[N.B. this is a corrected version of
https://gcc.gnu.org/pipermail/gcc-patches/2022-November/607443.html ]
Currently when resolving a TYPENAME_TYPE for 'typename T::m' via
make_typename_type, we consider only type bindings of 'm' and ignore
non-type ones. But [temp.res.general]/3 says, in a note, "the usual
qualified name lookup ([basic.lookup.qual]) applies even in the presence
of 'typename'", and qualified name lookup doesn't discriminate between
type and non-type bindings. So when resolving such a TYPENAME_TYPE
we want the lookup to consider all bindings.
An exception is when we have a TYPENAME_TYPE corresponding to the
qualifying scope appearing before the :: scope resolution operator, such
as 'T::type' in 'typename T::type::m'. In that case, [basic.lookup.qual]/1
applies, and lookup for such a TYPENAME_TYPE must ignore non-type
bindings. So in order to correctly handle all cases, make_typename_type
needs an additional flag controlling whether lookup should ignore
non-types or not.
To that end this patch adds a type_only flag to make_typename_type and
defaults it to false (do not ignore non-types). In contexts where we do
want to ignore non-types (when substituting into the scope of a
TYPENAME_TYPE, SCOPE_REF, USING_DECL) we call tsubst_typename_type
directly with type_only=true.
Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look OK for
trunk?
PR c++/107773
gcc/cp/ChangeLog:
* cp-tree.h (make_typename_type): Add another boolean parameter
that defaults to false.
* decl.cc (make_typename_type): Use lookup_member instead of
lookup_field. Pass want_type=type_only instead of =false to
lookup_member. Generalize format specifier in diagnostic to
handle both type and non-type bindings.
* pt.cc (tsubst_typename_type): Add another boolean parameter
that defaults to false and pass it to make_typename_type. If
TYPE_CONTEXT is a TYPENAME_TYPE recurse with type_only=true
instead of substituting it via tsubst.
(tsubst_decl) <case USING_DECL>: If the scpoe is a TYPENAME_TYPE
call tsubst_typename_type directly with type_only=true instead
of substituting it via tsubst.
(tsubst_qualified_id): Likewise.
* search.cc (lookup_member): Document default argument.
gcc/testsuite/ChangeLog:
* g++.dg/template/typename24.C: New test.
* g++.dg/template/typename25.C: New test.
* g++.dg/template/typename26.C: New test.
---
gcc/cp/cp-tree.h | 2 +-
gcc/cp/decl.cc | 14 ++++-----
gcc/cp/pt.cc | 24 +++++++++++----
gcc/cp/search.cc | 2 +-
gcc/testsuite/g++.dg/template/typename24.C | 18 ++++++++++++
gcc/testsuite/g++.dg/template/typename25.C | 34 ++++++++++++++++++++++
gcc/testsuite/g++.dg/template/typename26.C | 20 +++++++++++++
7 files changed, 100 insertions(+), 14 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/template/typename24.C
create mode 100644 gcc/testsuite/g++.dg/template/typename25.C
create mode 100644 gcc/testsuite/g++.dg/template/typename26.C
diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
index a7c5765fc33..1241dbf8037 100644
--- a/gcc/cp/cp-tree.h
+++ b/gcc/cp/cp-tree.h
@@ -6845,7 +6845,7 @@ extern tree define_label (location_t,
tree);
extern void check_goto (tree);
extern bool check_omp_return (void);
extern tree make_typename_type (tree, tree, enum
tag_types, tsubst_flags_t,
- bool = false, bool = false);
+ bool = false, bool = false,
bool = false);
extern tree build_typename_type (tree, tree, tree,
tag_types);
extern tree make_unbound_class_template (tree, tree, tree,
tsubst_flags_t);
extern tree make_unbound_class_template_raw (tree, tree, tree);
diff --git a/gcc/cp/decl.cc b/gcc/cp/decl.cc
index 430533606b0..c741dc23d99 100644
--- a/gcc/cp/decl.cc
+++ b/gcc/cp/decl.cc
@@ -4232,13 +4232,14 @@ build_typename_type (tree context, tree name, tree
fullname,
return that, rather than the _TYPE it corresponds to, in other
cases we look through the type decl. If TEMPLATE_OK is true and
we found a TEMPLATE_DECL then we return a CTAD placeholder for the
- TEMPLATE_DECL. If TF_ERROR is set, complain about errors, otherwise
- be quiet. */
+ TEMPLATE_DECL. If TYPE_ONLY is true, lookup of NAME in CONTEXT
+ ignores non-type bindings. If TF_ERROR is set, complain about errors,
+ otherwise be quiet. */
tree
make_typename_type (tree context, tree name, enum tag_types tag_type,
tsubst_flags_t complain, bool keep_type_decl /* = false */,
- bool template_ok /* = false */)
+ bool template_ok /* = false */, bool type_only /* = false
*/)
{
tree fullname;
tree t;
@@ -4308,9 +4309,8 @@ make_typename_type (tree context, tree name, enum
tag_types tag_type,
member of the current instantiation or a non-dependent base;
lookup will stop when we hit a dependent base. */
if (!dependent_scope_p (context))
- /* We should only set WANT_TYPE when we're a nested typename type.
