On Thu, May 23, 2024 at 05:11:39PM -0400, Jason Merrill wrote:
> On 5/23/24 10:54, Nathaniel Shead wrote:
> > Bootstrapped and regtested (so far just modules.exp and dg.exp) on
> > x86_64-pc-linux-gnu, OK for trunk if full regtest succeeds?
> >
> > -- >8 --
> >
> > This fixes an ICE when a module directive is not given at global scope.
> > Although not explicitly mentioned, it seems implied from [basic.link] p1
> > and [module.global.frag] that a module-declaration must appear at the
> > global scope after preprocessing. Apart from this the patch also
> > slightly improves the errors given when accidentally using a module
> > control-line in other situations where it is not expected.
>
> This could also come up with something like
>
> int module;
> int i =
> module; // error, unexpected module directive
>
> Adding a line break seems like confusing advice for this problem; rather,
> they need to remove the line break before 'module'. And possibly add it in
> somewhere else, but the problem is that 'module' is the first token on the
> line. And if I put that in a namespace,
>
> namespace A {
> int module;
> int i =
> module; // error, unexpected module directive
> }
>
> the problem is the same, but we get a different diagnostic.
>
True.
FWIW I just used the same wording as in 'cp_parser_import_declaration';
my understanding is it's because you can disambiguate by adding a
newline after the 'module' itself:
int module;
int i =
module
;
is OK. But I'll update this message to be clearer.
> I think I'd leave the "must be at global scope" diagnostic to
> cp_parser_module_declaration, and assume that if we see a module keyword at
> function scope it wasn't intended to be a module directive.
>
How about this then? Bootstrapped and regtested on x86_64-pc-linux-gnu.
-- >8 --
This fixes an ICE when a module directive is not given at global scope.
Although not explicitly mentioned, it seems implied from [basic.link] p1
and [module.global.frag] that a module-declaration must appear at the
global scope after preprocessing. Apart from this the patch also
slightly improves the errors given when accidentally using a module
control-line in other situations where it is not expected.
PR c++/115200
gcc/cp/ChangeLog:
* parser.cc (cp_parser_error_1): Special-case unexpected module
directives for better diagnostics.
(cp_parser_module_declaration): Check that the module
declaration is at global scope.
(cp_parser_import_declaration): Sync error message with that in
cp_parser_error_1.
gcc/testsuite/ChangeLog:
* g++.dg/modules/mod-decl-1.C: Update error messages.
* g++.dg/modules/mod-decl-6.C: New test.
* g++.dg/modules/mod-decl-7.C: New test.
* g++.dg/modules/mod-decl-8.C: New test.
Signed-off-by: Nathaniel Shead <nathanielosh...@gmail.com>
---
gcc/cp/parser.cc | 26 ++++++++++++++++++++---
gcc/testsuite/g++.dg/modules/mod-decl-1.C | 8 ++++---
gcc/testsuite/g++.dg/modules/mod-decl-6.C | 11 ++++++++++
gcc/testsuite/g++.dg/modules/mod-decl-7.C | 11 ++++++++++
gcc/testsuite/g++.dg/modules/mod-decl-8.C | 14 ++++++++++++
5 files changed, 64 insertions(+), 6 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/modules/mod-decl-6.C
create mode 100644 gcc/testsuite/g++.dg/modules/mod-decl-7.C
create mode 100644 gcc/testsuite/g++.dg/modules/mod-decl-8.C
diff --git a/gcc/cp/parser.cc b/gcc/cp/parser.cc
index 476ddc0d63a..779625144db 100644
--- a/gcc/cp/parser.cc
+++ b/gcc/cp/parser.cc
@@ -3230,6 +3230,19 @@ cp_parser_error_1 (cp_parser* parser, const char* gmsgid,
return;
}
+ if (cp_token_is_module_directive (token))
+ {
+ auto_diagnostic_group d;
+ error_at (token->location, "unexpected module directive");
+ if (token->keyword != RID__EXPORT)
+ inform (token->location, "perhaps insert a line break after"
