name:other index:0 type:kotlin.Any?
+      FUN FAKE_OVERRIDE name:hashCode visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.Int [fake_override]
+        overridden:
+          public open fun hashCode (): kotlin.Int declared in kotlin.Any
+        $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+      FUN FAKE_OVERRIDE name:toString visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.String [fake_override]
+        overridden:
+          public open fun toString (): kotlin.String declared in kotlin.Any
+        $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+    FUN name:withExponentialBackoff visibility:public modality:FINAL <W> ($this:<root>.Retry, action:kotlin.Function0<W of <root>.Retry.withExponentialBackoff>) returnType:<root>.Retry.Builder<W of <root>.Retry.withExponentialBackoff>
+      TYPE_PARAMETER name:W index:0 variance: superTypes:[kotlin.Any?] reified:false
+      $this: VALUE_PARAMETER name:<this> type:<root>.Retry
+      VALUE_PARAMETER name:action index:0 type:kotlin.Function0<W of <root>.Retry.withExponentialBackoff>
+      BLOCK_BODY
+        RETURN type=kotlin.Nothing from='public final fun withExponentialBackoff <W> (action: kotlin.Function0<W of <root>.Retry.withExponentialBackoff>): <root>.Retry.Builder<W of <root>.Retry.withExponentialBackoff> declared in <root>.Retry'
+          CONSTRUCTOR_CALL 'public constructor <init> (action: kotlin.coroutines.SuspendFunction0<B of <root>.Retry.Builder>) [primary] declared in <root>.Retry.Builder' type=<root>.Retry.Builder<W of <root>.Retry.withExponentialBackoff> origin=null
+            <class: B>: W of <root>.Retry.withExponentialBackoff
+            action: BLOCK type=kotlin.coroutines.SuspendFunction0<B of <root>.Retry.Builder> origin=SUSPEND_CONVERSION
+              FUN ADAPTER_FOR_SUSPEND_CONVERSION name:suspendConversion visibility:local modality:FINAL <> ($receiver:kotlin.Function0<W of <root>.Retry.withExponentialBackoff>) returnType:B of <root>.Retry.Builder [suspend]
+                $receiver: VALUE_PARAMETER ADAPTER_PARAMETER_FOR_SUSPEND_CONVERSION name:callee type:kotlin.Function0<W of <root>.Retry.withExponentialBackoff>
+                BLOCK_BODY
+                  RETURN type=kotlin.Nothing from='local final fun suspendConversion (): B of <root>.Retry.Builder [suspend] declared in <root>.Retry.withExponentialBackoff'
+                    CALL 'public abstract fun invoke (): R of kotlin.Function0 [operator] declared in kotlin.Function0' type=B of <root>.Retry.Builder origin=null
+                      $this: GET_VAR 'callee: kotlin.Function0<W of <root>.Retry.withExponentialBackoff> declared in <root>.Retry.withExponentialBackoff.suspendConversion' type=kotlin.Function0<W of <root>.Retry.withExponentialBackoff> origin=null
+              FUNCTION_REFERENCE 'local final fun suspendConversion (): B of <root>.Retry.Builder [suspend] declared in <root>.Retry.withExponentialBackoff' type=kotlin.coroutines.SuspendFunction0<B of <root>.Retry.Builder> origin=SUSPEND_CONVERSION reflectionTarget=null
+                $receiver: GET_VAR 'action: kotlin.Function0<W of <root>.Retry.withExponentialBackoff> declared in <root>.Retry.withExponentialBackoff' type=kotlin.Function0<W of <root>.Retry.withExponentialBackoff> origin=null
+    FUN FAKE_OVERRIDE name:equals visibility:public modality:OPEN <> ($this:kotlin.Any, other:kotlin.Any?) returnType:kotlin.Boolean [fake_override,operator]
+      overridden:
+        public open fun equals (other: kotlin.Any?): kotlin.Boolean [operator] declared in kotlin.Any
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+      VALUE_PARAMETER name:other index:0 type:kotlin.Any?
+    FUN FAKE_OVERRIDE name:hashCode visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.Int [fake_override]
+      overridden:
+        public open fun hashCode (): kotlin.Int declared in kotlin.Any
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+    FUN FAKE_OVERRIDE name:toString visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.String [fake_override]
+      overridden:
+        public open fun toString (): kotlin.String declared in kotlin.Any
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any

compiler/testData/ir/irText/firProblems/TypeParameterInNestedClass.fir.kt.txt

@@ -0,0 +1,31 @@
+object Retry {
+  private constructor() /* primary */ {
+    super/*Any*/()
+    /* <init>() */
+
+  }
+
+  class Builder<B : Any?> {
+    constructor(action: SuspendFunction0<B>) /* primary */ {
+      super/*Any*/()
+      /* <init>() */
+
+    }
+
+    private val action: SuspendFunction0<B>
+      field = action
+      private get
+
+  }
+
+  fun <W : Any?> withExponentialBackoff(action: Function0<W>): Builder<W> {
+    return Builder<W>(action = { // BLOCK
+      local suspend fun Function0<W>.suspendConversion(): B {
+        return callee.invoke()
+      }
+
+      action::suspendConversion
+    })
+  }
+
+}