[NFC] Eliminate const_casts in constraint system dumpers

Author: beccadax

lib/Sema/CSBindings.cpp

@@ -207,7 +207,7 @@ bool ConstraintSystem::PotentialBindings::isViable(
 }
 
 static bool hasNilLiteralConstraint(TypeVariableType *typeVar,
-                                    ConstraintSystem &CS) {
+                                    const ConstraintSystem &CS) {
   // Look for a literal-conformance constraint on the type variable.
   auto constraints =
       CS.getConstraintGraph().gatherConstraints(
@@ -230,7 +230,7 @@ ConstraintSystem::getPotentialBindingForRelationalConstraint(
     PotentialBindings &result, Constraint *constraint,
     bool &hasDependentMemberRelationalConstraints,
     bool &hasNonDependentMemberRelationalConstraints,
-    bool &addOptionalSupertypeBindings) {
+    bool &addOptionalSupertypeBindings) const {
   assert(constraint->getClassification() ==
              ConstraintClassification::Relational &&
          "only relational constraints handled here");
@@ -378,7 +378,7 @@ ConstraintSystem::getPotentialBindingForRelationalConstraint(
 /// representative type variable, along with flags indicating whether
 /// those types should be opened.
 ConstraintSystem::PotentialBindings
-ConstraintSystem::getPotentialBindings(TypeVariableType *typeVar) {
+ConstraintSystem::getPotentialBindings(TypeVariableType *typeVar) const {
   assert(typeVar->getImpl().getRepresentative(nullptr) == typeVar &&
          "not a representative");
   assert(!typeVar->getImpl().getFixedType(nullptr) && "has a fixed type");
@@ -796,7 +796,7 @@ ConstraintSystem::getPotentialBindings(TypeVariableType *typeVar) {
 ///
 /// \returns the type to bind to, if the binding is okay.
 Optional<Type> ConstraintSystem::checkTypeOfBinding(TypeVariableType *typeVar,
-                                                    Type type) {
+                                                    Type type) const {
   // Simplify the type.
   type = simplifyType(type);
 

lib/Sema/ConstraintGraph.cpp

@@ -1319,7 +1319,7 @@ void ConstraintGraph::incrementConstraintsPerContractionCounter() {
 
 #pragma mark Debugging output
 
-void ConstraintGraphNode::print(llvm::raw_ostream &out, unsigned indent) {
+void ConstraintGraphNode::print(llvm::raw_ostream &out, unsigned indent) const {
   out.indent(indent);
   TypeVar->print(out);
   out << ":\n";
@@ -1351,7 +1351,7 @@ void ConstraintGraphNode::print(llvm::raw_ostream &out, unsigned indent) {
      out << ' ';
      adj->print(out);
 
-     auto &info = AdjacencyInfo[adj];
+     const auto info = AdjacencyInfo.lookup(adj);
      auto degree = info.NumConstraints;
      if (degree > 1) {
        out << " (" << degree << ")";
@@ -1397,7 +1397,7 @@ void ConstraintGraphNode::print(llvm::raw_ostream &out, unsigned indent) {
 void ConstraintGraphNode::dump() const {
   llvm::SaveAndRestore<bool>
     debug(TypeVar->getASTContext().LangOpts.DebugConstraintSolver, true);
-  const_cast<ConstraintGraphNode*>(this)->print(llvm::dbgs(), 0);
+  print(llvm::dbgs(), 0);
 }
 
 void ConstraintGraph::print(ArrayRef<TypeVariableType *> typeVars,

lib/Sema/ConstraintGraph.h

@@ -160,7 +160,7 @@ class ConstraintGraphNode {
   mutable SmallVector<TypeVariableType *, 2> EquivalenceClass;
 
   /// Print this graph node.
-  void print(llvm::raw_ostream &out, unsigned indent);
+  void print(llvm::raw_ostream &out, unsigned indent) const;
 
   SWIFT_DEBUG_DUMP;
 

lib/Sema/ConstraintSystem.cpp

@@ -746,7 +746,7 @@ bool ConstraintSystem::isAnyHashableType(Type type) {
 
 Type ConstraintSystem::getFixedTypeRecursive(Type type,
                                              TypeMatchOptions &flags,
-                                             bool wantRValue) {
+                                             bool wantRValue) const {
 
   if (wantRValue)
     type = type->getRValueType();
@@ -2259,7 +2259,8 @@ void ConstraintSystem::resolveOverload(ConstraintLocator *locator,
 }
 
 template <typename Fn>
-Type simplifyTypeImpl(ConstraintSystem &cs, Type type, Fn getFixedTypeFn) {
+Type simplifyTypeImpl(const ConstraintSystem &cs, Type type,
+                      Fn getFixedTypeFn) {
   return type.transform([&](Type type) -> Type {
     if (auto tvt = dyn_cast<TypeVariableType>(type.getPointer()))
       return getFixedTypeFn(tvt);
@@ -2305,7 +2306,7 @@ Type simplifyTypeImpl(ConstraintSystem &cs, Type type, Fn getFixedTypeFn) {
   });
 }
 