+ " %qs, or other disambiguation, to prevent this being"
+ " considered a module control-line",
+ (token->keyword == RID__MODULE) ? "module" : "import");
+ cp_parser_skip_to_pragma_eol (parser, token);
+ return;
+ }
+
/* If this is actually a conflict marker, report it as such. */
if (token->type == CPP_LSHIFT
|| token->type == CPP_RSHIFT
@@ -15135,12 +15148,19 @@ cp_parser_module_declaration (cp_parser *parser,
module_parse mp_state,
parser->lexer->in_pragma = true;
cp_token *token = cp_lexer_consume_token (parser->lexer);
+ tree scope = current_scope ();
if (flag_header_unit)
{
error_at (token->location,
"module-declaration not permitted in header-unit");
goto skip_eol;
}
+ else if (scope != global_namespace)
+ {
+ error_at (token->location, "module-declaration must be at global scope");
+ inform (DECL_SOURCE_LOCATION (scope), "scope opened here");
+ goto skip_eol;
+ }
else if (mp_state == MP_FIRST && !exporting
&& cp_lexer_next_token_is (parser->lexer, CPP_SEMICOLON))
{
@@ -15217,9 +15237,9 @@ cp_parser_import_declaration (cp_parser *parser,
module_parse mp_state,
error_at (token->location, "post-module-declaration"
" imports must be contiguous");
note_lexer:
- inform (token->location, "perhaps insert a line break, or other"
- " disambiguation, to prevent this being considered a"
- " module control-line");
+ inform (token->location, "perhaps insert a line break after"
+ " %<import%>, or other disambiguation, to prevent this"
+ " being considered a module control-line");
skip_eol:
cp_parser_skip_to_pragma_eol (parser, token);
}
diff --git a/gcc/testsuite/g++.dg/modules/mod-decl-1.C
b/gcc/testsuite/g++.dg/modules/mod-decl-1.C
index 23d34483dd7..df398b3ef50 100644
--- a/gcc/testsuite/g++.dg/modules/mod-decl-1.C
+++ b/gcc/testsuite/g++.dg/modules/mod-decl-1.C
@@ -10,17 +10,19 @@ module foo.second; // { dg-error "only permitted as" }
namespace Foo
{
-module third; // { dg-error "only permitted as" }
+module third; // { dg-error "must be at global scope" }
}
struct Baz
{
- module forth; // { dg-error "expected" }
+ module forth; // { dg-error "unexpected module directive" }
+ // { dg-message "line break after .module." "" { target *-*-* } .-1 }
};
void Bink ()
{
- module fifth; // { dg-error "expected" }
+ module fifth; // { dg-error "unexpected module directive" }
+ // { dg-message "line break after .module." "" { target *-*-* } .-1 }
}
module a.; // { dg-error "only permitted as" }
diff --git a/gcc/testsuite/g++.dg/modules/mod-decl-6.C
b/gcc/testsuite/g++.dg/modules/mod-decl-6.C
new file mode 100644
index 00000000000..5fb342455e5
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/mod-decl-6.C
@@ -0,0 +1,11 @@
+// PR c++/115200
+// { dg-additional-options "-fmodules-ts -Wno-global-module" }
+// { dg-module-cmi !M }
+
+module;
+
+namespace ns { // { dg-message "scope opened here" }
+
+export module M; // { dg-error "global scope" }
+
+}
diff --git a/gcc/testsuite/g++.dg/modules/mod-decl-7.C
b/gcc/testsuite/g++.dg/modules/mod-decl-7.C
new file mode 100644
index 00000000000..d25a1938044
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/mod-decl-7.C
@@ -0,0 +1,11 @@
+// PR c++/115200
+// { dg-additional-options "-fmodules-ts -Wno-global-module" }
+// { dg-module-cmi !M }
+
+module;
+
+void foo() {
+
+export module M; // { dg-error "unexpected module directive" }
+
+}
diff --git a/gcc/testsuite/g++.dg/modules/mod-decl-8.C
b/gcc/testsuite/g++.dg/modules/mod-decl-8.C
new file mode 100644
index 00000000000..9f5f1de544a
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/mod-decl-8.C
@@ -0,0 +1,14 @@
+// { dg-additional-options "-fmodules-ts" }
+// { dg-module-cmi M }
+
+export module M;
+
+struct module {};
+struct import {};
+
+void foo() {
+ module
+ x; // OK
+ import
+ y; // OK
+}
--
2.43.2
