Merge pull request swiftlang#34315 from hborla/remove-operator-designated-types

[ConstraintSystem] Remove implementation of operator designated types in the solver.

Author: hborla

include/swift/Basic/LangOptions.h

@@ -538,10 +538,6 @@ namespace swift {
     /// Disable constraint system performance hacks.
     bool DisableConstraintSolverPerformanceHacks = false;
 
-    /// Enable constraint solver support for experimental
-    ///        operator protocol designator feature.
-    bool SolverEnableOperatorDesignatedTypes = false;
-
     /// Enable experimental support for one-way constraints for the
     /// parameters of closures.
     bool EnableOneWayClosureParameters = false;

include/swift/Option/FrontendOptions.td

@@ -480,10 +480,6 @@ def enable_operator_designated_types :
   Flag<["-"], "enable-operator-designated-types">,
   HelpText<"Enable operator designated types">;
 
-def solver_enable_operator_designated_types :
-  Flag<["-"], "solver-enable-operator-designated-types">,
-  HelpText<"Enable operator designated types in constraint solver">;
-
 def enable_invalid_ephemeralness_as_error :
   Flag<["-"], "enable-invalid-ephemeralness-as-error">,
   HelpText<"Diagnose invalid ephemeral to non-ephemeral conversions as errors">;

include/swift/Sema/ConstraintSystem.h

@@ -5034,8 +5034,6 @@ class ConstraintSystem {
   /// \returns The selected disjunction.
   Constraint *selectDisjunction();
 
-  Constraint *selectApplyDisjunction();
-
   /// Solve the system of constraints generated from provided expression.
   ///
   /// \param target The target to generate constraints from.
@@ -5295,19 +5293,6 @@ class ConstraintSystem {
   typedef std::function<void(SmallVectorImpl<unsigned> &options)>
       PartitionAppendCallback;
 
-  // Attempt to sort nominalTypes based on what we can discover about
-  // calls into the overloads in the disjunction that bindOverload is
-  // a part of.
-  void sortDesignatedTypes(SmallVectorImpl<NominalTypeDecl *> &nominalTypes,
-                           Constraint *bindOverload);
-
-  // Partition the choices in a disjunction based on those that match
-  // the designated types for the operator that the disjunction was
-  // formed for.
-  void partitionForDesignatedTypes(ArrayRef<Constraint *> Choices,
-                                   ConstraintMatchLoop forEachChoice,
-                                   PartitionAppendCallback appendPartition);
-
   // Partition the choices in the disjunction into groups that we will
   // iterate over in an order appropriate to attempt to stop before we
   // have to visit all of the options.

lib/Frontend/CompilerInvocation.cpp

@@ -742,8 +742,6 @@ static bool ParseTypeCheckerArgs(TypeCheckerOptions &Opts, ArgList &Args,
   // Always enable operator designated types for the standard library.
   Opts.EnableOperatorDesignatedTypes |= FrontendOpts.ParseStdlib;
 
-  Opts.SolverEnableOperatorDesignatedTypes |=
-      Args.hasArg(OPT_solver_enable_operator_designated_types);
   Opts.EnableOneWayClosureParameters |=
       Args.hasArg(OPT_experimental_one_way_closure_params);
 

lib/Sema/CSSolver.cpp

@@ -1929,30 +1929,6 @@ Constraint *ConstraintSystem::getUnboundBindOverloadDisjunction(
   return result->first;
 }
 
-// Find a disjunction associated with an ApplicableFunction constraint
-// where we have some information about all of the types of in the
-// function application (even if we only know something about what the
-// types conform to and not actually a concrete type).
-Constraint *ConstraintSystem::selectApplyDisjunction() {
-  for (auto &constraint : InactiveConstraints) {
-    if (constraint.getKind() != ConstraintKind::ApplicableFunction)
-      continue;
-
-    auto *applicable = &constraint;
-    if (haveTypeInformationForAllArguments(
-            applicable->getFirstType()->castTo<FunctionType>())) {
-      auto *tyvar = applicable->getSecondType()->castTo<TypeVariableType>();
-
-      // If we have created the disjunction for this apply, find it.
-      auto *disjunction = getUnboundBindOverloadDisjunction(tyvar);
-      if (disjunction)
-        return disjunction;
-    }
-  }
-
-  return nullptr;
-}
-
 static bool isOperatorBindOverload(Constraint *bindOverload) {
   if (bindOverload->getKind() != ConstraintKind::BindOverload)
     return false;
@@ -1965,165 +1941,6 @@ static bool isOperatorBindOverload(Constraint *bindOverload) {
   return funcDecl && funcDecl->getOperatorDecl();
 }
 
