Merge pull request #81744 from DougGregor/more-migratable-features-6.2

[6.2] Make `InferIsolatedConformances` and `StrictMemorySafety` migratable features

Author: DougGregor

include/swift/AST/DiagnosticsSema.def

@@ -8545,6 +8545,9 @@ GROUPED_ERROR(isolated_conformance_with_sendable_simple,IsolatedConformances,
 GROUPED_ERROR(isolated_conformance_wrong_domain,IsolatedConformances,none,
       "%0 conformance of %1 to %2 cannot be used in %3 context",
       (ActorIsolation, Type, DeclName, ActorIsolation))
+GROUPED_WARNING(isolated_conformance_will_become_nonisolated,IsolatedConformances,none,
+      "conformance of %0 to %1 should be marked 'nonisolated' to retain its behavior with upcoming feature 'InferIsolatedConformances'",
+      (const ValueDecl *, const ValueDecl *))
 
 //===----------------------------------------------------------------------===//
 // MARK: @_inheritActorContext

include/swift/Basic/Features.def

@@ -155,6 +155,11 @@
   #endif
 #endif
 
+#ifndef MIGRATABLE_OPTIONAL_LANGUAGE_FEATURE
+  #define MIGRATABLE_OPTIONAL_LANGUAGE_FEATURE(FeatureName, SENumber, Name)   \
+      OPTIONAL_LANGUAGE_FEATURE(FeatureName, SENumber, #Name)
+#endif
+
 #ifndef UPCOMING_FEATURE
   #define UPCOMING_FEATURE(FeatureName, SENumber, Version)                     \
     LANGUAGE_FEATURE(FeatureName, SENumber, #FeatureName)
@@ -283,14 +288,14 @@ UPCOMING_FEATURE(GlobalActorIsolatedTypesUsability, 0434, 6)
 MIGRATABLE_UPCOMING_FEATURE(ExistentialAny, 335, 7)
 UPCOMING_FEATURE(InternalImportsByDefault, 409, 7)
 UPCOMING_FEATURE(MemberImportVisibility, 444, 7)
-UPCOMING_FEATURE(InferIsolatedConformances, 470, 7)
+MIGRATABLE_UPCOMING_FEATURE(InferIsolatedConformances, 470, 7)
 MIGRATABLE_UPCOMING_FEATURE(NonisolatedNonsendingByDefault, 461, 7)
 
 // Optional language features / modes
 
 /// Diagnose uses of language constructs and APIs that can violate memory
 /// safety.
-OPTIONAL_LANGUAGE_FEATURE(StrictMemorySafety, 458, "Strict memory safety")
+MIGRATABLE_OPTIONAL_LANGUAGE_FEATURE(StrictMemorySafety, 458, "Strict memory safety")
 
 // Experimental features
 
@@ -522,6 +527,7 @@ EXPERIMENTAL_FEATURE(CopyBlockOptimization, true)
 #undef UPCOMING_FEATURE
 #undef MIGRATABLE_UPCOMING_FEATURE
 #undef MIGRATABLE_EXPERIMENTAL_FEATURE
+#undef MIGRATABLE_OPTIONAL_LANGUAGE_FEATURE
 #undef BASELINE_LANGUAGE_FEATURE
 #undef OPTIONAL_LANGUAGE_FEATURE
 #undef CONDITIONALLY_SUPPRESSIBLE_EXPERIMENTAL_FEATURE

include/swift/Basic/LangOptions.h

@@ -872,7 +872,9 @@ namespace swift {
     FeatureState getFeatureState(Feature feature) const;
 
     /// Returns whether the given feature is enabled.
-    bool hasFeature(Feature feature) const;
+    ///
+    /// If allowMigration is set, also returns true when the feature has been enabled for migration.
+    bool hasFeature(Feature feature, bool allowMigration = false) const;
 
     /// Returns whether a feature with the given name is enabled. Returns
     /// `false` if a feature by this name is not known.

