[NI] Support callable references to suspend functions

#KT-30658 Fixed

compiler/resolution/src/org/jetbrains/kotlin/resolve/calls/components/CallableReferenceResolution.kt

@@ -315,7 +315,7 @@ class CallableReferencesCandidateFactory(
 
                 return callComponents.reflectionTypes.getKFunctionType(
                     Annotations.EMPTY, null, argumentsAndReceivers, null,
-                    returnType, descriptor.builtIns, isSuspend = false
+                    returnType, descriptor.builtIns, descriptor.isSuspend
                 ) to defaults
             }
             else -> error("Unsupported descriptor type: $descriptor")
@@ -347,17 +347,22 @@ fun extractInputOutputTypesFromCallableReferenceExpectedType(expectedType: Unwra
     if (expectedType == null) return null
 
     return when {
-        expectedType.isFunctionType ->
+        expectedType.isFunctionType || expectedType.isSuspendFunctionType ->
             extractInputOutputTypesFromFunctionType(expectedType)
 
         ReflectionTypes.isBaseTypeForNumberedReferenceTypes(expectedType) ->
             InputOutputTypes(emptyList(), expectedType.arguments.single().type.unwrap())
 
-        ReflectionTypes.isNumberedKFunctionOrKSuspendFunction(expectedType) -> {
+        ReflectionTypes.isNumberedKFunction(expectedType) -> {
             val functionFromSupertype = expectedType.immediateSupertypes().first { it.isFunctionType }.unwrap()
             extractInputOutputTypesFromFunctionType(functionFromSupertype)
         }
 
+        ReflectionTypes.isNumberedKSuspendFunction(expectedType) -> {
+            val kSuspendFunctionType = expectedType.immediateSupertypes().first { it.isSuspendFunctionType }.unwrap()
+            extractInputOutputTypesFromFunctionType(kSuspendFunctionType)
+        }
+
         ReflectionTypes.isNumberedKPropertyOrKMutablePropertyType(expectedType) -> {
             val functionFromSupertype = expectedType.supertypes().first { it.isFunctionType }.unwrap()
             extractInputOutputTypesFromFunctionType(functionFromSupertype)

compiler/testData/diagnostics/testsWithStdLib/coroutines/inference/callableReferenceToASuspendFunction.kt

@@ -0,0 +1,22 @@
+// !LANGUAGE: +NewInference
+// !DIAGNOSTICS: -UNUSED_PARAMETER
+// !USE_EXPERIMENTAL: kotlin.Experimental
+
+import kotlin.reflect.KSuspendFunction0
+import kotlin.reflect.KSuspendFunction1
+import kotlin.reflect.KFunction0
+import kotlin.reflect.KFunction1
+
+fun test0(serialize: KSuspendFunction0<Unit>) {}
+fun test1(serialize: KSuspendFunction1<Int, Unit>) {}
+
+suspend fun foo() {}
+suspend fun bar(x: Int) {}
+
+fun test() {
+    test0(::foo)
+    test1(<!TYPE_MISMATCH!>::foo<!>)
+
+    test0(<!TYPE_MISMATCH!>::bar<!>)
+    test1(::bar)
+}

compiler/testData/diagnostics/testsWithStdLib/coroutines/inference/callableReferenceToASuspendFunction.txt

@@ -0,0 +1,7 @@
+package
+
+public suspend fun bar(/*0*/ x: kotlin.Int): kotlin.Unit
+public suspend fun foo(): kotlin.Unit
+public fun test(): kotlin.Unit
+public fun test0(/*0*/ serialize: kotlin.reflect.KSuspendFunction0<kotlin.Unit>): kotlin.Unit
+public fun test1(/*0*/ serialize: kotlin.reflect.KSuspendFunction1<kotlin.Int, kotlin.Unit>): kotlin.Unit

compiler/tests/org/jetbrains/kotlin/checkers/DiagnosticsTestWithStdLibGenerated.java

@@ -1802,6 +1802,11 @@ public class DiagnosticsTestWithStdLibGenerated extends AbstractDiagnosticsTestW
                 runTest("compiler/testData/diagnostics/testsWithStdLib/coroutines/inference/applyInsideCoroutine.kt");
             }
 
+            @TestMetadata("callableReferenceToASuspendFunction.kt")
+            public void testCallableReferenceToASuspendFunction() throws Exception {
+                runTest("compiler/testData/diagnostics/testsWithStdLib/coroutines/inference/callableReferenceToASuspendFunction.kt");
+            }
+
             @TestMetadata("chainCallWithExtensionExplicitTypes.kt")
             public void testChainCallWithExtensionExplicitTypes() throws Exception {
                 runTest("compiler/testData/diagnostics/testsWithStdLib/coroutines/inference/chainCallWithExtensionExplicitTypes.kt");

compiler/tests/org/jetbrains/kotlin/checkers/javac/DiagnosticsTestWithStdLibUsingJavacGenerated.java

@@ -1802,6 +1802,11 @@ public class DiagnosticsTestWithStdLibUsingJavacGenerated extends AbstractDiagno
                 runTest("compiler/testData/diagnostics/testsWithStdLib/coroutines/inference/applyInsideCoroutine.kt");
             }
 
+            @TestMetadata("callableReferenceToASuspendFunction.kt")
+            public void testCallableReferenceToASuspendFunction() throws Exception {
+                runTest("compiler/testData/diagnostics/testsWithStdLib/coroutines/inference/callableReferenceToASuspendFunction.kt");
+            }
+
             @TestMetadata("chainCallWithExtensionExplicitTypes.kt")
             public void testChainCallWithExtensionExplicitTypes() throws Exception {
                 runTest("compiler/testData/diagnostics/testsWithStdLib/coroutines/inference/chainCallWithExtensionExplicitTypes.kt");

core/descriptors/src/org/jetbrains/kotlin/builtins/ReflectionTypes.kt

@@ -152,11 +152,14 @@ class ReflectionTypes(module: ModuleDescriptor, private val notFoundClasses: Not
         }
 
         fun isNumberedKFunctionOrKSuspendFunction(type: KotlinType): Boolean {
+            return isNumberedKFunction(type) || isNumberedKSuspendFunction(type)
+        }
+
+        fun isNumberedKFunction(type: KotlinType): Boolean {
             val descriptor = type.constructor.declarationDescriptor as? ClassDescriptor ?: return false
             val shortName = descriptor.name.asString()
 
-            return (shortName.length > K_FUNCTION_PREFIX.length && shortName.startsWith(K_FUNCTION_PREFIX) ||
-                    isNumberedKSuspendFunction(type)) &&
+            return (shortName.length > K_FUNCTION_PREFIX.length && shortName.startsWith(K_FUNCTION_PREFIX)) &&
                     DescriptorUtils.getFqName(descriptor).parent().toSafe() == KOTLIN_REFLECT_FQ_NAME
         }