Store full locator info on ForceOptional

For the purposes of fix deduplication, we want to use the simplified
locator. However for the purposes of diagnostics, preserve the full
locator, which gives us more information to work with.

Author: hamishknight

lib/Sema/CSFix.cpp

@@ -67,16 +67,17 @@ ForceDowncast *ForceDowncast::create(ConstraintSystem &cs, Type toType,
 
 bool ForceOptional::diagnose(Expr *root, bool asNote) const {
   MissingOptionalUnwrapFailure failure(root, getConstraintSystem(), BaseType,
-                                       UnwrappedType, getLocator());
+                                       UnwrappedType, FullLocator);
   return failure.diagnose(asNote);
 }
 
 ForceOptional *ForceOptional::create(ConstraintSystem &cs, Type baseType,
                                      Type unwrappedType,
                                      ConstraintLocator *locator) {
-  return new (cs.getAllocator()) ForceOptional(
-      cs, baseType, unwrappedType,
-      cs.getConstraintLocator(simplifyLocatorToAnchor(cs, locator)));
+  auto *simplifiedLocator =
+      cs.getConstraintLocator(simplifyLocatorToAnchor(cs, locator));
+  return new (cs.getAllocator())
+      ForceOptional(cs, baseType, unwrappedType, simplifiedLocator, locator);
 }
 
 bool UnwrapOptionalBase::diagnose(Expr *root, bool asNote) const {

lib/Sema/CSFix.h

@@ -231,11 +231,14 @@ class ForceDowncast final : public ConstraintFix {
 class ForceOptional final : public ConstraintFix {
   Type BaseType;
   Type UnwrappedType;
+  ConstraintLocator *FullLocator;
 
   ForceOptional(ConstraintSystem &cs, Type baseType, Type unwrappedType,
-                ConstraintLocator *locator)
-      : ConstraintFix(cs, FixKind::ForceOptional, locator), BaseType(baseType),
-        UnwrappedType(unwrappedType) {
+                ConstraintLocator *simplifiedLocator,
+                ConstraintLocator *fullLocator)
+      : ConstraintFix(cs, FixKind::ForceOptional, simplifiedLocator),
+        BaseType(baseType), UnwrappedType(unwrappedType),
+        FullLocator(fullLocator) {
     assert(baseType && "Base type must not be null");
     assert(unwrappedType && "Unwrapped type must not be null");
   }