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History log of /src/tests/usr.bin/xlint/lint1/msg_132.c
RevisionDateAuthorComments
 1.56  14-Sep-2025  rillig lint: warn about signed '<<' that ends up exactly in the msb
 1.55  14-Sep-2025  rillig lint: add more type details to several messages

In most expressions, the integer promotions are performed on the
operands, making the actual type different from the "visible" type of an
operand. To properly explain the situation, mention the type before the
integer promotions in case it differs from the resulting type.
 1.54  08-Jul-2025  rillig lint: reword message about 'extra bits set to 0'

The word 'extra' in the previous wording was too unspecific to make
sense of. In the reworded message, focus on the problem instead of
mentioning only the effect.
 1.53  03-Jan-2025  rillig tests/lint: move a platform-specific test

The test failed on i386, as ptrdiff_t fits in a uint32_t after
conversion, thus not generating a warning.
 1.52  02-Jan-2025  rillig lint: fix possible loss of accuracy in multiplication and division
 1.51  02-Jan-2025  rillig lint: fix assertion failure in pointer subtraction
 1.50  02-Jan-2025  rillig lint: fix a few wrong warnings about possible loss of accuracy
 1.49  02-Jan-2025  rillig lint: compute integer constraints for xor and minus

These operators allow lint to correctly track the possible values in
expressions that sign-extend an integer.
 1.48  01-Jan-2025  rillig lint: fix wrong warning about possible loss of accuracy

The expression "'0' + random() % 10" always fits in a signed or unsigned
char.
 1.47  01-Jan-2025  rillig tests/lint: demonstrate wrong warnings for 'char = int + long'
 1.46  12-Oct-2024  rillig lint: reduce wrong warnings about loss of accuracy in signed '%'
 1.45  12-Oct-2024  rillig tests/lint: extend test for integer constraints
 1.44  08-Oct-2024  rillig lint: compute integer constraints for unsigned multiplication

This fixes the wrong warning about possible loss of accuracy in
libc/c16rtomb.
 1.43  08-Oct-2024  rillig tests/lint: test integer constraint on multiplication
 1.42  18-Aug-2024  rillig lint: add value propagation for '/' combined with bit operations

Fixes __SHIFTIN/__SHIFTOUT expressions, as in PR toolchain/58617.
 1.41  18-Aug-2024  rillig tests/lint: demonstrate wrong warning about accuracy loss

Demonstrates PR toolchain/58617.
 1.40  01-May-2024  rillig branches: 1.40.2;
lint: fix warning about out-of-bounds bit-field value
 1.39  01-May-2024  rillig lint: demonstrate wrong warning about out-of-range bit-field
 1.38  25-Mar-2024  rillig lint: fix warnings about loss of accuracy on bit-field operations
 1.37  25-Mar-2024  rillig tests/lint: demonstrate wrong warnings about lossy bit field operations
 1.36  12-Mar-2024  rillig tests/lint: extend test for previously wrong warning about bit-fields
 1.35  12-Mar-2024  rillig lint: fix warning about loss of conversion for unsigned bit-fields

Since decl.c 1.180 from 2021-05-02.
 1.34  12-Mar-2024  rillig tests/lint: demonstrate wrong warning when comparing a bit-field

Since decl.c 1.180 from 2021-05-02, which allowed arbitrary integer
types to be used as the underlying type for bit-fields in GCC mode.
 1.33  28-Jan-2024  rillig tests/lint: sort multiple diagnostics per line chronologically

For now, the chronologic order is not enforced but has to be established
manually, for example by removing all 'expect' comment lines and
regenerating them with 'accept.sh -u'.

While here, clean up a few instances that came up when regenerating the
'expect' comments, such as wrong indentation or needless deviation from
the 'expect+1' form.
 1.32  06-Aug-2023  rillig lint: since C99, a non-void function must return a value
 1.31  03-Jun-2023  rillig lint: provide more detailed types when operands do not match
 1.30  09-May-2023  rillig lint: track integer constraints through conditional expressions
 1.29  09-May-2023  rillig lint: preserve integer constraints on cast
 1.28  09-May-2023  rillig tests/lint: demonstrate wrong warning about loss of accuracy
 1.27  09-May-2023  rillig tests/lint: demonstrate wrong warning about losing accuracy
 1.26  28-Mar-2023  rillig lint: warn about extern declarations outside headers

https://mail-index.netbsd.org/tech-userlevel/2023/03/15/msg013727.html
 1.25  29-Jan-2023  rillig tests/lint: merge tests for '>>'
 1.24  07-Jul-2022  rillig tests/lint: document why in ic_expr, '&' does not need before_conversion
 1.23  06-Jul-2022  rillig lint: do not warn about 'may lose accuracy' in safe cases of '%'

The possible values of the expression 'a % b' for unsigned integers lie
between 0 and (b - 1). For signed integers, it's more complicated, so
ignore them for now.
 1.22  06-Jul-2022  rillig tests/lint: test 'may lose accuracy' for '%'

For unsigned integers, the possible range of the result can be narrowed
down by looking at the right operand of the '%'. Right now, lint
doesn't do this though.
 1.21  03-Jul-2022  rillig lint: include the width of bit-fields in the type name
 1.20  02-Jul-2022  rillig tests/lint: test bit shift with large integer types

build_bit_shift converts the right-hand operand to INT or UINT, even
though C11 6.5.7 doesn't say anything about narrowing conversions.

Traditional C says that the operators '<<' and '>>' perform the usual
arithmetic conversions. This has been dropped in C90.

