Merge pull request #27220 from slavapestov/default-arg-self-capture-diagnostic

Default arguments: implement captures for local functions, diagnose 'Self' for methods

Author: slavapestov

include/swift/AST/Decl.h

@@ -5164,6 +5164,7 @@ class ParamDecl : public VarDecl {
     PointerUnion<Expr *, VarDecl *> DefaultArg;
     Initializer *InitContext = nullptr;
     StringRef StringRepresentation;
+    CaptureInfo Captures;
   };
 
   enum class Flags : uint8_t {
@@ -5249,6 +5250,13 @@ class ParamDecl : public VarDecl {
 
   void setDefaultArgumentInitContext(Initializer *initContext);
 
+  const CaptureInfo &getDefaultArgumentCaptureInfo() const {
+    assert(DefaultValueAndFlags.getPointer());
+    return DefaultValueAndFlags.getPointer()->Captures;
+  }
+
+  void setDefaultArgumentCaptureInfo(const CaptureInfo &captures);
+
   /// Extracts the text of the default argument attached to the provided
   /// ParamDecl, removing all inactive #if clauses and providing only the
   /// text of active #if clauses.

include/swift/AST/DiagnosticsSema.def

@@ -2655,6 +2655,8 @@ ERROR(dynamic_self_invalid_method,none,
       "covariant 'Self' can only appear at the top level of method result type", ())
 ERROR(dynamic_self_stored_property_init,none,
       "covariant 'Self' type cannot be referenced from a stored property initializer", ())
+ERROR(dynamic_self_default_arg,none,
+      "covariant 'Self' type cannot be referenced from a default argument expression", ())
 
 //------------------------------------------------------------------------------
 // MARK: Type Check Attributes

include/swift/SIL/TypeLowering.h

@@ -689,7 +689,7 @@ class TypeConverter {
 
   llvm::DenseMap<OverrideKey, SILConstantInfo *> ConstantOverrideTypes;
 
-  llvm::DenseMap<AnyFunctionRef, CaptureInfo> LoweredCaptures;
+  llvm::DenseMap<SILDeclRef, CaptureInfo> LoweredCaptures;
 
   /// Cache of loadable SILType to number of (estimated) fields
   ///
@@ -844,10 +844,13 @@ class TypeConverter {
   /// Returns the formal type, lowered AST type, and SILFunctionType
   /// for a constant reference.
   const SILConstantInfo &getConstantInfo(SILDeclRef constant);
-  
+
+  /// Get the generic environment for a constant.
+  GenericSignature *getConstantGenericSignature(SILDeclRef constant);
+
   /// Get the generic environment for a constant.
   GenericEnvironment *getConstantGenericEnvironment(SILDeclRef constant);
-  
+
   /// Returns the SIL type of a constant reference.
   SILType getConstantType(SILDeclRef constant) {
     return getConstantInfo(constant).getSILType();
@@ -893,11 +896,6 @@ class TypeConverter {
   SILType getEmptyTupleType() {
     return SILType::getPrimitiveObjectType(TupleType::getEmpty(Context));
   }
-  
-  /// Get a function type curried with its capture context.
-  CanAnyFunctionType getFunctionInterfaceTypeWithCaptures(
-                                              CanAnyFunctionType funcType,
-                                              AnyFunctionRef closure);
 
   /// Describes what we're trying to compute a bridged type for.
   ///
@@ -944,17 +942,6 @@ class TypeConverter {
   SILType getSubstitutedStorageType(AbstractStorageDecl *value,
                                     Type lvalueType);
 
-  /// Retrieve the set of archetypes closed over by the given function.
-  GenericEnvironment *getEffectiveGenericEnvironment(AnyFunctionRef fn,
-                                                     CaptureInfo captureInfo);
-
-  /// Retrieve the set of generic parameters closed over by the given function.
-  CanGenericSignature getEffectiveGenericSignature(AnyFunctionRef fn,
-                                                   CaptureInfo captureInfo);
-
-  /// Retrieve the set of generic parameters closed over by the context.
-  CanGenericSignature getEffectiveGenericSignature(DeclContext *dc);
-
   /// Push a generic function context. See GenericContextScope for an RAII
   /// interface to this function.
   ///
@@ -980,10 +967,10 @@ class TypeConverter {
   CanType get##BridgedType##Type();
 #include "swift/SIL/BridgedTypes.def"
 
