temporary should be created to hold the result of the
conversion. */
BOOL_BITFIELD need_temporary_p : 1;
- /* If KIND is ck_identity or ck_base_conv, true to indicate that the
- copy constructor must be accessible, even though it is not being
- used. */
- BOOL_BITFIELD check_copy_constructor_p : 1;
/* If KIND is ck_ptr or ck_pmem, true to indicate that a conversion
from a pointer-to-derived to pointer-to-base is being performed. */
BOOL_BITFIELD base_p : 1;
static bool magic_varargs_p (tree);
typedef void (*diagnostic_fn_t) (const char *, ...) ATTRIBUTE_GCC_CXXDIAG(1,2);
static tree build_temp (tree, tree, int, diagnostic_fn_t *);
-static void check_constructor_callable (tree, tree);
/* Returns nonzero iff the destructor name specified in NAME matches BASETYPE.
NAME can take many forms... */
else if (fcode == VECTOR_TYPE && tcode == VECTOR_TYPE
&& vector_types_convertible_p (from, to, false))
return build_conv (ck_std, to, conv);
- else if (!(flags & LOOKUP_CONSTRUCTOR_CALLABLE)
+ /* A derived-to-base conversion sequence is a user-defined conversion
+ because it involves a constructor call, even though it has the rank of
+ a standard conversion, so we don't consider it if we aren't allowing
+ user-defined conversions. But if we're binding directly to a
+ reference, it's only a pointer conversion. */
+ else if ((!(flags & LOOKUP_NO_CONVERSION)
+ || (flags & LOOKUP_NO_TEMP_BIND))
&& IS_AGGR_TYPE (to) && IS_AGGR_TYPE (from)
&& is_properly_derived_from (from, to))
{
/* The derived-to-base conversion indicates the initialization
of a parameter with base type from an object of a derived
type. A temporary object is created to hold the result of
- the conversion. */
- conv->need_temporary_p = true;
+ the conversion unless we're binding directly to a reference. */
+ conv->need_temporary_p = !(flags & LOOKUP_NO_TEMP_BIND);
}
else
return NULL;
compatible_p = reference_compatible_p (to, from);
/* Directly bind reference when target expression's type is compatible with
- the reference and expression is an lvalue. In C++0x, the wording in
- [8.5.3/5 dcl.init.ref] is changed to also allow direct bindings for const
- and rvalue references to rvalues of compatible class type, as part of
- DR391. */
+ the reference and expression is an lvalue. In DR391, the wording in
+ [8.5.3/5 dcl.init.ref] is changed to also require direct bindings for
+ const and rvalue references to rvalues of compatible class type. */
if (compatible_p
&& (lvalue_p
- || ((cxx_dialect != cxx98)
- && (CP_TYPE_CONST_NON_VOLATILE_P(to) || TYPE_REF_IS_RVALUE (rto))
+ || ((CP_TYPE_CONST_NON_VOLATILE_P(to) || TYPE_REF_IS_RVALUE (rto))
&& CLASS_TYPE_P (from))))
{
/* [dcl.init.ref]
is reference-compatible with "cv2 T2,"
the reference is bound directly to the initializer expression
- lvalue. */
+ lvalue.
+
+ [...]
+ If the initializer expression is an rvalue, with T2 a class type,
+ and "cv1 T1" is reference-compatible with "cv2 T2", the reference
+ is bound to the object represented by the rvalue or to a sub-object
+ within that object. */
+
conv = build_identity_conv (from, expr);
conv = direct_reference_binding (rto, conv);
if (!CP_TYPE_CONST_NON_VOLATILE_P (to) && !TYPE_REF_IS_RVALUE (rto))
return NULL;
- /* [dcl.init.ref]
-
- If the initializer expression is an rvalue, with T2 a class type,
- and "cv1 T1" is reference-compatible with "cv2 T2", the reference
- is bound in one of the following ways:
-
- -- The reference is bound to the object represented by the rvalue
- or to a sub-object within that object.
-
- -- ...
