Merge pull request #78487 from xedin/Sendable-to-Any-for-lvalues

[CSApply] Sendable-to-Any: Add support for l-value to l-value and inout unsafe casts

Author: xedin

include/swift/Sema/ConstraintSystem.h

@@ -1846,6 +1846,9 @@ class Solution {
   /// locator.
   ArgumentList *getArgumentList(ConstraintLocator *locator) const;
 
+  std::optional<ConversionRestrictionKind>
+  getConversionRestriction(CanType type1, CanType type2) const;
+
   SWIFT_DEBUG_DUMP;
 
   /// Dump this solution.

lib/Sema/CSApply.cpp

@@ -1716,7 +1716,16 @@ namespace {
         // pass it as an inout qualified type.
         auto selfParamTy = isDynamic ? selfTy : containerTy;
 
-        if (selfTy->isEqual(baseTy))
+        // If type equality check fails we need to check whether the types
+        // are the same with deep equality restriction since `any Sendable`
+        // to `Any` conversion is now supported in generic argument positions
+        // of @preconcurrency declarations. i.e. referencing a member on
+        // `[any Sendable]` if member declared in an extension that expects
+        // `Element` to be equal to `Any`.
+        if (selfTy->isEqual(baseTy) ||
+            solution.getConversionRestriction(baseTy->getCanonicalType(),
+                                              selfTy->getCanonicalType()) ==
+                ConversionRestrictionKind::DeepEquality)
           if (cs.getType(base)->is<LValueType>())
             selfParamTy = InOutType::get(selfTy);
 
@@ -7375,13 +7384,42 @@ Expr *ExprRewriter::coerceToType(Expr *expr, Type toType,
   // coercion.
   case TypeKind::LValue: {
     auto fromLValue = cast<LValueType>(desugaredFromType);
+
+    auto injectUnsafeLValueCast = [&](Type fromObjType,
+                                      Type toObjType) -> Expr * {
+      auto restriction = solution.getConversionRestriction(
+          fromObjType->getCanonicalType(), toObjType->getCanonicalType());
+      ASSERT(restriction == ConversionRestrictionKind::DeepEquality);
+      return cs.cacheType(
+          new (ctx) ABISafeConversionExpr(expr, LValueType::get(toObjType)));
+    };
+
+    // @lvalue <A> -> @lvalue <B> is only allowed if there is a
+    // deep equality conversion restriction between the types.
+    // This supports `any Sendable` -> `Any` conversion in generic
+    // argument positions.
+    if (auto *toLValue = toType->getAs<LValueType>()) {
+      return injectUnsafeLValueCast(fromLValue->getObjectType(),
+                                    toLValue->getObjectType());
+    }
+
     auto toIO = toType->getAs<InOutType>();
     if (!toIO)
       return coerceToType(cs.addImplicitLoadExpr(expr), toType, locator);
 
+    // @lvalue <A> -> inout <B> has to use an unsafe cast <A> -> <B>:
+    // @lvalue <A> <cast to> @lvalue B -> inout B.
+    //
+    // This can happen due to any Sendable -> Any conversion in generic
+    // argument positions. We need to inject a cast to get @l-value to
+    // match `inout` type exactly.
+    if (!toIO->getObjectType()->isEqual(fromLValue->getObjectType())) {
+      expr = injectUnsafeLValueCast(fromLValue->getObjectType(),
+                                    toIO->getObjectType());
+    }
+
     // In an 'inout' operator like "i += 1", the operand is converted from
     // an implicit lvalue to an inout argument.
-    assert(toIO->getObjectType()->isEqual(fromLValue->getObjectType()));
     return cs.cacheType(new (ctx) InOutExpr(expr->getStartLoc(), expr,
                                             toIO->getObjectType(),
                                             /*isImplicit*/ true));
@@ -7948,24 +7986,7 @@ ExprRewriter::coerceSelfArgumentToType(Expr *expr,
                                        Type baseTy, ValueDecl *member,
                                        ConstraintLocatorBuilder locator) {
   Type toType = adjustSelfTypeForMember(expr, baseTy, member, dc);
-
-  // If our expression already has the right type, we're done.
-  Type fromType = cs.getType(expr);
-  if (fromType->isEqual(toType))
-    return expr;
-
-  // If we're coercing to an rvalue type, just do it.
-  auto toInOutTy = toType->getAs<InOutType>();
-  if (!toInOutTy)
-    return coerceToType(expr, toType, locator);
-
-  assert(fromType->is<LValueType>() && "Can only convert lvalues to inout");
-
-  // Use InOutExpr to convert it to an explicit inout argument for the
-  // receiver.
-  return cs.cacheType(new (ctx) InOutExpr(expr->getStartLoc(), expr, 
-                                          toInOutTy->getInOutObjectType(),
-                                          /*isImplicit*/ true));
+  return coerceToType(expr, toType, locator);
 }
 
