Track the pre-adjusted "reference" type for declaration reference.

Author: DougGregor

include/swift/Sema/ConstraintSystem.h

@@ -621,8 +621,12 @@ struct SelectedOverload {
   /// The opened type produced by referring to this overload.
   const Type openedType;
 
+  /// The opened type produced by referring to this overload, adjusted for
+  /// `@preconcurrency` or other contextual type-altering attributes.
+  const Type adjustedOpenedType;
+
   /// The type that this overload binds. Note that this may differ from
-  /// openedType, for example it will include any IUO unwrapping that has taken
+  /// adjustedOpenedType, for example it will include any IUO unwrapping that has taken
   /// place.
   const Type boundType;
 };
@@ -2489,10 +2493,15 @@ struct DeclReferenceType {
   /// operation.
   Type adjustedOpenedType;
 
+  /// The type of the reference, based on the original opened type. This is the
+  /// type that the expression used to form the declaration reference would
+  /// have if no adjustments had been applied.
+  Type referenceType;
+
   /// The type of the reference, which is the adjusted opened type after
   /// (e.g.) applying the base of a member access. This is the type of the
-  /// expression used to form the declaration reference type.
-  Type referenceType;
+  /// expression used to form the declaration reference.
+  Type adjustedReferenceType;
 };
 
 /// Describes a system of constraints on type variables, the
@@ -4510,6 +4519,14 @@ class ConstraintSystem {
           return Type();
         });
 
+  /// Given the opened type and a pile of information about a member reference,
+  /// determine the reference type of the member reference.
+  Type getMemberReferenceTypeFromOpenedType(
+      Type &openedType, Type baseObjTy, ValueDecl *value, DeclContext *outerDC,
+      ConstraintLocator *locator, bool hasAppliedSelf,
+      bool isStaticMemberRefOnProtocol, bool isDynamicResult,
+      OpenedTypeMap &replacements);
+
   /// Retrieve the type of a reference to the given value declaration,
   /// as a member with a base of the given type.
   ///

lib/Sema/CSApply.cpp

@@ -1388,7 +1388,7 @@ namespace {
                          ConstraintLocatorBuilder memberLocator, bool Implicit,
                          AccessSemantics semantics) {
       const auto &choice = overload.choice;
-      const auto adjustedOpenedType = overload.openedType;
+      const auto adjustedOpenedType = overload.adjustedOpenedType;
 
       ValueDecl *member = choice.getDecl();
 
@@ -1595,16 +1595,21 @@ namespace {
         ref->setImplicit(Implicit);
         // FIXME: FunctionRefKind
 
-        // Compute the type of the reference.
-        Type refType = simplifyType(adjustedOpenedType);
+        auto computeRefType = [&](Type openedType) {
+          // Compute the type of the reference.
+          Type refType = simplifyType(adjustedOpenedType);
 
-        // If the base was an opened existential, erase the opened
-        // existential.
-        if (openedExistential) {
-          refType = refType->typeEraseOpenedArchetypesWithRoot(
-              baseTy->castTo<OpenedArchetypeType>(), dc);
-        }
+          // If the base was an opened existential, erase the opened
+          // existential.
+          if (openedExistential) {
+            refType = refType->typeEraseOpenedArchetypesWithRoot(
+                baseTy->castTo<OpenedArchetypeType>(), dc);
+          }
+
+          return refType;
+        };
 
+        Type refType = computeRefType(adjustedOpenedType);
         cs.setType(ref, refType);
 
         closeExistentials(ref, locator, /*force=*/openedExistential);
@@ -1967,7 +1972,7 @@ namespace {
       // Apply a key path if we have one.
       if (choice.getKind() == OverloadChoiceKind::KeyPathApplication) {
         auto applicationTy =
-            simplifyType(selected.openedType)->castTo<FunctionType>();
+            simplifyType(selected.adjustedOpenedType)->castTo<FunctionType>();
 
         // The index argument should be (keyPath: KeyPath<Root, Value>).
         // Dig the key path expression out of the arguments.
@@ -2095,7 +2100,7 @@ namespace {
         // TODO: diagnose if semantics != AccessSemantics::Ordinary?
         auto subscriptExpr = DynamicSubscriptExpr::create(
             ctx, base, args, subscriptRef, isImplicit);
-        auto resultTy = simplifyType(selected.openedType)
+        auto resultTy = simplifyType(selected.adjustedOpenedType)
                             ->castTo<FunctionType>()
                             ->getResult();
         assert(!selected.adjustedOpenedFullType->hasOpenedExistential()
@@ -2152,7 +2157,7 @@ namespace {
       // base object type.
       if (hasDynamicSelf) {
         const auto conversionTy = simplifyType(
-            selected.openedType->castTo<FunctionType>()->getResult());
+            selected.adjustedOpenedType->castTo<FunctionType>()->getResult());
 
         if (!containerTy->isEqual(conversionTy)) {
           result = cs.cacheType(
@@ -2852,7 +2857,7 @@ namespace {
         return nullptr;
 
       auto fnType =
-          simplifyType(selectedOverload->openedType)->castTo<FunctionType>();
+          simplifyType(selectedOverload->adjustedOpenedType)->castTo<FunctionType>();
 
       auto newArgs = coerceCallArguments(
           expr->getArgs(), fnType, witness, /*applyExpr=*/nullptr,
@@ -5027,7 +5032,7 @@ namespace {
         const SelectedOverload &overload, SourceLoc componentLoc,
         ConstraintLocator *locator,
         SmallVectorImpl<KeyPathExpr::Component> &components) {
-      auto resolvedTy = simplifyType(overload.openedType);
+      auto resolvedTy = simplifyType(overload.adjustedOpenedType);
       if (auto *property = overload.choice.getDeclOrNull()) {
         // Key paths can only refer to properties currently.
         auto varDecl = cast<VarDecl>(property);
@@ -5088,7 +5093,7 @@ namespace {
       }
 
       auto subscriptType =
-          simplifyType(overload.openedType)->castTo<AnyFunctionType>();
+          simplifyType(overload.adjustedOpenedType)->castTo<AnyFunctionType>();
       auto resolvedTy = subscriptType->getResult();
 
