Merge pull request #4115 from practicalswift/swiftc-28391-swift-typechecker-validatedecl

[swiftc (44 vs. 5156)] Add crasher in swift::TypeChecker::validateDecl(...)

Author: gribozavr

validation-test/compiler_crashers/28391-swift-typechecker-validatedecl.swift

@@ -0,0 +1,10 @@
+// This source file is part of the Swift.org open source project
+// Copyright (c) 2014 - 2016 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See http://swift.org/LICENSE.txt for license information
+// See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+
+// RUN: not --crash %target-swift-frontend %s -parse
+// REQUIRES: asserts
+protocol c{typealias B)class a{func f(f)typealias f=B