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| author | Patrick Palka <ppalka@redhat.com> | 2021-02-25 16:38:08 -0500 |
|---|---|---|
| committer | Patrick Palka <ppalka@redhat.com> | 2021-02-25 16:38:08 -0500 |
| commit | 676f6f3277181662cf3ed07769edfa2d4fb7df28 (patch) | |
| tree | c61df9191b1964205ac5d2a49f343c08616f50c0 /gcc | |
| parent | 2ffc26458dd7ba7b3fa00897f2d8c6cd24ba06f3 (diff) | |
| download | gcc-676f6f3277181662cf3ed07769edfa2d4fb7df28.zip gcc-676f6f3277181662cf3ed07769edfa2d4fb7df28.tar.gz gcc-676f6f3277181662cf3ed07769edfa2d4fb7df28.tar.bz2 | |
c++: Fix CTAD of single-element initializer list [PR99103]
When determining whether to rule out initializer-list constructors
during CTAD with a single-element initializer list (as per P0702), the
element type's cv-qualifiers should be irrelevant. This patch fixes
this by making is_spec_or_derived strip cv-qualifiers from the supplied
expression type.
In passing, I noticed in maybe_aggr_guide we were calling
is_spec_or_derived with swapped arguments. This led us to prefer the
aggregate deduction candidate over copying deduction in the second
testcase below with -std=c++20.
gcc/cp/ChangeLog:
PR c++/99103
* pt.c (is_spec_or_derived): Drop cv-qualifiers from 'etype'.
(maybe_aggr_guide): Fix order of arguments to is_spec_or_derived.
gcc/testsuite/ChangeLog:
PR c++/99103
* g++.dg/cpp1z/class-deduction79.C: New test.
* g++.dg/cpp1z/class-deduction80.C: New test.
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/cp/pt.c | 3 | ||||
| -rw-r--r-- | gcc/testsuite/g++.dg/cpp1z/class-deduction79.C | 10 | ||||
| -rw-r--r-- | gcc/testsuite/g++.dg/cpp1z/class-deduction80.C | 9 |
3 files changed, 21 insertions, 1 deletions
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c index 3576e0e..0623e92 100644 --- a/gcc/cp/pt.c +++ b/gcc/cp/pt.c @@ -28833,6 +28833,7 @@ is_spec_or_derived (tree etype, tree tmpl) if (!etype || !CLASS_TYPE_P (etype)) return false; + etype = cv_unqualified (etype); tree type = TREE_TYPE (tmpl); tree tparms = (INNERMOST_TEMPLATE_PARMS (DECL_TEMPLATE_PARMS (tmpl))); @@ -28863,7 +28864,7 @@ maybe_aggr_guide (tree tmpl, tree init, vec<tree,va_gc> *args) if (args->length() == 1) { tree val = (*args)[0]; - if (is_spec_or_derived (tmpl, TREE_TYPE (val))) + if (is_spec_or_derived (TREE_TYPE (val), tmpl)) return NULL_TREE; } diff --git a/gcc/testsuite/g++.dg/cpp1z/class-deduction79.C b/gcc/testsuite/g++.dg/cpp1z/class-deduction79.C new file mode 100644 index 0000000..ebbe2b2 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp1z/class-deduction79.C @@ -0,0 +1,10 @@ +// PR c++/99103 +// { dg-do compile { target c++17 } } +#include <initializer_list> + +template <class T> +struct S { S(std::initializer_list<T>); }; + +extern const S<int> x; +using type = decltype(S{x}); +using type = S<int>; // not S<S<int>> diff --git a/gcc/testsuite/g++.dg/cpp1z/class-deduction80.C b/gcc/testsuite/g++.dg/cpp1z/class-deduction80.C new file mode 100644 index 0000000..5ccfc93 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp1z/class-deduction80.C @@ -0,0 +1,9 @@ +// PR c++/99103 +// { dg-do compile { target c++17 } } + +template <class T> struct X { T a; }; +template <class T> struct Y : X<T> {}; + +extern const Y<int> y; +using type = decltype(X{y}); +using type = X<int>; // not X<Y<int>> |