-Type ConstraintSystem::simplifyType(Type type) {
+Type ConstraintSystem::simplifyType(Type type) const {
   if (!type->hasTypeVariable())
     return type;
 

lib/Sema/ConstraintSystem.h

@@ -2360,7 +2360,7 @@ class ConstraintSystem {
 
   /// Retrieve the representative of the equivalence class containing
   /// this type variable.
-  TypeVariableType *getRepresentative(TypeVariableType *typeVar) {
+  TypeVariableType *getRepresentative(TypeVariableType *typeVar) const {
     return typeVar->getImpl().getRepresentative(getSavedBindings());
   }
 
@@ -2467,7 +2467,7 @@ class ConstraintSystem {
   ///
   /// \param wantRValue Whether this routine should look through
   /// lvalues at each step.
-  Type getFixedTypeRecursive(Type type, bool wantRValue) {
+  Type getFixedTypeRecursive(Type type, bool wantRValue) const {
     TypeMatchOptions flags = None;
     return getFixedTypeRecursive(type, flags, wantRValue);
   }
@@ -2485,7 +2485,7 @@ class ConstraintSystem {
   /// \param wantRValue Whether this routine should look through
   /// lvalues at each step.
   Type getFixedTypeRecursive(Type type, TypeMatchOptions &flags,
-                             bool wantRValue);
+                             bool wantRValue) const;
 
   /// Determine whether the given type variable occurs within the given type.
   ///
@@ -3027,7 +3027,7 @@ class ConstraintSystem {
   ///
   /// The resulting types can be compared canonically, so long as additional
   /// type equivalence requirements aren't introduced between comparisons.
-  Type simplifyType(Type type);
+  Type simplifyType(Type type) const;
 
   /// Simplify a type, by replacing type variables with either their
   /// fixed types (if available) or their representatives.
@@ -3478,15 +3478,15 @@ class ConstraintSystem {
     }
   };
 
-  Optional<Type> checkTypeOfBinding(TypeVariableType *typeVar, Type type);
+  Optional<Type> checkTypeOfBinding(TypeVariableType *typeVar, Type type) const;
   Optional<PotentialBindings> determineBestBindings();
   Optional<ConstraintSystem::PotentialBinding>
   getPotentialBindingForRelationalConstraint(
       PotentialBindings &result, Constraint *constraint,
       bool &hasDependentMemberRelationalConstraints,
       bool &hasNonDependentMemberRelationalConstraints,
-      bool &addOptionalSupertypeBindings);
-  PotentialBindings getPotentialBindings(TypeVariableType *typeVar);
+      bool &addOptionalSupertypeBindings) const;
+  PotentialBindings getPotentialBindings(TypeVariableType *typeVar) const;
 
 private:
   /// Add a constraint to the constraint system.
@@ -3836,8 +3836,8 @@ class ConstraintSystem {
   SWIFT_DEBUG_DUMP;
   SWIFT_DEBUG_DUMPER(dump(Expr *));
 
-  void print(raw_ostream &out);
-  void print(raw_ostream &out, Expr *);
+  void print(raw_ostream &out) const;
+  void print(raw_ostream &out, Expr *) const;
 };
 
 /// Compute the shuffle required to map from a given tuple type to

lib/Sema/TypeCheckConstraints.cpp

@@ -3618,14 +3618,14 @@ void Solution::dump(raw_ostream &out) const {
 }
 
 void ConstraintSystem::dump() const {
-  const_cast<ConstraintSystem*>(this)->print(llvm::errs());
+  print(llvm::errs());
 }
 
 void ConstraintSystem::dump(Expr *E) const {
-  const_cast<ConstraintSystem*>(this)->print(llvm::errs(), E);
+  print(llvm::errs(), E);
 }
 
-void ConstraintSystem::print(raw_ostream &out, Expr *E) {
+void ConstraintSystem::print(raw_ostream &out, Expr *E) const {
   auto getTypeOfExpr = [&](const Expr *E) -> Type {
     if (hasType(E))
       return getType(E);
@@ -3646,7 +3646,7 @@ void ConstraintSystem::print(raw_ostream &out, Expr *E) {
   E->dump(out, getTypeOfExpr, getTypeOfTypeLoc, getTypeOfKeyPathComponent);
 }
 
-void ConstraintSystem::print(raw_ostream &out) {
+void ConstraintSystem::print(raw_ostream &out) const {
   // Print all type variables as $T0 instead of _ here.
   llvm::SaveAndRestore<bool> X(getASTContext().LangOpts.DebugConstraintSolver,
                                true);