diff --git a/clang-tools-extra/clang-tidy/abseil/UpgradeDurationConversionsCheck.h b/clang-tools-extra/clang-tidy/abseil/UpgradeDurationConversionsCheck.h
--- a/clang-tools-extra/clang-tidy/abseil/UpgradeDurationConversionsCheck.h
+++ b/clang-tools-extra/clang-tidy/abseil/UpgradeDurationConversionsCheck.h
@@ -11,7 +11,8 @@
 
 #include "../ClangTidyCheck.h"
 
-#include <unordered_set>
+#include "clang/Basic/SourceLocation.h"
+#include "llvm/ADT/DenseSet.h"
 
 namespace clang {
 namespace tidy {
@@ -32,7 +33,7 @@
   void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
 
 private:
-  std::unordered_set<unsigned> MatchedTemplateLocations;
+  llvm::DenseSet<SourceLocation> MatchedTemplateLocations;
 };
 
 } // namespace abseil
diff --git a/clang-tools-extra/clang-tidy/abseil/UpgradeDurationConversionsCheck.cpp b/clang-tools-extra/clang-tidy/abseil/UpgradeDurationConversionsCheck.cpp
--- a/clang-tools-extra/clang-tidy/abseil/UpgradeDurationConversionsCheck.cpp
+++ b/clang-tools-extra/clang-tidy/abseil/UpgradeDurationConversionsCheck.cpp
@@ -128,7 +128,7 @@
 
   if (!match(isInTemplateInstantiation(), *OuterExpr, *Result.Context)
            .empty()) {
-    if (MatchedTemplateLocations.count(Loc.getRawEncoding()) == 0) {
+    if (MatchedTemplateLocations.count(Loc) == 0) {
       // For each location matched in a template instantiation, we check if the
       // location can also be found in `MatchedTemplateLocations`. If it is not
       // found, that means the expression did not create a match without the
@@ -144,7 +144,7 @@
   internal::Matcher<Stmt> IsInsideTemplate =
       hasAncestor(decl(anyOf(classTemplateDecl(), functionTemplateDecl())));
   if (!match(IsInsideTemplate, *ArgExpr, *Result.Context).empty())
-    MatchedTemplateLocations.insert(Loc.getRawEncoding());
+    MatchedTemplateLocations.insert(Loc);
 
   DiagnosticBuilder Diag = diag(Loc, Message);
   CharSourceRange SourceRange = Lexer::makeFileCharRange(