From e592a475030d99647de736d294cb3c6a7588af49 Mon Sep 17 00:00:00 2001 From: qingzhe huang Date: Fri, 1 Oct 2021 10:46:35 -0400 Subject: [PATCH] The root cause of this bug is that it considers reference with cv-qualifiers as an error by generating value for variable "bad_quals". However, this is not correct for case of typedef. Here I quote spec [dcl.ref]/1 : "Cv-qualified references are ill-formed except when the cv-qualifiers are introduced through the use of a typedef-name ([dcl.typedef], [temp.param]) or decltype-specifier ([dcl.type.decltype]), in which case the cv-qualifiers are ignored." 2021-09-30 qingzhe huang gcc/cp/ChangeLog: PR c++/101783 * tree.c (cp_build_qualified_type_real): Exclude typedef from error. gcc/testsuite/ChangeLog: PR c++/101783 * g++.dg/parse/pr101783.C: New test. --- gcc/cp/tree.c | 9 ++++++++- gcc/testsuite/g++.dg/parse/pr101783.C | 5 +++++ 2 files changed, 13 insertions(+), 1 deletion(-) create mode 100644 gcc/testsuite/g++.dg/parse/pr101783.C diff --git a/gcc/cp/tree.c b/gcc/cp/tree.c index 8840932dba2..6a6f8a642cb 100644 --- a/gcc/cp/tree.c +++ b/gcc/cp/tree.c @@ -1356,11 +1356,18 @@ cp_build_qualified_type_real (tree type, /* A reference or method type shall not be cv-qualified. [dcl.ref], [dcl.fct]. This used to be an error, but as of DR 295 (in CD1) we always ignore extra cv-quals on functions. */ + + /* [dcl.ref/1] Cv-qualified references are ill-formed except when + the cv-qualifiers are introduced through the use of a typedef-name + ([dcl.typedef], [temp.param]) or decltype-specifier + ([dcl.type.decltype]),in which case the cv-qualifiers are + ignored. */ if (type_quals & (TYPE_QUAL_CONST | TYPE_QUAL_VOLATILE) && (TYPE_REF_P (type) || FUNC_OR_METHOD_TYPE_P (type))) { - if (TYPE_REF_P (type)) + if (TYPE_REF_P (type) + && (!typedef_variant_p (type) || FUNC_OR_METHOD_TYPE_P (type))) bad_quals |= type_quals & (TYPE_QUAL_CONST | TYPE_QUAL_VOLATILE); type_quals &= ~(TYPE_QUAL_CONST | TYPE_QUAL_VOLATILE); } diff --git a/gcc/testsuite/g++.dg/parse/pr101783.C b/gcc/testsuite/g++.dg/parse/pr101783.C new file mode 100644 index 00000000000..4e0a435dd0b --- /dev/null +++ b/gcc/testsuite/g++.dg/parse/pr101783.C @@ -0,0 +1,5 @@ +template struct A{ + typedef T& Type; +}; +template void f(const typename A::Type){} +template <> void f(const typename A::Type){} -- 2.17.1