1.7.0 does not compile with -std=c++0x flag on gcc 4.6

[Martyn Gigg]

Our project embeds googlemock into a larger CMake project and we use the -std=c++0x flag on gcc.

This worked with gmock-1.6 but fails with the following output on gmock-1.7

Scanning dependencies of target gmock

[ 14%] Building CXX object CMakeFiles/gmock.dir/gtest/src/gtest-all.cc.o

[ 28%] Building CXX object CMakeFiles/gmock.dir/src/gmock-all.cc.o

In file included from /mnt/data1/Code/gmock-1.7.0/include/gmock/gmock-spec-builders.h:75:0,

                 from /mnt/data1/Code/gmock-1.7.0/include/gmock/gmock-generated-function-mockers.h:43,

                 from /mnt/data1/Code/gmock-1.7.0/include/gmock/gmock.h:61,

                 from /mnt/data1/Code/gmock-1.7.0/src/gmock-all.cc:40:

/mnt/data1/Code/gmock-1.7.0/include/gmock/gmock-matchers.h:1485:41: sorry, unimplemented: cannot expand ‘Tail ...’ into a fixed-length argument list

/mnt/data1/Code/gmock-1.7.0/include/gmock/gmock-matchers.h:1486:63: error: template argument 2 is invalid

/mnt/data1/Code/gmock-1.7.0/include/gmock/gmock-matchers.h: In static member function ‘static testing::internal::MatcherList<kSize, Head, Tail>::ListType testing::internal::MatcherList<kSize, Head, Tail>::BuildList(const Head&, const Tail& ...)’:

/mnt/data1/Code/gmock-1.7.0/include/gmock/gmock-matchers.h:1493:20: error: expected primary-expression before ‘(’ token

/mnt/data1/Code/gmock-1.7.0/include/gmock/gmock-matchers.h:1493:30: error: ‘MatcherListTail’ is not a class, namespace, or enumeration

/mnt/data1/Code/gmock-1.7.0/include/gmock/gmock-matchers.h: In static member function ‘static testing::Matcher<T> testing::internal::MatcherList<kSize, Head, Tail>::CreateMatcher(const ListType&)’:

/mnt/data1/Code/gmock-1.7.0/include/gmock/gmock-matchers.h:1503:37: error: request for member ‘first’ in ‘matchers’, which is of non-class type ‘const ListType {aka const int}’

/mnt/data1/Code/gmock-1.7.0/include/gmock/gmock-matchers.h:1505:22: error: request for member ‘second’ in ‘matchers’, which is of non-class type ‘const ListType {aka const int}’

/mnt/data1/Code/gmock-1.7.0/include/gmock/gmock-matchers.h:1502:22: error: expected primary-expression before ‘(’ token

/mnt/data1/Code/gmock-1.7.0/include/gmock/gmock-matchers.h:1503:37: error: request for member ‘first’ in ‘matchers’, which is of non-class type ‘const ListType {aka const int}’

/mnt/data1/Code/gmock-1.7.0/include/gmock/gmock-matchers.h:1504:9: error: ‘MatcherListTail’ is not a class, namespace, or enumeration

/mnt/data1/Code/gmock-1.7.0/include/gmock/gmock-matchers.h:1504:50: error: expected primary-expression before ‘,’ token

/mnt/data1/Code/gmock-1.7.0/include/gmock/gmock-matchers.h:1504:68: error: missing template arguments before ‘>’ token

/mnt/data1/Code/gmock-1.7.0/include/gmock/gmock-matchers.h:1505:22: error: request for member ‘second’ in ‘matchers’, which is of non-class type ‘const ListType {aka const int}’

/mnt/data1/Code/gmock-1.7.0/include/gmock/gmock-matchers.h: At global scope:

/mnt/data1/Code/gmock-1.7.0/include/gmock/gmock-matchers.h:1548:47: sorry, unimplemented: cannot expand ‘Args ...’ into a fixed-length argument list

/mnt/data1/Code/gmock-1.7.0/include/gmock/gmock-matchers.h:1550:18: error: ‘MatcherListType’ is not a class, namespace, or enumeration

/mnt/data1/Code/gmock-1.7.0/include/gmock/gmock-matchers.h: In constructor ‘testing::internal::VariadicMatcher<CombiningMatcher, Args>::VariadicMatcher(const Args& ...)’:

/mnt/data1/Code/gmock-1.7.0/include/gmock/gmock-matchers.h:1536:19: error: ‘MatcherListType’ is not a class, namespace, or enumeration

