On Fri, Dec 15, 2017 at 08:09:20PM +0100, Jakub Jelinek wrote:
> On Fri, Dec 15, 2017 at 02:01:36PM -0500, Jason Merrill wrote:
> > On 11/29/2017 08:19 PM, Martin Sebor wrote:
> > > On 11/29/2017 03:32 PM, Jakub Jelinek wrote:
> > > > + if (!tree_fits_uhwi_p (tsize))
> > > > + {
> > > > + error_at (loc, "%u names provided while %qT decomposes into "
> > >
> > > When count is 1 as in the test below the error isn't grammatically
> > > correct ("1 names"). I see that the same message is already issued
> > > elsewhere in the function so this seems like an opportunity to use
> > > the right form here and also fix the other one at the same time or
> > > in a followup. The error_n function exists to issue the right form
> > > for the language, singular or plural. It's not as convenient when
> > > the sentence contains two terms that may be singular or plural,
> > > but that can also be dealt with.
> >
> > Agreed.
>
> Yeah, I've implemented it as an incremental patch.
> So
> http://gcc.gnu.org/ml/gcc-patches/2017-11/msg02521.html
> for the ICE and
> http://gcc.gnu.org/ml/gcc-patches/2017-11/msg02538.html
> on top of it. The latter is what Nathan approved already, the former
> needs review.
If it helps any, here are the 2 patches combined, re-tested on x86_64-linux
with check-c++-all.
2017-12-15 Jakub Jelinek <ja...@redhat.com>
PR c++/83205
* decl.c (cp_finish_decomp): Handle the case when tsize is not
error_mark_node, but doesn't fit into uhwi. Split up count != eltscnt
and !tree_fits_uhwi_p (tsize) error_at calls into error_n and inform_n
to handle plural forms properly.
* g++.dg/cpp1z/decomp3.C: Adjust for structured binding count
mismatch diagnostics split into error and warning with plural
forms.
* g++.dg/cpp1z/decomp10.C: Likewise.
* g++.dg/cpp1z/decomp32.C: New test.
--- gcc/cp/decl.c.jj 2017-12-15 20:40:00.601221086 +0100
+++ gcc/cp/decl.c 2017-12-15 20:42:25.917445216 +0100
@@ -7427,11 +7427,20 @@ cp_finish_decomp (tree decl, tree first,
{
cnt_mismatch:
if (count > eltscnt)
- error_at (loc, "%u names provided while %qT decomposes into "
- "%wu elements", count, type, eltscnt);
+ error_n (loc, count,
+ "%u name provided for structured binding",
+ "%u names provided for structured binding", count);
else
- error_at (loc, "only %u names provided while %qT decomposes into "
- "%wu elements", count, type, eltscnt);
+ error_n (loc, count,
+ "only %u name provided for structured binding",
+ "only %u names provided for structured binding", count);
+ /* Some languages have special plural rules even for large values,
+ but it is periodic with period of 10, 100, 1000 etc. */
+ inform_n (loc, eltscnt > INT_MAX
+ ? (eltscnt % 1000000) + 1000000 : eltscnt,
+ "while %qT decomposes into %wu element",
+ "while %qT decomposes into %wu elements",
+ type, eltscnt);
goto error_out;
}
eltype = TREE_TYPE (type);
@@ -7500,6 +7509,15 @@ cp_finish_decomp (tree decl, tree first,
"constant expression", type);
goto error_out;
}
+ if (!tree_fits_uhwi_p (tsize))
+ {
+ error_n (loc, count,
+ "%u name provided for structured binding",
+ "%u names provided for structured binding", count);
+ inform (loc, "while %qT decomposes into %E elements",
+ type, tsize);
+ goto error_out;
+ }
eltscnt = tree_to_uhwi (tsize);
if (count != eltscnt)
goto cnt_mismatch;
--- gcc/testsuite/g++.dg/cpp1z/decomp3.C.jj 2017-11-30 11:18:00.078805693
+0100
+++ gcc/testsuite/g++.dg/cpp1z/decomp3.C 2017-12-15 20:42:25.917445216
+0100
@@ -51,16 +51,21 @@ int arr[4];
void
test3 (A &b, B c)
{
- auto [ d, e, f ] = arr; // { dg-error "only 3 names provided
while 'int .4.' decomposes into 4 elements" }
- // { dg-warning "structured bindings
only available with -std=c..17 or -std=gnu..17" "" { target c++14_down } .-1 }
- auto & [ g, h, i, j, k ] = arr; // { dg-error "5 names provided while
'int .4.' decomposes into 4 elements" }
- // { dg-warning "structured bindings
only available with -std=c..17 or -std=gnu..17" "" { target c++14_down } .-1 }
- auto [ l, m ] = b; // { dg-error "only 2 names provided
while 'A' decomposes into 3 elements" }
- // { dg-warning "structured bindings
only available with -std=c..17 or -std=gnu..17" "" { target c++14_down } .-1 }
- auto & [ n, o, p, q ] = b; // { dg-error "4 names provided while
'A' decomposes into 3 elements" }
- // { dg-warning "structured bindings
only available with -std=c..17 or -std=gnu..17" "" { target c++14_down } .-1 }
+ auto [ d, e, f ] = arr; // { dg-error "only 3 names provided" }
+ // { dg-message "while 'int .4.'
