FIR IDE: add APIs about FunctionClassKind

analysis/analysis-api-fe10/src/org/jetbrains/kotlin/analysis/api/descriptors/components/KtFe10TypeInfoProvider.kt

@@ -11,6 +11,8 @@ import org.jetbrains.kotlin.analysis.api.descriptors.types.base.KtFe10Type
 import org.jetbrains.kotlin.analysis.api.tokens.ValidityToken
 import org.jetbrains.kotlin.analysis.api.types.KtType
 import org.jetbrains.kotlin.analysis.api.withValidityAssertion
+import org.jetbrains.kotlin.builtins.functions.FunctionClassKind
+import org.jetbrains.kotlin.builtins.getFunctionalClassKind
 import org.jetbrains.kotlin.load.java.sam.JavaSingleAbstractMethodUtils
 import org.jetbrains.kotlin.types.TypeUtils
 
@@ -23,8 +25,13 @@ internal class KtFe10TypeInfoProvider(override val analysisSession: KtFe10Analys
         return JavaSingleAbstractMethodUtils.isSamType(type.type)
     }
 
+    override fun getFunctionClassKind(type: KtType): FunctionClassKind? {
+        require(type is KtFe10Type)
+        return type.type.constructor.declarationDescriptor?.getFunctionalClassKind()
+    }
+
     override fun canBeNull(type: KtType): Boolean = withValidityAssertion {
         require(type is KtFe10Type)
         return TypeUtils.isNullableType(type.type)
     }
-}
+}

analysis/analysis-api-fe10/tests/org/jetbrains/kotlin/analysis/api/descriptors/test/components/AbstractKtFe10FunctionClassKindTest.kt

@@ -0,0 +1,11 @@
+/*
+ * Copyright 2010-2021 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.analysis.api.descriptors.test.components
+
+import org.jetbrains.kotlin.analysis.api.descriptors.test.KtFe10FrontendApiTestConfiguratorService
+import org.jetbrains.kotlin.analysis.api.impl.base.test.components.AbstractFunctionClassKindTest
+
+abstract class AbstractKtFe10FunctionClassKindTest : AbstractFunctionClassKindTest(KtFe10FrontendApiTestConfiguratorService)