-// Given a bind overload constraint for an operator, return the
-// protocol designated as the first place to look for overloads of the
-// operator.
-static ArrayRef<NominalTypeDecl *>
-getOperatorDesignatedNominalTypes(Constraint *bindOverload) {
-  auto choice = bindOverload->getOverloadChoice();
-  auto *funcDecl = cast<FuncDecl>(choice.getDecl());
-  auto *operatorDecl = funcDecl->getOperatorDecl();
-  return operatorDecl->getDesignatedNominalTypes();
-}
-
-void ConstraintSystem::sortDesignatedTypes(
-    SmallVectorImpl<NominalTypeDecl *> &nominalTypes,
-    Constraint *bindOverload) {
-  auto *tyvar = bindOverload->getFirstType()->castTo<TypeVariableType>();
-  auto applicableFns = getConstraintGraph().gatherConstraints(
-      tyvar, ConstraintGraph::GatheringKind::EquivalenceClass,
-      [](Constraint *match) {
-        return match->getKind() == ConstraintKind::ApplicableFunction;
-      });
-
-  // FIXME: This is not true when we run the constraint optimizer.
-  // assert(applicableFns.size() <= 1);
-
-  // We have a disjunction for an operator but no application of it,
-  // so it's being passed as an argument.
-  if (applicableFns.size() == 0)
-    return;
-
-  // FIXME: We have more than one applicable per disjunction as a
-  //        result of merging disjunction type variables. We may want
-  //        to rip that out at some point.
-  Constraint *foundApplicable = nullptr;
-  SmallVector<Optional<Type>, 2> argumentTypes;
-  for (auto *applicableFn : applicableFns) {
-    argumentTypes.clear();
-    auto *fnTy = applicableFn->getFirstType()->castTo<FunctionType>();
-    ArgumentInfoCollector argInfo(*this, fnTy);
-    // Stop if we hit anything with concrete types or conformances to
-    // literals.
-    if (!argInfo.getTypes().empty() || !argInfo.getLiteralProtocols().empty()) {
-      foundApplicable = applicableFn;
-      break;
-    }
-  }
-
-  if (!foundApplicable)
-    return;
-
-  // FIXME: It would be good to avoid this redundancy.
-  auto *fnTy = foundApplicable->getFirstType()->castTo<FunctionType>();
-  ArgumentInfoCollector argInfo(*this, fnTy);
-
-  size_t nextType = 0;
-  for (auto argType : argInfo.getTypes()) {
-    auto *nominal = argType->getAnyNominal();
-    for (size_t i = nextType; i < nominalTypes.size(); ++i) {
-      if (nominal == nominalTypes[i]) {
-        std::swap(nominalTypes[nextType], nominalTypes[i]);
-        ++nextType;
-        break;
-      } else if (auto *protoDecl = dyn_cast<ProtocolDecl>(nominalTypes[i])) {
-        if (TypeChecker::conformsToProtocol(argType, protoDecl, DC)) {
-          std::swap(nominalTypes[nextType], nominalTypes[i]);
-          ++nextType;
-          break;
-        }
-      }
-    }
-  }
-
-  if (nextType + 1 >= nominalTypes.size())
-    return;
-
-  for (auto *protocol : argInfo.getLiteralProtocols()) {
-    auto defaultType = TypeChecker::getDefaultType(protocol, DC);
-    // ExpressibleByNilLiteral does not have a default type.
-    if (!defaultType)
-      continue;
-    auto *nominal = defaultType->getAnyNominal();
-    for (size_t i = nextType + 1; i < nominalTypes.size(); ++i) {
-      if (nominal == nominalTypes[i]) {
-        std::swap(nominalTypes[nextType], nominalTypes[i]);
-        ++nextType;
-        break;
-      }
-    }
-  }
-}
-
-void ConstraintSystem::partitionForDesignatedTypes(
-    ArrayRef<Constraint *> Choices, ConstraintMatchLoop forEachChoice,
-    PartitionAppendCallback appendPartition) {
-
-  auto types = getOperatorDesignatedNominalTypes(Choices[0]);
-  if (types.empty())
-    return;
-
-  SmallVector<NominalTypeDecl *, 4> designatedNominalTypes(types.begin(),
-                                                           types.end());
-
-  if (designatedNominalTypes.size() > 1)
-    sortDesignatedTypes(designatedNominalTypes, Choices[0]);
-
-  SmallVector<SmallVector<unsigned, 4>, 4> definedInDesignatedType;
-  SmallVector<SmallVector<unsigned, 4>, 4> definedInExtensionOfDesignatedType;
-
-  auto examineConstraint =
-    [&](unsigned constraintIndex, Constraint *constraint) -> bool {
-    auto *decl = constraint->getOverloadChoice().getDecl();
-    auto *funcDecl = cast<FuncDecl>(decl);
-
-    auto *parentDC = funcDecl->getParent();
-    auto *parentDecl = parentDC->getSelfNominalTypeDecl();
-
-    // Skip anything not defined in a nominal type.
-    if (!parentDecl)
-      return false;
-
-    for (auto designatedTypeIndex : indices(designatedNominalTypes)) {
-      auto *designatedNominal =
-        designatedNominalTypes[designatedTypeIndex];
-
-      if (parentDecl != designatedNominal)
-        continue;
-
-      auto &constraints =
-          isa<ExtensionDecl>(parentDC)
-              ? definedInExtensionOfDesignatedType[designatedTypeIndex]
-              : definedInDesignatedType[designatedTypeIndex];
-
-      constraints.push_back(constraintIndex);
-      return true;
-    }
-
-    return false;
-  };
-
-  definedInDesignatedType.resize(designatedNominalTypes.size());
-  definedInExtensionOfDesignatedType.resize(designatedNominalTypes.size());
-
-  forEachChoice(Choices, examineConstraint);
-
-  // Now collect the overload choices that are defined within the type
-  // that was designated in the operator declaration.
-  // Add partitions for each of the overloads we found in types that
-  // were designated as part of the operator declaration.
-  for (auto designatedTypeIndex : indices(designatedNominalTypes)) {
-    if (designatedTypeIndex < definedInDesignatedType.size()) {
-      auto &primary = definedInDesignatedType[designatedTypeIndex];
-      appendPartition(primary);
-    }
-    if (designatedTypeIndex < definedInExtensionOfDesignatedType.size()) {
-      auto &secondary = definedInExtensionOfDesignatedType[designatedTypeIndex];
-      appendPartition(secondary);
-    }
-  }
-}
-
 // Performance hack: if there are two generic overloads, and one is
 // more specialized than the other, prefer the more-specialized one.
 static Constraint *tryOptimizeGenericDisjunction(
@@ -2266,8 +2083,7 @@ void ConstraintSystem::partitionDisjunction(
   }
 