decomposes into 4 elements" "" { target *-*-* } .-1 }
+ // { dg-warning "structured bindings
only available with -std=c..17 or -std=gnu..17" "" { target c++14_down } .-2 }
+ auto & [ g, h, i, j, k ] = arr; // { dg-error "5 names provided" }
+ // { dg-message "while 'int .4.'
decomposes into 4 elements" "" { target *-*-* } .-1 }
+ // { dg-warning "structured bindings
only available with -std=c..17 or -std=gnu..17" "" { target c++14_down } .-2 }
+ auto [ l, m ] = b; // { dg-error "only 2 names provided" }
+ // { dg-message "while 'A' decomposes
into 3 elements" "" { target *-*-* } .-1 }
+ // { dg-warning "structured bindings
only available with -std=c..17 or -std=gnu..17" "" { target c++14_down } .-2 }
+ auto & [ n, o, p, q ] = b; // { dg-error "4 names provided" }
+ // { dg-message "while 'A' decomposes
into 3 elements" "" { target *-*-* } .-1 }
+ // { dg-warning "structured bindings
only available with -std=c..17 or -std=gnu..17" "" { target c++14_down } .-2 }
auto [] { c }; // { dg-error "empty structured binding
declaration" }
// { dg-warning "structured bindings
only available with -std=c..17 or -std=gnu..17" "" { target c++14_down } .-1 }
- auto [ r, s ] = c; // { dg-error "2 names provided while
'B' decomposes into 1 elements" }
- // { dg-warning "structured bindings
only available with -std=c..17 or -std=gnu..17" "" { target c++14_down } .-1 }
+ auto [ r, s ] = c; // { dg-error "2 names provided" }
+ // { dg-message "while 'B' decomposes
into 1 element" "" { target *-*-* } .-1 }
+ // { dg-warning "structured bindings
only available with -std=c..17 or -std=gnu..17" "" { target c++14_down } .-2 }
}
--- gcc/testsuite/g++.dg/cpp1z/decomp10.C.jj 2017-11-30 11:18:00.102805393
+0100
+++ gcc/testsuite/g++.dg/cpp1z/decomp10.C 2017-12-15 20:42:25.918445204
+0100
@@ -11,7 +11,8 @@ void f1() { auto [ x ] = a1; } // { dg-e
struct A2 { int i,j; } a2;
template<> struct std::tuple_size<A2> { enum { value = 5 }; };
-void f2() { auto [ x ] = a2; } // { dg-error "decomposes into 5" }
+void f2() { auto [ x ] = a2; } // { dg-error "only 1 name provided" }
+ // { dg-message "decomposes into 5" "" { target
*-*-* } .-1 }
struct A3 { int i,j; } a3;
template<> struct std::tuple_size<A3> { enum { value = 1 }; };
--- gcc/testsuite/g++.dg/cpp1z/decomp32.C.jj 2017-12-15 20:42:58.977041204
+0100
+++ gcc/testsuite/g++.dg/cpp1z/decomp32.C 2017-12-15 20:42:25.918445204
+0100
@@ -0,0 +1,32 @@
+// PR c++/83205
+// { dg-do compile { target c++11 } }
+// { dg-options "" }
+
+struct A { int i; };
+struct B { int i; };
+namespace std {
+ template <typename T> struct tuple_size;
+ template <> struct tuple_size<A> {
+ static constexpr int value = -1;
+ };
+#ifdef __SIZEOF_INT128__
+ template <> struct tuple_size<B> {
+ static constexpr unsigned __int128 value = -1;
+ };
+#endif
+}
+
+auto [a] = A{}; // { dg-error "1 name provided" }
+ // { dg-message "while 'A' decomposes into -1 elements" "" {
target *-*-* } .-1 }
+ // { dg-warning "structured bindings only available with" "" {
target c++14_down } .-2 }
+#ifdef __SIZEOF_INT128__
+auto [b] = B{}; // { dg-error "1 name provided" "" { target int128 } }
+ // { dg-message "while 'B' decomposes into \[0-9xa-fXA-F]*
elements" "" { target int128 } .-1 }
+ // { dg-warning "structured bindings only available with" "" {
target { c++14_down && int128 } } .-2 }
+auto [c, d] = B{}; // { dg-error "2 names provided" "" { target int128 } }
+ // { dg-message "while 'B' decomposes into
\[0-9xa-fXA-F]* elements" "" { target int128 } .-1 }
+ // { dg-warning "structured bindings only available
with" "" { target { c++14_down && int128 } } .-2 }
+#endif
+auto [e, f, g] = A{}; // { dg-error "3 names provided" }
+ // { dg-message "while 'A' decomposes into -1 elements"
"" { target *-*-* } .-1 }
+ // { dg-warning "structured bindings only available
with" "" { target c++14_down } .-2 }
Jakub
