Use evaluator's dependency printing for cycles

Author: Harlan Haskins

include/swift/AST/Evaluator.h

@@ -78,14 +78,12 @@ struct CyclicalRequestError :
 public:
   static char ID;
   const Request &request;
+  const Evaluator &evaluator;
 
-  CyclicalRequestError(const Request &request): request(request) {}
+  CyclicalRequestError(const Request &request, const Evaluator &evaluator)
+    : request(request), evaluator(evaluator) {}
 
-  virtual void log(llvm::raw_ostream &out) const {
-    out << "Cycle detected:\n";
-    simple_display(out, request);
-    out << "\n";
-  }
+  virtual void log(llvm::raw_ostream &out) const;
 
   virtual std::error_code convertToErrorCode() const {
     // This is essentially unused, but is a temporary requirement for
@@ -259,7 +257,7 @@ class Evaluator {
     // Check for a cycle.
     if (checkDependency(AnyRequest(request))) {
       return llvm::Error(
-        llvm::make_unique<CyclicalRequestError<Request>>(request));
+        llvm::make_unique<CyclicalRequestError<Request>>(request, *this));
     }
 
     // Make sure we remove this from the set of active requests once we're
@@ -429,6 +427,13 @@ class Evaluator {
     "Only meant for use in the debugger");
 };
 
+template <typename Request>
+void CyclicalRequestError<Request>::log(llvm::raw_ostream &out) const {
+  out << "Cycle detected:\n";
+  evaluator.printDependencies(request, out);
+  out << "\n";
+}
+
 } // end namespace evaluator
 
 #endif // SWIFT_AST_EVALUATOR_H

unittests/AST/ArithmeticEvaluator.cpp

@@ -244,13 +244,8 @@ TEST(ArithmeticEvaluator, Simple) {
   // Dependency printing.
 
   // Cache some values first, so they show up in the result.
-  auto cachedResult = evaluator(InternallyCachedEvaluationRule(product));
-  if (auto err = cachedResult.takeError()) {
-    llvm::handleAllErrors(std::move(err),
-      [](const CyclicalRequestError<InternallyCachedEvaluationRule> &E) {
-        llvm_unreachable("no explicit cycles were requested");
-      });
-  }
+  (void)llvm::cantFail(evaluator(InternallyCachedEvaluationRule(product)),
+                       "no explicit cycles were requested");
 
   std::string productDependencies;
   {