Assertion failed: Shift >= 0, file C:\src\llvm_package_303050\llvm\tools\clang\lib\Format\WhitespaceManager.cpp, line 245

[llvmbot]

Bugzilla Link	33507
Resolution	FIXED
Resolved on	Aug 25, 2017 13:31
Version	trunk
OS	Windows NT
Blocks	#33196
Reporter	LLVM Bugzilla Contributor
CC	@zmodem,@donhinton,@krasimir-google

Extended Description

We have a dozen of C++ files with some lambdas that make clang-format crash.

One example is this code:

auto found = range::find_if(vsProducts, [&](auto * aProduct) {
static const Version verVs2017;
return true;
});

If I add this code to another C++ file and try to format (on save), it will crash and create a dump file. (the example code was reduced, but still two lines)

I've trimmed the config file to just these two lines to reproduce the problem:

BasedOnStyle: Mozilla
AlignConsecutiveDeclarations: 'true'

Thanks

[zmodem]

I can reproduce with trunk and 5.0 but not 4.0, so this is a regression.

Daniel: is there someone besides yourself who like looking into clang-format bugs? :-)

[zmodem]

*** Bug llvm/llvm-bugzilla-archive#34071 has been marked as a duplicate of this bug. ***

[llvmbot]

I have made an workaround for me - simply commented out this assert. And it looks quite normal. I don't know why. :)

[llvmbot]

Some blame history:

1. assert added in rev 248999
   [clang-format] Add support of consecutive declarations alignment

2. rev 295586 the assert was still valid

3. rev 306282 the assert is NOT valid anymore

This means only four revisions left, most likely rev 298574 by nikola:

Fix issues in clang-format's AlignConsecutive modes.

Indeed, a quick check confirms that rev 5.0.0.300231 is also affected.

[zmodem]

+Nikola

[zmodem]

krasimir: Maybe you could take a look?

[zmodem]

I have made an workaround for me - simply commented out this assert. And it
looks quite normal. I don't know why. :)

It seems to misformat the test case if I do that:

$ cat | bin/clang-format -style="{BasedOnStyle: Mozilla,AlignConsecutiveDeclarations: 'true'}"
auto found = range::find_if(vsProducts, [&](auto * aProduct) {
static const Version verVs2017;
return true;
});
auto found = range::find_if(vsProducts, [&](auto* aProduct) {
static const VersionverVs2017;
return true;
});

Note that it breaks the code by concatenating "Version" and "verVs2017" :-(

[zmodem]

Note that it breaks the code by concatenating "Version" and "verVs2017" :-(

Confirmed that both the assert and the concatenation started with r298574.

[llvmbot]

Hello, I've sent this patch for review if anyone wants to give it a try: https://reviews.llvm.org/D37137

[donhinton]

Not sure exactly how to fix it, but here's a minimal example that asserts:

echo "v f( {y x; x;});" | bin/clang-format -style="{AlignConsecutiveDeclarations: 'true'}"

And, interestingly, the following doesn't assert, but as you can see, the formatting is a bit odd:

echo "vvvvvvvvvvvv f( {y x; x;});" | bin/clang-format -style="{AlignConsecutiveDeclarations: 'true'}"
vvvvvvvvvvvv f( {
y x;
x;
});

[donhinton]

Sorry, didn't see your post/patch before I commented, but I tested it with my test case and it works great...

[zmodem]

The patch was committed in r311792. I'll let it bake a little bit and then merge.

[zmodem]

Merged in r311800. Thanks for fixing!

[zmodem]

mentioned in issue #33196

[zmodem]

mentioned in issue llvm/llvm-bugzilla-archive#34071