Merge pull request #20795 from DougGregor/sr-8767

[Test] Add tests from SR-8767 / rdar://problem/44522298.

Author: DougGregor

test/decl/protocol/sr8767.swift

@@ -0,0 +1,64 @@
+// RUN: %target-typecheck-verify-swift
+
+// SR-8767: a number of related problems with unqualified lookup of
+// associated type names.
+
+
+// #1
+public protocol PA {
+    associatedtype F
+}
+
+public protocol PDA : PA {
+}
+
+public protocol PrB {
+    associatedtype F
+}
+
+extension PDA where Self : PrB {
+    public init(first: F?) {
+        fatalError()
+    }
+}
+
+// #2
+public protocol S { associatedtype F }
+public protocol AM : S {}
+public protocol AL { associatedtype F }
+extension AM where Self : AL {
+    public init(first: F?) { fatalError() }
+}
+
+// #3
+public protocol S2 { associatedtype F }
+public protocol A2 : S2 {}
+public protocol Z2 { associatedtype F }
+extension A2 where Self : Z2 {
+    public init(first: F?) { fatalError() }
+}
+
+// #4
+public protocol BM { associatedtype F }
+public protocol C : BM {}
+public protocol BL { associatedtype F }
+extension C where Self : BL { public init(first: F?) { fatalError() } }
+
+// #5
+public protocol AZ { associatedtype F }
+public protocol ZA : AZ {}
+public protocol AA { associatedtype F }
+extension ZA where Self : AA { public init(first: F?) { fatalError() } }
+
+// #6
+public protocol AZ2 { associatedtype F }
+public protocol ZA2 : AZ2 {}
+public protocol ZZ2 { associatedtype F }
+extension ZA2 where Self : ZZ2 { public init(first: F?) { fatalError() } }
+
+// #7
+public protocol ZA3 { associatedtype F }
+public protocol AZ3 : ZA3 {}
+public protocol ZZ3 { associatedtype F }
+extension AZ3 where Self : ZZ3 { public init(first: F?) { fatalError() } }
+