include/swift/Option/Options.td

@@ -1018,6 +1018,10 @@ def strict_memory_safety : Flag<["-"], "strict-memory-safety">,
   Flags<[FrontendOption, ModuleInterfaceOptionIgnorable,
          SwiftAPIDigesterOption, SwiftSynthesizeInterfaceOption]>,
   HelpText<"Enable strict memory safety checking">;
+def strict_memory_safety_migrate : Flag<["-"], "strict-memory-safety:migrate">,
+  Flags<[FrontendOption, ModuleInterfaceOptionIgnorable,
+         SwiftAPIDigesterOption, SwiftSynthesizeInterfaceOption]>,
+  HelpText<"Enable migration to strict memory safety checking">;
 
 def Rpass_EQ : Joined<["-"], "Rpass=">,
   Flags<[FrontendOption]>,

lib/Basic/Feature.cpp

@@ -73,6 +73,7 @@ bool Feature::isMigratable() const {
   switch (kind) {
 #define MIGRATABLE_UPCOMING_FEATURE(FeatureName, SENumber, Version)
 #define MIGRATABLE_EXPERIMENTAL_FEATURE(FeatureName, AvailableInProd)
+#define MIGRATABLE_OPTIONAL_LANGUAGE_FEATURE(FeatureName, SENumber, Name)
 #define LANGUAGE_FEATURE(FeatureName, SENumber, Description)                   \
   case Feature::FeatureName:
 #include "swift/Basic/Features.def"
@@ -82,6 +83,8 @@ bool Feature::isMigratable() const {
   case Feature::FeatureName:
 #define MIGRATABLE_EXPERIMENTAL_FEATURE(FeatureName, AvailableInProd)          \
   case Feature::FeatureName:
+#define MIGRATABLE_OPTIONAL_LANGUAGE_FEATURE(FeatureName, SENumber, Name)      \
+  case Feature::FeatureName:
 #include "swift/Basic/Features.def"
     return true;
   }

lib/Basic/LangOptions.cpp

@@ -335,13 +335,17 @@ LangOptions::FeatureState LangOptions::getFeatureState(Feature feature) const {
   return state;
 }
 
-bool LangOptions::hasFeature(Feature feature) const {
-  if (featureStates.getState(feature).isEnabled())
+bool LangOptions::hasFeature(Feature feature, bool allowMigration) const {
+  auto state = featureStates.getState(feature);
+  if (state.isEnabled())
     return true;
 
   if (auto version = feature.getLanguageVersion())
     return isSwiftVersionAtLeast(*version);
 
+  if (allowMigration && state.isEnabledForMigration())
+    return true;
+
   return false;
 }
 

lib/Basic/SupportedFeatures.cpp

@@ -13,6 +13,7 @@
 #include <array>
 #include <vector>
 
+#include "swift/AST/DiagnosticGroups.h"
 #include "swift/Basic/Feature.h"
 #include "swift/Frontend/Frontend.h"
 
@@ -22,6 +23,33 @@ using namespace swift;
 
 namespace swift {
 namespace features {
+
+/// The subset of diagnostic groups (called categories by the diagnostic machinery) whose diagnostics should be
+/// considered to be part of the migration for this feature.
+///
+///  When making a feature migratable, ensure that all of the warnings that are used to drive the migration are
+///  part of a diagnostic group, and put that diagnostic group into the list for that feature here.
+static std::vector<DiagGroupID> migratableCategories(Feature feature) {
+  switch (feature) {
+    case Feature::InnerKind::ExistentialAny:
+      return { DiagGroupID::ExistentialAny };
+    case Feature::InnerKind::InferIsolatedConformances:
+      return { DiagGroupID::IsolatedConformances };
+    case Feature::InnerKind::NonisolatedNonsendingByDefault:
+      return { DiagGroupID::NonisolatedNonsendingByDefault };
+    case Feature::InnerKind::StrictMemorySafety:
+      return { DiagGroupID::StrictMemorySafety };
+
+    // Provide unreachable cases for all of the non-migratable features.
+#define LANGUAGE_FEATURE(FeatureName, SENumber, Description) case Feature::FeatureName:
+#define MIGRATABLE_UPCOMING_FEATURE(FeatureName, SENumber, Version)
+#define MIGRATABLE_EXPERIMENTAL_FEATURE(FeatureName, AvailableInProd)
+#define MIGRATABLE_OPTIONAL_LANGUAGE_FEATURE(FeatureName, SENumber, Name)
+#include "swift/Basic/Features.def"
+    llvm_unreachable("Not a migratable feature");
+  }
+}
+
 /// Print information about what features upcoming/experimental are
 /// supported by the compiler.
 /// The information includes whether a feature is adoptable and for
@@ -50,9 +78,18 @@ void printSupportedFeatures(llvm::raw_ostream &out) {
     out << "{ \"name\": \"" << feature.getName() << "\"";
     if (feature.isMigratable()) {
       out << ", \"migratable\": true";
+
+      auto categories = migratableCategories(feature);
+      out << ", \"categories\": [";
+      llvm::interleave(categories, [&out](DiagGroupID diagGroupID) {
+        out << "\"" << getDiagGroupInfoByID(diagGroupID).name << "\"";
+      }, [&out] {
+        out << ", ";
+      });
+      out << "]";
     }
     if (auto version = feature.getLanguageVersion()) {
-      out << ", \"enabled_in\": " << *version;
+      out << ", \"enabled_in\": \"" << *version << "\"";
     }
     out << " }";
   };
@@ -71,4 +108,4 @@ void printSupportedFeatures(llvm::raw_ostream &out) {
 }
 
