On Apr 4, 2018, Jason Merrill <ja...@redhat.com> wrote:
>> else
>> expr = lookup_template_function (expr, template_args);
>> +
>> + /* We may be repeating a check already done during parsing, but
>> + if it was well-formed and passed then, it will pass again
>> + now, and if it didn't, we wouldn't have got here. The case
>> + we want to catch is when we couldn't tell then, and can now,
>> + namely when templ prior to substitution was an
>> + identifier. */
>> + if (flag_concepts && check_auto_in_tmpl_args (expr, template_args))
>> + return error_mark_node;
> I think we want this added code to go at the beginning of the block,
Uhh, it can't be too early, or we will still have an identifier, and
then the check function will just return.
> before we've wrapped the template in a TEMPLATE_ID_EXPR. OK with that
> change.
Aah, maybe you mean the smaller block under 'if (is_template)', as in
the so-modified patch below? Heh, yeah, lookup_template_function and
lookup_template_variable are very misleading function names! They don't
perform any of the lookups I expected of them! ;-)
I'm testing this patch now, and if it passes I'll proceed to install it
under the assumption that this is what you approved.
Thanks!
[PR c++/84979] reject auto in explicit tmpl args for tmpl-fn
With concepts, we accept auto in explicit template arguments, but we
should only accept them for template classes. Passing them to
template functions or variables is not allowed. So, reject it, at
parse time if possible, at specialization time otherwise.
for gcc/cp/ChangeLog
PR c++/84979
* pt.c (check_auto_in_tmpl_args): New.
(tsubst_qualified_id): Use it to reject template args
referencing auto for non-type templates.
* parser.c (cp_parser_template_id): Likewise.
* cp-tree.h (check_auto_in_tmpl_args): Declare.
* typeck2.c (build_functional_cast): Report correct location
for invalid use of auto.
for gcc/testsuite/ChangeLog
PR c++/84979
* g++.dg/concepts/pr84979.C: New.
* g++.dg/concepts/pr84979-2.C: New.
* g++.dg/concepts/pr84979-3.C: New.
---
gcc/cp/cp-tree.h | 1 +
gcc/cp/parser.c | 10 +++++-
gcc/cp/pt.c | 52 +++++++++++++++++++++++++++++
gcc/cp/typeck2.c | 3 +-
gcc/testsuite/g++.dg/concepts/pr84979-2.C | 41 +++++++++++++++++++++++
gcc/testsuite/g++.dg/concepts/pr84979-3.C | 45 +++++++++++++++++++++++++
gcc/testsuite/g++.dg/concepts/pr84979.C | 9 +++++
7 files changed, 159 insertions(+), 2 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/concepts/pr84979-2.C
create mode 100644 gcc/testsuite/g++.dg/concepts/pr84979-3.C
create mode 100644 gcc/testsuite/g++.dg/concepts/pr84979.C
diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
index f7bacd08c8f8..c8f2b1696525 100644
--- a/gcc/cp/cp-tree.h
+++ b/gcc/cp/cp-tree.h
@@ -6500,6 +6500,7 @@ extern void maybe_show_extern_c_location (void);
/* in pt.c */
extern bool check_template_shadow (tree);
+extern bool check_auto_in_tmpl_args (tree, tree);
extern tree get_innermost_template_args (tree, int);
extern void maybe_begin_member_template_processing (tree);
extern void maybe_end_member_template_processing (void);
diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c
index d526a4eb3652..af19f77acca3 100644
--- a/gcc/cp/parser.c
+++ b/gcc/cp/parser.c