 Expr *ExprRewriter::convertLiteralInPlace(

lib/Sema/CSSimplify.cpp

@@ -3737,6 +3737,10 @@ static bool matchSendableExistentialToAnyInGenericArgumentPosition(
             return isPreconcurrencyContext(
                 cs.getConstraintLocator(UDE->getBase()));
           }
+          if (auto *SE = getAsExpr<SubscriptExpr>(calleeLoc->getAnchor())) {
+            return isPreconcurrencyContext(
+                cs.getConstraintLocator(SE->getBase()));
+          }
           return false;
         }
 

lib/Sema/ConstraintSystem.cpp

@@ -3949,6 +3949,14 @@ ArgumentList *Solution::getArgumentList(ConstraintLocator *locator) const {
   return nullptr;
 }
 
+std::optional<ConversionRestrictionKind>
+Solution::getConversionRestriction(CanType type1, CanType type2) const {
+  auto restriction = ConstraintRestrictions.find({type1, type2});
+  if (restriction != ConstraintRestrictions.end())
+    return restriction->second;
+  return std::nullopt;
+}
+
 #ifndef NDEBUG
 /// Given an apply expr, returns true if it is expected to have a direct callee
 /// overload, resolvable using `getChoiceFor`. Otherwise, returns false.

test/Concurrency/sendable_to_any_for_generic_arguments.swift

@@ -150,3 +150,28 @@ struct TestGeneral {
     let _: S<((Any) -> Void) -> Void> = funcInFunc // Ok
   }
 }
+
+// Make sure that properties and subscripts and mutating methods work.
+extension Dictionary where Key == String, Value == Any {
+  subscript<T>(entry object: T) -> T? {
+    get { nil }
+    set { }
+  }
+
+  var test: Int? {
+    get { nil }
+    set { }
+  }
+
+  mutating func testMutating() {}
+}
+
+func test_subscript_computed_property_and_mutating_access(u: User) {
+  _ = u.dict[entry: ""] // Ok
+  u.dict[entry: 42] = 42 // Ok
+
+  _ = u.dict.test // Ok
+  u.dict.test = 42 // Ok
+
+  u.dict.testMutating() // Ok
+}

test/Interpreter/sendable_erasure_to_any_in_preconcurrency.swift

@@ -12,6 +12,20 @@ class C {
 
 extension Dictionary where Key == String, Value == Any {
   func answer() -> Int { self["a"] as! Int }
+
+  subscript(entry e: String) -> (any Sendable)? {
+    get { self["Entry#" + e] }
+    set { self["Entry#" + e] = newValue }
+  }
+
+  var entryB: (any Sendable)? {
+    get { self["Entry#B"] }
+    set { self["Entry#B"] = newValue }
+  }
+
+  mutating func addEntry() {
+    self["ultimate question"] = "???"
+  }
 }
 
 extension Array where Element == Any {
@@ -29,13 +43,36 @@ struct Test {
 
 
 func test() {
-  let c = C()
+  var c = C()
 
   print(c.dict.answer())
   // CHECK: 42
   print(c.arr.answer())
   // CHECK: 42
 
+  print(c.dict[entry: "A"] ?? "no A")
+  // CHECK: no A
+
+  // Insert a new value
+  c.dict[entry: "A"] = "forty two"
+
+  // Make sure that the dictionary got mutated
+  print(c.dict[entry: "A"] ?? "no A")
+  // CHECK: forty two
+
+  print(c.dict.entryB ?? "no B")
+  // CHECK: no B
+
+  // Insert new value
+  c.dict.entryB = (q: "", a: 42)
+
+  print(c.dict.entryB ?? "no B")
+  // CHECK: (q: "", a: 42)
+
+  c.dict.addEntry()
+  print(c.dict["ultimate question"] ?? "no question")
+  // CHECK: ???
+
   let v1 = Test(data: S(v: 42))
   let v2 = Test(data: S(v: "ultimate question"))
 

