-- >8 --
Subject: [PATCH] c++: TYPENAME_TYPE lookup ignoring non-types [PR107773]
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 of 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 new tsubst flag tf_qualifying_scope to
communicate to make_typename_type whether we want to ignore non-type
bindings during the lookup (by default we don't want to ignore them).
In contexts where we do want to ignore non-types (when substituting
into the scope of TYPENAME_TYPE, SCOPE_REF or USING_DECL) we simply
pass tf_qualifying_scope to the relevant tsubst / tsubst_copy call.
This flag is intended to apply only to top-level TYPENAME_TYPEs so
we must be careful to clear the flag to avoid propagating it during
substitution of sub-trees.
PR c++/107773
gcc/cp/ChangeLog:
* cp-tree.h (enum tsubst_flags): New flag tf_qualifying_scope.
* decl.cc (make_typename_type): Use lookup_member instead of
lookup_field. If tf_qualifying_scope is set, pass want_type=true
instead of =false to lookup_member. Generalize format specifier
in diagnostic to handle both type and non-type bindings.
* pt.cc (tsubst_aggr_type_1): Clear tf_qualifying_scope. Tidy
the function.
(tsubst_decl) <case USING_DECL>: Set tf_qualifying_scope when
substituting USING_DECL_SCOPE.
(tsubst): Clear tf_qualifying_scope right away and remember if
it was set. Do the same for tf_tst_ok sooner.
<case TYPENAME_TYPE>: Set tf_qualifying_scope when substituting
TYPE_CONTEXT. Pass tf_qualifying_scope to make_typename_type
if it was set.
(tsubst_qualified_id): Set tf_qualifying_scope when substituting
the scope.
(tsubst_copy): Clear tf_qualifying_scope and remember if it was
set.
<case SCOPE_REF>: Set tf_qualifying_scope when substituting the
scope.
<case *_TYPE>: Pass tf_qualifying_scope to tsubst if it was set.
* 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/typename25a.C: New test.
* g++.dg/template/typename26.C: New test.
---
gcc/cp/cp-tree.h | 3 ++
gcc/cp/decl.cc | 9 ++--
gcc/cp/pt.cc | 58 ++++++++++++---------
gcc/cp/search.cc | 2 +-
gcc/testsuite/g++.dg/template/typename24.C | 18 +++++++
gcc/testsuite/g++.dg/template/typename25.C | 33 ++++++++++++
gcc/testsuite/g++.dg/template/typename25a.C | 37 +++++++++++++
gcc/testsuite/g++.dg/template/typename26.C | 20 +++++++
8 files changed, 150 insertions(+), 30 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/typename25a.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 be8775ed0f8..891fcf521a8 100644
--- a/gcc/cp/cp-tree.h
+++ b/gcc/cp/cp-tree.h
@@ -5597,6 +5597,9 @@ enum tsubst_flags {
tf_tst_ok = 1 << 12, /* Allow a typename-specifier to name
a template (C++17 or later). */
tf_dguide = 1 << 13, /* Building a deduction guide from a
ctor. */
+ tf_qualifying_scope = 1 << 14, /* Substituting the LHS of the ::
operator.