@@ -15831,8 +15831,16 @@ cp_parser_template_id (cp_parser *parser,
location_t combined_loc
= make_location (token->location, token->location, finish_loc);
+ /* Check for concepts autos where they don't belong. We could
+ identify types in some cases of idnetifier TEMPL, looking ahead
+ for a CPP_SCOPE, but that would buy us nothing: we accept auto in
+ types. We reject them in functions, but if what we have is an
+ identifier, even with none_type we can't conclude it's NOT a
+ type, we have to wait for template substitution. */
+ if (flag_concepts && check_auto_in_tmpl_args (templ, arguments))
+ template_id = error_mark_node;
/* Build a representation of the specialization. */
- if (identifier_p (templ))
+ else if (identifier_p (templ))
template_id = build_min_nt_loc (combined_loc,
TEMPLATE_ID_EXPR,
templ, arguments);
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index 80670a4826b6..4bc1f6e61e46 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -14903,6 +14903,15 @@ tsubst_qualified_id (tree qualified_id, tree args,
if (is_template)
{
+ /* We may be repeating a check already done during parsing, but
+ if it was well-formed and passed then, it will pass again
+ now, and if it didn't, we wouldn't have got here. The case
+ we want to catch is when we couldn't tell then, and can now,
+ namely when templ prior to substitution was an
+ identifier. */
+ if (flag_concepts && check_auto_in_tmpl_args (expr, template_args))
+ return error_mark_node;
+
if (variable_template_p (expr))
expr = lookup_and_finish_template_variable (expr, template_args,
complain);
@@ -26547,6 +26556,49 @@ type_uses_auto (tree type)
return find_type_usage (type, is_auto);
}
+/* Report ill-formed occurrences of auto types in ARGUMENTS. If
+ concepts are enabled, auto is acceptable in template arguments, but
+ only when TEMPL identifies a template class. Return TRUE if any
+ such errors were reported. */
+
+bool
+check_auto_in_tmpl_args (tree tmpl, tree args)
+{
+ /* If there were previous errors, nevermind. */
+ if (!args || TREE_CODE (args) != TREE_VEC)
+ return false;
+
+ /* If TMPL is an identifier, we're parsing and we can't tell yet
+ whether TMPL is supposed to be a type, a function or a variable.
+ We'll only be able to tell during template substitution, so we
+ expect to be called again then. If concepts are enabled and we
+ know we have a type, we're ok. */
+ if (flag_concepts
+ && (identifier_p (tmpl)
+ || (DECL_P (tmpl)
+ && (DECL_TYPE_TEMPLATE_P (tmpl)
+ || DECL_TEMPLATE_TEMPLATE_PARM_P (tmpl)))))
+ return false;
+
+ /* Quickly search for any occurrences of auto; usually there won't
+ be any, and then we'll avoid allocating the vector. */
+ if (!type_uses_auto (args))
+ return false;
+
+ bool errors = false;
+
+ tree vec = extract_autos (args);
+ for (int i = 0; i < TREE_VEC_LENGTH (vec); i++)
+ {
+ tree xauto = TREE_VALUE (TREE_VEC_ELT (vec, i));
+ error_at (DECL_SOURCE_LOCATION (xauto),
+ "invalid use of %qT in template argument", xauto);
+ errors = true;
+ }
+
+ return errors;
+}
+
/* For a given template T, return the vector of typedefs referenced
in T for which access check is needed at T instantiation time.
T is either a FUNCTION_DECL or a RECORD_TYPE.
