Add test case for https://bugs.swift.org/browse/SR-9868

rdar://problem/47871647

Author: rintaro

test/IDE/complete_override_typealias.swift

@@ -8,8 +8,10 @@ protocol MyProtocol {
   associatedtype Result
   typealias Arg1 = Generic<Self>
   typealias Arg2<X> = Generic<X>
+  typealias Func = () -> Int
   func foo<U>(arg1: Arg1, arg2: Arg2<U>, arg3: Arg2<Int>, arg4: [Arg1], arg5: Arg2<U>? arg6: Generic<Arg2<Generic<Arg2<Int>>>>) -> Result
   func bar() -> Result
+  func baz(arg: @escaping Func)
 }
 
 struct MyStruct1 : MyProtocol {
@@ -29,17 +31,20 @@ struct MyStruct3 : MyProtocol {
   func #^OVERRIDE_3^#
 }
 
-// OVERRIDE_1: Begin completions, 2 items
+// OVERRIDE_1: Begin completions, 3 items
 // OVERRIDE_1-DAG: Decl[InstanceMethod]/Super: foo<U>(arg1: Arg1, arg2: Arg2<U>, arg3: Arg2<Int>, arg4: [Arg1], arg5: Arg2<U>?, arg6: Generic<Arg2<Generic<Arg2<Int>>>>) -> Result {|};
 // OVERRIDE_1-DAG: Decl[InstanceMethod]/Super: bar() -> Result {|};
+// OVERRIDE_1-DAG: Decl[InstanceMethod]/Super: baz(arg: @escaping Func) {|};
 // OVERRIDE_1: End completions
 
-// OVERRIDE_2: Begin completions, 2 items
+// OVERRIDE_2: Begin completions, 3 items
 // OVERRIDE_2-DAG: Decl[InstanceMethod]/Super: foo<U>(arg1: Arg1, arg2: Arg2<U>, arg3: Arg2<Int>, arg4: [Arg1], arg5: Arg2<U>?, arg6: Generic<Arg2<Generic<Arg2<Int>>>>) -> String {|};
 // OVERRIDE_2-DAG: Decl[InstanceMethod]/Super: bar() -> String {|};
+// OVERRIDE_2-DAG: Decl[InstanceMethod]/Super: baz(arg: @escaping Func) {|};
 // OVERRIDE_2: End completions
 
-// OVERRIDE_3-DAG: Begin completions, 1 items
+// OVERRIDE_3-DAG: Begin completions, 2 items
 // OVERRIDE_3-DAG: Decl[InstanceMethod]/Super: foo<U>(arg1: Arg1, arg2: Arg2<U>, arg3: Arg2<Int>, arg4: [Arg1], arg5: Arg2<U>?, arg6: Generic<Arg2<Generic<Arg2<Int>>>>) -> String {|};
+// OVERRIDE_3-DAG: Decl[InstanceMethod]/Super: baz(arg: @escaping Func) {|};
 // OVERRIDE_3-DAG: End completions
 

test/decl/protocol/conforms/fixit_stub_editor.swift

@@ -72,3 +72,12 @@ struct Struct3: PropertyMutabilityProto { // expected-error{{type 'Struct3' does
 class Class4 {}
 extension Class4: PropertyMutabilityProto { // expected-error{{type 'Class4' does not conform to protocol 'PropertyMutabilityProto'}} expected-note{{do you want to add protocol stubs?}} {{44-44=\n    var computed: Int {\n        get {\n            <#code#>\n        \}\n        set {\n            <#code#>\n        \}\n    \}\n\n    var stored: Int {\n        get {\n            <#code#>\n        \}\n        set {\n            <#code#>\n        \}\n    \}\n}}
 }
+
+// https://bugs.swift.org/browse/SR-9868
+protocol FooProto {
+ typealias CompletionType = (Int) -> Void
+ func doSomething(then completion: @escaping CompletionType)
+}
+
+struct FooType : FooProto { // expected-error {{type 'FooType' does not conform to protocol 'FooProto'}} expected-note {{do you want to add protocol stubs?}} {{28-28=\n    func doSomething(then completion: @escaping CompletionType) {\n        <#code#>\n    \}\n}}
+}