'SuspendFunction$n' should not be visible in member scopes (should be unresolved).

'SuspendFunction$n' class descriptors are created on demand by KotlinBuiltIns (and cached).
On serialization, types constructed with 'SuspendFunction$n' are written as 'Function$n' with extra flag (SUSPEND_TYPE).
On deserialization, corresponding 'SuspendFunction$n' classes are used.

idea/idea-analysis/src/org/jetbrains/kotlin/idea/decompiler/stubBuilder/TypeClsStubBuilder.kt

@@ -127,9 +127,8 @@ class TypeClsStubBuilder(private val c: ClsStubBuilderContext) {
         if (!type.hasClassName() && !type.hasTypeAliasName()) return emptySet()
 
         val result = hashSetOf<KtModifierKeywordToken>()
-        val classId = c.nameResolver.getClassId(if (type.hasClassName()) type.className else type.typeAliasName)
 
-        if (classId.asSingleFqName().toUnsafe().getFunctionalClassKind() == FunctionClassDescriptor.Kind.SuspendFunction) {
+        if (Flags.SUSPEND_TYPE.get(type.flags)) {
             result.add(KtTokens.SUSPEND_KEYWORD)
         }
 

idea/testData/decompiler/decompiledText/TypeModifiers.expected.kt

@@ -0,0 +1,15 @@
+// IntelliJ API Decompiler stub source generated from a class file
+// Implementation of methods is not available
+
+package test
+
+public final class TypeModifiers public constructor() {
+    public final val function: () -> kotlin.Unit /* compiled code */
+
+    public final val functionOnSuspendFunction: (suspend () -> kotlin.Unit).() -> kotlin.Unit /* compiled code */
+
+    public final val suspendExtFunction: suspend kotlin.Any.() -> kotlin.Unit /* compiled code */
+
+    public final val suspendFunction: suspend () -> kotlin.Unit /* compiled code */
+}
+

idea/testData/decompiler/decompiledText/TypeModifiers/TypeModifiers.kt

@@ -0,0 +1,11 @@
+package test
+
+class TypeModifiers {
+    val function: () -> Unit = null!!
+
+    val suspendFunction: suspend () -> Unit = null!!
+
+    val suspendExtFunction: suspend Any.() -> Unit = null!!
+
+    val functionOnSuspendFunction: (suspend () -> Unit).() -> Unit = null!!
+}

idea/tests/org/jetbrains/kotlin/idea/decompiler/textBuilder/CommonDecompiledTextFromJsMetadataTestGenerated.java

@@ -150,4 +150,10 @@ public class CommonDecompiledTextFromJsMetadataTestGenerated extends AbstractCom
         doTest(fileName);
     }
 
+    @TestMetadata("TypeModifiers")
+    public void testTypeModifiers() throws Exception {
+        String fileName = KotlinTestUtils.navigationMetadata("idea/testData/decompiler/decompiledText/TypeModifiers/");
+        doTest(fileName);
+    }
+
 }

idea/tests/org/jetbrains/kotlin/idea/decompiler/textBuilder/CommonDecompiledTextTestGenerated.java

@@ -156,4 +156,10 @@ public class CommonDecompiledTextTestGenerated extends AbstractCommonDecompiledT
         doTest(fileName);
     }
 
+    @TestMetadata("TypeModifiers")
+    public void testTypeModifiers() throws Exception {
+        String fileName = KotlinTestUtils.navigationMetadata("idea/testData/decompiler/decompiledText/TypeModifiers/");
+        doTest(fileName);
+    }
+
 }

idea/tests/org/jetbrains/kotlin/idea/stubs/ResolveByStubTestGenerated.java

@@ -3038,6 +3038,12 @@ public class ResolveByStubTestGenerated extends AbstractResolveByStubTest {
             doTest(fileName);
         }
 
+        @TestMetadata("SuspendFunction.kt")
+        public void testSuspendFunction() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/loadJava/compiledKotlin/type/SuspendFunction.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("Unit.kt")
         public void testUnit() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/loadJava/compiledKotlin/type/Unit.kt");