Merge pull request #6568 from rudkx/const-exprs

Make ConstraintSystem's hasType/getType take const Exprs.

Author: rudkx

lib/Sema/ConstraintSystem.h

@@ -906,7 +906,7 @@ class ConstraintSystem {
   /// nodes themselves. This allows us to typecheck an expression and
   /// run through various diagnostics passes without actually mutating
   /// the types on the expression nodes.
-  llvm::DenseMap<Expr *, TypeBase *> ExprTypes;
+  llvm::DenseMap<const Expr *, TypeBase *> ExprTypes;
 
   /// There can only be a single contextual type on the root of the expression
   /// being checked.  If specified, this holds its type along with the base
@@ -1388,16 +1388,16 @@ class ConstraintSystem {
   }
 
   /// Check to see if we have a type for an expression.
-  bool hasType(Expr *E) {
+  bool hasType(const Expr *E) const {
     return ExprTypes.find(E) != ExprTypes.end();
   }
 
   /// Get the type for an expression.
-  Type getType(Expr *E) {
+  Type getType(const Expr *E) const {
     assert(hasType(E) && "Expected type to have been set!");
-    assert(ExprTypes[E]->isEqual(E->getType()) &&
+    assert(ExprTypes.find(E)->second->isEqual(E->getType()) &&
            "Expected type in map to be the same type in expression!");
-    return ExprTypes[E];
+    return ExprTypes.find(E)->second;
   }
 
   /// Cache the type of the expression argument and return that same