xref: /src/tests/usr.bin/xlint/lint1/msg_132.c

/*	$NetBSD: msg_132.c,v 1.8 2022/04/20 22:50:56 rillig Exp $	*/
# 3 "msg_132.c"

// Test for message: conversion from '%s' to '%s' may lose accuracy [132]

/*
 * NetBSD's default lint flags only include a single -a, which only flags
 * narrowing conversions from long.  To get warnings for all narrowing
 * conversions, -aa needs to be given more than once.
 *
 * https://gnats.netbsd.org/14531
 */

/* lint1-extra-flags: -aa */

typedef unsigned char u8;
typedef unsigned short u16;
typedef unsigned int u32;
typedef unsigned long long u64;

typedef signed char i8;
typedef signed short i16;
typedef signed int i32;
typedef signed long long i64;

void
convert_unsigned(u8 v8, u16 v16, u32 v32, u64 v64)
{
	v8 = v16;		/* expect: 132 */
	v8 = v32;		/* expect: 132 */
	v8 = v64;		/* expect: 132 */

	v16 = v8;
	v16 = v32;		/* expect: 132 */
	v16 = v64;		/* expect: 132 */

	v32 = v8;
	v32 = v16;
	v32 = v64;		/* expect: 132 */

	v64 = v8;
	v64 = v16;
	v64 = v32;
}

void
convert_signed(i8 v8, i16 v16, i32 v32, i64 v64)
{
	v8 = v16;		/* expect: 132 */
	v8 = v32;		/* expect: 132 */
	v8 = v64;		/* expect: 132 */

	v16 = v8;
	v16 = v32;		/* expect: 132 */
	v16 = v64;		/* expect: 132 */

	v32 = v8;
	v32 = v16;
	v32 = v64;		/* expect: 132 */

	v64 = v8;
	v64 = v16;
	v64 = v32;
}

/*
 * Before tree.c 1.268 from 2021-04-06, lint wrongly warned that conversion to
 * _Bool might lose accuracy.  C99 6.3.1.2 defines a special conversion rule
 * from scalar to _Bool though.
 */
_Bool
to_bool(long a, long b)
{
	/* seen in fp_lib.h, function wideRightShiftWithSticky */
	return a | b;
}

/* ARGSUSED */
const char *
cover_build_plus_minus(const char *arr, double idx)
{
	/* expect+3: error: operands of '+' have incompatible types (pointer != double) [107] */
	/* expect+2: warning: function 'cover_build_plus_minus' expects to return value [214] */
	if (idx > 0.0)
		return arr + idx;
	return arr + (unsigned int)idx;
}

int
non_constant_expression(void)
{
	/*
	 * Even though this variable definition looks like a constant, it
	 * does not fall within C's definition of an integer constant
	 * expression.  Due to that, lint does not perform constant folding
	 * on the expression built from this variable and thus doesn't know
	 * that the conversion will always succeed.
	 */
	const int not_a_constant = 8;
	/* expect+1: warning: conversion from 'unsigned long long' to 'int' may lose accuracy [132] */
	return not_a_constant * 8ULL;
}