On Fri, 17 Feb 2023, Marek Polacek via Gcc-patches wrote:
> Here we crash in is_capture_proxy:
>
> /* Location wrappers should be stripped or otherwise handled by the
> caller before using this predicate. */
> gcc_checking_assert (!location_wrapper_p (decl));
>
> so fixed as the comment suggests. We only crash with the redundant
> capture:
>
> int abyPage = [=, abyPage] { ... }
>
> because prune_lambda_captures is only called when there was a default
> capture, and with [=] only abyPage won't be in LAMBDA_EXPR_CAPTURE_LIST.
It's weird that we even get this far in var_to_maybe_prune. Shouldn't
LAMBDA_CAPTURE_EXPLICIT_P be true for abyPage?
>
> Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk/12?
>
> PR c++/108829
>
> gcc/cp/ChangeLog:
>
> * lambda.cc (var_to_maybe_prune): Strip location wrappers before
> checking for a capture proxy.
>
> gcc/testsuite/ChangeLog:
>
> * g++.dg/cpp0x/lambda/lambda-108829.C: New test.
> ---
> gcc/cp/lambda.cc | 1 +
> gcc/testsuite/g++.dg/cpp0x/lambda/lambda-108829.C | 11 +++++++++++
> 2 files changed, 12 insertions(+)
> create mode 100644 gcc/testsuite/g++.dg/cpp0x/lambda/lambda-108829.C
>
> diff --git a/gcc/cp/lambda.cc b/gcc/cp/lambda.cc
> index c752622816d..a12b9c183c2 100644
> --- a/gcc/cp/lambda.cc
> +++ b/gcc/cp/lambda.cc
> @@ -1700,6 +1700,7 @@ var_to_maybe_prune (tree cap)
> return NULL_TREE;
>
> tree init = TREE_VALUE (cap);
> + STRIP_ANY_LOCATION_WRAPPER (init);
> if (is_normal_capture_proxy (init))
> init = DECL_CAPTURED_VARIABLE (init);
> if (decl_constant_var_p (init))
> diff --git a/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-108829.C
> b/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-108829.C
> new file mode 100644
> index 00000000000..e621a0d14d0
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-108829.C
> @@ -0,0 +1,11 @@
> +// PR c++/108829
> +// { dg-do compile { target c++11 } }
> +
> +template <int>
> +void f(void) {
> + constexpr int IDX_PAGE_SIZE = 4096;
> + int abyPage = [=, abyPage] { return IDX_PAGE_SIZE; }(); // { dg-error
> "redundant" }
> +}
> +void h() {
> + f<1>();
> +}
>
> base-commit: 6245441e124846d0c3551f312d2feef598fe251c
> --
> 2.39.2
>
>
