Add test cases for special subscript name

Author: ahoppen

test/SILGen/vtables.swift

@@ -169,3 +169,15 @@ class DerivedWithoutDefaults : BaseWithDefaults {
 
 // CHECK-LABEL: sil_vtable DerivedWithoutDefaults {
 // CHECK:         #BaseWithDefaults.a!1: {{.*}} : _T07vtables22DerivedWithoutDefaultsC1a{{[_0-9a-zA-Z]*}}F
+
+
+
+// Escape identifiers that represent special names
+
+class SubscriptAsFunction {
+  func `subscript`() {}
+}
+
+// CHECK-LABEL: sil_vtable SubscriptAsFunction {
+// CHECK-NOT:     #SubscriptAsFunction.subscript
+// CHECK:         #SubscriptAsFunction.`subscript`!1

test/Sema/subscripting.swift

@@ -0,0 +1,16 @@
+// RUN: %target-run-simple-swift | %FileCheck %s
+
+// Check that subscripts and functions named subscript can exist side-by-side
+struct Foo {
+  subscript() -> String {
+    return "subscript"
+  }
+  
+  func `subscript`() -> String {
+    return "func"
+  }
+}
+
+let f = Foo()
+print(f[]) // CHECK: subscript
+print(f.subscript()) // CHECK: func

test/decl/protocol/conforms/fixit_stub.swift

@@ -145,3 +145,10 @@ protocol ProtocolRequiresInit3 {
 
 struct Adopter14 {} // expected-note{{candidate}}
 extension Adopter14 : ProtocolRequiresInit3 {} //expected-error {{type 'Adopter14' does not conform to protocol 'ProtocolRequiresInit3'}}
+
+protocol ProtocolHasSubscriptFunction {
+  func `subscript`() // expected-note{{protocol requires function 'subscript()' with type '() -> ()'; do you want to add a stub?}} {{74-74=\n    func `subscript`() {\n        <#code#>\n    \}\n}}
+}
+class ProtocolHasSubscriptFunctionAdopter: ProtocolHasSubscriptFunction { // expected-error{{type 'ProtocolHasSubscriptFunctionAdopter' does not conform to protocol 'ProtocolHasSubscriptFunction'}}
+
+}

test/decl/subscript/subscripting.swift

@@ -310,3 +310,12 @@ struct S4 {
     }
   }
 }
+
+// SR-2575
+struct SR2575 {
+  subscript() -> Int {
+    return 1
+  }
+}
+
+SR2575().subscript() // expected-error{{type 'SR2575' has no member 'subscript'}}