[CSBindings] const qualify ConstraintSystem passed to inference methods

Author: xedin

lib/Sema/CSBindings.cpp

@@ -22,7 +22,7 @@ using namespace swift;
 using namespace constraints;
 
 void ConstraintSystem::PotentialBindings::inferTransitiveBindings(
-    ConstraintSystem &cs, llvm::SmallPtrSetImpl<CanType> &existingTypes,
+    const ConstraintSystem &cs, llvm::SmallPtrSetImpl<CanType> &existingTypes,
     const llvm::SmallDenseMap<TypeVariableType *,
                               ConstraintSystem::PotentialBindings>
         &inferredBindings) {
@@ -119,7 +119,7 @@ isUnviableDefaultType(Type defaultType,
 }
 
 void ConstraintSystem::PotentialBindings::inferDefaultTypes(
-    ConstraintSystem &cs, llvm::SmallPtrSetImpl<CanType> &existingTypes) {
+    const ConstraintSystem &cs, llvm::SmallPtrSetImpl<CanType> &existingTypes) {
   auto isDirectRequirement = [&](Constraint *constraint) -> bool {
     if (auto *typeVar = constraint->getFirstType()->getAs<TypeVariableType>()) {
       auto *repr = cs.getRepresentative(typeVar);
@@ -275,7 +275,7 @@ void ConstraintSystem::PotentialBindings::inferDefaultTypes(
 }
 
 void ConstraintSystem::PotentialBindings::finalize(
-    ConstraintSystem &cs,
+    const ConstraintSystem &cs,
     const llvm::SmallDenseMap<TypeVariableType *,
                               ConstraintSystem::PotentialBindings>
         &inferredBindings) {

lib/Sema/ConstraintSystem.h

@@ -4595,20 +4595,21 @@ class ConstraintSystem {
     /// \param inferredBindings The set of all bindings inferred for type
     /// variables in the workset.
     void inferTransitiveBindings(
-        ConstraintSystem &cs, llvm::SmallPtrSetImpl<CanType> &existingTypes,
+        const ConstraintSystem &cs,
+        llvm::SmallPtrSetImpl<CanType> &existingTypes,
         const llvm::SmallDenseMap<TypeVariableType *,
                                   ConstraintSystem::PotentialBindings>
             &inferredBindings);
 
     /// Infer bindings based on any protocol conformances that have default
     /// types.
-    void inferDefaultTypes(ConstraintSystem &cs,
+    void inferDefaultTypes(const ConstraintSystem &cs,
                            llvm::SmallPtrSetImpl<CanType> &existingTypes);
 
 public:
     /// Finalize binding computation for this type variable by
     /// inferring bindings from context e.g. transitive bindings.
-    void finalize(ConstraintSystem &cs,
+    void finalize(const ConstraintSystem &cs,
                   const llvm::SmallDenseMap<TypeVariableType *,
                                             ConstraintSystem::PotentialBindings>
                       &inferredBindings);