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| author | Marek Polacek <polacek@redhat.com> | 2021-11-03 11:04:22 -0400 |
|---|---|---|
| committer | Marek Polacek <polacek@redhat.com> | 2021-11-18 18:00:08 -0500 |
| commit | 93810fd673654db9ff16170624a6d36449eab241 (patch) | |
| tree | f31a7d9ee315aff919b2dd0a393c981dae0e4b54 /gcc/cp/semantics.c | |
| parent | 6f4ac4f81f89caac7e74127ed2e6db6bbb3d7426 (diff) | |
| download | gcc-93810fd673654db9ff16170624a6d36449eab241.zip gcc-93810fd673654db9ff16170624a6d36449eab241.tar.gz gcc-93810fd673654db9ff16170624a6d36449eab241.tar.bz2 | |
c++: Implement C++23 P0849R8 - auto(x) [PR103049]
This patch implements P0849R8 which allows auto in a functional cast,
the result of which is a prvalue.
[expr.type.conv]/1 says that the type is determined by placeholder type
deduction. We only accept 'auto', not 'decltype(auto)' -- that the
type shall be auto comes from [dcl.type.auto.deduct]. Therefore the
rules are like for [temp.deduct.call], deducing template arguments from
a function call, so the result type will never be a reference, and we
decay arrays/functions.
PR c++/103049
gcc/cp/ChangeLog:
* semantics.c (finish_compound_literal): Accept C++23 auto{x}.
* typeck2.c (build_functional_cast_1): Accept C++23 auto(x).
gcc/testsuite/ChangeLog:
* g++.dg/cpp0x/auto25.C: Adjust dg-error.
* g++.dg/cpp0x/auto9.C: Likewise.
* g++.dg/cpp2a/concepts-pr84979-2.C: Likewise.
* g++.dg/cpp2a/concepts-pr84979-3.C: Likewise.
* g++.dg/cpp23/auto-fncast1.C: New test.
* g++.dg/cpp23/auto-fncast2.C: New test.
* g++.dg/cpp23/auto-fncast3.C: New test.
* g++.dg/cpp23/auto-fncast4.C: New test.
* g++.dg/cpp23/auto-fncast5.C: New test.
* g++.dg/cpp23/auto-fncast6.C: New test.
Diffstat (limited to 'gcc/cp/semantics.c')
| -rw-r--r-- | gcc/cp/semantics.c | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/gcc/cp/semantics.c b/gcc/cp/semantics.c index 8f79f04..d962b29 100644 --- a/gcc/cp/semantics.c +++ b/gcc/cp/semantics.c @@ -3134,6 +3134,20 @@ finish_compound_literal (tree type, tree compound_literal, if (type == error_mark_node) return error_mark_node; } + /* C++23 auto{x}. */ + else if (is_auto (type) + && !AUTO_IS_DECLTYPE (type) + && CONSTRUCTOR_NELTS (compound_literal) == 1) + { + if (cxx_dialect < cxx23) + pedwarn (input_location, OPT_Wc__23_extensions, + "%<auto{x}%> only available with " + "%<-std=c++2b%> or %<-std=gnu++2b%>"); + type = do_auto_deduction (type, compound_literal, type, complain, + adc_variable_type); + if (type == error_mark_node) + return error_mark_node; + } /* Used to hold a copy of the compound literal in a template. */ tree orig_cl = NULL_TREE; |