test/SILGen/sendable_to_any_for_generic_arguments.swift

@@ -182,3 +182,82 @@ struct TestGeneral {
     accepts_any(test.data)
   }
 }
+
+extension Dictionary where Key == String, Value == Any {
+  subscript<T>(entry object: T) -> T? {
+    get { nil }
+    set { }
+  }
+
+  var test: Int? {
+    get { nil }
+    set { }
+  }
+
+  mutating func testMutating() {}
+}
+
+func test_subscript_computed_property_and_mutating_access(u: User) {
+  // CHECK:  [[DICT_GETTER:%.*]] = class_method %0, #User.dict!getter : (User) -> () -> [String : any Sendable], $@convention(method) (@guaranteed User) -> @owned Dictionary<String, any Sendable>
+  // CHECK-NEXT: [[DICT:%.*]] = apply [[DICT_GETTER]]({{.*}}) : $@convention(method) (@guaranteed User) -> @owned Dictionary<String, any Sendable>
+  // CHECK-NEXT: [[ANY_DICT:%.*]] = unchecked_bitwise_cast [[DICT]] to $Dictionary<String, Any>
+  // CHECK-NEXT: [[ANY_DICT_COPY:%.*]] = copy_value [[ANY_DICT]]
+  // CHECK-NEXT: [[BORROWED_COPY:%.*]] = begin_borrow [[ANY_DICT_COPY]]
+  // CHECK: [[SUBSCRIPT_GETTER:%.*]] = function_ref @$sSD37sendable_to_any_for_generic_argumentsSSRszypRs_rlE5entryqd__Sgqd___tcluig
+  // CHECK-NEXT: {{.*}} = apply [[SUBSCRIPT_GETTER]]<String, Any, String>({{.*}}, [[BORROWED_COPY]])
+  _ = u.dict[entry: ""]
+
+  // CHECK: [[DICT_GETTER:%.*]] = class_method %0, #User.dict!modify : (User) -> () -> (), $@yield_once @convention(method) (@guaranteed User) -> @yields @inout Dictionary<String, any Sendable>
+  // CHECK-NEXT: ([[DICT_ADDR:%.*]], {{.*}}) = begin_apply [[DICT_GETTER]]({{.*}}) : $@yield_once @convention(method) (@guaranteed User) -> @yields @inout Dictionary<String, any Sendable>
+  // CHECK-NEXT: [[ANY_DICT:%.*]] = alloc_stack $Dictionary<String, Any>
+  // CHECK-NEXT: [[LOADED_DICT:%.*]] = load [copy] [[DICT_ADDR]]
+  // CHECK-NEXT: [[ANY_LOADED_DICT:%.*]] = unchecked_bitwise_cast [[LOADED_DICT]] to $Dictionary<String, Any>
+  // CHECK-NEXT: [[COPIED_ANY_DICT:%.*]] = copy_value [[ANY_LOADED_DICT]]
+  // CHECK-NEXT: store [[COPIED_ANY_DICT]] to [init] [[ANY_DICT]]
+  // CHECK: [[SUBSCRIPT_SETTER:%.*]] = function_ref @$sSD37sendable_to_any_for_generic_argumentsSSRszypRs_rlE5entryqd__Sgqd___tcluis
+  // CHECK-NEXT: %48 = apply [[SUBSCRIPT_SETTER]]<String, Any, Int>({{.*}}, [[ANY_DICT]])
+  // CHECK-NEXT: [[LOADED_ANY_DICT:%.*]] = load [take] [[ANY_DICT]]
+  // CHECK-NEXT: [[SENDABLE_DICT:%.*]] = unchecked_bitwise_cast [[LOADED_ANY_DICT]] to $Dictionary<String, any Sendable>
+  // CHECK-NEXT: [[COPIED_SENDABLE_DICT:%.*]] = copy_value [[SENDABLE_DICT]]
+  // CHECK-NEXT: assign [[COPIED_SENDABLE_DICT]] to [[DICT_ADDR]]
+  u.dict[entry: 42] = 42
+
+  // CHECK: [[DICT_GETTER:%.*]] = class_method %0, #User.dict!getter : (User) -> () -> [String : any Sendable], $@convention(method) (@guaranteed User) -> @owned Dictionary<String, any Sendable>
+  // CHECK-NEXT: [[SENDABLE_DICT:%.*]] = apply [[DICT_GETTER]]({{.*}}) : $@convention(method) (@guaranteed User) -> @owned Dictionary<String, any Sendable>
+  // CHECK-NEXT: [[DICT_CAST_TO_ANY:%.*]] = unchecked_bitwise_cast [[SENDABLE_DICT]] to $Dictionary<String, Any>
+  // CHECK-NEXT: [[ANY_DICT_COPY:%.*]] = copy_value [[DICT_CAST_TO_ANY]]
