diff --git a/clang/include/clang/Serialization/ASTReader.h b/clang/include/clang/Serialization/ASTReader.h
index 7d4b4467eb97..43b4576093cf 100644
--- a/clang/include/clang/Serialization/ASTReader.h
+++ b/clang/include/clang/Serialization/ASTReader.h
@@ -525,7 +525,7 @@ private:
   ContinuousRangeMap<unsigned, ModuleFile*, 64> GlobalSLocEntryMap;
 
   using GlobalSLocOffsetMapType =
-      ContinuousRangeMap<unsigned, ModuleFile *, 64>;
+      ContinuousRangeMap<SourceLocation::UIntTy, ModuleFile *, 64>;
 
   /// A map of reversed (SourceManager::MaxLoadedOffset - SLocOffset)
   /// SourceLocation offsets to the modules containing them.