On Thu, 19 Oct 2023, Patrick Palka wrote: > On Tue, 3 Oct 2023, David Malcolm wrote: > > > As mentioned in my Cauldron talk, this patch adds a call to > > diagnostic_show_locus to the "required from here" messages > > in print_instantiation_partial_context_line, so that e.g., rather > > than the rather mystifying: > > > > In file included from ../x86_64-pc-linux-gnu/libstdc++-v3/include/memory:78, > > from ../../src/demo-1.C:1: > > ../x86_64-pc-linux-gnu/libstdc++-v3/include/bits/unique_ptr.h: In instantiation of ‘std::__detail::__unique_ptr_t<_Tp> std::make_unique(_Args&& ...) [with _Tp = bar; _Args = {}; __detail::__unique_ptr_t<_Tp> = __detail::__unique_ptr_t]’: > > ../../src/demo-1.C:15:32: required from here > > ../x86_64-pc-linux-gnu/libstdc++-v3/include/bits/unique_ptr.h:1066:30: error: no matching function for call to ‘bar::bar()’ > > 1066 | { return unique_ptr<_Tp>(new _Tp(std::forward<_Args>(__args)...)); } > > | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > ../../src/demo-1.C:10:3: note: candidate: ‘bar::bar(int)’ > > 10 | bar (int); > > | ^~~ > > ../../src/demo-1.C:10:3: note: candidate expects 1 argument, 0 provided > > ../../src/demo-1.C:7:7: note: candidate: ‘constexpr bar::bar(const bar&)’ > > 7 | class bar : public foo > > | ^~~ > > ../../src/demo-1.C:7:7: note: candidate expects 1 argument, 0 provided > > ../../src/demo-1.C:7:7: note: candidate: ‘constexpr bar::bar(bar&&)’ > > ../../src/demo-1.C:7:7: note: candidate expects 1 argument, 0 provided > > > > we emit: > > > > In file included from ../x86_64-pc-linux-gnu/libstdc++-v3/include/memory:78, > > from ../../src/demo-1.C:1: > > ../x86_64-pc-linux-gnu/libstdc++-v3/include/bits/unique_ptr.h: In instantiation of ‘std::__detail::__unique_ptr_t<_Tp> std::make_unique(_Args&& ...) [with _Tp = bar; _Args = {}; __detail::__unique_ptr_t<_Tp> = __detail::__unique_ptr_t]’: > > ../../src/demo-1.C:15:32: required from here > > 15 | return std::make_unique (); > > | ~~~~~~~~~~~~~~~~~~~~~~^~ > > ../x86_64-pc-linux-gnu/libstdc++-v3/include/bits/unique_ptr.h:1066:30: error: no matching function for call to ‘bar::bar()’ > > 1066 | { return unique_ptr<_Tp>(new _Tp(std::forward<_Args>(__args)...)); } > > | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > ../../src/demo-1.C:10:3: note: candidate: ‘bar::bar(int)’ > > 10 | bar (int); > > | ^~~ > > ../../src/demo-1.C:10:3: note: candidate expects 1 argument, 0 provided > > ../../src/demo-1.C:7:7: note: candidate: ‘constexpr bar::bar(const bar&)’ > > 7 | class bar : public foo > > | ^~~ > > ../../src/demo-1.C:7:7: note: candidate expects 1 argument, 0 provided > > ../../src/demo-1.C:7:7: note: candidate: ‘constexpr bar::bar(bar&&)’ > > ../../src/demo-1.C:7:7: note: candidate expects 1 argument, 0 provided > > > > which shows the code that's leading to the error (the bad call to > > std::make_unique). > > This is great! I noticed however that the source code gets printed in a > surprising way in some contexts. Consider: > > template void f(typename T::type); > > int main() { > f(0); > } > > For this testcase we emit: > > testcase.C: In function ‘int main()’: > testcase.C:4:9: error: no matching function for call to ‘f(int)’ > 4 | f(0); > | ~~~~~~^~~ > testcase.C:1:24: note: candidate: ‘template void f(typename T::type)’ > 1 | template void f(typename T::type); > | ^ > testcase.C:1:24: note: template argument deduction/substitution failed: > testcase.C: In substitution of ‘template void f(typename T::type) [with T = int]’: > testcase.C:4:9: required from here > testcase.C:1:24: note: 4 | f(0); > testcase.C:1:24: note: | ~~~~~~^~~ > testcase.C:1:24: error: ‘int’ is not a class, struct, or union type > 1 | template void f(typename T::type); > | ^ > > In particular