Hi! As the following testcases shows, when adding static operator[] support I've missed that the 2 build_min_non_dep_op_overload functions need to be adjusted. The first one we only use for the single index case, but as cp_tree_code_length (ARRAY_REF) is 2, we were running into an assertion there which compared nargs and expected_nargs. For ARRAY_REF, the operator[] is either a non-static member or newly static member, never out of class and for the static member case if user uses single index the operator[] needs to have a single argument as well, but the function is called with 2 - the object it is invoked on and the index. We need to evaluate side-effects of the object and use just a single argument in the call - the index. The other build_min_non_dep_op_overload overload has been added solely for ARRAY_REF - CALL_EXPR is the other operator that accepts variable number of operands but that one goes through different routines. There we asserted it is a METHOD_TYPE, so again we shouldn't assert that but handle the case when it is not one by making sure object's side-effects are evaluated if needed and passing all the index arguments to the static operator[].
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk? 2023-01-19 Jakub Jelinek <ja...@redhat.com> PR c++/108437 * cp-tree.h (keep_unused_object_arg): Declare. * call.cc (keep_unused_object_arg): No longer static. * tree.cc (build_min_non_dep_op_overload): Handle ARRAY_REF with overload being static member function. * g++.dg/cpp23/subscript12.C: New test. * g++.dg/cpp23/subscript13.C: New test. --- gcc/cp/cp-tree.h.jj 2023-01-16 11:52:16.067734300 +0100 +++ gcc/cp/cp-tree.h 2023-01-18 16:47:55.258697839 +0100 @@ -6599,6 +6599,7 @@ inline tree build_new_op (const op_locat return build_new_op (loc, code, flags, arg1, arg2, NULL_TREE, NULL_TREE, NULL, complain); } +extern tree keep_unused_object_arg (tree, tree, tree); extern tree build_op_call (tree, vec<tree, va_gc> **, tsubst_flags_t); extern tree build_op_subscript (const op_location_t &, tree, --- gcc/cp/call.cc.jj 2023-01-16 11:52:16.059734418 +0100 +++ gcc/cp/call.cc 2023-01-18 16:48:02.966586328 +0100 @@ -5187,7 +5187,7 @@ build_operator_new_call (tree fnname, ve or static operator(), in which cases the source expression would be `obj[...]' or `obj(...)'. */ -static tree +tree keep_unused_object_arg (tree result, tree obj, tree fn) { if (result == NULL_TREE --- gcc/cp/tree.cc.jj 2023-01-16 11:52:16.093733917 +0100 +++ gcc/cp/tree.cc 2023-01-18 17:01:08.937242864 +0100 @@ -3693,14 +3693,14 @@ build_min_non_dep_op_overload (enum tree { va_list p; int nargs, expected_nargs; - tree fn, call; + tree fn, call, obj = NULL_TREE; non_dep = extract_call_expr (non_dep); nargs = call_expr_nargs (non_dep); expected_nargs = cp_tree_code_length (op); - if (TREE_CODE (TREE_TYPE (overload)) == METHOD_TYPE) + if (TREE_CODE (TREE_TYPE (overload)) == METHOD_TYPE || op == ARRAY_REF) expected_nargs -= 1; if ((op == POSTINCREMENT_EXPR || op == POSTDECREMENT_EXPR) @@ -3715,6 +3715,8 @@ build_min_non_dep_op_overload (enum tree if (TREE_CODE (TREE_TYPE (overload)) == FUNCTION_TYPE) { fn = overload; + if (op == ARRAY_REF) + obj = va_arg (p, tree); for (int i = 0; i < nargs; i++) { tree arg = va_arg (p, tree); @@ -3746,6 +3748,8 @@ build_min_non_dep_op_overload (enum tree CALL_EXPR_ORDERED_ARGS (call_expr) = CALL_EXPR_ORDERED_ARGS (non_dep); CALL_EXPR_REVERSE_ARGS (call_expr) = CALL_EXPR_REVERSE_ARGS (non_dep); + if (obj) + return keep_unused_object_arg (call, obj, overload); return call; } @@ -3759,11 +3763,15 @@ build_min_non_dep_op_overload (tree non_ non_dep = extract_call_expr (non_dep); unsigned int nargs = call_expr_nargs (non_dep); - gcc_assert (TREE_CODE (TREE_TYPE (overload)) == METHOD_TYPE); - tree binfo = TYPE_BINFO (TREE_TYPE (object)); - tree method = build_baselink (binfo, binfo, overload, NULL_TREE); - tree fn = build_min (COMPONENT_REF, TREE_TYPE (overload), - object, method, NULL_TREE); + tree fn = overload; + if (TREE_CODE (TREE_TYPE (overload)) == METHOD_TYPE) + { + tree binfo = TYPE_BINFO (TREE_TYPE (object)); + tree method = build_baselink (binfo, binfo, overload, NULL_TREE); + fn = build_min (COMPONENT_REF, TREE_TYPE (overload), + object, method, NULL_TREE); + object = NULL_TREE; + } gcc_assert (vec_safe_length (args) == nargs); tree call = build_min_non_dep_call_vec (non_dep, fn, args); @@ -3774,6 +3782,8 @@ build_min_non_dep_op_overload (tree non_ CALL_EXPR_ORDERED_ARGS (call_expr) = CALL_EXPR_ORDERED_ARGS (non_dep); CALL_EXPR_REVERSE_ARGS (call_expr) = CALL_EXPR_REVERSE_ARGS (non_dep); + if (object) + return keep_unused_object_arg (call, object, overload); return call; } --- gcc/testsuite/g++.dg/cpp23/subscript12.C.jj 2023-01-18 17:15:04.963153521 +0100 +++ gcc/testsuite/g++.dg/cpp23/subscript12.C 2023-01-18 17:14:40.816503156 +0100 @@ -0,0 +1,34 @@ +// PR c++/108437 +// { dg-do run { target c++23 } } + +struct S { static int &operator[] (int x) { static int a[2]; return a[x]; } }; +struct U { static int &operator[] (int x, int y, int z) { static int a[2]; return a[x + y + z]; } }; +struct V { static int &operator[] () { static int a; return a; } }; + +template <class T, class W, class X> void +foo () +{ + S s; + s[0]++; + T t; + t[0]++; + U u; + u[0, 0, 0]++; + V v; + v[]++; + W w; + w[0, 0, 0]++; + X x; + x[]++; +} + +int +main () +{ + S::operator[] (0) = 1; + U::operator[] (0, 0, 0) = 2; + V::operator[] () = 3; + foo <S, U, V> (); + if (S::operator[] (0) != 3 || U::operator[] (0, 0, 0) != 4 || V::operator[] () != 5) + __builtin_abort (); +} --- gcc/testsuite/g++.dg/cpp23/subscript13.C.jj 2023-01-18 17:15:08.110107955 +0100 +++ gcc/testsuite/g++.dg/cpp23/subscript13.C 2023-01-18 17:14:55.833285718 +0100 @@ -0,0 +1,43 @@ +// PR c++/108437 +// { dg-do run { target c++23 } } + +struct S { static int &operator[] (int x) { static int a[2]; return a[x]; } }; +struct U { static int &operator[] (int x, int y, int z) { static int a[2]; return a[x + y + z]; } }; +struct V { static int &operator[] () { static int a; return a; } }; +int cnt; + +template <typename T> +T & +bar (T &x) +{ + ++cnt; + return x; +} + +template <class T, class W, class X> void +foo () +{ + S s; + bar (s)[0]++; + T t; + bar (t)[0]++; + U u; + bar (u)[0, 0, 0]++; + V v; + bar (v)[]++; + W w; + bar (w)[0, 0, 0]++; + X x; + bar (x)[]++; +} + +int +main () +{ + S::operator[] (0) = 1; + U::operator[] (0, 0, 0) = 2; + V::operator[] () = 3; + foo <S, U, V> (); + if (S::operator[] (0) != 3 || U::operator[] (0, 0, 0) != 4 || V::operator[] () != 5 || cnt != 6) + __builtin_abort (); +} Jakub