AST: Skip accessors in isDeclVisibleInLookupMode()

They never appear in completion or typo correction results,
so we shouldn't waste time validating them.

Author: slavapestov

lib/AST/LookupVisibleDecls.cpp

@@ -124,6 +124,10 @@ static bool areTypeDeclsVisibleInLookupMode(LookupState LS) {
 static bool isDeclVisibleInLookupMode(ValueDecl *Member, LookupState LS,
                                       const DeclContext *FromContext,
                                       LazyResolver *TypeResolver) {
+  // Accessors are never visible directly in the source language.
+  if (isa<AccessorDecl>(Member))
+    return false;
+
   if (TypeResolver) {
     TypeResolver->resolveDeclSignature(Member);
     TypeResolver->resolveAccessControl(Member);