/mnt/data1/Code/gmock-1.7.0/include/gmock/gmock-matchers.h: In member function ‘testing::internal::VariadicMatcher<CombiningMatcher, Args>::operator testing::Matcher<T>() const’:

/mnt/data1/Code/gmock-1.7.0/include/gmock/gmock-matchers.h:1543:12: error: ‘MatcherListType’ is not a class, namespace, or enumeration

/mnt/data1/Code/gmock-1.7.0/include/gmock/gmock-matchers.h:1543:53: error: expected primary-expression before ‘,’ token

/mnt/data1/Code/gmock-1.7.0/include/gmock/gmock-matchers.h:1543:71: error: missing template arguments before ‘>’ token

/mnt/data1/Code/gmock-1.7.0/include/gmock/gmock-matchers.h: At global scope:

/mnt/data1/Code/gmock-1.7.0/include/gmock/gmock-matchers.h:1556:1: error: expected unqualified-id before ‘using’

/mnt/data1/Code/gmock-1.7.0/include/gmock/gmock-matchers.h:1650:1: error: expected unqualified-id before ‘using’

In file included from /mnt/data1/Code/gmock-1.7.0/include/gmock/gmock-spec-builders.h:75:0,

                 from /mnt/data1/Code/gmock-1.7.0/include/gmock/gmock-generated-function-mockers.h:43,

                 from /mnt/data1/Code/gmock-1.7.0/include/gmock/gmock.h:61,

                 from /mnt/data1/Code/gmock-1.7.0/src/gmock-all.cc:40:

/mnt/data1/Code/gmock-1.7.0/include/gmock/gmock-matchers.h:3954:8: error: ‘AllOfMatcher’ in namespace ‘testing::internal’ does not name a type

/mnt/data1/Code/gmock-1.7.0/include/gmock/gmock-matchers.h:3959:8: error: ‘AnyOfMatcher’ in namespace ‘testing::internal’ does not name a type

make[2]: *** [CMakeFiles/gmock.dir/src/gmock-all.cc.o] Error 1

make[1]: *** [CMakeFiles/gmock.dir/all] Error 2

make: *** [all] Error 2

What steps will reproduce the problem?

1. cd gmock-1.7.0

2. mkdir build && cd build

2. CXXFLAGS="-std=c++0x" cmake ../

3. make

What is the expected output? What do you see instead?

The expected output is that the code compiles and gmock/gtest libraries are produced.

Which version of Google Mock are you using? On what operating system?

Using googlemock version 1.7.0 on Ubuntu 12.04 with gcc version: gcc (Ubuntu/Linaro 4.6.3-1ubuntu5) 4.6.3

[Vlad Losev]

1.7 implemented AllOf and AnyOf using variadic templates in C++11 mode in order to remove limitations on the number of their arguments. It seems to be hitting a bug in GCC which was fixed in 4.7.

For now, I guess you can either upgrade your GCC to 4.7, revert back to using gmock 1.7, or stop using -std=c++0x.

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[Martyn Gigg]

I see. Many thanks for the information.

We will stick to using 1.6 for now.

[Lukasz Forynski]

Or perhaps gmock could be patched to skip this variadic implementation for matchers for gcc < 4.7,
i.e. something like:

===================================================================
--- include/gmock/gmock-matchers.h    (revision 501)
+++ include/gmock/gmock-matchers.h    (working copy)
@@ -1591,7 +1591,10 @@
         SafeMatcherCast<T>(matchers.second)));
   }
 };
-
+// Skip variadic implementation of matchers if using GCC < 4.7 due to
+// Bug 35722 -[C++0x] Variadic templates expansion into non-variadic class template
+// https://gcc.gnu.org/bugzilla/show_bug.cgi?id=35722
+#if !defined(__GNUC__) || (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 7 ) )
 // VariadicMatcher is used for the variadic implementation of
 // AllOf(m_1, m_2, ...) and AnyOf(m_1, m_2, ...).
 // CombiningMatcher<T> is used to recursively combine the provided matchers
@@ -1621,7 +1624,7 @@
 
 template <typename... Args>
 using AllOfMatcher = VariadicMatcher<BothOfMatcherImpl, Args...>;
-
+#endif  // GCC >= 4.7
 #endif  // GTEST_LANG_CXX11
 
 // Used for implementing the AllOf(m_1, ..., m_n) matcher, which

On Wednesday, November 13, 2013 3:15:12 PM UTC, Vlad Losev wrote: