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| author | Marek Polacek <polacek@redhat.com> | 2022-03-02 12:12:33 -0500 |
|---|---|---|
| committer | Marek Polacek <polacek@redhat.com> | 2022-03-10 11:22:40 -0500 |
| commit | 97f76b5fc4b637033229e53033b4f8b6dc23472c (patch) | |
| tree | 55f2a369772fc52fbba7886a31818f2639c7114b | |
| parent | ac8310dd122172bf9d7217e3367da55f9bf9b21b (diff) | |
| download | gcc-97f76b5fc4b637033229e53033b4f8b6dc23472c.zip gcc-97f76b5fc4b637033229e53033b4f8b6dc23472c.tar.gz gcc-97f76b5fc4b637033229e53033b4f8b6dc23472c.tar.bz2 | |
c++: Don't allow type-constraint auto(x) [PR104752]
104752 points out that
template<class T>
concept C = true;
auto y = C auto(1);
is ill-formed as per [dcl.type.auto.deduct]: "For an explicit type conversion,
T is the specified type, which shall be auto." which doesn't allow
type-constraint auto.
PR c++/104752
gcc/cp/ChangeLog:
* semantics.cc (finish_compound_literal): Disallow auto{x} for
is_constrained_auto.
* typeck2.cc (build_functional_cast_1): Likewise.
gcc/testsuite/ChangeLog:
* g++.dg/cpp23/auto-fncast12.C: New test.
| -rw-r--r-- | gcc/cp/semantics.cc | 8 | ||||
| -rw-r--r-- | gcc/cp/typeck2.cc | 8 | ||||
| -rw-r--r-- | gcc/testsuite/g++.dg/cpp23/auto-fncast12.C | 8 |
3 files changed, 22 insertions, 2 deletions
diff --git a/gcc/cp/semantics.cc b/gcc/cp/semantics.cc index 799ce94..2174006 100644 --- a/gcc/cp/semantics.cc +++ b/gcc/cp/semantics.cc @@ -3150,7 +3150,13 @@ finish_compound_literal (tree type, tree compound_literal, && !AUTO_IS_DECLTYPE (type) && CONSTRUCTOR_NELTS (compound_literal) == 1) { - if (cxx_dialect < cxx23) + if (is_constrained_auto (type)) + { + if (complain & tf_error) + error ("%<auto{x}%> cannot be constrained"); + return error_mark_node; + } + else if (cxx_dialect < cxx23) pedwarn (input_location, OPT_Wc__23_extensions, "%<auto{x}%> only available with " "%<-std=c++2b%> or %<-std=gnu++2b%>"); diff --git a/gcc/cp/typeck2.cc b/gcc/cp/typeck2.cc index 39d03e4..a4c825f 100644 --- a/gcc/cp/typeck2.cc +++ b/gcc/cp/typeck2.cc @@ -2308,7 +2308,13 @@ build_functional_cast_1 (location_t loc, tree exp, tree parms, && list_length (parms) == 1) { init = TREE_VALUE (parms); - if (cxx_dialect < cxx23) + if (is_constrained_auto (anode)) + { + if (complain & tf_error) + error_at (loc, "%<auto(x)%> cannot be constrained"); + return error_mark_node; + } + else if (cxx_dialect < cxx23) pedwarn (loc, OPT_Wc__23_extensions, "%<auto(x)%> only available with " "%<-std=c++2b%> or %<-std=gnu++2b%>"); diff --git a/gcc/testsuite/g++.dg/cpp23/auto-fncast12.C b/gcc/testsuite/g++.dg/cpp23/auto-fncast12.C new file mode 100644 index 0000000..2856c28 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp23/auto-fncast12.C @@ -0,0 +1,8 @@ +// PR c++/104752 +// { dg-do compile { target c++23 } } + +template<class T> +concept C = true; +auto x = auto(1); // valid (P0849R8) +auto y = C auto(1); // { dg-error "cannot be constrained" } +auto z = C auto{1}; // { dg-error "cannot be constrained" } |