 } // end namespace features
-} // end namespace swift
+} // end namespace swift

lib/Driver/ToolChains.cpp

@@ -284,7 +284,8 @@ void ToolChain::addCommonFrontendArgs(const OutputInfo &OI,
                                    options::OPT_disable_experimental_feature,
                                    options::OPT_enable_upcoming_feature,
                                    options::OPT_disable_upcoming_feature});
-  inputArgs.AddLastArg(arguments, options::OPT_strict_memory_safety);
+  inputArgs.AddLastArg(arguments, options::OPT_strict_memory_safety,
+                       options::OPT_strict_memory_safety_migrate);
   inputArgs.AddLastArg(arguments, options::OPT_warn_implicit_overrides);
   inputArgs.AddLastArg(arguments, options::OPT_typo_correction_limit);
   inputArgs.AddLastArg(arguments, options::OPT_enable_app_extension);

lib/Frontend/CompilerInvocation.cpp

@@ -996,6 +996,8 @@ static bool ParseEnabledFeatureArgs(LangOptions &Opts, ArgList &Args,
 
   if (Args.hasArg(OPT_strict_memory_safety))
     Opts.enableFeature(Feature::StrictMemorySafety);
+  else if (Args.hasArg(OPT_strict_memory_safety_migrate))
+    Opts.enableFeature(Feature::StrictMemorySafety, /*forMigration=*/true);
 
   return HadError;
 }

lib/Sema/CSApply.cpp

@@ -8172,7 +8172,7 @@ Expr *ExprRewriter::convertLiteralInPlace(
     Diag<> brokenProtocolDiag, Diag<> brokenBuiltinProtocolDiag) {
   // If coercing a literal to an unresolved type, we don't try to look up the
   // witness members, just do it.
-  if (type->is<UnresolvedType>()) {
+  if (type->is<UnresolvedType>() || type->is<ErrorType>()) {
     cs.setType(literal, type);
     return literal;
   }

lib/Sema/DerivedConformance/DerivedConformanceDistributedActor.cpp

@@ -171,7 +171,7 @@ deriveBodyDistributed_doInvokeOnReturn(AbstractFunctionDecl *afd, void *arg) {
                          new (C) DeclRefExpr(ConcreteDeclRef(returnTypeParam),
                                              dloc, implicit))}));
 
-    if (C.LangOpts.hasFeature(Feature::StrictMemorySafety))
+    if (C.LangOpts.hasFeature(Feature::StrictMemorySafety, /*allowMigration=*/true))
       resultLoadCall = new (C) UnsafeExpr(sloc, resultLoadCall, Type(), true);
 
     auto resultPattern = NamedPattern::createImplicit(C, resultVar);

lib/Sema/DerivedConformance/DerivedConformanceRawRepresentable.cpp

@@ -106,7 +106,7 @@ deriveBodyRawRepresentable_raw(AbstractFunctionDecl *toRawDecl, void *) {
     auto *argList = ArgumentList::forImplicitCallTo(functionRef->getName(),
                                                     {selfRef, typeExpr}, C);
     Expr *call = CallExpr::createImplicit(C, functionRef, argList);
-    if (C.LangOpts.hasFeature(Feature::StrictMemorySafety))
+    if (C.LangOpts.hasFeature(Feature::StrictMemorySafety, /*allowMigration=*/true))
       call = UnsafeExpr::createImplicit(C, SourceLoc(), call);
     auto *returnStmt = ReturnStmt::createImplicit(C, call);
     auto body = BraceStmt::create(C, SourceLoc(), ASTNode(returnStmt),

lib/Sema/TypeCheckDeclOverride.cpp

@@ -2262,7 +2262,7 @@ static bool checkSingleOverride(ValueDecl *override, ValueDecl *base) {
     diagnoseOverrideForAvailability(override, base);
   }
 
