diff --git a/clang-tools-extra/clang-tidy/bugprone/ArgumentCommentCheck.cpp b/clang-tools-extra/clang-tidy/bugprone/ArgumentCommentCheck.cpp
--- a/clang-tools-extra/clang-tidy/bugprone/ArgumentCommentCheck.cpp
+++ b/clang-tools-extra/clang-tidy/bugprone/ArgumentCommentCheck.cpp
@@ -60,7 +60,7 @@
 
 void ArgumentCommentCheck::registerMatchers(MatchFinder *Finder) {
   Finder->addMatcher(
-      callExpr(unless(cxxOperatorCallExpr()),
+      callExpr(unless(cxxOperatorCallExpr()), unless(userDefinedLiteral()),
                // NewCallback's arguments relate to the pointed function,
                // don't check them against NewCallback's parameter names.
                // FIXME: Make this configurable.
diff --git a/clang-tools-extra/test/clang-tidy/checkers/bugprone-argument-comment-literals.cpp b/clang-tools-extra/test/clang-tidy/checkers/bugprone-argument-comment-literals.cpp
--- a/clang-tools-extra/test/clang-tidy/checkers/bugprone-argument-comment-literals.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/bugprone-argument-comment-literals.cpp
@@ -29,7 +29,7 @@
 void i(const char *c);
 void j(int a, int b, int c);
 
-double operator"" _km(long double);
+double operator"" _km(long double value);
 
 void test() {
   A a;
@@ -171,6 +171,8 @@
   g((1));
   // FIXME But we should not add argument comments here.
   g(_Generic(0, int : 0));
+
+  402.0_km;
 }
 
 void f(bool _with_underscores_);