diff --git a/gcc/cp/typeck2.c b/gcc/cp/typeck2.c
index 3aae0a362d5d..3bdeae1501f5 100644
--- a/gcc/cp/typeck2.c
+++ b/gcc/cp/typeck2.c
@@ -2081,7 +2081,8 @@ build_functional_cast (tree exp, tree parms,
tsubst_flags_t complain)
if (!CLASS_PLACEHOLDER_TEMPLATE (anode))
{
if (complain & tf_error)
- error ("invalid use of %qT", anode);
+ error_at (DECL_SOURCE_LOCATION (TEMPLATE_TYPE_DECL (anode)),
+ "invalid use of %qT", anode);
return error_mark_node;
}
else if (!parms)
diff --git a/gcc/testsuite/g++.dg/concepts/pr84979-2.C
b/gcc/testsuite/g++.dg/concepts/pr84979-2.C
new file mode 100644
index 000000000000..ce69a0f8ac53
--- /dev/null
+++ b/gcc/testsuite/g++.dg/concepts/pr84979-2.C
@@ -0,0 +1,41 @@
+// { dg-do compile { target c++11 } }
+// { dg-options "-fconcepts" }
+
+template <typename T>
+void foo1(T& t) {
+ typename T::template C<void> tcv = t;
+ typename T::template C<auto> u = tcv;
+ T::template C<auto>::f (tcv, u); // { dg-error "incomplete" }
+ (typename T::template D<auto> (t)); // { dg-error "invalid" }
+}
+
+struct T1 {
+ template <typename T> struct C {
+ C(T1&);
+ static void f(T1&, C&);
+ };
+ template <typename T> struct D {
+ D(T1&);
+ };
+};
+
+template <typename T>
+void foo2(T& t) {
+ typename T::template C<void> tcv = t;
+ typename T::template C<auto> u = tcv;
+ T::template C<auto>::f (tcv, u); // { dg-error "incomplete" }
+ T::template D<auto> (t); // { dg-error "invalid" }
+}
+
+struct T2 {
+ template <typename T> struct C {
+ C(T2&);
+ static void f(T2&, C&);
+ };
+ template <typename T> static void D(T2&);
+};
+
+void f(T1& t1, T2& t2) {
+ foo1 (t1);
+ foo2 (t2);
+}
diff --git a/gcc/testsuite/g++.dg/concepts/pr84979-3.C
b/gcc/testsuite/g++.dg/concepts/pr84979-3.C
new file mode 100644
index 000000000000..3809c2d3033b
--- /dev/null
+++ b/gcc/testsuite/g++.dg/concepts/pr84979-3.C
@@ -0,0 +1,45 @@
+// { dg-do compile { target c++11 } }
+// { dg-options "-fconcepts" }
+
+// This is like pr84979-2.C, except that we swap the types passed to
+// the template functions foo1 and foo2, so that the expectations WRT
+// D's typeness are not met.
+
+template <typename T>
+void foo1(T& t) {
+ typename T::template C<void> tcv = t;
+ typename T::template C<auto> u = tcv;
+ T::template C<auto>::f (tcv, u); // { dg-error "incomplete" }
+ (typename T::template D<auto> (t)); // { dg-error "invalid" }
+}
+
+struct T1 {
+ template <typename T> struct C {
+ C(T1&);
+ static void f(T1&, C&);
+ };
+ template <typename T> struct D {
+ D(T1&);
+ };
+};
+
+template <typename T>
+void foo2(T& t) {
+ typename T::template C<void> tcv = t;
+ typename T::template C<auto> u = tcv;
+ T::template C<auto>::f (tcv, u); // { dg-error "incomplete" }
+ T::template D<auto> (t); // { dg-error "yields a type" }
+}
+
+struct T2 {
+ template <typename T> struct C {
+ C(T2&);
+ static void f(T2&, C&);
+ };
+ template <typename T> static void D(T2&);
+};
+
+void f(T1& t1, T2& t2) {
+ foo1 (t2);
+ foo2 (t1);
+}
diff --git a/gcc/testsuite/g++.dg/concepts/pr84979.C
b/gcc/testsuite/g++.dg/concepts/pr84979.C
new file mode 100644
index 000000000000..9bd40df103a8
--- /dev/null
+++ b/gcc/testsuite/g++.dg/concepts/pr84979.C
@@ -0,0 +1,9 @@
+// { dg-do compile { target c++11 } }
+// { dg-options "-fconcepts" }
+
+template<typename> void foo() {}
+
+void bar()
+{
+ foo<auto>(); // { dg-error "invalid" }
+}
--
Alexandre Oliva, freedom fighter http://FSFLA.org/~lxoliva/
You must be the change you wish to see in the world. -- Gandhi
Be Free! -- http://FSFLA.org/ FSF Latin America board member
Free Software Evangelist|Red Hat Brasil GNU Toolchain Engineer