   // Partition SIMD operators.
-  if (!getASTContext().TypeCheckerOpts.SolverEnableOperatorDesignatedTypes &&
-      isOperatorBindOverload(Choices[0])) {
+  if (isOperatorBindOverload(Choices[0])) {
     forEachChoice(Choices, [&](unsigned index, Constraint *constraint) -> bool {
       if (!isOperatorBindOverload(constraint))
         return false;
@@ -2291,11 +2107,6 @@ void ConstraintSystem::partitionDisjunction(
         }
       };
 
-  if (getASTContext().TypeCheckerOpts.SolverEnableOperatorDesignatedTypes &&
-      isOperatorBindOverload(Choices[0])) {
-    partitionForDesignatedTypes(Choices, forEachChoice, appendPartition);
-  }
-
   SmallVector<unsigned, 4> everythingElse;
   // Gather the remaining options.
   forEachChoice(Choices, [&](unsigned index, Constraint *constraint) -> bool {
@@ -2320,17 +2131,6 @@ Constraint *ConstraintSystem::selectDisjunction() {
   if (disjunctions.empty())
     return nullptr;
 
-  // Attempt apply disjunctions first. When we have operators with
-  // designated types, this is important, because it allows us to
-  // select all the preferred operator overloads prior to other
-  // disjunctions that we may not be able to short-circuit, allowing
-  // us to eliminate behavior that is exponential in the number of
-  // operators in the expression.
-  if (getASTContext().TypeCheckerOpts.SolverEnableOperatorDesignatedTypes) {
-    if (auto *disjunction = selectApplyDisjunction())
-      return disjunction;
-  }
-
   if (auto *disjunction = selectBestBindingDisjunction(*this, disjunctions))
     return disjunction;
 

