Properly collect all enclosing features.

Author: DougGregor

lib/AST/ASTPrinter.cpp

@@ -2697,15 +2697,30 @@ static std::vector<Feature> getUniqueFeaturesUsed(Decl *decl) {
   if (features.empty())
     return features;
 
-  Decl *enclosingDecl;
-  if (auto accessor = dyn_cast<AccessorDecl>(decl))
-    enclosingDecl = accessor->getStorage();
-  else
-    enclosingDecl = decl->getDeclContext()->getAsDecl();
-  if (!enclosingDecl)
-    return features;
+  // Gather the features used by all enclosing declarations.
+  Decl *enclosingDecl = decl;
+  std::vector<Feature> enclosingFeatures;
+  while (true) {
+    // Find the next outermost enclosing declaration.
+    if (auto accessor = dyn_cast<AccessorDecl>(enclosingDecl))
+      enclosingDecl = accessor->getStorage();
+    else
+      enclosingDecl = enclosingDecl->getDeclContext()->getAsDecl();
+    if (!enclosingDecl)
+      break;
+
+    auto outerEnclosingFeatures = getFeaturesUsed(enclosingDecl);
+    if (outerEnclosingFeatures.empty())
+      continue;
+
+    auto currentEnclosingFeatures = std::move(enclosingFeatures);
+    enclosingFeatures.clear();
+    std::merge(outerEnclosingFeatures.begin(), outerEnclosingFeatures.end(),
+               currentEnclosingFeatures.begin(), currentEnclosingFeatures.end(),
+               std::back_inserter(enclosingFeatures));
+  }
 
-  auto enclosingFeatures = getFeaturesUsed(enclosingDecl);
+  // If there were no enclosing features, we're done.
   if (enclosingFeatures.empty())
     return features;
 

test/ModuleInterface/features.swift

@@ -78,7 +78,7 @@ public class OldSchool2: MP {
 // CHECK: #if compiler(>=5.3) && $RethrowsProtocol
 // CHECK-NEXT: @rethrows public protocol RP
 @rethrows public protocol RP {
-  func f() throws
+  func f() throws -> Bool
 }
 
 // CHECK: public struct UsesRP {
@@ -95,7 +95,15 @@ public struct UsesRP {
 // CHECK: #if compiler(>=5.3) && $RethrowsProtocol
 // CHECK-NEXT: public struct IsRP
 public struct IsRP: RP {
-  public func f() { }
+  // CHECK-NEXT: public func f()
+  public func f() -> Bool { }
+
+  // CHECK-NOT: $RethrowsProtocol
+  // CHECK-NEXT: public var isF: 
+  // CHECK-NEXT: get
+  public var isF: Bool {
+    f()
+  }
 }
 
 // CHECK: #if compiler(>=5.3) && $RethrowsProtocol