https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87504
--- Comment #2 from David Malcolm <dmalcolm at gcc dot gnu.org> --- Author: dmalcolm Date: Wed Dec 19 15:15:42 2018 New Revision: 267273 URL: https://gcc.gnu.org/viewcvs?rev=267273&root=gcc&view=rev Log: C++: improvements to binary operator diagnostics (PR c++/87504) The C frontend is able (where expression locations are available) to print problems with binary operators in 3-location form, labelling the types of the expressions: arg_0 op arg_1 ~~~~~ ^~ ~~~~~ | | | arg1 type arg0 type The C++ frontend currently just shows the combined location: arg_0 op arg_1 ~~~~~~^~~~~~~~ and fails to highlight where the subexpressions are, or their types. This patch introduces a op_location_t struct for handling the above operator-location vs combined-location split, and a new class binary_op_rich_location for displaying the above, so that the C++ frontend is able to use the more detailed 3-location form for type mismatches in binary operators, and for -Wtautological-compare (where types are not displayed). Both forms can be seen in this example: bad-binary-ops.C:69:20: error: no match for 'operator&&' (operand types are 's' and 't') 69 | return ns_4::foo && ns_4::inner::bar; | ~~~~~~~~~ ^~ ~~~~~~~~~~~~~~~~ | | | | s t bad-binary-ops.C:69:20: note: candidate: 'operator&&(bool, bool)' <built-in> 69 | return ns_4::foo && ns_4::inner::bar; | ~~~~~~~~~~^~~~~~~~~~~~~~~~~~~ The patch also allows for some uses of macros in -Wtautological-compare, where both sides of the comparison have been spelled the same way, e.g.: Wtautological-compare-ranges.c:23:11: warning: self-comparison always evaluates to true [-Wtautological-compare] 23 | if (FOO == FOO); | ^~ gcc/c-family/ChangeLog: PR c++/87504 * c-common.h (warn_tautological_cmp): Convert 1st param from location_t to const op_location_t &. * c-warn.c (find_array_ref_with_const_idx_r): Call fold_for_warn when testing for INTEGER_CST. (warn_tautological_bitwise_comparison): Convert 1st param from location_t to const op_location_t &; use it to build a binary_op_rich_location, and use this. (spelled_the_same_p): New function. (warn_tautological_cmp): Convert 1st param from location_t to const op_location_t &. Warn for macro expansions if spelled_the_same_p. Use binary_op_rich_location. gcc/c/ChangeLog: PR c++/87504 * c-typeck.c (class maybe_range_label_for_tree_type_mismatch): Move from here to gcc-rich-location.h and gcc-rich-location.c. (build_binary_op): Use struct op_location_t and class binary_op_rich_location. gcc/cp/ChangeLog: PR c++/87504 * call.c (op_error): Convert 1st param from location_t to const op_location_t &. Use binary_op_rich_location for binary ops. (build_conditional_expr_1): Convert 1st param from location_t to const op_location_t &. (build_conditional_expr): Likewise. (build_new_op_1): Likewise. (build_new_op): Likewise. * cp-tree.h (build_conditional_expr): Likewise. (build_new_op): Likewise. (build_x_binary_op): Likewise. (cp_build_binary_op): Likewise. * parser.c (cp_parser_primary_expression): Build a location for id-expression nodes. (cp_parser_binary_expression): Use an op_location_t when calling build_x_binary_op. (cp_parser_operator): Build a location for user-defined literals. * typeck.c (build_x_binary_op): Convert 1st param from location_t to const op_location_t &. (cp_build_binary_op): Likewise. Use binary_op_rich_location. gcc/ChangeLog: PR c++/87504 * gcc-rich-location.c (maybe_range_label_for_tree_type_mismatch::get_text): Move here from c/c-typeck.c. (binary_op_rich_location::binary_op_rich_location): New ctor. (binary_op_rich_location::use_operator_loc_p): New function. * gcc-rich-location.h (class maybe_range_label_for_tree_type_mismatch)): Move here from c/c-typeck.c. (struct op_location_t): New forward decl. (class binary_op_rich_location): New class. * tree.h (struct op_location_t): New struct. gcc/testsuite/ChangeLog: * c-c++-common/Wtautological-compare-ranges.c: New test. * g++.dg/cpp0x/pr51420.C: Add -fdiagnostics-show-caret and update expected output. * g++.dg/diagnostic/bad-binary-ops.C: Update expected output from 1-location form to 3-location form, with labelling of ranges with types. Add examples of id-expression nodes with namespaces. * g++.dg/diagnostic/param-type-mismatch-2.C: Likewise. Added: trunk/gcc/testsuite/c-c++-common/Wtautological-compare-ranges.c Modified: trunk/gcc/ChangeLog trunk/gcc/c-family/ChangeLog trunk/gcc/c-family/c-common.h trunk/gcc/c-family/c-warn.c trunk/gcc/c/ChangeLog trunk/gcc/c/c-typeck.c trunk/gcc/cp/ChangeLog trunk/gcc/cp/call.c trunk/gcc/cp/cp-tree.h trunk/gcc/cp/parser.c trunk/gcc/cp/typeck.c trunk/gcc/gcc-rich-location.c trunk/gcc/gcc-rich-location.h trunk/gcc/testsuite/ChangeLog trunk/gcc/testsuite/g++.dg/cpp0x/pr51420.C trunk/gcc/testsuite/g++.dg/diagnostic/bad-binary-ops.C trunk/gcc/testsuite/g++.dg/diagnostic/param-type-mismatch-2.C trunk/gcc/tree.h
