2 files changed, 71 insertions, 0 deletions
diff --git a/clang-tools-extra/test/clang-tidy/Inputs/absl/time/time.h b/clang-tools-extra/test/clang-tidy/Inputs/absl/time/time.h
index 385eed82f64..8da3c2c3f79 100644
--- a/clang-tools-extra/test/clang-tidy/Inputs/absl/time/time.h
+++ b/clang-tools-extra/test/clang-tidy/Inputs/absl/time/time.h
@@ -14,6 +14,8 @@ public:
   Duration &operator/=(float r);
   Duration &operator/=(double r);
   template <typename T> Duration &operator/=(T r);
+
+  Duration &operator+(Duration d);
 };
 
 template <typename T> Duration operator*(Duration lhs, T rhs);
diff --git a/clang-tools-extra/test/clang-tidy/abseil-duration-unnecessary-conversion.cpp b/clang-tools-extra/test/clang-tidy/abseil-duration-unnecessary-conversion.cpp
new file mode 100644
index 00000000000..9414182c8c9
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/abseil-duration-unnecessary-conversion.cpp
@@ -0,0 +1,69 @@
+// RUN: %check_clang_tidy %s abseil-duration-unnecessary-conversion %t -- -- -I%S/Inputs
+
+#include "absl/time/time.h"
+
+void f() {
+  absl::Duration d1, d2;
+
+  // Floating point
+  d2 = absl::Hours(absl::ToDoubleHours(d1));
+  // CHECK-MESSAGES: [[@LINE-1]]:8: warning: remove unnecessary absl::Duration conversions [abseil-duration-unnecessary-conversion]
+  // CHECK-FIXES: d1
+  d2 = absl::Minutes(absl::ToDoubleMinutes(d1));
+  // CHECK-MESSAGES: [[@LINE-1]]:8: warning: remove unnecessary absl::Duration conversions [abseil-duration-unnecessary-conversion]
+  // CHECK-FIXES: d1
+  d2 = absl::Seconds(absl::ToDoubleSeconds(d1));
+  // CHECK-MESSAGES: [[@LINE-1]]:8: warning: remove unnecessary absl::Duration conversions [abseil-duration-unnecessary-conversion]
+  // CHECK-FIXES: d1
+  d2 = absl::Milliseconds(absl::ToDoubleMilliseconds(d1));
+  // CHECK-MESSAGES: [[@LINE-1]]:8: warning: remove unnecessary absl::Duration conversions [abseil-duration-unnecessary-conversion]
+  // CHECK-FIXES: d1
+  d2 = absl::Microseconds(absl::ToDoubleMicroseconds(d1));
+  // CHECK-MESSAGES: [[@LINE-1]]:8: warning: remove unnecessary absl::Duration conversions [abseil-duration-unnecessary-conversion]
+  // CHECK-FIXES: d1
+  d2 = absl::Nanoseconds(absl::ToDoubleNanoseconds(d1));
+  // CHECK-MESSAGES: [[@LINE-1]]:8: warning: remove unnecessary absl::Duration conversions [abseil-duration-unnecessary-conversion]
+  // CHECK-FIXES: d1
+
+  // Integer point
+  d2 = absl::Hours(absl::ToInt64Hours(d1));
+  // CHECK-MESSAGES: [[@LINE-1]]:8: warning: remove unnecessary absl::Duration conversions [abseil-duration-unnecessary-conversion]
+  // CHECK-FIXES: d1
+  d2 = absl::Minutes(absl::ToInt64Minutes(d1));
+  // CHECK-MESSAGES: [[@LINE-1]]:8: warning: remove unnecessary absl::Duration conversions [abseil-duration-unnecessary-conversion]
+  // CHECK-FIXES: d1
+  d2 = absl::Seconds(absl::ToInt64Seconds(d1));
+  // CHECK-MESSAGES: [[@LINE-1]]:8: warning: remove unnecessary absl::Duration conversions [abseil-duration-unnecessary-conversion]
+  // CHECK-FIXES: d1
+  d2 = absl::Milliseconds(absl::ToInt64Milliseconds(d1));
+  // CHECK-MESSAGES: [[@LINE-1]]:8: warning: remove unnecessary absl::Duration conversions [abseil-duration-unnecessary-conversion]
+  // CHECK-FIXES: d1
+  d2 = absl::Microseconds(absl::ToInt64Microseconds(d1));
+  // CHECK-MESSAGES: [[@LINE-1]]:8: warning: remove unnecessary absl::Duration conversions [abseil-duration-unnecessary-conversion]
+  // CHECK-FIXES: d1
+  d2 = absl::Nanoseconds(absl::ToInt64Nanoseconds(d1));
+  // CHECK-MESSAGES: [[@LINE-1]]:8: warning: remove unnecessary absl::Duration conversions [abseil-duration-unnecessary-conversion]
+  // CHECK-FIXES: d1
+
+  // As macro argument
+#define PLUS_FIVE_S(x) x + absl::Seconds(5)
+  d2 = PLUS_FIVE_S(absl::Seconds(absl::ToInt64Seconds(d1)));
+  // CHECK-MESSAGES: [[@LINE-1]]:20: warning: remove unnecessary absl::Duration conversions [abseil-duration-unnecessary-conversion]
+  // CHECK-FIXES: PLUS_FIVE_S(d1)
+#undef PLUS_FIVE_S
+
+  // Split by macro: should not change
+#define TOSECONDS(x) absl::Seconds(x)
+  d2 = TOSECONDS(absl::ToInt64Seconds(d1));
+#undef TOSECONDS
+
+  // Don't change something inside a macro definition
+#define VALUE(x) absl::Hours(absl::ToInt64Hours(x));
+  d2 = VALUE(d1);
+#undef VALUE
+
+  // These should not match
+  d2 = absl::Seconds(absl::ToDoubleMilliseconds(d1));
+  d2 = absl::Seconds(4);
+  int i = absl::ToInt64Milliseconds(d1);
+}