On Fri, Mar 01, 2024 at 07:58:24PM -0500, Marek Polacek wrote: > Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for 15? (Or even trunk?) > > -- >8 -- > <https://wg21.link/p1381r1> clarifies that it's OK to capture structured > bindings. > > [expr.prim.lambda.capture]/4 says "The identifier in a simple-capture shall > denote a local entity" and [basic.pre]/3: "An entity is a [...] structured > binding". > > It doesn't appear that this was made a DR, so, strictly speaking, we > should have a -Wc++20-extensions warning, like clang++. > > PR c++/85889 > > gcc/cp/ChangeLog: > > * lambda.cc (add_capture): Add a pedwarn for capturing structured > bindings. > > gcc/testsuite/ChangeLog: > > * g++.dg/cpp2a/decomp3.C: Use -Wno-c++20-extensions. > * g++.dg/cpp1z/decomp60.C: New test. > --- > gcc/cp/lambda.cc | 9 +++++++++ > gcc/testsuite/g++.dg/cpp1z/decomp60.C | 12 ++++++++++++ > gcc/testsuite/g++.dg/cpp2a/decomp3.C | 2 +- > 3 files changed, 22 insertions(+), 1 deletion(-) > create mode 100644 gcc/testsuite/g++.dg/cpp1z/decomp60.C > > diff --git a/gcc/cp/lambda.cc b/gcc/cp/lambda.cc > index 4b1f9391fee..470f9d2c4f1 100644 > --- a/gcc/cp/lambda.cc > +++ b/gcc/cp/lambda.cc > @@ -607,6 +607,15 @@ add_capture (tree lambda, tree id, tree orig_init, bool > by_reference_p, > TCTX_CAPTURE_BY_COPY, type)) > return error_mark_node; > } > + > + if (cxx_dialect < cxx20) > + { > + tree stripped_init = tree_strip_any_location_wrapper (initializer);
I was missing an auto_diagnostic_group here. Fixed. > + if (DECL_DECOMPOSITION_P (stripped_init) > + && pedwarn (input_location, OPT_Wc__20_extensions, > + "captured structured bindings are a C++20 extension")) > + inform (DECL_SOURCE_LOCATION (stripped_init), "declared here");