What lint actually does is something completely different. In the
operators table in ops.def, the operators '<<' and '>>' are not marked
as performing the usual arithmetic conversions (column 'balance'). This
leaves all conversions to 'build_bit_shift', which converts the
right-hand side to INT or UINT. There is no obvious reason for this
conversion, as the bounds checks need to be performed no matter whether
the type is INT or UINT128.
 1.19  19-Jun-2022  rillig lint: add quotes around placeholders in 4 messages
 1.18  16-Jun-2022  rillig tests/lint: make expectation lines in the tests more detailed

This commit migrates msg_100 until msg_199.
 1.17  10-Jun-2022  rillig tests/lint: fix test for loss of accuracy on ILP32 platforms

The test had been wrong since msg_132.c 1.14 from 2022-05-30.

Using 'unsigned long' in a test that was intended to behave the same on
ILP32 and LP64 was an accident. Use 'unsigned long long' instead, which
is 64-bits wide on all platforms supported by lint.

Move the test about conversion from 'long' to 'int' to the
platform-specific test files.

Noticed by martin@ on powerpc.
 1.16  30-May-2022  rillig lint: fix assertion failure in '(unsigned long)(ptr) >> 12'

Since tree.c 1.449 from 2022-05-26.
 1.15  29-May-2022  rillig lint: fix wrong errors about sizeof of a bit-field (since 2022-05-26)
 1.14  29-May-2022  rillig tests/lint: demonstrate wrong errors 'size/alignment of bit-field'

Since tree.c 1.444 from 2022-05-26, which added range and bit checks for
integer expressions, not taking into account that querying for the size
of a bit-field type triggers an error message.
 1.13  26-May-2022  rillig lint: do not warn about 'uint32_t = uint64_t >> 32'

If all possible values fit into the destination type, there is no
possibility of losing accuracy.

Enhances PR 36668.
 1.12  26-May-2022  rillig tests/lint: demonstrate wrong warnings about loss of accuracy
 1.11  26-May-2022  rillig lint: do not warn about loss in accuracy if the actual value fits

The expression 'any & 0xff' can always be assigned to 'uint8_t' without
loss of any value bits. In the same way, '(any & 0xff) << 8' can always
be assigned to 'uint16_t'.

Previously, lint warned about these cases. Fix these wrong warnings by
tracking the possible values of integer expressions across a single
expression.

Fixes PR 36668, so that <sys/endian.h> does not need to be cluttered
with useless casts anymore.
 1.10  26-May-2022  rillig tests/lint: demonstrate wrong 'may lose accuracy' warning

Reported in PR 36668, fixed in sys/sys/endian.h 1.26 from 2007-07-20,
unfixed in sys/sys/endian.h 1.29 from 2014-03-18.
 1.9  21-Apr-2022  rillig tests/lint: extend test for lossy integer conversion
 1.8  20-Apr-2022  rillig tests/lint: fix test for message 132 to be platform-independent

On i386, the test failed because the warning in line 101 was not
generated. This was because size_t on i386 is unsigned int (see
arch/i386/targparam.h, SIZEOF_TSPEC). The result of the multiplication
had type unsigned int, and message 132 does not trigger for a conversion
from unsigned int to signed int because both types have the same size
(see check_integer_conversion, portable_size_in_bits).

Change the involved type from size_t (which the original code used) to
unsigned long long (which is uint64_t on all platforms supported by
lint), so that the warning is generated on all platforms in the same
way.
 1.7  19-Apr-2022  rillig tests/lint: add test case for integer non-constant expression

Seen in sqlite3.c.
 1.6  25-Aug-2021  rillig tests/lint: test conversion from long long to intptr_t on ilp32

Seen in usr.bin/make/var.c:1608.
 1.5  06-Apr-2021  rillig lint: fix wrong warning about losing accuracy when converting to _Bool
 1.4  06-Apr-2021  rillig tests/lint: demonstrate wrong warning about losing accuracy
 1.3  28-Feb-2021  rillig tests/lint: add test for narrowing conversions

Lint can warn about narrowing conversions, it just doesn't do so by
default.

The option -a (which is included in the default LINTFLAGS in sys.mk)
only reports narrowing conversions from 'long' or larger. To get
warnings about all possible narrowing conversions, the option -a has to
be given more than once.

PR bin/14531
 1.2  21-Feb-2021  rillig lint: force each test to declare the expected diagnostics

By listing the expected diagnostics directly at the code that triggers
the diagnostics, it is easier to cross-check whether the diagnostics
make sense.

No functional change to lint itself.
 1.1  02-Jan-2021  rillig lint: add a test for each message produced by lint1

Having a test for each message ensures that upcoming refactorings don't
break the basic functionality. Adding the tests will also discover
previously unknown bugs in lint.

The tests ensure that every lint message can actually be triggered, and
they demonstrate how to do so. Having a separate file for each test
leaves enough space for documenting historical anecdotes, rationale or
edge cases, keeping them away from the source code.

The interesting details of this commit are in Makefile and
t_integration.sh. All other files are just auto-generated.

When running the tests as part of ATF, they are packed together as a
single test case. Conceptually, it would have been better to have each
test as a separate test case, but ATF quickly becomes very slow as soon
as a test program defines too many test cases, and 50 is already too
many. The time complexity is O(n^2), not O(n) as one would expect.
It's the same problem as in tests/usr.bin/make, which has over 300 test
cases as well.
 1.40.2.1  02-Aug-2025  perseant Sync with HEAD

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