Merge pull request swiftlang#30603 from slavapestov/testcase-rdar60081992

Add test case for rdar://problem/60081992

Author: slavapestov

validation-test/compiler_crashers_2_fixed/rdar60081992.swift

@@ -0,0 +1,18 @@
+// RUN: %target-swift-frontend -typecheck %s
+
+struct Model<E> where E: Comparable {
+  enum TimePeriod: CaseIterable {
+    case day, week, month, year
+  }
+}
+
+struct MyStruct<E> where E: Comparable {
+  init<EA>(entries: EA) where EA: BidirectionalCollection, EA.Element == E, EA.Index == Int {
+    typealias MDict<T> = [Model<E>.TimePeriod : T] where T: Numeric
+    func maxDict<T>(_ keyPath: KeyPath<Model<E>, MDict<T>>) -> MDict<T> {
+      fatalError()
+    }
+
+    fatalError()
+  }
+}