+ Controls TYPENAME_TYPE resolution from
+ make_typename_type. */
/* Convenient substitution flags combinations. */
tf_warning_or_error = tf_warning | tf_error
};
diff --git a/gcc/cp/decl.cc b/gcc/cp/decl.cc
index d606b31d7a7..2f6412d04e6 100644
--- a/gcc/cp/decl.cc
+++ b/gcc/cp/decl.cc
@@ -4305,9 +4305,10 @@ 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);
+ {
+ bool want_type = (complain & tf_qualifying_scope);
+ t = lookup_member (context, name, /*protect=*/2, want_type,
complain);
+ }
else
t = NULL_TREE;
@@ -4359,7 +4360,7 @@ 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 e89dbf47097..d11d540ab44 100644
--- a/gcc/cp/pt.cc
+++ b/gcc/cp/pt.cc
@@ -13919,8 +13919,7 @@ tsubst_aggr_type_1 (tree t,
{
if (TYPE_TEMPLATE_INFO (t) && uses_template_parms (t))
{
- tree argvec;
- tree r;
+ complain &= ~tf_qualifying_scope;
/* Figure out what arguments are appropriate for the
type we are trying to find. For example, given:
@@ -13931,18 +13930,14 @@ tsubst_aggr_type_1 (tree t,
and supposing that we are instantiating f<int, double>,
then our ARGS will be {int, double}, but, when looking up
S we only want {double}. */
- argvec = tsubst_template_args (TYPE_TI_ARGS (t), args,
- complain, in_decl);
+ tree argvec = tsubst_template_args (TYPE_TI_ARGS (t), args,
+ complain, in_decl);
if (argvec == error_mark_node)
- r = error_mark_node;
- else
- {
- r = lookup_template_class (t, argvec, in_decl, NULL_TREE,
- entering_scope, complain);
- r = cp_build_qualified_type (r, cp_type_quals (t), complain);
- }
+ return error_mark_node;
- return r;
+ tree r = lookup_template_class (t, argvec, in_decl, NULL_TREE,
+ entering_scope, complain);
+ return cp_build_qualified_type (r, cp_type_quals (t), complain);
}
else
/* This is not a template type, so there's nothing to do. */
@@ -15003,11 +14998,15 @@ tsubst_decl (tree t, tree args, tsubst_flags_t
complain)
tree scope = USING_DECL_SCOPE (t);
if (PACK_EXPANSION_P (scope))
{
- scope = tsubst_pack_expansion (scope, args, complain, in_decl);
+ scope = tsubst_pack_expansion (scope, args,
+ complain | tf_qualifying_scope,
+ in_decl);
variadic_p = true;
}
else
- scope = tsubst_copy (scope, args, complain, in_decl);
+ scope = tsubst_copy (scope, args,
+ complain | tf_qualifying_scope,
+ in_decl);
tree name = DECL_NAME (t);
if (IDENTIFIER_CONV_OP_P (name)
@@ -15821,6 +15820,12 @@ tsubst (tree t, tree args, tsubst_flags_t complain,
tree in_decl)
|| TREE_CODE (t) == TRANSLATION_UNIT_DECL)
return t;
+ tsubst_flags_t tst_ok_flag = (complain & tf_tst_ok);
+ complain &= ~tf_tst_ok;
+
+ tsubst_flags_t qualifying_scope_flag = (complain & tf_qualifying_scope);
+ complain &= ~tf_qualifying_scope;
+
if (DECL_P (t))
return tsubst_decl (t, args, complain);
@@ -15889,9 +15894,6 @@ tsubst (tree t, tree args, tsubst_flags_t
complain, tree in_decl)
bool fndecl_type = (complain & tf_fndecl_type);
complain &= ~tf_fndecl_type;
- bool tst_ok = (complain & tf_tst_ok);
- complain &= ~tf_tst_ok;
-
if (type
&& code != TYPENAME_TYPE
&& code != TEMPLATE_TYPE_PARM
@@ -16428,7 +16430,9 @@ tsubst (tree t, tree args, tsubst_flags_t complain,
tree in_decl)
tree ctx = TYPE_CONTEXT (t);
if (TREE_CODE (ctx) == TYPE_PACK_EXPANSION)
{
- ctx = tsubst_pack_expansion (ctx, args, complain, in_decl);
+ ctx = tsubst_pack_expansion (ctx, args,
+ complain | tf_qualifying_scope,
+ in_decl);
if (ctx == error_mark_node
|| TREE_VEC_LENGTH (ctx) > 1)
return error_mark_node;
@@ -16442,8 +16446,9 @@ tsubst (tree t, tree args, tsubst_flags_t complain,
tree in_decl)
