static tree try_class_unification (tree, tree, tree, tree);
static int coerce_template_template_parms (tree, tree, tsubst_flags_t,
tree, tree);
+static bool template_template_parm_bindings_ok_p (tree, tree);
static int template_args_equal (tree, tree);
static void tsubst_default_arguments (tree);
static tree for_each_template_parm_r (tree *, int *, void *);
return 1;
}
+/* Verifies that the deduced template arguments (in TARGS) for the
+ template template parameters (in TPARMS) represent valid bindings,
+ by comparing the template parameter list of each template argument
+ to the template parameter list of its corresponding template
+ template parameter, in accordance with DR150. This
+ routine can only be called after all template arguments have been
+ deduced. It will return TRUE if all of the template template
+ parameter bindings are okay, FALSE otherwise. */
+bool
+template_template_parm_bindings_ok_p (tree tparms, tree targs)
+{
+ int i, ntparms = TREE_VEC_LENGTH (tparms);
+
+ targs = INNERMOST_TEMPLATE_ARGS (targs);
+
+ for (i = 0; i < ntparms; ++i)
+ {
+ tree tparm = TREE_VALUE (TREE_VEC_ELT (tparms, i));
+ tree targ = TREE_VEC_ELT (targs, i);
+
+ if (TREE_CODE (tparm) == TEMPLATE_DECL && targ)
+ {
+ tree packed_args = NULL_TREE;
+ int idx, len = 1;
+
+ if (ARGUMENT_PACK_P (targ))
+ {
+ /* Look inside the argument pack. */
+ packed_args = ARGUMENT_PACK_ARGS (targ);
+ len = TREE_VEC_LENGTH (packed_args);
+ }
+
+ for (idx = 0; idx < len; ++idx)
+ {
+ tree targ_parms = NULL_TREE;
+
+ if (packed_args)
+ /* Extract the next argument from the argument
+ pack. */
+ targ = TREE_VEC_ELT (packed_args, idx);
+
+ if (PACK_EXPANSION_P (targ))
+ /* Look at the pattern of the pack expansion. */
+ targ = PACK_EXPANSION_PATTERN (targ);
+
+ /* Extract the template parameters from the template
+ argument. */
+ if (TREE_CODE (targ) == TEMPLATE_DECL)
+ targ_parms = DECL_INNERMOST_TEMPLATE_PARMS (targ);
+ else if (TREE_CODE (targ) == TEMPLATE_TEMPLATE_PARM)
+ targ_parms = DECL_INNERMOST_TEMPLATE_PARMS (TYPE_NAME (targ));
+
+ /* Verify that we can coerce the template template
+ parameters from the template argument to the template
+ parameter. This requires an exact match. */
+ if (targ_parms
+ && !coerce_template_template_parms
+ (DECL_INNERMOST_TEMPLATE_PARMS (tparm),
+ targ_parms,
+ tf_none,
+ tparm,
+ targs))
+ return false;
+ }
+ }
+ }
+
+ /* Everything is okay. */
+ return true;
+}
+
/* Convert the indicated template ARG as necessary to match the
indicated template PARM. Returns the converted ARG, or
error_mark_node if the conversion was unsuccessful. Error and
if (arg && PACK_EXPANSION_P (arg))
{
- /* If ARG is a pack expansion, but PARM is not a
- template parameter pack (if it were, we would have
- handled it above), we're trying to expand into a
- fixed-length argument list. */
- if (TREE_CODE (arg) == EXPR_PACK_EXPANSION)
- error ("cannot expand %<%E%> into a fixed-length "
- "argument list", arg);
- else
- error ("cannot expand %<%T%> into a fixed-length "
- "argument list", arg);
+ if (complain & tf_error)
+ {
+ /* If ARG is a pack expansion, but PARM is not a
+ template parameter pack (if it were, we would have
+ handled it above), we're trying to expand into a
+ fixed-length argument list. */
+ if (TREE_CODE (arg) == EXPR_PACK_EXPANSION)
+ error ("cannot expand %<%E%> into a fixed-length "
+ "argument list", arg);
+ else
+ error ("cannot expand %<%T%> into a fixed-length "
+ "argument list", arg);
+ }
return error_mark_node;
}
}
}
}
+ /* Now that we have bindings for all of the template arguments,
+ ensure that the arguments deduced for the template template
+ parameters have compatible template parameter lists. We cannot
