Sema: Remove needless indirection

Author: slavapestov

include/swift/Sema/ConstraintSystem.h

@@ -2335,7 +2335,7 @@ class ConstraintSystem {
   ConstraintList InactiveConstraints;
 
   /// The constraint graph.
-  ConstraintGraph &CG;
+  ConstraintGraph CG;
 
   /// A mapping from constraint locators to the set of opened types associated
   /// with that locator.
@@ -2772,7 +2772,7 @@ class ConstraintSystem {
   ~ConstraintSystem();
 
   /// Retrieve the constraint graph associated with this constraint system.
-  ConstraintGraph &getConstraintGraph() const { return CG; }
+  ConstraintGraph &getConstraintGraph() { return CG; }
 
   /// Retrieve the AST context.
   ASTContext &getASTContext() const { return Context; }

lib/Sema/ConstraintSystem.cpp

@@ -117,7 +117,7 @@ ConstraintSystem::ConstraintSystem(DeclContext *dc,
   : Context(dc->getASTContext()), DC(dc), Options(options),
     diagnosticTransaction(diagnosticTransaction),
     Arena(dc->getASTContext(), Allocator),
-    CG(*new ConstraintGraph(*this))
+    CG(*this)
 {
   assert(DC && "context required");
   // Respect the global debugging flag, but turn off debugging while
@@ -130,9 +130,7 @@ ConstraintSystem::ConstraintSystem(DeclContext *dc,
     Options |= ConstraintSystemFlags::UseClangFunctionTypes;
 }
 
-ConstraintSystem::~ConstraintSystem() {
-  delete &CG;
-}
+ConstraintSystem::~ConstraintSystem() {}
 
 void ConstraintSystem::startExpressionTimer(ExpressionTimer::AnchorType anchor) {
   ASSERT(!Timer);
@@ -1102,7 +1100,7 @@ TypeVariableType *ConstraintSystem::isRepresentativeFor(
   if (getRepresentative(typeVar) != typeVar)
     return nullptr;
 
-  auto &CG = getConstraintGraph();
+  auto &CG = const_cast<ConstraintSystem *>(this)->getConstraintGraph();
   auto &result = CG[typeVar];
   auto equivalence = result.getEquivalenceClass();
   auto member = llvm::find_if(equivalence, [=](TypeVariableType *eq) {