Add transitive capture test

Author: gregomni

test/SILGen/capture-transitive.swift

@@ -0,0 +1,20 @@
+// RUN: %target-swift-emit-silgen -enable-sil-ownership %s | %FileCheck %s
+// SR-8398
+func fibonacci(_ n: Int) -> Int {
+  var cache: [Int: Int] = [:]
+
+  func recursive(_ m: Int) -> Int {
+    return cache[m] ?? {
+      // Make sure cache is only captured once in the closure
+      // CHECK: implicit closure #1 in recursive #1
+      // CHECK-LABEL: sil private [transparent] @{{.*}}9fibonacci{{.*}}9recursive{{.*}} : $@convention(thin) (Int, @guaranteed { var Dictionary<Int, Int> }) -> (Int, @error Error)
+      // CHECK: closure #1 in implicit closure #1 in recursive #1
+      // CHECK-LABEL: sil private @{{.*}}9fibonacci{{.*}}9recursive{{.*}} : $@convention(thin) (Int, @guaranteed { var Dictionary<Int, Int> }) -> Int
+      let output = m < 2 ? m : recursive(m - 1) + recursive(m - 2)
+      cache[m] = output
+      return output
+      }()
+  }
+  return recursive(n)
+}
+