Tue Jan 5 22:38:51 2021 UTC ()

lint: add test for "suggest cast" [324]

This warning is the only one that calls print_tnode, which in turn uses
the redundant operator names in str_op_t.

There is another list of operator names in ops.c, but those names
include more clutter, for example "p + p" instead of a simple "+".
Using those operator names would therefore rather be confusing. These
two lists should be merged, to remove unnecessary redundancy.


(rillig)

diff -r1.1 -r1.2 src/tests/usr.bin/xlint/lint1/msg_324.c
diff -r1.1 -r1.2 src/tests/usr.bin/xlint/lint1/msg_324.exp

--- src/tests/usr.bin/xlint/lint1/msg_324.c 2021/01/02 10:22:44	1.1
+++ src/tests/usr.bin/xlint/lint1/msg_324.c 2021/01/05 22:38:51	1.2

 @@ -1,7 +1,40 @@
-/*	$NetBSD: msg_324.c,v 1.1 2021/01/02 10:22:44 rillig Exp $	*/
+/*	$NetBSD: msg_324.c,v 1.2 2021/01/05 22:38:51 rillig Exp $	*/
 # 3 "msg_324.c"
 // Test for message: suggest cast from '%s' to '%s' on op %s to avoid overflow [324]
-TODO: "Add example code that triggers the above message."
+/*
-TODO: "Add example code that almost triggers the above message."
+ * This warning applies to binary operators if the result of the operator
  * is converted to a type that is bigger than the operands' result type
  * after the usual arithmetic promotions.
+ *
  * In such a case, the operator's result would be truncated to the operator's
  * result type (invoking undefined behavior for signed integers), and that
  * truncated value would then be converted.  At that point, a few bits may
  * have been lost.
  */
 /* lint1-flags: -g -S -w -P */
 void
 example(char c, int i, unsigned u)
+{
 	long l;
 	unsigned long ul;
 	l = c + i;
 	l = i - c;
 	ul = c * u;
 	ul = u + c;
 	ul = i - u;
 	ul = u * i;
 	l = i << c;
 	/*
 	 * The operators SHR, DIV and MOD cannot produce an overflow,
 	 * therefore no warning is necessary for them.
 	 */
 	l = i >> c;
 	ul = u / c;
 	ul = u % c;
+}

--- src/tests/usr.bin/xlint/lint1/Attic/msg_324.exp 2021/01/02 10:22:44	1.1
+++ src/tests/usr.bin/xlint/lint1/Attic/msg_324.exp 2021/01/05 22:38:51	1.2