[NFC] Let SynthesizedProtocolAttrs be @unchecked

This is not yet used by anything.

Author: beccadax

include/swift/AST/Attr.h

@@ -168,8 +168,9 @@ class DeclAttribute : public AttributeBase {
     );
 
     SWIFT_INLINE_BITFIELD(SynthesizedProtocolAttr, DeclAttribute,
-                          NumKnownProtocolKindBits,
-      kind : NumKnownProtocolKindBits
+                          NumKnownProtocolKindBits+1,
+      kind : NumKnownProtocolKindBits,
+      isUnchecked : 1
     );
   } Bits;
 
@@ -1276,11 +1277,13 @@ class SynthesizedProtocolAttr : public DeclAttribute {
 
 public:
   SynthesizedProtocolAttr(KnownProtocolKind protocolKind,
-                          LazyConformanceLoader *Loader)
+                          LazyConformanceLoader *Loader,
+                          bool isUnchecked)
     : DeclAttribute(DAK_SynthesizedProtocol, SourceLoc(), SourceRange(),
                     /*Implicit=*/true), Loader(Loader)
   {
     Bits.SynthesizedProtocolAttr.kind = unsigned(protocolKind);
+    Bits.SynthesizedProtocolAttr.isUnchecked = unsigned(isUnchecked);
   }
 
   /// Retrieve the known protocol kind naming the protocol to be
@@ -1289,6 +1292,10 @@ class SynthesizedProtocolAttr : public DeclAttribute {
     return KnownProtocolKind(Bits.SynthesizedProtocolAttr.kind);
   }
 
+  bool isUnchecked() const {
+    return bool(Bits.SynthesizedProtocolAttr.isUnchecked);
+  }
+
   /// Retrieve the lazy loader that will be used to populate the
   /// synthesized conformance.
   LazyConformanceLoader *getLazyLoader() const { return Loader; }

include/swift/AST/ProtocolConformance.h

@@ -514,6 +514,13 @@ class NormalProtocolConformance : public RootProtocolConformance,
     return ContextAndBits.getInt() & UncheckedFlag;
   }
 
+  /// Mark the conformance as unchecked (equivalent to the @unchecked
+  /// conformance attribute).
+  void setUnchecked() {
+    // OK to mutate because the flags are not part of the folding set node ID.
+    ContextAndBits.setInt(ContextAndBits.getInt() | UncheckedFlag);
+  }
+
   /// Get the kind of source from which this conformance comes.
   ConformanceEntryKind getSourceKind() const {
     return SourceKindAndImplyingConformance.getInt();

lib/AST/ASTPrinter.cpp

@@ -5901,6 +5901,7 @@ swift::getInheritedForPrinting(
   // Collect synthesized conformances.
   auto &ctx = decl->getASTContext();
   llvm::SetVector<ProtocolDecl *> protocols;
+  llvm::TinyPtrVector<ProtocolDecl *> uncheckedProtocols;
   for (auto attr : decl->getAttrs().getAttributes<SynthesizedProtocolAttr>()) {
     if (auto *proto = ctx.getProtocol(attr->getProtocolKind())) {
       // The SerialExecutor conformance is only synthesized on the root
@@ -5913,11 +5914,14 @@ swift::getInheritedForPrinting(
           cast<EnumDecl>(decl)->hasRawType())
         continue;
       protocols.insert(proto);
+      if (attr->isUnchecked())
+        uncheckedProtocols.push_back(proto);
     }
   }
 
   for (size_t i = 0; i < protocols.size(); i++) {
     auto proto = protocols[i];
+    bool isUnchecked = llvm::is_contained(uncheckedProtocols, proto);
 
     if (!options.shouldPrint(proto)) {
       // If private stdlib protocols are skipped and this is a private stdlib
@@ -5928,12 +5932,14 @@ swift::getInheritedForPrinting(
           proto->isPrivateStdlibDecl(!options.SkipUnderscoredStdlibProtocols)) {
         auto inheritedProtocols = proto->getInheritedProtocols();
         protocols.insert(inheritedProtocols.begin(), inheritedProtocols.end());
+        if (isUnchecked)
+          copy(inheritedProtocols, std::back_inserter(uncheckedProtocols));
       }
       continue;
     }
 
     Results.push_back({TypeLoc::withoutLoc(proto->getDeclaredInterfaceType()),
-                       /*isUnchecked=*/false});
+                       isUnchecked});
   }
 }
 

lib/AST/ConformanceLookupTable.cpp

@@ -904,6 +904,8 @@ ConformanceLookupTable::getConformance(NominalTypeDecl *nominal,
           // Set the conformance loader to the loader stashed inside
           // the attribute.
           normalConf->setLazyLoader(attr->getLazyLoader(), /*context=*/0);
+          if (attr->isUnchecked())
+            normalConf->setUnchecked();
           break;
         }
       }

lib/ClangImporter/ImportDecl.cpp

@@ -1468,10 +1468,12 @@ createValueConstructor(ClangImporter::Implementation &Impl,
 static void addSynthesizedProtocolAttrs(
     ClangImporter::Implementation &Impl,
     NominalTypeDecl *nominal,
-    ArrayRef<KnownProtocolKind> synthesizedProtocolAttrs) {
+    ArrayRef<KnownProtocolKind> synthesizedProtocolAttrs,
+    bool isUnchecked = false) {
   for (auto kind : synthesizedProtocolAttrs) {
     nominal->getAttrs().add(new (Impl.SwiftContext)
-                                 SynthesizedProtocolAttr(kind, &Impl));
+                                 SynthesizedProtocolAttr(kind, &Impl,
+                                                         isUnchecked));
   }
 }