+ check this property before we have deduced all template
+ arguments, because the template parameter types of a template
+ template parameter might depend on prior template parameters
+ deduced after the template template parameter. The following
+ ill-formed example illustrates this issue:
+
+ template<typename T, template<T> class C> void f(C<5>, T);
+
+ template<int N> struct X {};
+
+ void g() {
+ f(X<5>(), 5l); // error: template argument deduction fails
+ }
+
+ The template parameter list of 'C' depends on the template type
+ parameter 'T', but 'C' is deduced to 'X' before 'T' is deduced to
+ 'long'. Thus, we can't check that 'C' cannot bind to 'X' at the
+ time that we deduce 'C'. */
+ if (result == 0
+ && !template_template_parm_bindings_ok_p
+ (DECL_INNERMOST_TEMPLATE_PARMS (fn), targs))
+ return 1;
+
if (result == 0)
/* All is well so far. Now, check:
tree argvec = INNERMOST_TEMPLATE_ARGS (TYPE_TI_ARGS (arg));
tree argtmplvec
= DECL_INNERMOST_TEMPLATE_PARMS (TYPE_TI_TEMPLATE (arg));
- int i;
+ int i, len;
+ int parm_variadic_p = 0;
/* The resolution to DR150 makes clear that default
arguments for an N-argument may not be used to bind T
rather than the whole TREE_VEC since they can have
different number of elements. */
- for (i = 0; i < TREE_VEC_LENGTH (parmvec); ++i)
+ parmvec = expand_template_argument_pack (parmvec);
+ argvec = expand_template_argument_pack (argvec);
+
+ len = TREE_VEC_LENGTH (parmvec);
+
+ /* Check if the parameters end in a pack, making them
+ variadic. */
+ if (len > 0
+ && PACK_EXPANSION_P (TREE_VEC_ELT (parmvec, len - 1)))
+ parm_variadic_p = 1;
+
+ if (TREE_VEC_LENGTH (argvec) < len - parm_variadic_p)
+ return 1;
+
+ for (i = 0; i < len - parm_variadic_p; ++i)
{
if (unify (tparms, targs,
TREE_VEC_ELT (parmvec, i),
UNIFY_ALLOW_NONE))
return 1;
}
+
+ if (parm_variadic_p
+ && unify_pack_expansion (tparms, targs,
+ parmvec, argvec,
+ UNIFY_ALLOW_NONE,
+ /*call_args_p=*/false,
+ /*subr=*/false))
+ return 1;
}
arg = TYPE_TI_TEMPLATE (arg);
INNERMOST_TEMPLATE_ARGS (args)))
return NULL_TREE;
+ /* Now that we have bindings for all of the template arguments,
+ ensure that the arguments deduced for the template template
+ parameters have compatible template parameter lists. See the use
+ of template_template_parm_bindings_ok_p in fn_type_unification
+ for more information. */
+ if (!template_template_parm_bindings_ok_p (tparms, deduced_args))
+ return NULL_TREE;
+
return deduced_args;
}
--- /dev/null
+// PR c++/32565
+// { dg-do compile }
+// { dg-options "-std=c++0x" }
+
+template<typename...> struct A1;
+template<template<int...> class T> struct A1<T<0> > {};
+template<typename...> struct A2;
+template<template<int...> class T> struct A2<T<0, 1> > {};
+template<typename...> struct A3;
+template<template<int, int...> class T> struct A3<T<0, 1> > {};
+template<typename...> struct A4;
+template<template<typename...> class T> struct A4<T<int> > {};
+template<typename...> struct A5;
+template<template<typename...> class T> struct A5<T<int, long> > {};
+template<typename...> struct A6;
+template<template<typename, typename...> class T> struct A6<T<int, long> > {};
+template<int> struct B1 {};
+template<int, int> struct B2 {};
+template<typename> struct B3 {};
+template<typename, typename> struct B4 {};
+A1<B1<0> > a1; // { dg-error "incomplete type" }
+A2<B2<0, 1> > a2; // { dg-error "incomplete type" }
+A3<B2<0, 1> > a3; // { dg-error "incomplete type" }
+A4<B3<int> > a4; // { dg-error "incomplete type" }
+A5<B4<int, long> > a5; // { dg-error "incomplete type" }
+A6<B4<int, long> > a6; // { dg-error "incomplete type" }
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