diff --git a/plugins/fir-plugin-prototype/plugin-annotations/src/org/jetbrains/kotlin/fir/plugin/annotations.kt b/plugins/fir-plugin-prototype/plugin-annotations/src/org/jetbrains/kotlin/fir/plugin/annotations.kt
index f1c117494b5..d7106fb2a31 100644
--- a/plugins/fir-plugin-prototype/plugin-annotations/src/org/jetbrains/kotlin/fir/plugin/annotations.kt
+++ b/plugins/fir-plugin-prototype/plugin-annotations/src/org/jetbrains/kotlin/fir/plugin/annotations.kt
@@ -33,3 +33,7 @@ enum class Visibility {
 annotation class SupertypeWithTypeArgument(val kClass: KClass<*>)
 
 annotation class MetaSupertype
+
+@Target(AnnotationTarget.FUNCTION, AnnotationTarget.TYPE, AnnotationTarget.EXPRESSION)
+@Retention(AnnotationRetention.SOURCE)
+annotation class MyComposable
diff --git a/plugins/fir-plugin-prototype/src/org/jetbrains/kotlin/fir/plugin/FirPluginPrototypeExtensionRegistrar.kt b/plugins/fir-plugin-prototype/src/org/jetbrains/kotlin/fir/plugin/FirPluginPrototypeExtensionRegistrar.kt
index 7ac71ce36be..e84c83644de 100644
--- a/plugins/fir-plugin-prototype/src/org/jetbrains/kotlin/fir/plugin/FirPluginPrototypeExtensionRegistrar.kt
+++ b/plugins/fir-plugin-prototype/src/org/jetbrains/kotlin/fir/plugin/FirPluginPrototypeExtensionRegistrar.kt
@@ -12,6 +12,7 @@ import org.jetbrains.kotlin.fir.extensions.FirExtensionRegistrar
 import org.jetbrains.kotlin.fir.extensions.FirExtensionRegistrarAdapter
 import org.jetbrains.kotlin.fir.plugin.generators.*
 import org.jetbrains.kotlin.fir.plugin.types.FirNumberSignAttributeExtension
+import org.jetbrains.kotlin.fir.plugin.types.ComposableLikeFunctionalTypeKindExtension
 import org.jetbrains.kotlin.ir.plugin.GeneratedDeclarationsIrBodyFiller
 
 class FirPluginPrototypeExtensionRegistrar : FirExtensionRegistrar() {
@@ -23,6 +24,7 @@ class FirPluginPrototypeExtensionRegistrar : FirExtensionRegistrar() {
         +::PluginAdditionalCheckers
         +::FirNumberSignAttributeExtension
         +::AlgebraReceiverInjector
+        +::ComposableLikeFunctionalTypeKindExtension
 
         // Declaration generators
         +::TopLevelDeclarationsGenerator
diff --git a/plugins/fir-plugin-prototype/src/org/jetbrains/kotlin/fir/plugin/types/ComposableLikeFunctionalTypeKindExtension.kt b/plugins/fir-plugin-prototype/src/org/jetbrains/kotlin/fir/plugin/types/ComposableLikeFunctionalTypeKindExtension.kt
new file mode 100644
index 00000000000..6db97eac5e5
--- /dev/null
+++ b/plugins/fir-plugin-prototype/src/org/jetbrains/kotlin/fir/plugin/types/ComposableLikeFunctionalTypeKindExtension.kt
@@ -0,0 +1,44 @@
+/*
+ * Copyright 2010-2023 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.fir.plugin.types
+
+import org.jetbrains.kotlin.builtins.functions.FunctionalTypeKind
+import org.jetbrains.kotlin.fir.FirSession
+import org.jetbrains.kotlin.fir.extensions.FirFunctionalTypeKindExtension
+import org.jetbrains.kotlin.fir.plugin.fqn
+import org.jetbrains.kotlin.name.ClassId
+import org.jetbrains.kotlin.name.FqName
+import org.jetbrains.kotlin.name.Name
+
+class ComposableLikeFunctionalTypeKindExtension(session: FirSession) : FirFunctionalTypeKindExtension(session) {
+    override fun FunctionalTypeKindRegistrar.registerKinds() {
+        registerKind(ComposableFunction, KComposableFunction)
+    }
+}
+
+private val COMPOSABLE_PACKAGE_FQN = FqName.topLevel(Name.identifier("some"))
+private val MY_COMPOSABLE_ANNOTATION_CLASS_ID = ClassId.topLevel("MyComposable".fqn())
+
+object ComposableFunction : FunctionalTypeKind(
+    COMPOSABLE_PACKAGE_FQN,
+    "MyComposableFunction",
+    MY_COMPOSABLE_ANNOTATION_CLASS_ID,
+    isReflectType = false
+) {
+    override val prefixForTypeRender: String
