| Message ID | 20200304210222.GI3554@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | c++: Backport PR90505 fix to 9 | expand |
On 3/4/20 4:02 PM, Marek Polacek wrote: > While backporting our 90505 fix to 9 I noticed a bunch of concepts regressions. > Fortunately I think the following variant of the fix is safe and still fixes > the deduction issue. In 9, we want to reject 'auto' when tf_partial before > returning cp_build_qualified_type_real for TEMPLATE_TYPE_PARM and similar. > And then to fix 90505, return early before reducing the template level. > > The difference is caused by the huge concepts merge, so it's tough to figure > out what specific change caused it. > > Bootstrapped/regtested on x86_64-linux, ok for 9? OK. > 2020-03-04 Jason Merrill <jason@redhat.com> > Marek Polacek <polacek@redhat.com> > > PR c++/90505 - mismatch in template argument deduction. > * pt.c (tsubst): Don't reduce the template level of template > parameters when tf_partial. > > * g++.dg/template/deduce4.C: New test. > * g++.dg/template/deduce5.C: New test. > * g++.dg/template/deduce6.C: New test. > * g++.dg/template/deduce7.C: New test. > > diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c > index f233e78cc45..2de9036b647 100644 > --- a/gcc/cp/pt.c > +++ b/gcc/cp/pt.c > @@ -14630,6 +14630,11 @@ tsubst (tree t, tree args, tsubst_flags_t complain, tree in_decl) > about the template parameter in question. */ > return t; > > + /* Like with 'auto', don't reduce the level of template parameters > + to avoid mismatches when deducing their types. */ > + if (complain & tf_partial) > + return t; > + > /* If we get here, we must have been looking at a parm for a > more deeply nested template. Make a new version of this > template parameter, but with a lower level. */ > diff --git a/gcc/testsuite/g++.dg/template/deduce4.C b/gcc/testsuite/g++.dg/template/deduce4.C > new file mode 100644 > index 00000000000..e2c165dc788 > --- /dev/null > +++ b/gcc/testsuite/g++.dg/template/deduce4.C > @@ -0,0 +1,17 @@ > +// PR c++/90505 - mismatch in template argument deduction. > +// { dg-do compile } > + > +template <typename T> > +struct S { > + template <typename U, typename V> > + static void foo(V) { } > + > + void bar () { foo<int>(10); } > +}; > + > +void > +test () > +{ > + S<int> s; > + s.bar (); > +} > diff --git a/gcc/testsuite/g++.dg/template/deduce5.C b/gcc/testsuite/g++.dg/template/deduce5.C > new file mode 100644 > index 00000000000..9d382bfe03a > --- /dev/null > +++ b/gcc/testsuite/g++.dg/template/deduce5.C > @@ -0,0 +1,17 @@ > +// PR c++/90505 - mismatch in template argument deduction. > +// { dg-do compile { target c++11 } } > + > +template <typename T> > +struct S { > + template <typename U, typename V = void> > + static void foo(U) { } > + > + void bar () { foo<int>(10); } > +}; > + > +void > +test () > +{ > + S<int> s; > + s.bar (); > +} > diff --git a/gcc/testsuite/g++.dg/template/deduce6.C b/gcc/testsuite/g++.dg/template/deduce6.C > new file mode 100644 > index 00000000000..8fee6124f5a > --- /dev/null > +++ b/gcc/testsuite/g++.dg/template/deduce6.C > @@ -0,0 +1,17 @@ > +// PR c++/90505 - mismatch in template argument deduction. > +// { dg-do compile { target c++11 } } > + > +template <typename T> > +struct S { > + template <typename U = int, typename V> > + static void foo(V) { } > + > + void bar () { foo<>(10); } > +}; > + > +void > +test () > +{ > + S<int> s; > + s.bar (); > +} > diff --git a/gcc/testsuite/g++.dg/template/deduce7.C b/gcc/testsuite/g++.dg/template/deduce7.C > new file mode 100644 > index 00000000000..fbc28e5150d > --- /dev/null > +++ b/gcc/testsuite/g++.dg/template/deduce7.C > @@ -0,0 +1,10 @@ > +// PR c++/90505 - mismatch in template argument deduction. > +// { dg-do compile { target c++11 } } > + > +template <typename> class a { > + using b = int; > + using c = int; > + b d; > + void e() { g<c>(d); } > + template <typename... f> static void g(f...); > +}; >
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c index f233e78cc45..2de9036b647 100644 --- a/gcc/cp/pt.c +++ b/gcc/cp/pt.c @@ -14630,6 +14630,11 @@ tsubst (tree t, tree args, tsubst_flags_t complain, tree in_decl) about the template parameter in question. */ return t; + /* Like with 'auto', don't reduce the level of template parameters + to avoid mismatches when deducing their types. */ + if (complain & tf_partial) + return t; + /* If we get here, we must have been looking at a parm for a more deeply nested template. Make a new version of this template parameter, but with a lower level. */ diff --git a/gcc/testsuite/g++.dg/template/deduce4.C b/gcc/testsuite/g++.dg/template/deduce4.C new file mode 100644 index 00000000000..e2c165dc788 --- /dev/null +++ b/gcc/testsuite/g++.dg/template/deduce4.C @@ -0,0 +1,17 @@ +// PR c++/90505 - mismatch in template argument deduction. +// { dg-do compile } + +template <typename T> +struct S { + template <typename U, typename V> + static void foo(V) { } + + void bar () { foo<int>(10); } +}; + +void +test () +{ + S<int> s; + s.bar (); +} diff --git a/gcc/testsuite/g++.dg/template/deduce5.C b/gcc/testsuite/g++.dg/template/deduce5.C new file mode 100644 index 00000000000..9d382bfe03a --- /dev/null +++ b/gcc/testsuite/g++.dg/template/deduce5.C @@ -0,0 +1,17 @@ +// PR c++/90505 - mismatch in template argument deduction. +// { dg-do compile { target c++11 } } + +template <typename T> +struct S { + template <typename U, typename V = void> + static void foo(U) { } + + void bar () { foo<int>(10); } +}; + +void +test () +{ + S<int> s; + s.bar (); +} diff --git a/gcc/testsuite/g++.dg/template/deduce6.C b/gcc/testsuite/g++.dg/template/deduce6.C new file mode 100644 index 00000000000..8fee6124f5a --- /dev/null +++ b/gcc/testsuite/g++.dg/template/deduce6.C @@ -0,0 +1,17 @@ +// PR c++/90505 - mismatch in template argument deduction. +// { dg-do compile { target c++11 } } + +template <typename T> +struct S { + template <typename U = int, typename V> + static void foo(V) { } + + void bar () { foo<>(10); } +}; + +void +test () +{ + S<int> s; + s.bar (); +} diff --git a/gcc/testsuite/g++.dg/template/deduce7.C b/gcc/testsuite/g++.dg/template/deduce7.C new file mode 100644 index 00000000000..fbc28e5150d --- /dev/null +++ b/gcc/testsuite/g++.dg/template/deduce7.C @@ -0,0 +1,10 @@ +// PR c++/90505 - mismatch in template argument deduction. +// { dg-do compile { target c++11 } } + +template <typename> class a { + using b = int; + using c = int; + b d; + void e() { g<c>(d); } + template <typename... f> static void g(f...); +};