[Constraint solver] Remove some dead instance variables.

Author: DougGregor

lib/Sema/CSGen.cpp

@@ -1727,7 +1727,6 @@ namespace {
       if (arrayElementTy->isTypeVariableOrMember()) {
         CS.addConstraint(ConstraintKind::Defaultable, arrayElementTy,
                          tc.Context.TheAnyType, locator);
-        CS.ArrayElementTypes[expr] = arrayElementTy;
       }
 
       return arrayTy;
@@ -1871,11 +1870,6 @@ namespace {
                          tc.Context.TheAnyType, locator);
       }
 
-      // Record key/value type variables.
-      if (dictionaryKeyTy->isTypeVariableOrMember() ||
-          dictionaryValueTy->isTypeVariableOrMember())
-        CS.DictionaryElementTypes[expr] = {dictionaryKeyTy, dictionaryValueTy};
-
       return dictionaryTy;
     }
 

lib/Sema/ConstraintSystem.h

@@ -998,15 +998,6 @@ class ConstraintSystem {
   /// The locators of \c Defaultable constraints whose defaults were used.
   SmallVector<ConstraintLocator *, 8> DefaultedConstraints;
 
-  /// The types used to describe the element type of the given array
-  /// literal.
-  llvm::SmallDenseMap<ArrayExpr *, Type> ArrayElementTypes;
-
-  /// The types used to describe the key and value types of the given
-  /// dictionary literal.
-  llvm::SmallDenseMap<DictionaryExpr *, std::pair<Type, Type>>
-    DictionaryElementTypes;
-
 private:
   /// \brief Describe the candidate expression for partial solving.
   /// This class used by shrink & solve methods which apply