diff --git a/clang/lib/StaticAnalyzer/Core/SarifDiagnostics.cpp b/clang/lib/StaticAnalyzer/Core/SarifDiagnostics.cpp
--- a/clang/lib/StaticAnalyzer/Core/SarifDiagnostics.cpp
+++ b/clang/lib/StaticAnalyzer/Core/SarifDiagnostics.cpp
@@ -158,7 +158,7 @@
   assert(!Loc.isInvalid() && "invalid Loc when adjusting column position");
 
   std::pair<FileID, unsigned> LocInfo = SM.getDecomposedExpansionLoc(Loc);
-  assert(LocInfo.second > SM.getExpansionColumnNumber(Loc) &&
+  assert(LocInfo.second + 1 >= SM.getExpansionColumnNumber(Loc) &&
          "position in file is before column number?");
 
   Optional<MemoryBufferRef> Buf = SM.getBufferOrNone(LocInfo.first);