[ConstraintLocator] Add accessors for assignemnt and coerce expression

Author: xedin

lib/Sema/ConstraintLocator.cpp

@@ -227,6 +227,16 @@ bool ConstraintLocator::isForContextualType() const {
   return isLastElement<LocatorPathElt::ContextualType>();
 }
 
+bool ConstraintLocator::isForAssignment() const {
+  auto *anchor = getAnchor();
+  return anchor && isa<AssignExpr>(anchor) && getPath().empty();
+}
+
+bool ConstraintLocator::isForCoercion() const {
+  auto *anchor = getAnchor();
+  return anchor && isa<CoerceExpr>(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

@@ -360,6 +360,12 @@ class ConstraintLocator : public llvm::FoldingSetNode {
   /// Determine whether this locator points to the contextual type.
   bool isForContextualType() const;
 
+  /// Determine whether this locator points to the assignment expression.
+  bool isForAssignment() const;
+
+  /// Determine whether this locator points to the coercion expression.
+  bool isForCoercion() 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.