[TypeChecker] Add types nested in protocol to lookup results

Although such functionality is not yet supported we have to
mirror AST lookup and add such members into results, otherwise
there is a risk of inner/outer results mismatch.

Author: xedin

lib/Sema/TypeCheckNameLookup.cpp

@@ -195,6 +195,12 @@ namespace {
           addResult(found);
           return;
         }
+      } else if (isa<NominalTypeDecl>(found)) {
+        // Declaring nested types inside other types is currently
+        // not supported by lookup would still return such members
+        // so we have to account for that here as well.
+        addResult(found);
+        return;
       }
 
       // FIXME: the "isa<ProtocolDecl>()" check will be wrong for

test/decl/nested/protocol.swift

@@ -19,7 +19,7 @@ class OuterGenericClass<T> {
   }
 }
 
-protocol OuterProtocol { // expected-note{{'OuterProtocol' declared here}}
+protocol OuterProtocol {
   associatedtype Hen
   protocol InnerProtocol { // expected-error{{protocol 'InnerProtocol' cannot be nested inside another declaration}}
     associatedtype Rooster
@@ -32,7 +32,7 @@ struct ConformsToOuterProtocol : OuterProtocol {
   typealias Hen = Int
 
   func f() { let _ = InnerProtocol.self }
-  // expected-error@-1 {{use of unresolved identifier 'InnerProtocol'}}
+  // expected-error@-1 {{protocol 'InnerProtocol' can only be used as a generic constraint because it has Self or associated type requirements}}
 }
 
 protocol Racoon {