Fix synthesis of get/set protocol constraints when borrow/mutate accessors are present

Author: meg-gupta

lib/AST/Decl.cpp

@@ -3264,6 +3264,10 @@ static AccessStrategy getOpaqueReadAccessStrategy(
     return AccessStrategy::getAccessor(AccessorKind::Read2, dispatch);
   if (storage->requiresOpaqueReadCoroutine())
     return AccessStrategy::getAccessor(AccessorKind::Read, dispatch);
+
+  if (storage->getParsedAccessor(AccessorKind::Borrow)) {
+    return AccessStrategy::getAccessor(AccessorKind::Borrow, dispatch);
+  }
   return AccessStrategy::getAccessor(AccessorKind::Get, dispatch);
 }
 
@@ -3435,11 +3439,6 @@ bool AbstractStorageDecl::requiresOpaqueSetter() const {
   if (!supportsMutation()) {
     return false;
   }
-
-  // If a mutate accessor is present, we don't need a setter.
-  if (getAccessor(AccessorKind::Mutate)) {
-    return false;
-  }
   return true;
 }
 
@@ -3450,7 +3449,7 @@ bool AbstractStorageDecl::requiresOpaqueReadCoroutine() const {
         AccessorKind::Read2);
 
   // If a borrow accessor is present, we don't need a read coroutine.
-  if (getAccessor(AccessorKind::Borrow)) {
+  if (getParsedAccessor(AccessorKind::Borrow)) {
     return false;
   }
   return getOpaqueReadOwnership() != OpaqueReadOwnership::Owned;
@@ -3462,7 +3461,7 @@ bool AbstractStorageDecl::requiresOpaqueRead2Coroutine() const {
     return false;
 
   // If a borrow accessor is present, we don't need a read coroutine.
-  if (getAccessor(AccessorKind::Borrow)) {
+  if (getParsedAccessor(AccessorKind::Borrow)) {
     return false;
   }
   return getOpaqueReadOwnership() != OpaqueReadOwnership::Owned;

lib/Sema/TypeCheckStorage.cpp

@@ -1875,6 +1875,13 @@ synthesizeModify2CoroutineSetterBody(AccessorDecl *setter, ASTContext &ctx) {
       setter, TargetImpl::Implementation, setter->getStorage(), ctx);
 }
 
+static std::pair<BraceStmt *, bool>
+synthesizeMutateSetterBody(AccessorDecl *setter, ASTContext &ctx) {
+  // This should call the mutate accessor.
+  return synthesizeTrivialSetterBodyWithStorage(
+      setter, TargetImpl::Implementation, setter->getStorage(), ctx);
+}
+
 static Expr *maybeWrapInOutExpr(Expr *expr, ASTContext &ctx) {
   if (auto lvalueType = expr->getType()->getAs<LValueType>()) {
     auto type = lvalueType->getObjectType();
@@ -2071,7 +2078,7 @@ synthesizeSetterBody(AccessorDecl *setter, ASTContext &ctx) {
     return synthesizeModify2CoroutineSetterBody(setter, ctx);
 
   case WriteImplKind::Mutate:
-    llvm_unreachable("synthesizing setter from mutate");
+    return synthesizeMutateSetterBody(setter, ctx);
   }
   llvm_unreachable("bad WriteImplKind");
 }
@@ -2476,7 +2483,9 @@ static AccessorDecl *createSetterPrototype(AbstractStorageDecl *storage,
     }
     break;
   case WriteImplKind::Mutate:
-    llvm_unreachable("mutate accessor is not yet implemented");
+    if (auto mutate = storage->getOpaqueAccessor(AccessorKind::Mutate)) {
+      asAvailableAs.push_back(mutate);
+    }
   }
 
   if (!asAvailableAs.empty()) {
@@ -2804,11 +2813,6 @@ bool RequiresOpaqueModifyCoroutineRequest::evaluate(
     if (protoDecl->isObjC())
       return false;
 
-  // If a mutate accessor is present, we don't need a modify coroutine
-  if (storage->getAccessor(AccessorKind::Mutate)) {
-    return false;
-  }
-
   return true;
 }
 
@@ -2937,9 +2941,8 @@ IsAccessorTransparentRequest::evaluate(Evaluator &evaluator,
     case WriteImplKind::MutableAddress:
     case WriteImplKind::Modify:
     case WriteImplKind::Modify2:
-      break;
     case WriteImplKind::Mutate:
-      llvm_unreachable("mutate accessor is not yet implemented");
+      break;
     }
     break;
 
@@ -2950,14 +2953,12 @@ IsAccessorTransparentRequest::evaluate(Evaluator &evaluator,
   case AccessorKind::Init:
     break;
   case AccessorKind::Borrow:
-    llvm_unreachable("borrow accessor is not yet implemented");
   case AccessorKind::WillSet:
   case AccessorKind::DidSet:
   case AccessorKind::Address:
   case AccessorKind::MutableAddress:
-    llvm_unreachable("bad synthesized function kind");
   case AccessorKind::Mutate:
-    llvm_unreachable("mutate accessor is not yet implemented");
+    llvm_unreachable("bad synthesized function kind");
   }
 
   switch (storage->getReadWriteImpl()) {

test/Parse/borrow_and_mutate_accessors.swift

@@ -15,23 +15,23 @@ struct Wrapper {
     }
   }
   var k2: Klass {
-    borrow { // expected-error{{variable cannot provide both  a 'borrow' accessor and a getter}}
+    borrow { // expected-error{{variable cannot provide both a 'borrow' accessor and a getter}}
       return _k
     }
     get { // expected-note{{getter defined here}}
       return _k
     }
   }
   var k3: Klass {
-    borrow { // expected-error{{variable cannot provide both  a 'borrow' accessor and a '_read' accessor}}
+    borrow { // expected-error{{variable cannot provide both a 'borrow' accessor and a '_read' accessor}}
       return _k
     }
     _read { // expected-note{{'_read' accessor defined here}}
       yield _k
     }
   }
   var k4: Klass {
-    borrow { // expected-error{{variable cannot provide both  a 'borrow' accessor and a 'read' accessor}}
+    borrow { // expected-error{{variable cannot provide both a 'borrow' accessor and a 'read' accessor}}
       return _k
     }
     read { // expected-note{{'read' accessor defined here}}