Assert enum type equivalence in UMA_HISTOGRAM_ENUMERATION

base/metrics/histogram_macros.h

Index: base/metrics/histogram_macros.h
diff --git a/base/metrics/histogram_macros.h b/base/metrics/histogram_macros.h
index 63cca694e9ad2d3d5ab36b99b6b426f14e628692..ded241b9906686992c72029b659d2e7d50b855af 100644
--- a/base/metrics/histogram_macros.h
+++ b/base/metrics/histogram_macros.h
@@ -41,10 +41,15 @@
 // delete and reused. The value in |sample| must be strictly less than
 // |enum_max|.
 
-#define UMA_HISTOGRAM_ENUMERATION(name, sample, enum_max)                      \
-    INTERNAL_HISTOGRAM_ENUMERATION_WITH_FLAG(                                  \
-        name, sample, enum_max,                                                \
-        base::HistogramBase::kUmaTargetedHistogramFlag)
+#define UMA_HISTOGRAM_ENUMERATION(name, sample, enum_max)                   \
+  static_assert(                                                            \

[Alexei Svitkine (slow), 2016/11/02 15:48:47]

Thanks for working on this!

Just a nit, can you move the assert to
INTERNAL_HISTOGRAM_ENUMERATION_WITH_FLAG()? We'd like all the implementation
details to live there so as not to clutter this file.

[wychen, 2016/11/02 21:45:04]

Done.

+      !std::is_enum<decltype(sample)>::value ||                             \
+          !std::is_enum<decltype(enum_max)>::value ||                       \
+          std::is_same<std::remove_const<decltype(sample)>::type,           \
+                       std::remove_const<decltype(enum_max)>::type>::value, \
+      "UMA_HISTOGRAM_ENUMERATION type incompatible");                       \
+  INTERNAL_HISTOGRAM_ENUMERATION_WITH_FLAG(                                 \
+      name, sample, enum_max, base::HistogramBase::kUmaTargetedHistogramFlag)
 
 // Histogram for boolean values.