- Then we can give better diagnostics if we find a non-type. */
- t = lookup_field (context, name, 2, /*want_type=*/true);
+ t = lookup_member (context, name, /*protect=*/2,
+ /*want_type=*/type_only, complain);
else
t = NULL_TREE;
@@ -4362,7 +4362,7 @@ make_typename_type (tree context, tree name, enum tag_types tag_type,
else
{
if (complain & tf_error)
- error ("%<typename %T::%D%> names %q#T, which is not a type",
+ error ("%<typename %T::%D%> names %q#D, which is not a type",
context, name, t);
return error_mark_node;
}
diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
index bc47bf15d38..27fc0b93484 100644
--- a/gcc/cp/pt.cc
+++ b/gcc/cp/pt.cc
@@ -13949,12 +13949,12 @@ tsubst_aggr_type_1 (tree t,
return t;
}
-/* Substitute ARGS into the TYPENAME_TYPE T. The flag TEMPLATE_OK
- is passed to make_typename_type. */
+/* Substitute ARGS into the TYPENAME_TYPE T. The flags TEMPLATE_OK and
+ TYPE_ONLY are passed to make_typename_type. */
static tree
tsubst_typename_type (tree t, tree args, tsubst_flags_t complain, tree
in_decl,
- bool template_ok = false)
+ bool template_ok = false, bool type_only = false)
{
tree ctx = TYPE_CONTEXT (t);
if (TREE_CODE (ctx) == TYPE_PACK_EXPANSION)
@@ -13972,6 +13972,10 @@ tsubst_typename_type (tree t, tree args,
tsubst_flags_t complain, tree in_decl,
}
ctx = TREE_VEC_ELT (ctx, 0);
}
+ else if (TREE_CODE (ctx) == TYPENAME_TYPE
+ && !typedef_variant_p (ctx))
+ ctx = tsubst_typename_type (ctx, args, complain, in_decl,
+ /*template_ok=*/false, /*type_only=*/true);
else
ctx = tsubst_aggr_type (ctx, args, complain, in_decl,
/*entering_scope=*/1);
@@ -14004,7 +14008,7 @@ tsubst_typename_type (tree t, tree args, tsubst_flags_t
complain, tree in_decl,
}
f = make_typename_type (ctx, f, typename_type, complain,
- /*keep_type_decl=*/true, template_ok);
+ /*keep_type_decl=*/true, template_ok, type_only);
if (f == error_mark_node)
return f;
if (TREE_CODE (f) == TYPE_DECL)
@@ -15094,6 +15098,11 @@ tsubst_decl (tree t, tree args, tsubst_flags_t
complain)
scope = tsubst_pack_expansion (scope, args, complain, in_decl);
variadic_p = true;
}
+ else if (TREE_CODE (scope) == TYPENAME_TYPE
+ && !typedef_variant_p (scope))
+ scope = tsubst_typename_type (scope, args, complain, in_decl,
+ /*template_ok=*/false,
+ /*type_only=*/true);
else
scope = tsubst_copy (scope, args, complain, in_decl);
@@ -16885,7 +16894,12 @@ tsubst_qualified_id (tree qualified_id, tree args,
scope = TREE_OPERAND (qualified_id, 0);
if (args)
{
- scope = tsubst (scope, args, complain, in_decl);
+ if (TREE_CODE (scope) == TYPENAME_TYPE
+ && !typedef_variant_p (scope))
+ scope = tsubst_typename_type (scope, args, complain, in_decl,
+ /*template_ok=*/false,
/*type_only=*/true);
+ else
+ scope = tsubst (scope, args, complain, in_decl);