-  if (ctx.LangOpts.hasFeature(Feature::StrictMemorySafety)) {
+  if (ctx.LangOpts.hasFeature(Feature::StrictMemorySafety, /*allowMigration=*/true)) {
     // If the override is unsafe but the base declaration is not, then the
     // inheritance itself is unsafe.
     auto subs = SubstitutionMap::getOverrideSubstitutions(base, override);

lib/Sema/TypeCheckDeclPrimary.cpp

@@ -2430,7 +2430,8 @@ class DeclChecker : public DeclVisitor<DeclChecker> {
 
         // If strict memory safety checking is enabled, check the storage
         // of the nominal type.
-        if (Ctx.LangOpts.hasFeature(Feature::StrictMemorySafety) &&
+        if (Ctx.LangOpts.hasFeature(
+                Feature::StrictMemorySafety, /*allowMigration=*/true) &&
             !isa<ProtocolDecl>(nominal)) {
           checkUnsafeStorage(nominal);
         }

lib/Sema/TypeCheckEffects.cpp

@@ -1187,8 +1187,7 @@ class Classification {
     Classification result;
     bool considerAsync = !onlyEffect || *onlyEffect == EffectKind::Async;
     bool considerThrows = !onlyEffect || *onlyEffect == EffectKind::Throws;
-    bool considerUnsafe = (!onlyEffect || *onlyEffect == EffectKind::Unsafe) &&
-        ctx.LangOpts.hasFeature(Feature::StrictMemorySafety);
+    bool considerUnsafe = (!onlyEffect || *onlyEffect == EffectKind::Unsafe);
 
     // If we're tracking "unsafe" effects, compute them here.
     if (considerUnsafe) {
@@ -1710,8 +1709,7 @@ class ApplyClassifier {
         !fnType->isAsync() &&
         !E->isImplicitlyAsync() &&
         !hasAnyConformances &&
-        (fnRef.getExplicitSafety() == ExplicitSafety::Safe ||
-         !ctx.LangOpts.hasFeature(Feature::StrictMemorySafety))) {
+        fnRef.getExplicitSafety() == ExplicitSafety::Safe) {
       return Classification();
     }
 
@@ -1932,7 +1930,6 @@ class ApplyClassifier {
     // If the safety of the callee is unspecified, check the safety of the
     // arguments specifically.
     if (hasUnspecifiedSafety &&
-        ctx.LangOpts.hasFeature(Feature::StrictMemorySafety) &&
         !(assumedSafeArguments && assumedSafeArguments->contains(E))) {
       classifyApplyEffect(EffectKind::Unsafe);
     }
@@ -4553,13 +4550,13 @@ class CheckEffectsCoverage : public EffectsHandlingWalker<CheckEffectsCoverage>
     if (classification.hasUnsafe()) {
       // If there is no such effect, complain.
       if (S->getUnsafeLoc().isInvalid() &&
-          Ctx.LangOpts.hasFeature(Feature::StrictMemorySafety)) {
+          Ctx.LangOpts.hasFeature(Feature::StrictMemorySafety,
+                                  /*allowMigration=*/true)) {
         auto insertionLoc = S->getPattern()->getStartLoc();
         Ctx.Diags.diagnose(S->getForLoc(), diag::for_unsafe_without_unsafe)
           .fixItInsert(insertionLoc, "unsafe ");
       }
-    } else if (S->getUnsafeLoc().isValid() &&
-               Ctx.LangOpts.hasFeature(Feature::StrictMemorySafety)) {
+    } else if (S->getUnsafeLoc().isValid()) {
       // Extraneous "unsafe" on the sequence.
       Ctx.Diags.diagnose(S->getUnsafeLoc(), diag::no_unsafe_in_unsafe_for)
         .fixItRemove(S->getUnsafeLoc());
@@ -4604,9 +4601,6 @@ class CheckEffectsCoverage : public EffectsHandlingWalker<CheckEffectsCoverage>
   }
 
   void diagnoseRedundantUnsafe(UnsafeExpr *E) const {
-    if (!Ctx.LangOpts.hasFeature(Feature::StrictMemorySafety))
-      return;
-
     // Silence this warning in the expansion of the _SwiftifyImport macro.
     // This is a hack because it's tricky to determine when to insert "unsafe".
     unsigned bufferID =
@@ -4880,7 +4874,7 @@ class CheckEffectsCoverage : public EffectsHandlingWalker<CheckEffectsCoverage>
 