+  // CHECK-NEXT: [[ANY_DICT:%.*]] = begin_borrow [[ANY_DICT_COPY]]
+  // CHECK: [[GETTER:%.*]] = function_ref @$sSD37sendable_to_any_for_generic_argumentsSSRszypRs_rlE4testSiSgvg
+  // CHECK-NEXT: {{.*}} = apply [[GETTER]]([[ANY_DICT]]) : $@convention(method) (@guaranteed Dictionary<String, Any>) -> Optional<Int>
+  _ = u.dict.test
+
+  // CHECK: [[DICT_GETTER:%.*]] = class_method %0, #User.dict!modify : (User) -> () -> (), $@yield_once @convention(method) (@guaranteed User) -> @yields @inout Dictionary<String, any Sendable>
+  // CHECK-NEXT: ([[DICT:%.*]], {{.*}}) = begin_apply [[DICT_GETTER]]({{.*}}) : $@yield_once @convention(method) (@guaranteed User) -> @yields @inout Dictionary<String, any Sendable>
+  // CHECK-NEXT: [[ANY_DICT:%.*]] = alloc_stack $Dictionary<String, Any>
+  // CHECK-NEXT: [[LOADED_DICT:%.*]] = load [copy] [[DICT]]
+  // CHECK-NEXT: [[CASTED_DICT:%.*]] = unchecked_bitwise_cast [[LOADED_DICT]] to $Dictionary<String, Any>
+  // CHECK-NEXT: [[COPIED_CASTED_DICT:%.*]] = copy_value [[CASTED_DICT]]
+  // CHECK-NEXT: store [[COPIED_CASTED_DICT]] to [init] [[ANY_DICT]]
+  // CHECK: [[SETTER:%.*]] = function_ref @$sSD37sendable_to_any_for_generic_argumentsSSRszypRs_rlE4testSiSgvs
+  // CHECK-NEXT: {{.*}} = apply [[SETTER]]({{.*}}, [[ANY_DICT]]) : $@convention(method) (Optional<Int>, @inout Dictionary<String, Any>) -> ()
+  // CHECK-NEXT: [[LOADED_ANY_DICT:%.*]] = load [take] [[ANY_DICT]]
+  // CHECK-NEXT: [[SENDABLE_DICT:%.*]] = unchecked_bitwise_cast [[LOADED_ANY_DICT]] to $Dictionary<String, any Sendable>
+  // CHECK-NEXT: [[COPIED_SENDABLE_DICT:%.*]] = copy_value [[SENDABLE_DICT]]
+  // CHECK-NEXT: assign [[COPIED_SENDABLE_DICT]] to [[DICT]]
+  u.dict.test = 42
+
+  // CHECK: [[DICT_GETTER:%.*]] = class_method %0, #User.dict!modify : (User) -> () -> (), $@yield_once @convention(method) (@guaranteed User) -> @yields @inout Dictionary<String, any Sendable>
+  // CHECK-NEXT: ([[DICT:%.*]], {{.*}}) = begin_apply [[DICT_GETTER:%.*]](%0) : $@yield_once @convention(method) (@guaranteed User) -> @yields @inout Dictionary<String, any Sendable>
+  // CHECK-NEXT: [[ANY_DICT:%.*]] = alloc_stack $Dictionary<String, Any>
+  // CHECK-NEXT: [[LOADED_DICT:%.*]] = load [copy] [[DICT]]
+  // CHECK-NEXT: [[CASTED_DICT:%.*]] = unchecked_bitwise_cast [[LOADED_DICT]] to $Dictionary<String, Any>
+  // CHECK-NEXT: [[COPIED_DICT:%.*]] = copy_value [[CASTED_DICT]]
+  // CHECK-NEXT: store [[COPIED_DICT]] to [init] [[ANY_DICT]]
+  // CHECK: [[MUTATING_METHOD:%.*]] = function_ref @$sSD37sendable_to_any_for_generic_argumentsSSRszypRs_rlE12testMutatingyyF : $@convention(method) (@inout Dictionary<String, Any>) -> ()
+  // CHECK-NEXT: %101 = apply [[MUTATING_METHOD]]([[ANY_DICT]]) : $@convention(method) (@inout Dictionary<String, Any>) -> ()
+  // CHECK-NEXT: [[LOADED_ANY_DICT:%.*]] = load [take] [[ANY_DICT]]
+  // CHECK-NEXT: [[SENDABLE_DICT:%.*]] = unchecked_bitwise_cast [[LOADED_ANY_DICT]] to $Dictionary<String, any Sendable>
+  // CHECK-NEXT: [[COPIED_SENDABLE_DICT:%.*]] = copy_value [[SENDABLE_DICT]]
+  // CHECK-NEXT: assign [[COPIED_SENDABLE_DICT]] to [[DICT]]
+  u.dict.testMutating()
+}