lib/Sema/CSStep.cpp

@@ -660,8 +660,7 @@ bool DisjunctionStep::shortCircuitDisjunctionAt(
   if (currentChoice->getKind() == ConstraintKind::BindOverload &&
       isSIMDOperator(currentChoice->getOverloadChoice().getDecl()) &&
       lastSuccessfulChoice->getKind() == ConstraintKind::BindOverload &&
-      !isSIMDOperator(lastSuccessfulChoice->getOverloadChoice().getDecl()) &&
-      !ctx.TypeCheckerOpts.SolverEnableOperatorDesignatedTypes) {
+      !isSIMDOperator(lastSuccessfulChoice->getOverloadChoice().getDecl())) {
     return true;
   }
 

test/Constraints/add_with_nil.swift

@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -swift-version 5 -solver-enable-operator-designated-types -solver-disable-shrink -disable-constraint-solver-performance-hacks
+// RUN: %target-typecheck-verify-swift -swift-version 5
 
 func test(_ x: Int) -> Int {
   return x + nil

test/attr/attr_implements_fp.swift

@@ -1,6 +1,6 @@
 // RUN: %empty-directory(%t)
 // RUN: echo 'main()' >%t/main.swift
-// RUN: %target-swiftc_driver -o %t/a.out %s %t/main.swift -Xfrontend -enable-operator-designated-types -Xfrontend -solver-enable-operator-designated-types
+// RUN: %target-swiftc_driver -o %t/a.out %s %t/main.swift
 // RUN: %target-codesign %t/a.out
 // RUN: %target-run %t/a.out | %FileCheck %s
 // REQUIRES: executable_test
@@ -13,7 +13,7 @@
 public var comparedAsCauxmparablesCount : Int = 0
 public var comparedAsFauxtsCount : Int = 0
 
-infix operator  .<  : ComparisonPrecedence, BinaryFauxtingPoint, Cauxmparable
+infix operator  .<  : ComparisonPrecedence
 
 public protocol Cauxmparable {
   static func .< (lhs: Self, rhs: Self) -> Bool

test/attr/attr_implements_serial.swift

@@ -1,6 +1,6 @@
 // RUN: %empty-directory(%t)
 // RUN: echo 'client()' >%t/main.swift
-// RUN: %target-build-swift-dylib(%t/%target-library-name(AttrImplFP)) -module-name AttrImplFP -emit-module -emit-module-path %t/AttrImplFP.swiftmodule %S/attr_implements_fp.swift -Xfrontend -enable-operator-designated-types -Xfrontend -solver-enable-operator-designated-types
+// RUN: %target-build-swift-dylib(%t/%target-library-name(AttrImplFP)) -module-name AttrImplFP -emit-module -emit-module-path %t/AttrImplFP.swiftmodule %S/attr_implements_fp.swift
 // RUN: %target-build-swift -I %t -o %t/a.out %s %t/main.swift -L %t %target-rpath(%t) -lAttrImplFP
 // RUN: %target-codesign %t/a.out
 // RUN: %target-codesign %t/%target-library-name(AttrImplFP)

…perf/fast/expression_too_complex_4.swift …perf/slow/expression_too_complex_4.swiftvalidation-test/Sema/type_checker_perf/fast/expression_too_complex_4.swift renamed to validation-test/Sema/type_checker_perf/slow/expression_too_complex_4.swift validation-test/Sema/type_checker_perf/fast/expression_too_complex_4.swift renamed to validation-test/Sema/type_checker_perf/slow/expression_too_complex_4.swift

@@ -1,8 +1,9 @@
-// RUN: %target-typecheck-verify-swift -swift-version 4 -solver-expression-time-threshold=1 -solver-disable-shrink -disable-constraint-solver-performance-hacks -solver-enable-operator-designated-types
+// RUN: %target-typecheck-verify-swift -swift-version 4 -solver-expression-time-threshold=1
 // REQUIRES: tools-release,no_asan
 
 func test(_ i: Int, _ j: Int) -> Int {
   return 1 + (((i >> 1) + (i >> 2) + (i >> 3) + (i >> 4) << 1) << 1) & 0x40 +
          1 + (((i >> 1) + (i >> 2) + (i >> 3) + (i >> 4) << 1) << 1) & 0x40 +
          1 + (((i >> 1) + (i >> 2) + (i >> 3) + (i >> 4) << 1) << 1) & 0x40
+  // expected-error@-1 {{the compiler is unable to type-check this expression in reasonable time}}
 }