<div dir="ltr">Could this be related to the Incomplete flag we started passing to libclang a while ago?</div><div class="gmail_extra"><br><div class="gmail_quote">On Sun, Nov 1, 2015 at 9:11 AM, Manuel Klimek <span dir="ltr"><<a href="mailto:klimek@google.com" target="_blank">klimek@google.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">+Benjamin <div><br><div class="gmail_quote"><div><div class="h5"><div dir="ltr">On Tue, Oct 27, 2015 at 5:15 PM Val Markovic <<a href="mailto:val@markovic.io" target="_blank">val@markovic.io</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">+klimek</div><div dir="ltr"><div class="gmail_extra"><br><div class="gmail_quote">On Mon, Oct 26, 2015 at 3:09 PM, Ben Jackson <span dir="ltr"><<a href="mailto:puremourning@gmail.com" target="_blank">puremourning@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Hi there,<br>
<br>
An issue was raised against ycmd that we were not reporting errors as a result of failed template instantiations. This is because, seemingly, libclang does not report diagnostics for template instantiations where instantiation fails (in the sense that the generated code is not valid).<br>
<br>
A fairly canonical test case is as follows:<br>
<br>
template<typename T><br>
void get_size(const T& t)<br>
{<br>
return t.size();<br>
}<br>
<br>
struct Test<br>
{<br>
void not_size() const;<br>
};<br>
<br>
int run_test()<br>
{<br>
Test t;<br>
<br>
get_size(t);<br>
<br>
return "not_an_int";<br>
}<br>
<br>
Expected: a diagnostic reported at the line ‘get_size(t)’ as struct Test does not have a size()const method. However, no diagnostic is reported.<br>
<br>
The ‘return “not_an_int”’ is just to prove that diagnostics reporting is working in general in the test case.<br>
<br>
When running the above with ‘c-index-test -index-file’, grepping for ‘[diagnostic]’, the result is :<br>
<br>
$ ./bin/c-index-test -index-file ../llvm/tools/clang/test/Index/diagnostics-template-instantiation.cpp | grep '\[diagnostic\]'<br>
../llvm/tools/clang/test/Index/diagnostics-template-instantiation.cpp:18:12: error: cannot initialize return object of type 'int' with an lvalue of type 'const char [11]'<br>
[diagnostic]: ../llvm/tools/clang/test/Index/diagnostics-template-instantiation.cpp:18:12: error: cannot initialize return object of type ‘int' with an lvalue of type 'const char [11]'<br>
<br>
However, when running clang directly, we get the diagnostic for get_size(t):<br>
<br>
clang++ ../llvm/tools/clang/test/Index/diagnostics-template-instantiation.cpp<br>
../llvm/tools/clang/test/Index/diagnostics-template-instantiation.cpp:18:12: error: cannot initialize return object of type 'int' with an lvalue of type 'const char [11]'<br>
return "not_an_int";<br>
^~~~~~~~~~~~<br>
../llvm/tools/clang/test/Index/diagnostics-template-instantiation.cpp:4:14: error: no member named 'size' in 'Test'<br>
return t.size();<br>
~ ^<br>
../llvm/tools/clang/test/Index/diagnostics-template-instantiation.cpp:16:5: note: in instantiation of function template specialization 'get_size<Test>' requested here<br>
get_size(t);<br>
^<br>
2 errors generated.<br>
<br>
Is this a bug or simply a limitation of the libclang interface? Or is there something required to get these diagnostics to report. Apologies, I must confess I have not looked into this in detail within clang.<br></blockquote></div></div></div></blockquote><div><br></div></div></div><div>I'd expect there to be a way to drive libclang to get those diagnostics. On the other hand, it would probably mean a significant slow-down, because template instantiation can be a significant amount of the parse time.</div><span class=""><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div class="gmail_extra"><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<br>
Many thanks and kind regards,<br>
Ben<br>
<span><font color="#888888"><br>
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