-  /// Get the capture list from a closure, with transitive function captures
-  /// flattened.
-  CaptureInfo getLoweredLocalCaptures(AnyFunctionRef fn);
-  bool hasLoweredLocalCaptures(AnyFunctionRef fn);
+  /// Get the capture list for a function or default argument, with transitive
+  /// function captures flattened.
+  CaptureInfo getLoweredLocalCaptures(SILDeclRef fn);
+  bool hasLoweredLocalCaptures(SILDeclRef fn);
 
   enum class ABIDifference : uint8_t {
     // No ABI differences, function can be trivially bitcast to result type.

lib/AST/ASTDumper.cpp

@@ -988,9 +988,17 @@ namespace {
       if (P->isAutoClosure())
         OS << " autoclosure";
 
-      if (P->getDefaultArgumentKind() != DefaultArgumentKind::None)
+      if (P->getDefaultArgumentKind() != DefaultArgumentKind::None) {
         printField("default_arg",
                    getDefaultArgumentKindString(P->getDefaultArgumentKind()));
+      }
+
+      if (P->getDefaultValue() &&
+        !P->getDefaultArgumentCaptureInfo().isTrivial()) {
+        OS << " ";
+        P->getDefaultArgumentCaptureInfo().print(
+          PrintWithColorRAII(OS, CapturesColor).getOS());
+      }
 
       if (auto init = P->getDefaultValue()) {
         OS << " expression=\n";

lib/AST/Decl.cpp

@@ -5866,6 +5866,11 @@ void ParamDecl::setDefaultArgumentInitContext(Initializer *initContext) {
   DefaultValueAndFlags.getPointer()->InitContext = initContext;
 }
 
+void ParamDecl::setDefaultArgumentCaptureInfo(const CaptureInfo &captures) {
+  assert(DefaultValueAndFlags.getPointer());
+  DefaultValueAndFlags.getPointer()->Captures = captures;
+}
+
 /// Return nullptr if there is no property wrapper
 Expr *swift::findOriginalPropertyWrapperInitialValue(VarDecl *var,
                                                      Expr *init) {

lib/SIL/SILFunctionType.cpp

@@ -715,7 +715,7 @@ static std::pair<AbstractionPattern, CanType> updateResultTypeForForeignError(
 /// If we ever add that ability, it will be a different capture list
 /// from the function to which the argument is attached.
 static void
-lowerCaptureContextParameters(TypeConverter &TC, AnyFunctionRef function,
+lowerCaptureContextParameters(TypeConverter &TC, SILDeclRef function,
                               CanGenericSignature genericSig,
                               ResilienceExpansion expansion,
                               SmallVectorImpl<SILParameterInfo> &inputs) {
@@ -725,8 +725,7 @@ lowerCaptureContextParameters(TypeConverter &TC, AnyFunctionRef function,
   // canonicalize references to the generic parameters that may appear in
   // non-canonical types in that context. We need the original generic
   // signature from the AST for that.
-  auto origGenericSig = function.getGenericSignature();
-
+  auto origGenericSig = function.getAnyFunctionRef()->getGenericSignature();
   auto loweredCaptures = TC.getLoweredLocalCaptures(function);
 
   for (auto capture : loweredCaptures.getCaptures()) {
@@ -999,18 +998,12 @@ static CanSILFunctionType getSILFunctionType(
                                 yields, coroutineKind);
 
   // Lower the capture context parameters, if any.
-  //
-  // *NOTE* Currently default arg generators can not capture anything.
-  // If we ever add that ability, it will be a different capture list
-  // from the function to which the argument is attached.
-  if (constant && !constant->isDefaultArgGenerator()) {
-    if (auto function = constant->getAnyFunctionRef()) {
-      auto expansion = ResilienceExpansion::Maximal;
-      if (constant->isSerialized())
-        expansion = ResilienceExpansion::Minimal;
-      lowerCaptureContextParameters(TC, *function, genericSig, expansion,
-                                    inputs);
-    }
+  if (constant && constant->getAnyFunctionRef()) {
+    auto expansion = ResilienceExpansion::Maximal;
+    if (constant->isSerialized())
+      expansion = ResilienceExpansion::Minimal;
+    lowerCaptureContextParameters(TC, *constant, genericSig, expansion,
+                                  inputs);
   }
 
   auto calleeConvention = ParameterConvention::Direct_Unowned;