[CSBindings] Fix double printing of type variables.

Fix spacing when printing initial Type Variables. Add
line break to bindings that print under Potential Bindings.

Author: Amritpan Kaur

include/swift/Sema/ConstraintSystem.h

@@ -590,7 +590,7 @@ class TypeVariableType::Implementation {
 
   /// Print the type variable to the given output stream.
   void print(llvm::raw_ostream &OS);
-  
+
 private:
   StringRef getTypeVariableOptions(TypeVariableOptions TVO) const {
   #define ENTRY(Kind, String) case TypeVariableOptions::Kind: return String

lib/Sema/CSBindings.cpp

@@ -1657,9 +1657,11 @@ void BindingSet::dump(llvm::raw_ostream &out, unsigned indent) const {
 
   out.indent(indent);
   out << "(";
-  if (auto typeVar = getTypeVariable())
-    out << "$T" << typeVar->getImpl().getID() << " ";
-  
+  if (auto typeVar = getTypeVariable()) {
+    typeVar->print(out, PO);
+    out << " ";
+  }
+
   std::vector<std::string> attributes;
   if (isDirectHole())
     attributes.push_back("hole");
@@ -1722,7 +1724,7 @@ void BindingSet::dump(llvm::raw_ostream &out, unsigned indent) const {
 
   auto numDefaultable = getNumViableDefaultableBindings();
   if (numDefaultable > 0)
-    out << "#defaultable_bindings: " << numDefaultable << " ";
+    out << "[#defaultable_bindings: " << numDefaultable << "] ";
 
   auto printBinding = [&](const PotentialBinding &binding) {
     auto type = binding.BindingType;
@@ -1769,9 +1771,9 @@ void BindingSet::dump(llvm::raw_ostream &out, unsigned indent) const {
                                AllowedBindingKind::Exact, constraint};
       printBinding(binding);
     }
-    out << "] ";
+    out << "]";
   }
-  out << ")\n";
+  out << ")";
 }
 
 // Given a possibly-Optional type, return the direct superclass of the

lib/Sema/CSStep.cpp

@@ -352,6 +352,7 @@ StepResult ComponentStep::take(bool prevFailed) {
   auto bestBindings = CS.determineBestBindings([&](const BindingSet &bindings) {
     if (CS.isDebugMode() && bindings.hasViableBindings()) {
       bindings.dump(bos, CS.solverState->getCurrentIndent() + 2);
+      bos << "\n";
     }
   });
 

lib/Sema/TypeCheckConstraints.cpp

@@ -1466,16 +1466,17 @@ void ConstraintSystem::print(raw_ostream &out) const {
              });
   for (auto tv : typeVariables) {
     out.indent(2);
-    tv->getImpl().print(out);
     auto rep = getRepresentative(tv);
     if (rep == tv) {
       if (auto fixed = getFixedType(tv)) {
+        tv->getImpl().print(out);
         out << " as ";
         Type(fixed).print(out, PO);
       } else {
         const_cast<ConstraintSystem *>(this)->getBindingsFor(tv).dump(out, 1);
       }
     } else {
+      tv->getImpl().print(out);
       out << " equivalent to ";
       Type(rep).print(out, PO);
     }