Merge pull request #3997 from practicalswift/swiftc-28383-swift-constraints-constraintgraphnode-getmembertype

[swiftc (38 vs. 5155)] Add crasher in swift::constraints::ConstraintGraphNode::getMemberType(...)

Author: gribozavr

validation-test/compiler_crashers/28383-swift-constraints-constraintgraphnode-getmembertype.swift

@@ -0,0 +1,14 @@
+// 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
+protocol A{associatedtype f:A
+typealias e:a
+protocol a
+}extension A
+protocol c:A{
+struct A{let c=g