Frontend support for function as expression

compiler/testData/diagnostics/tests/functionAsExpression/WithoutBody.kt

@@ -0,0 +1,12 @@
+// !DIAGNOSTICS: -UNUSED_PARAMETER
+
+annotation class ann
+val bas = <!NON_MEMBER_FUNCTION_NO_BODY!>fun ()<!>
+
+fun bar(a: Any) = <!NON_MEMBER_FUNCTION_NO_BODY!>fun name()<!>
+
+fun outer() {
+    bar(<!NON_MEMBER_FUNCTION_NO_BODY!>fun ()<!>)
+    bar(<!NON_MEMBER_FUNCTION_NO_BODY!>fun name()<!>)
+    bar(<!NON_MEMBER_FUNCTION_NO_BODY!>[ann] fun name()<!>)
+}