expr = tsubst_copy (name, args, complain, in_decl);
}
else
diff --git a/gcc/cp/search.cc b/gcc/cp/search.cc
index f3f19cafec6..e472a97679d 100644
--- a/gcc/cp/search.cc
+++ b/gcc/cp/search.cc
@@ -1109,7 +1109,7 @@ build_baselink (tree binfo, tree access_binfo, tree
functions, tree optype)
tree
lookup_member (tree xbasetype, tree name, int protect, bool want_type,
- tsubst_flags_t complain, access_failure_info *afi)
+ tsubst_flags_t complain, access_failure_info *afi /* = NULL */)
{
tree rval, rval_binfo = NULL_TREE;
tree type = NULL_TREE, basetype_path = NULL_TREE;
diff --git a/gcc/testsuite/g++.dg/template/typename24.C
b/gcc/testsuite/g++.dg/template/typename24.C
new file mode 100644
index 00000000000..8b2b3718442
--- /dev/null
+++ b/gcc/testsuite/g++.dg/template/typename24.C
@@ -0,0 +1,18 @@
+// PR c++/107773
+// Verify lookup for a non-neste TYPENAME_TYPE correctly considers
+// non-types.
+
+struct a {
+ typedef void get;
+};
+
+struct b : a {
+ int get(int i) const;
+};
+
+template<class T>
+void f() {
+ typedef typename T::get type; // { dg-error "'int b::get\\(int\\) const', which
is not a type" }
+}
+
+template void f<b>();
diff --git a/gcc/testsuite/g++.dg/template/typename25.C
b/gcc/testsuite/g++.dg/template/typename25.C
new file mode 100644
index 00000000000..924330ee8d4
--- /dev/null
+++ b/gcc/testsuite/g++.dg/template/typename25.C
@@ -0,0 +1,34 @@
+// PR c++/107773
+// Verify lookup for TYPENAME_TYPE appearing to the left of the scope (::)
+// operator in various contexts correctly ignores non-types.
+
+struct a {
+ typedef void type;
+};
+
+struct c {
+ struct b : a {
+ typedef b self;
+ static int m;
+ };
+ int b;
+};
+
+template<class T>
+void f() {
+ // T::b::type is a TYPENAME_TYPE whose TYPE_CONTEXT is a nested
+ // TYPENAME_TYPE.
+ typedef typename T::b::type type;
+ // T::b::m is a SCOPE_REF whose first operand is a TYPENAME_TYPE.
+ int m = T::b::m;
+}
+
+template void f<c>();
+
+template<class T>
+struct d : T::b::self {
+ // The using is a USING_DECL whose USING_DECL_SCOPE is a TYPENAME_TYPE.
+ using typename T::b::type;
+};
+
+template struct d<c>;
diff --git a/gcc/testsuite/g++.dg/template/typename26.C
b/gcc/testsuite/g++.dg/template/typename26.C
new file mode 100644
index 00000000000..4e6b764a97b
--- /dev/null
+++ b/gcc/testsuite/g++.dg/template/typename26.C
@@ -0,0 +1,20 @@
+// Example 4 from [temp.res.general]/3.
+
+struct A {
+ struct X { };
+ int X;
+};
+struct B {
+ struct X { };
+};
+template<class T> void f(T t) {
+ typename T::X x; // { dg-error "'int A::X', which is not a type" }
+}
+void foo() {
+ A a;
+ B b;
+ f(b); // OK, T::X refers to B::X
+ // { dg-bogus "" "" { target *-*-* } .-1 }
+ f(a); // error: T::X refers to the data member A::X not the struct A::X
+ // { dg-message "required from here" "" { target *-*-* } .-1 }
+}