       // Coerce the indices to the type the subscript expects.
@@ -5104,7 +5109,7 @@ namespace {
 
       auto hashable = ctx.getProtocol(KnownProtocolKind::Hashable);
 
-      auto fnType = overload.openedType->castTo<FunctionType>();
+      auto fnType = overload.adjustedOpenedType->castTo<FunctionType>();
       SmallVector<Identifier, 4> newLabels;
       for (auto &param : fnType->getParams()) {
         newLabels.push_back(param.getLabel());
@@ -7667,7 +7672,7 @@ Expr *ExprRewriter::finishApply(ApplyExpr *apply, Type openedType,
           cs.getConstraintLocator(applyFunctionLoc))) {
     auto *method = dyn_cast<FuncDecl>(selected->choice.getDecl());
     auto methodType =
-        simplifyType(selected->openedType)->getAs<AnyFunctionType>();
+        simplifyType(selected->adjustedOpenedType)->getAs<AnyFunctionType>();
     if (method && methodType) {
       // Handle a call to a @dynamicCallable method.
       if (isValidDynamicCallableMethod(method, methodType))

lib/Sema/CSDiagnostics.cpp

@@ -1296,7 +1296,7 @@ bool MemberAccessOnOptionalBaseFailure::diagnoseAsError() {
   // only a '?' fixit) even though the constraint system didn't need to add any
   // additional optionality.
   auto overload = getOverloadChoiceIfAvailable(locator);
-  if (overload && overload->openedType->getOptionalObjectType())
+  if (overload && overload->adjustedOpenedType->getOptionalObjectType())
     resultIsOptional = true;
 
   auto unwrappedBaseType = baseType->getOptionalObjectType();
@@ -4591,7 +4591,7 @@ bool MissingArgumentsFailure::diagnoseAsError() {
 bool MissingArgumentsFailure::diagnoseAsNote() {
   auto *locator = getLocator();
   if (auto overload = getCalleeOverloadChoiceIfAvailable(locator)) {
-    auto *fn = resolveType(overload->openedType)->getAs<AnyFunctionType>();
+    auto *fn = resolveType(overload->adjustedOpenedType)->getAs<AnyFunctionType>();
     auto loc = overload->choice.getDecl()->getLoc();
 
     if (loc.isInvalid())
@@ -4915,7 +4915,7 @@ bool MissingArgumentsFailure::isMisplacedMissingArgument(
     return false;
 
   auto *fnType =
-      solution.simplifyType(overloadChoice->openedType)->getAs<FunctionType>();
+      solution.simplifyType(overloadChoice->adjustedOpenedType)->getAs<FunctionType>();
   if (!(fnType && fnType->getNumParams() == 2))
     return false;
 

lib/Sema/CSFix.cpp

@@ -584,7 +584,7 @@ bool AllowFunctionTypeMismatch::diagnoseForAmbiguity(
       auto *decl = overload->choice.getDecl();
       if (decl->getLoc().isValid()) {
         DE.diagnose(decl, diag::found_candidate_type,
-                    solution.simplifyType(overload->openedType));
+                    solution.simplifyType(overload->adjustedOpenedType));
       }
     }
 

lib/Sema/CSSimplify.cpp

@@ -2525,7 +2525,7 @@ assessRequirementFailureImpact(ConstraintSystem &cs, Type requirementType,
     if (auto *typeVar = requirementType->getAs<TypeVariableType>()) {
       unsigned choiceImpact = 0;
       if (auto choice = cs.findSelectedOverloadFor(ODRE)) {
-        choice->openedType.visit([&](Type type) {
+        choice->adjustedOpenedType.visit([&](Type type) {
           if (type->isEqual(typeVar))
             ++choiceImpact;
         });
@@ -4350,7 +4350,7 @@ static bool repairOutOfOrderArgumentsInBinaryFunction(
   if (!(overload && overload->choice.isDecl()))
     return false;
 
-  auto *fnType = overload->openedType->getAs<FunctionType>();
+  auto *fnType = overload->adjustedOpenedType->getAs<FunctionType>();
   if (!(fnType && fnType->getNumParams() == 2))
     return false;
 
@@ -5306,7 +5306,7 @@ bool ConstraintSystem::repairFailures(
           auto callee = getCalleeLocator(loc);
           if (auto overload = findSelectedOverloadFor(callee)) {
             auto fnType =
-                simplifyType(overload->openedType)->castTo<FunctionType>();
+                simplifyType(overload->adjustedOpenedType)->castTo<FunctionType>();
             auto paramIdx = argToParamElt->getParamIdx();
             auto paramType = fnType->getParams()[paramIdx].getParameterType();
             if (auto paramFnType = paramType->getAs<FunctionType>()) {