'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)
         }