-
- We use the first alternative. The implicit conversion sequence
- is supposed to be same as we would obtain by generating a
- temporary. Fortunately, if the types are reference compatible,
- then this is either an identity conversion or the derived-to-base
- conversion, just as for direct binding. */
- if (CLASS_TYPE_P (from) && compatible_p)
- {
- conv = build_identity_conv (from, expr);
- conv = direct_reference_binding (rto, conv);
- conv->rvaluedness_matches_p = TYPE_REF_IS_RVALUE (rto);
- if (!(flags & LOOKUP_CONSTRUCTOR_CALLABLE))
- conv->u.next->check_copy_constructor_p = true;
- return conv;
- }
-
/* [dcl.init.ref]
Otherwise, a temporary of type "cv1 T1" is created and
if (related_p && !at_least_as_qualified_p (to, from))
return NULL;
+ /* We're generating a temporary now, but don't bind any more in the
+ conversion (specifically, don't slice the temporary returned by a
+ conversion operator). */
+ flags |= LOOKUP_NO_TEMP_BIND;
+
conv = implicit_conversion (to, from, expr, c_cast_p,
flags);
if (!conv)
&& (flags & LOOKUP_NO_CONVERSION) == 0)
{
struct z_candidate *cand;
+ int convflags = ((flags & LOOKUP_NO_TEMP_BIND)
+ |LOOKUP_ONLYCONVERTING);
- cand = build_user_type_conversion_1
- (to, expr, LOOKUP_ONLYCONVERTING);
+ cand = build_user_type_conversion_1 (to, expr, convflags);
if (cand)
conv = cand->second_conv;
conversion *conv = NULL;
tree args = NULL_TREE;
bool any_viable_p;
+ int convflags;
/* We represent conversion within a hierarchy using RVALUE_CONV and
BASE_CONV, as specified by [over.best.ics]; these become plain
candidates = 0;
flags |= LOOKUP_NO_CONVERSION;
+ /* It's OK to bind a temporary for converting constructor arguments, but
+ not in converting the return value of a conversion operator. */
+ convflags = ((flags & LOOKUP_NO_TEMP_BIND) | LOOKUP_NO_CONVERSION);
+ flags &= ~LOOKUP_NO_TEMP_BIND;
+
if (ctors)
{
tree t;
{
tree fns;
tree conversion_path = TREE_PURPOSE (conv_fns);
- int convflags = LOOKUP_NO_CONVERSION;
/* If we are called to convert to a reference type, we are trying to
find an lvalue binding, so don't even consider temporaries. If
return true;
}
-/* Check that a callable constructor to initialize a temporary of
- TYPE from an EXPR exists. */
-
-static void
-check_constructor_callable (tree type, tree expr)
-{
- build_special_member_call (NULL_TREE,
- complete_ctor_identifier,
- build_tree_list (NULL_TREE, expr),
- type,
- LOOKUP_NORMAL | LOOKUP_ONLYCONVERTING
- | LOOKUP_NO_CONVERSION
- | LOOKUP_CONSTRUCTOR_CALLABLE);
-}
-
/* Initialize a temporary of type TYPE with EXPR. The FLAGS are a
bitwise or of LOOKUP_* values. If any errors are warnings are
generated, set *DIAGNOSTIC_FN to "error" or "warning",
leave it as an lvalue. */
if (inner >= 0)
expr = decl_constant_value (expr);
- if (convs->check_copy_constructor_p)
- check_constructor_callable (totype, expr);
return expr;
case ck_ambig:
/* Call build_user_type_conversion again for the error. */
{
/* We are going to bind a reference directly to a base-class
subobject of EXPR. */
- if (convs->check_copy_constructor_p)
- check_constructor_callable (TREE_TYPE (expr), expr);
/* Build an expression for `*((base*) &expr)'. */
expr = build_unary_op (ADDR_EXPR, expr, 0);
expr = convert_to_base (expr, build_pointer_type (totype),
remember that the conversion was required. */
if (conv->kind == ck_base)
{
- if (conv->check_copy_constructor_p)
- check_constructor_callable (TREE_TYPE (expr), expr);
base_conv_type = conv->type;
conv = conv->u.next;
}
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