ctx = TREE_VEC_ELT (ctx, 0);
}
else
- ctx = tsubst_aggr_type (ctx, args, complain, in_decl,
- /*entering_scope=*/1);
+ ctx = tsubst_aggr_type (ctx, args,
+ complain | tf_qualifying_scope,
+ in_decl, /*entering_scope=*/1);
if (ctx == error_mark_node)
return error_mark_node;
@@ -16473,8 +16478,7 @@ tsubst (tree t, tree args, tsubst_flags_t
complain, tree in_decl)
}
tsubst_flags_t tcomplain = complain | tf_keep_type_decl;
- if (tst_ok)
- tcomplain |= tf_tst_ok;
+ tcomplain |= tst_ok_flag | qualifying_scope_flag;
f = make_typename_type (ctx, f, typename_type, tcomplain);
if (f == error_mark_node)
return f;
@@ -16879,7 +16883,7 @@ tsubst_qualified_id (tree qualified_id, tree args,
scope = TREE_OPERAND (qualified_id, 0);
if (args)
{
- scope = tsubst (scope, args, complain, in_decl);
+ scope = tsubst (scope, args, complain | tf_qualifying_scope,
in_decl);
expr = tsubst_copy (name, args, complain, in_decl);
}
else
@@ -17125,6 +17129,9 @@ tsubst_copy (tree t, tree args, tsubst_flags_t
complain, tree in_decl)
if (t == NULL_TREE || t == error_mark_node || args == NULL_TREE)
return t;
+ tsubst_flags_t qualifying_scope_flag = (complain &
tf_qualifying_scope);
+ complain &= ~tf_qualifying_scope;
+
if (tree d = maybe_dependent_member_ref (t, args, complain, in_decl))
return d;
@@ -17598,7 +17605,8 @@ tsubst_copy (tree t, tree args, tsubst_flags_t
complain, tree in_decl)
case SCOPE_REF:
{
- tree op0 = tsubst_copy (TREE_OPERAND (t, 0), args, complain, in_decl);
+ tree op0 = tsubst_copy (TREE_OPERAND (t, 0), args,
+ complain | tf_qualifying_scope, in_decl);
tree op1 = tsubst_copy (TREE_OPERAND (t, 1), args, complain, in_decl);
return build_qualified_name (/*type=*/NULL_TREE, op0, op1,
QUALIFIED_NAME_IS_TEMPLATE (t));
@@ -17713,7 +17721,7 @@ tsubst_copy (tree t, tree args, tsubst_flags_t
complain, tree in_decl)
case TYPEOF_TYPE:
case DECLTYPE_TYPE:
case TYPE_DECL:
- return tsubst (t, args, complain, in_decl);
+ return tsubst (t, args, complain | qualifying_scope_flag, in_decl);
case USING_DECL:
t = DECL_NAME (t);
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..04e48e11724
--- /dev/null
+++ b/gcc/testsuite/g++.dg/template/typename25.C
@@ -0,0 +1,33 @@
+// PR c++/107773
+// Verify lookup for TYPENAME_TYPE appearing to the left of the ::
+// scope resolution operator 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() {
+ // A TYPENAME_TYPE whose TYPE_CONTEXT is a nested TYPENAME_TYPE.
+ typedef typename T::b::type type;
+ // 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 {
+ // 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/typename25a.C
b/gcc/testsuite/g++.dg/template/typename25a.C
new file mode 100644
index 00000000000..ecb34aada34
--- /dev/null
+++ b/gcc/testsuite/g++.dg/template/typename25a.C
@@ -0,0 +1,37 @@
+// PR c++/107773
+// A variadic version of typename25.C
+// { dg-do compile { target c++11 } }
+
+struct a {
+ typedef void type;
+};
+
+struct c {
+ struct b : a {
+ typedef b self;
+ static int m;
+ };
+ int b;
+};
+
+template<class...> void sink(...);
+
+template<class... Ts>
+void f() {
+ // A TYPENAME_TYPE whose TYPE_CONTEXT is a nested TYPENAME_TYPE.
+ sink<typename Ts::b::type...>();
+ // A SCOPE_REF whose first operand is a TYPENAME_TYPE.
+ sink(Ts::b::m...);
+}
+
+template void f<c>();
+
+template<class... Ts>
+struct d : Ts::b::self... {
+#if __cpp_variadic_using
+ // A USING_DECL whose USING_DECL_SCOPE is a TYPENAME_TYPE.
+ using typename Ts::b::type...;
+#endif
+};
+
+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 }
+}