+        get() = "@MyComposable"
+
+    override fun reflectKind(): FunctionalTypeKind = KComposableFunction
+}
+
+object KComposableFunction : FunctionalTypeKind(
+    COMPOSABLE_PACKAGE_FQN,
+    "KMyComposableFunction",
+    MY_COMPOSABLE_ANNOTATION_CLASS_ID,
+    isReflectType = true
+) {
+    override fun nonReflectKind(): FunctionalTypeKind = ComposableFunction
+}
diff --git a/plugins/fir-plugin-prototype/testData/diagnostics/functionalTypes/ambigousKinds.fir.txt b/plugins/fir-plugin-prototype/testData/diagnostics/functionalTypes/ambigousKinds.fir.txt
new file mode 100644
index 00000000000..b51df49723e
--- /dev/null
+++ b/plugins/fir-plugin-prototype/testData/diagnostics/functionalTypes/ambigousKinds.fir.txt
@@ -0,0 +1,3 @@
+FILE: ambigousKinds.kt
+    public final fun incorrect(block: <ERROR TYPE REF: There are multiple functional kinds for functional type ref>): R|kotlin/Unit| {
+    }
diff --git a/plugins/fir-plugin-prototype/testData/diagnostics/functionalTypes/ambigousKinds.kt b/plugins/fir-plugin-prototype/testData/diagnostics/functionalTypes/ambigousKinds.kt
new file mode 100644
index 00000000000..a24a1a87c8f
--- /dev/null
+++ b/plugins/fir-plugin-prototype/testData/diagnostics/functionalTypes/ambigousKinds.kt
@@ -0,0 +1,3 @@
+import org.jetbrains.kotlin.fir.plugin.MyComposable
+
+fun incorrect(block: <!AMBIGUOUS_FUNCTIONAL_TYPE_KIND!>@MyComposable suspend () -> Unit<!>) {}
diff --git a/plugins/fir-plugin-prototype/testData/diagnostics/functionalTypes/simple.fir.txt b/plugins/fir-plugin-prototype/testData/diagnostics/functionalTypes/simple.fir.txt
new file mode 100644
index 00000000000..055f6fbc3a3
--- /dev/null
+++ b/plugins/fir-plugin-prototype/testData/diagnostics/functionalTypes/simple.fir.txt
@@ -0,0 +1,55 @@
+FILE: simple.kt
+    public final fun runUsual(block: R|() -> kotlin/Unit|): R|kotlin/Unit| {
+    }
+    public final fun runComposable(block: R|@R|org/jetbrains/kotlin/fir/plugin/MyComposable|()  some/MyComposableFunction0<kotlin/Unit>|): R|kotlin/Unit| {
+    }
+    public final fun test_1(): R|kotlin/Unit| {
+        lval l0: R|() -> kotlin/Unit| = fun <anonymous>(): R|kotlin/Unit| <inline=Unknown>  {
+            ^ Unit
+        }
+
+        lval l1: R|some/MyComposableFunction0<kotlin/Unit>| = fun <anonymous>(): R|kotlin/Unit| <inline=Unknown>  {
+            ^ Unit
+        }
+
+        lval l2: R|@R|org/jetbrains/kotlin/fir/plugin/MyComposable|()  some/MyComposableFunction0<kotlin/Unit>| = fun <anonymous>(): R|kotlin/Unit| <inline=Unknown>  {
+            ^ Unit
+        }
+
+        lval l3: R|some/MyComposableFunction0<kotlin/Unit>| = @R|org/jetbrains/kotlin/fir/plugin/MyComposable|() fun <anonymous>(): R|kotlin/Unit| <inline=Unknown>  {
+            ^ Unit
+        }
+
+        R|/runUsual|(R|<local>/l0|)
+        R|/runUsual<Inapplicable(INAPPLICABLE): /runUsual>#|(R|<local>/l1|)
+        R|/runUsual<Inapplicable(INAPPLICABLE): /runUsual>#|(R|<local>/l2|)
+        R|/runUsual<Inapplicable(INAPPLICABLE): /runUsual>#|(R|<local>/l3|)
+        R|/runUsual|(<L> = runUsual@fun <anonymous>(): R|kotlin/Unit| <inline=NoInline>  {
+            ^@runUsual Unit
+        }
+        )
+        R|/runUsual<Inapplicable(INAPPLICABLE): /runUsual>#|(<L> = @R|org/jetbrains/kotlin/fir/plugin/MyComposable|() runUsual@fun <anonymous>(): R|kotlin/Unit| <inline=Unknown>  {
+            ^@runUsual Unit
+        }
+        )
+        R|/runComposable|(R|<local>/l0|)
+        R|/runComposable|(R|<local>/l1|)
+        R|/runComposable|(R|<local>/l2|)
+        R|/runComposable|(R|<local>/l3|)
+        R|/runComposable|(<L> = runComposable@fun <anonymous>(): R|kotlin/Unit| <inline=NoInline>  {
