[ConstraintSystem] Allow to check presence of fix by kind and locator

Author: xedin

lib/Sema/ConstraintSystem.h

@@ -2095,10 +2095,15 @@ class ConstraintSystem {
 
   /// Determine whether constraint system already has a fix recorded
   /// for a particular location.
-  bool hasFixFor(ConstraintLocator *locator) const {
-    return llvm::any_of(Fixes, [&locator](const ConstraintFix *fix) {
-      return fix->getLocator() == locator;
-    });
+  bool hasFixFor(ConstraintLocator *locator,
+                 Optional<FixKind> expectedKind = None) const {
+    return llvm::any_of(
+        Fixes, [&locator, &expectedKind](const ConstraintFix *fix) {
+          if (fix->getLocator() == locator) {
+            return !expectedKind || fix->getKind() == *expectedKind;
+          }
+          return false;
+        });
   }
 
   /// If an UnresolvedDotExpr, SubscriptMember, etc has been resolved by the