diff --git a/lib/Analysis/PathDiagnostic.cpp b/lib/Analysis/PathDiagnostic.cpp
index 02fe165..69b11fb 100644
--- a/lib/Analysis/PathDiagnostic.cpp
+++ b/lib/Analysis/PathDiagnostic.cpp
@@ -140,6 +140,7 @@
 //===----------------------------------------------------------------------===//
 
 FullSourceLoc PathDiagnosticLocation::asLocation() const {
+  assert(isValid());
   // Note that we want a 'switch' here so that the compiler can warn us in
   // case we add more cases.
   switch (K) {
@@ -154,6 +155,7 @@
 }
 
 SourceRange PathDiagnosticLocation::asRange() const {
+  assert(isValid());
   // Note that we want a 'switch' here so that the compiler can warn us in
   // case we add more cases.
   switch (K) {