   void diagnoseUncoveredUnsafeSite(
       const Expr *anchor, ArrayRef<UnsafeUse> unsafeUses) {
-    if (!Ctx.LangOpts.hasFeature(Feature::StrictMemorySafety))
+    if (!Ctx.LangOpts.hasFeature(Feature::StrictMemorySafety, /*allowMigration=*/true))
       return;
 
     const auto &[loc, insertText] = getFixItForUncoveredSite(anchor, "unsafe");

lib/Sema/TypeCheckProtocol.cpp

@@ -2650,7 +2650,8 @@ checkIndividualConformance(NormalProtocolConformance *conformance) {
   // If we're enforcing strict memory safety and this conformance hasn't
   // opted out, look for safe/unsafe witness mismatches.
   if (conformance->getExplicitSafety() == ExplicitSafety::Unspecified &&
-      Context.LangOpts.hasFeature(Feature::StrictMemorySafety)) {
+      Context.LangOpts.hasFeature(Feature::StrictMemorySafety,
+                                  /*allowMigration=*/true)) {
     // Collect all of the unsafe uses for this conformance.
     SmallVector<UnsafeUse, 2> unsafeUses;
     for (auto requirement: Proto->getMembers()) {
@@ -6668,6 +6669,49 @@ void TypeChecker::checkConformancesInContext(IterableDeclContext *idc) {
     }
   }
 
+  // If we are migrating to InferIsolatedConformances, and the
+  // nominal type is global-actor-isolated, look for conformances
+  // that are nonisolated but were not explicitly marked as such.
+  // These conformances will need to be marked 'nonisolated' to
+  // retain their current behavior.
+  if (Context.LangOpts
+          .getFeatureState(Feature::InferIsolatedConformances)
+            .isEnabledForMigration() &&
+      getActorIsolation(const_cast<NominalTypeDecl *>(nominal))
+          .isGlobalActor()) {
+    for (auto conformance : conformances) {
+      auto normal = dyn_cast<NormalProtocolConformance>(conformance);
+      if (!normal)
+        continue;
+
+      // Explicit nonisolated and @preconcurrency suppress this.
+      auto options = normal->getOptions();
+      if (options.contains(ProtocolConformanceFlags::Nonisolated) ||
+          options.contains(ProtocolConformanceFlags::Preconcurrency))
+        continue;
+
+      // Only consider conformances that were explicitly written in the source.
+      if (normal->getSourceKind() != ConformanceEntryKind::Explicit)
+        continue;
+
+      // Only consider conformances to non-marker, nonisolated protocols.
+      auto proto = normal->getProtocol();
+      if (proto->isMarkerProtocol() || getActorIsolation(proto).isActorIsolated())
+        continue;
+
+      // Only nonisolated conformances can be affected.
+      if (!conformance->getIsolation().isNonisolated())
+        continue;
+
+      auto nameLoc = normal->getProtocolNameLoc();
+      if (nameLoc.isValid()) {
+        Context.Diags.diagnose(
+            nameLoc, diag::isolated_conformance_will_become_nonisolated, nominal, proto)
+          .fixItInsert(nameLoc, "nonisolated ");
+      }
+    }
+  }
+
   if (Context.TypeCheckerOpts.DebugGenericSignatures &&
       !conformances.empty()) {
     // Now that they're filled out, print out information about the conformances

lib/Sema/TypeCheckUnsafe.cpp

@@ -341,10 +341,6 @@ bool swift::enumerateUnsafeUses(ArrayRef<ProtocolConformanceRef> conformances,
     if (conformance.isInvalid())
       continue;
 
-    ASTContext &ctx = conformance.getProtocol()->getASTContext();
-    if (!ctx.LangOpts.hasFeature(Feature::StrictMemorySafety))
-      return false;
-
     if (!conformance.hasEffect(EffectKind::Unsafe))
       continue;
 
@@ -413,9 +409,6 @@ bool swift::isUnsafeInConformance(const ValueDecl *requirement,
 
 void swift::diagnoseUnsafeType(ASTContext &ctx, SourceLoc loc, Type type,
                                llvm::function_ref<void(Type)> diagnose) {
-  if (!ctx.LangOpts.hasFeature(Feature::StrictMemorySafety))
-    return;
-
   if (!type->isUnsafe())
     return;