Assert enum type equivalence in UMA_HISTOGRAM_ENUMERATION

base/metrics/histogram_macros.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef BASE_METRICS_HISTOGRAM_MACROS_H_
 #define BASE_METRICS_HISTOGRAM_MACROS_H_
 
 #include "base/metrics/histogram.h"
 #include "base/metrics/histogram_macros_internal.h"
 #include "base/metrics/histogram_macros_local.h"
@@ skipping 23 matching lines @@
 // You should be defining an associated Enum, and the input sample should be
 // an element of the Enum.
 // All of these macros must be called with |name| as a runtime constant.
 
 // Sample usage:
 //   UMA_HISTOGRAM_ENUMERATION("My.Enumeration", VALUE, EVENT_MAX_VALUE);
 // New Enum values can be added, but existing enums must never be renumbered or
 // 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.
 
 // Sample usage:
 //   UMA_HISTOGRAM_BOOLEAN("Histogram.Boolean", bool);
 #define UMA_HISTOGRAM_BOOLEAN(name, sample)                                    \
     STATIC_HISTOGRAM_POINTER_BLOCK(name, AddBoolean(sample),                   \
         base::BooleanHistogram::FactoryGet(name,                               \
             base::HistogramBase::kUmaTargetedHistogramFlag))
 
@@ skipping 214 matching lines @@
 // |custom_ranges|. See comments above CustomRanges::FactoryGet about the
 // requirement of |custom_ranges|. You can use the helper function
 // CustomHistogram::ArrayToCustomRanges to transform a C-style array of valid
 // sample values to a std::vector<int>.
 #define UMA_HISTOGRAM_CUSTOM_ENUMERATION(name, sample, custom_ranges)          \
     STATIC_HISTOGRAM_POINTER_BLOCK(name, Add(sample),                          \
         base::CustomHistogram::FactoryGet(name, custom_ranges,                 \
             base::HistogramBase::kUmaTargetedHistogramFlag))
 
 #endif  // BASE_METRICS_HISTOGRAM_MACROS_H_