the source code part following the "required from here" line > > testcase.C:4:9: required from here > testcase.C:1:24: note: 4 | f(0); > testcase.C:1:24: note: | ~~~~~~^~~ > > seems off, I would have expected it be > > testcase.C:4:9: required from here > 4 | f(0); > | ~~~~~~^~~ > > i.e. without the "testcase.C:1:24: note: " prefix. Does this look > expected? (I also wonder if we might want to omit printing the source > code altogether in this case, since we already printed that same line > earlier during the "no matching function" error?) Sorry for forgetting to ping this earlier, but I wonder what if anything we should do about this for GCC 14? > > > > > > > Successfully bootstrapped & regrtested on x86_64-pc-linux-gnu. > > > > OK for trunk? > > > > > > gcc/cp/ChangeLog: > > * error.cc (print_instantiation_partial_context_line): Call > > diagnostic_show_locus. > > > > gcc/testsuite/ChangeLog: > > * g++.dg/diagnostic/static_assert3.C: Add directives for > > additional source printing. > > * g++.dg/template/error60.C: New test. > > > > Signed-off-by: David Malcolm > > --- > > gcc/cp/error.cc | 2 + > > .../g++.dg/diagnostic/static_assert3.C | 7 +++- > > gcc/testsuite/g++.dg/template/error60.C | 37 +++++++++++++++++++ > > 3 files changed, 45 insertions(+), 1 deletion(-) > > create mode 100644 gcc/testsuite/g++.dg/template/error60.C > > > > diff --git a/gcc/cp/error.cc b/gcc/cp/error.cc > > index ef96e140f24..767478cf5fd 100644 > > --- a/gcc/cp/error.cc > > +++ b/gcc/cp/error.cc > > @@ -3774,6 +3774,8 @@ print_instantiation_partial_context_line (diagnostic_context *context, > > ? _("recursively required from here\n") > > : _("required from here\n")); > > } > > + gcc_rich_location rich_loc (loc); > > + diagnostic_show_locus (context, &rich_loc, DK_NOTE); > > } > > > > /* Same as print_instantiation_full_context but less verbose. */ > > diff --git a/gcc/testsuite/g++.dg/diagnostic/static_assert3.C b/gcc/testsuite/g++.dg/diagnostic/static_assert3.C > > index 5d363884508..4ec53f17120 100644 > > --- a/gcc/testsuite/g++.dg/diagnostic/static_assert3.C > > +++ b/gcc/testsuite/g++.dg/diagnostic/static_assert3.C > > @@ -5,6 +5,11 @@ > > template struct is_same { static constexpr bool value = false; }; > > template struct is_same { static constexpr bool value = true; }; > > > > +/* { dg-begin-multiline-output "" } > > + f(0, 1.3); > > + ~^~~~~~~~ > > + { dg-end-multiline-output "" } */ > > + > > template > > void f(T, U) > > { > > @@ -32,5 +37,5 @@ void f(T, U) > > > > void g() > > { > > - f(0, 1.3); > > + f(0, 1.3); // { dg-message " required from here" } > > } > > diff --git a/gcc/testsuite/g++.dg/template/error60.C b/gcc/testsuite/g++.dg/template/error60.C > > new file mode 100644 > > index 00000000000..8c2139b207c > > --- /dev/null > > +++ b/gcc/testsuite/g++.dg/template/error60.C > > @@ -0,0 +1,37 @@ > > +// { dg-options "-fdiagnostics-show-caret" } > > + > > +template > > +struct my_pointer > > +{ > > + my_pointer (Foo *ptr) // { dg-message " initializing argument 1" } > > + : m_ptr (ptr) > > + {} > > + > > + Foo *m_ptr; > > +}; > > + > > +template > > +void test (Foo val) > > +{ > > + my_pointer ptr (val); // { dg-error "invalid conversion from 'int' to 'int\\*'" } > > +} > > + > > +void usage () > > +{ > > + test (42); // { dg-message " required from here" } > > + /* { dg-begin-multiline-output "" } > > + test (42); > > + ~~~~~~~~~~^~~~ > > + { dg-end-multiline-output "" } */ > > +} > > + > > + /* { dg-begin-multiline-output "" } > > + my_pointer (Foo *ptr) > > + ~~~~~^~~ > > + { dg-end-multiline-output "" } */ > > + /* { dg-begin-multiline-output "" } > > + my_pointer ptr (val); > > + ^~~ > > + | > > + int > > + { dg-end-multiline-output "" } */ > > -- > > 2.26.3 > > > >