The cp_expr class doesn't have a const-qualified operator * accessor.
This leaves one with a confusing error message if one ever tries to
dereference a constant cp_expr object:
const cp_expr thing = ...;
tree bob = *thing; // ERROR
What happens is the non-const operator * is not suitable, but the
implicit conversion to a tree is, which is then dereferenced. so we end
up trying to assign a struct to a pointer-to-struct.
cp_expr::operator-> has a similar problem.
The attached patch adds const-qualified accessors.
I also noticed that some of the values of cp_tree_node_structure_enum
were no longer used, leading to warnings about them not being handled in
switch statements. (We never use LAST_TS_CP_ENUM to size an array).
Deleted in this patch.
Applying to trunk.
nathan
--
Nathan Sidwell
2017-10-12 Nathan Sidwell <nat...@acm.org>
* cp-tree.h (cp_expr): Add const operator * and operator->
accessors.
(cp_tree_node_structure_enum): Delete TS_CP_BINDING,
TS_CP_WRAPPER, LAST_TS_CP_ENUM.
Index: cp-tree.h
===================================================================
--- cp-tree.h (revision 253683)
+++ cp-tree.h (working copy)
@@ -65,7 +65,9 @@ public:
/* Implicit conversions to tree. */
operator tree () const { return m_value; }
tree & operator* () { return m_value; }
+ tree operator* () const { return m_value; }
tree & operator-> () { return m_value; }
+ tree operator-> () const { return m_value; }
tree get_value () const { return m_value; }
location_t get_location () const { return m_loc; }
@@ -1467,11 +1469,9 @@ enum cp_tree_node_structure_enum {
TS_CP_IDENTIFIER,
TS_CP_TPI,
TS_CP_PTRMEM,
- TS_CP_BINDING,
TS_CP_OVERLOAD,
TS_CP_BASELINK,
TS_CP_TEMPLATE_DECL,
- TS_CP_WRAPPER,
TS_CP_DEFAULT_ARG,
TS_CP_DEFERRED_NOEXCEPT,
TS_CP_STATIC_ASSERT,
@@ -1480,8 +1480,7 @@ enum cp_tree_node_structure_enum {
TS_CP_LAMBDA_EXPR,
TS_CP_TEMPLATE_INFO,
TS_CP_CONSTRAINT_INFO,
- TS_CP_USERDEF_LITERAL,
- LAST_TS_CP_ENUM
+ TS_CP_USERDEF_LITERAL
};
/* The resulting tree type. */
