Narrow, invaluable context and template function

Question

Consider the following code:

auto f() -> decltype(int{0.}, void()) { } int main() { f(); } 

It will not compile (as expected) the error:

narrowing the conversion of '0.0' from 'double' to 'int' inside {}

Both GCC and clang agree on this.
Now consider the following code:

 template <typename T> auto f(T) -> decltype(int{0.}, void()) { } int main(){ f(0); } 

In this case, clang 3.9 returns an error, and GCC 6.2 compiles without errors.

Is there a reason why narrowing the conversion should be taken in the case of a function template or is it a GCC error?

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I am going to open the problem for GCC because, in my opinion, it should not compile, but I would like to know if there is something important missing in the function template.