Merge pull request swiftlang#10497 from practicalswift/swiftc-28798-swift-genericenvironment-queryinterfacetypesubstitutions-operator-swift-substitu

[swiftc (40 vs. 5565)] Add crasher in swift::GenericEnvironment::QueryInterfaceTypeSubstitutions::operator(...)

Author: practicalswift

validation-test/compiler_crashers/28798-swift-genericenvironment-queryinterfacetypesubstitutions-operator-swift-substitu.swift

@@ -0,0 +1,9 @@
+// This source file is part of the Swift.org open source project
+// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+
+// RUN: not --crash %target-swift-frontend %s -emit-ir
+protocol P}{{{<(}}}{}extension P{class a{func<(t:a