+            ^@runComposable Unit
+        }
+        )
+        R|/runComposable|(<L> = @R|org/jetbrains/kotlin/fir/plugin/MyComposable|() runComposable@fun <anonymous>(): R|kotlin/Unit| <inline=NoInline>  {
+            ^@runComposable Unit
+        }
+        )
+    }
+    public final fun runComposable2(block: R|some/MyComposableFunction1<kotlin/String, kotlin/Int>|): R|kotlin/Unit| {
+    }
+    public final fun test_2(): R|kotlin/Unit| {
+        R|/runComposable2|(<L> = runComposable2@fun <anonymous>(it: R|kotlin/String|): R|kotlin/Int| <inline=NoInline>  {
+            ^ R|<local>/it|.R|kotlin/String.length|
+        }
+        )
+    }
diff --git a/plugins/fir-plugin-prototype/testData/diagnostics/functionalTypes/simple.kt b/plugins/fir-plugin-prototype/testData/diagnostics/functionalTypes/simple.kt
new file mode 100644
index 00000000000..aa54d8501c4
--- /dev/null
+++ b/plugins/fir-plugin-prototype/testData/diagnostics/functionalTypes/simple.kt
@@ -0,0 +1,31 @@
+import org.jetbrains.kotlin.fir.plugin.MyComposable
+
+fun runUsual(block: () -> Unit) {}
+fun runComposable(block: @MyComposable () -> Unit) {}
+
+fun test_1() {
+    val l0 = {}
+    val l1: some.MyComposableFunction0<Unit> = {}
+    val l2: @MyComposable (() -> Unit) = {}
+    val l3 = @MyComposable {}
+
+    runUsual(l0) // ok
+    runUsual(<!ARGUMENT_TYPE_MISMATCH!>l1<!>) // error
+    runUsual(<!ARGUMENT_TYPE_MISMATCH!>l2<!>) // error
+    runUsual(<!ARGUMENT_TYPE_MISMATCH!>l3<!>) // error
+    runUsual {} // ok
+    runUsual @MyComposable <!ARGUMENT_TYPE_MISMATCH!>{}<!> // error
+
+    runComposable(l0) // ok
+    runComposable(l1) // ok
+    runComposable(l2) // ok
+    runComposable(l3) // ok
+    runComposable {} // ok
+    runComposable @MyComposable {} // ok
+}
+
+fun runComposable2(block: some.MyComposableFunction1<String, Int>) {}
+
+fun test_2() {
+    runComposable2 { it.length }
+}
diff --git a/plugins/fir-plugin-prototype/tests-gen/org/jetbrains/kotlin/fir/plugin/runners/FirPluginDiagnosticTestGenerated.java b/plugins/fir-plugin-prototype/tests-gen/org/jetbrains/kotlin/fir/plugin/runners/FirPluginDiagnosticTestGenerated.java
index 31337e6f15e..96ed142b53b 100644
--- a/plugins/fir-plugin-prototype/tests-gen/org/jetbrains/kotlin/fir/plugin/runners/FirPluginDiagnosticTestGenerated.java
+++ b/plugins/fir-plugin-prototype/tests-gen/org/jetbrains/kotlin/fir/plugin/runners/FirPluginDiagnosticTestGenerated.java
@@ -46,6 +46,28 @@ public class FirPluginDiagnosticTestGenerated extends AbstractFirPluginDiagnosti
         }
     }
 
+    @Nested
+    @TestMetadata("plugins/fir-plugin-prototype/testData/diagnostics/functionalTypes")
+    @TestDataPath("$PROJECT_ROOT")
+    public class FunctionalTypes {
+        @Test
+        public void testAllFilesPresentInFunctionalTypes() throws Exception {
+            KtTestUtil.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("plugins/fir-plugin-prototype/testData/diagnostics/functionalTypes"), Pattern.compile("^(.+)\\.kt$"), null, true);
+        }
+
+        @Test
+        @TestMetadata("ambigousKinds.kt")
+        public void testAmbigousKinds() throws Exception {
+            runTest("plugins/fir-plugin-prototype/testData/diagnostics/functionalTypes/ambigousKinds.kt");
+        }
+
+        @Test
+        @TestMetadata("simple.kt")
+        public void testSimple() throws Exception {
+            runTest("plugins/fir-plugin-prototype/testData/diagnostics/functionalTypes/simple.kt");
+        }
+    }
+
     @Nested
     @TestMetadata("plugins/fir-plugin-prototype/testData/diagnostics/memberGen")
     @TestDataPath("$PROJECT_ROOT")