[ConstraintLocator] Add an accessor to check whether locator points directly at try?

Author: xedin

lib/Sema/ConstraintLocator.cpp

@@ -243,6 +243,11 @@ bool ConstraintLocator::isForCoercion() const {
   return anchor && isa<CoerceExpr>(anchor) && getPath().empty();
 }
 
+bool ConstraintLocator::isForOptionalTry() const {
+  auto *anchor = getAnchor();
+  return anchor && isa<OptionalTryExpr>(anchor) && getPath().empty();
+}
+
 GenericTypeParamType *ConstraintLocator::getGenericParameter() const {
   // Check whether we have a path that terminates at a generic parameter.
   return isForGenericParameter() ?

lib/Sema/ConstraintLocator.h

@@ -371,6 +371,9 @@ class ConstraintLocator : public llvm::FoldingSetNode {
   /// Determine whether this locator points to the coercion expression.
   bool isForCoercion() const;
 
+  /// Determine whether this locator points to the `try?` expression.
+  bool isForOptionalTry() const;
+
   /// Attempts to cast the first path element of the locator to a specific
   /// \c LocatorPathElt subclass, returning \c None if either unsuccessful or
   /// the locator has no path elements.