[CSApply] Don't diagnose a 'static let none' as ambiguous none unless its type matches the enum

Author: theblixguy

lib/Sema/CSApply.cpp

@@ -2487,7 +2487,14 @@ namespace {
             if (member->isInstanceMember()) {
               return;
             }
-            
+
+            // If we have something like 'static let none = 1', then ignore.
+            if (auto VD = dyn_cast<VarDecl>(member)) {
+              if (!VD->getInterfaceType()->isEqual(
+                      baseTyNominalDecl->getDeclaredInterfaceType()))
+                return;
+            }
+
             // Return if the member is an enum case w/ assoc values, as we only
             // care (for now) about cases with no assoc values (like none)
             if (auto EED = dyn_cast<EnumElementDecl>(member)) {

test/decl/enum/enumtest.swift

@@ -441,4 +441,21 @@ class C {}
 protocol P {}
 
 enum E : C & P {}
-// expected-error@-1 {{inheritance from class-constrained protocol composition type 'C & P'}}
+// expected-error@-1 {{inheritance from class-constrained protocol composition type 'C & P'}}
+
+// SR-11522
+
+enum EnumWithStaticNone1 {
+  case a
+  static let none = 1
+}
+
+enum EnumWithStaticNone2 {
+  case a
+  static let none = EnumWithStaticNone2.a
+}
+
+let _: EnumWithStaticNone1? = .none // Okay
+let _: EnumWithStaticNone2? = .none // expected-warning {{assuming you mean 'Optional<EnumWithStaticNone2>.none'; did you mean 'EnumWithStaticNone2.none' instead?}}
+// expected-note@-1 {{explicitly specify 'Optional' to silence this warning}}{{31-31=Optional}}
+// expected-note@-2 {{use 'EnumWithStaticNone2.none' instead}}{{31-31=EnumWithStaticNone2}}