Merge pull request #5421 from DougGregor/finish-lazy-constraints

Author: swift-ci

lib/Sema/CSSimplify.cpp

@@ -4156,6 +4156,7 @@ ConstraintSystem::addConstraintImpl(ConstraintKind kind, Type first,
   TypeMatchOptions subflags = TMF_GenerateConstraints;
   switch (kind) {
   case ConstraintKind::Equal:
+  case ConstraintKind::Bind:
   case ConstraintKind::BindParam:
   case ConstraintKind::Subtype:
   case ConstraintKind::Conversion:
@@ -4188,16 +4189,6 @@ ConstraintSystem::addConstraintImpl(ConstraintKind kind, Type first,
   case ConstraintKind::Defaultable:
     return simplifyDefaultableConstraint(first, second, subflags, locator);
 
-  case ConstraintKind::Bind: { // FIXME: This should go through matchTypes() above
-    // FALLBACK CASE: do the slow thing.
-    auto c = Constraint::create(*this, kind, first, second, DeclName(),
-                                FunctionRefKind::Compound,
-                                getConstraintLocator(locator));
-    if (isFavored) c->setFavored();
-    addConstraint(c);
-    return SolutionKind::Solved;
-  }
-
   case ConstraintKind::ValueMember:
   case ConstraintKind::UnresolvedValueMember:
   case ConstraintKind::TypeMember:

lib/Sema/ConstraintSystem.cpp

@@ -333,37 +333,6 @@ ConstraintLocator *ConstraintSystem::getConstraintLocator(
   return getConstraintLocator(anchor, path, builder.getSummaryFlags());
 }
 
-bool ConstraintSystem::addConstraint(Constraint *constraint) {
-  switch (simplifyConstraint(*constraint)) {
-  case SolutionKind::Error:
-    if (!failedConstraint) {
-      failedConstraint = constraint;
-    }
-
-    if (solverState) {
-      solverState->retiredConstraints.push_front(constraint);
-      solverState->generatedConstraints.push_back(constraint);
-    }
-
-    return false;
-
-  case SolutionKind::Solved:
-    // This constraint has already been solved; there is nothing more
-    // to do.
-    // Record solved constraint.
-    if (solverState) {
-      solverState->retiredConstraints.push_front(constraint);
-      solverState->generatedConstraints.push_back(constraint);
-    }
-
-    return true;
-
-  case SolutionKind::Unsolved:
-    addUnsolvedConstraint(constraint);
-    return false;
-  }
-}
-
 TypeVariableType *
 ConstraintSystem::getMemberType(TypeVariableType *baseTypeVar, 
                                 AssociatedTypeDecl *assocType,
@@ -1389,6 +1358,12 @@ void ConstraintSystem::addOverloadSet(Type boundType,
                                       OverloadChoice *favoredChoice) {
   assert(!choices.empty() && "Empty overload set");
 
+  // If there is a single choice, add the bind overload directly.
+  if (choices.size() == 1) {
+    addBindOverloadConstraint(boundType, choices.front(), locator);
+    return;
+  }
+
   SmallVector<Constraint *, 4> overloads;
 
   // As we do for other favored constraints, if a favored overload has been

lib/Sema/ConstraintSystem.h

@@ -1373,12 +1373,6 @@ class ConstraintSystem {
   /// emits an error message.
   void diagnoseFailureForExpr(Expr *expr);
 
-  /// \brief Add a newly-allocated constraint after attempting to simplify
-  /// it.
-  ///
-  /// \returns true if this constraint was solved.
-  bool addConstraint(Constraint *constraint);
-
   /// \brief Add a constraint to the constraint system.
   void addConstraint(ConstraintKind kind, Type first, Type second,
                      ConstraintLocatorBuilder locator,
@@ -1490,7 +1484,7 @@ class ConstraintSystem {
     if (isFavored)
       constraint->setFavored();
 
-    addConstraint(constraint);
+    addUnsolvedConstraint(constraint);
   }
 
   /// Whether we should add a new constraint to capture a failure.