}
}
+/* Try to find a legal C++-style cast to DST_TYPE for ORIG_EXPR, trying them
+ in the order: const_cast, static_cast, reinterpret_cast.
+
+ Don't suggest dynamic_cast.
+
+ Return the first legal cast kind found, or NULL otherwise. */
+
+static const char *
+get_cast_suggestion (tree dst_type, tree orig_expr)
+{
+ tree trial;
+
+ /* Reuse the parser logic by attempting to build the various kinds of
+ cast, with "complain" disabled.
+ Identify the first such cast that is valid. */
+
+ /* Don't attempt to run such logic within template processing. */
+ if (processing_template_decl)
+ return NULL;
+
+ /* First try const_cast. */
+ trial = build_const_cast (dst_type, orig_expr, tf_none);
+ if (trial != error_mark_node)
+ return "const_cast";
+
+ /* If that fails, try static_cast. */
+ trial = build_static_cast (dst_type, orig_expr, tf_none);
+ if (trial != error_mark_node)
+ return "static_cast";
+
+ /* Finally, try reinterpret_cast. */
+ trial = build_reinterpret_cast (dst_type, orig_expr, tf_none);
+ if (trial != error_mark_node)
+ return "reinterpret_cast";
+
+ /* No such cast possible. */
+ return NULL;
+}
+
+/* If -Wold-style-cast is enabled, add fix-its to RICHLOC,
+ suggesting how to convert a C-style cast of the form:
+
+ (DST_TYPE)ORIG_EXPR
+
+ to a C++-style cast.
+
+ The primary range of RICHLOC is asssumed to be that of the original
+ expression. OPEN_PAREN_LOC and CLOSE_PAREN_LOC give the locations
+ of the parens in the C-style cast. */
+
+static void
+maybe_add_cast_fixit (rich_location *rich_loc, location_t open_paren_loc,
+ location_t close_paren_loc, tree orig_expr,
+ tree dst_type)
+{
+ /* This function is non-trivial, so bail out now if the warning isn't
+ going to be emitted. */
+ if (!warn_old_style_cast)
+ return;
+
+ /* Try to find a legal C++ cast, trying them in order:
+ const_cast, static_cast, reinterpret_cast. */
+ const char *cast_suggestion = get_cast_suggestion (dst_type, orig_expr);
+ if (!cast_suggestion)
+ return;
+
+ /* Replace the open paren with "CAST_SUGGESTION<". */
+ pretty_printer pp;
+ pp_printf (&pp, "%s<", cast_suggestion);
+ rich_loc->add_fixit_replace (open_paren_loc, pp_formatted_text (&pp));
+
+ /* Replace the close paren with "> (". */
+ rich_loc->add_fixit_replace (close_paren_loc, "> (");
+
+ /* Add a closing paren after the expr (the primary range of RICH_LOC). */
+ rich_loc->add_fixit_insert_after (")");
+}
+
+
/* Parse a cast-expression.
cast-expression:
/* Consume the `('. */
cp_token *open_paren = cp_lexer_consume_token (parser->lexer);
location_t open_paren_loc = open_paren->location;
+ location_t close_paren_loc = UNKNOWN_LOCATION;
/* A very tricky bit is that `(struct S) { 3 }' is a
compound-literal (which we permit in C++ as an extension).
/* Look for the type-id. */
type = cp_parser_type_id (parser);
/* Look for the closing `)'. */
- cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN);
+ cp_token *close_paren
+ = cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN);
+ if (close_paren)
+ close_paren_loc = close_paren->location;
parser->in_type_id_in_expr_p = saved_in_type_id_in_expr_p;
}
&& !in_system_header_at (input_location)
&& !VOID_TYPE_P (type)
&& current_lang_name != lang_name_c)
- warning (OPT_Wold_style_cast,
- "use of old-style cast to %qT", type);
+ {
+ gcc_rich_location rich_loc (input_location);
+ maybe_add_cast_fixit (&rich_loc, open_paren_loc, close_paren_loc,
+ expr, type);
+ warning_at_rich_loc (&rich_loc, OPT_Wold_style_cast,
+ "use of old-style cast to %qT", type);
+ }
/* Only type conversions to integral or enumeration types
can be used in constant-expressions. */
--- /dev/null
+// { dg-options "-Wold-style-cast -fdiagnostics-show-caret" }
+
+struct foo {};
+struct bar { const foo *field; };
+
+void test_1 (void *ptr)
+{
+ foo *f = (foo *)ptr; // { dg-warning "old-style cast" }
+ /* { dg-begin-multiline-output "" }
+ foo *f = (foo *)ptr;
+ ^~~
+ ----------
+ static_cast<foo *> (ptr)
+ { dg-end-multiline-output "" } */
+}
+
+void test_2 (const foo *ptr)
+{
+ foo *f = (foo *)ptr; // { dg-warning "old-style cast" }
+ /* { dg-begin-multiline-output "" }
+ foo *f = (foo *)ptr;
+ ^~~
+ ----------
+ const_cast<foo *> (ptr)
+ { dg-end-multiline-output "" } */
+}
+
+void test_3 (bar *ptr)
+{
+ foo *f = (foo *)ptr; // { dg-warning "old-style cast" }
+ /* { dg-begin-multiline-output "" }
+ foo *f = (foo *)ptr;
+ ^~~
+ ----------
+ reinterpret_cast<foo *> (ptr)
+ { dg-end-multiline-output "" } */
+}
+
+void test_4 (bar *ptr)
+{
+ foo *f = (foo *)ptr->field; // { dg-warning "old-style cast" }
+ /* { dg-begin-multiline-output "" }
+ foo *f = (foo *)ptr->field;
+ ^~~~~
+ -----------------
+ const_cast<foo *> (ptr->field)
+ { dg-end-multiline-output "" } */
+}
+
+void test_5 ()
+{
+ bar b_inst;
+ foo *f = (foo *)&b_inst; // { dg-warning "old-style cast" }
+ /* { dg-begin-multiline-output "" }
+ foo *f = (foo *)&b_inst;
+ ^~~~~~
+ --------------
+ reinterpret_cast<foo *> (&b_inst)
+ { dg-end-multiline-output "" } */
+}
+
+/* We don't offer suggestions for templates. */
+
+template <typename T>
+void test_6 (void *ptr)
+{
+ foo *f = (foo *)ptr; // { dg-warning "old-style cast" }
+ /* { dg-begin-multiline-output "" }
+ foo *f = (foo *)ptr;
+ ^~~
+ { dg-end-multiline-output "" } */
+}
+
+/* We don't offer suggestions where a single C++-style cast can't be
+ used. */
+
+void test_7 (const void *ptr)
+{
+ foo *f = (foo *)ptr; // { dg-warning "old-style cast" }
+ /* { dg-begin-multiline-output "" }
+ foo *f = (foo *)ptr;
+ ^~~
+ { dg-end-multiline-output "" } */
+}
+
+/* Likewise, no single C++-style cast is usable here. */
+
+void test_8 (const bar &b_inst)
+{
+ foo *f = (foo *)&b_inst; // { dg-warning "old-style cast" }
+ /* { dg-begin-multiline-output "" }
+ foo *f = (foo *)&b_inst;
+ ^~~~~~
+ { dg-end-multiline-output "" } */
+}
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