Truncation of intellisense inlay hints doesn't respect editor.inlayHints.maximumLength option

[bradphelan]

Environment

System Info

Item	Value
CPUs	AMD Ryzen 9 5900X 12-Core Processor (24 x 3700)
GPU Status	2d_canvas: enabled canvas_oop_rasterization: enabled_on direct_rendering_display_compositor: disabled_off_ok gpu_compositing: enabled multiple_raster_threads: enabled_on opengl: enabled_on rasterization: enabled raw_draw: disabled_off_ok skia_graphite: disabled_off video_decode: enabled video_encode: enabled vulkan: disabled_off webgl: enabled webgl2: enabled webgpu: enabled webnn: disabled_off
Load (avg)	undefined
Memory (System)	63.93GB (43.07GB free)
Process Argv
Screen Reader	no
VM	0%

Extensions (62)

Extension	Author (truncated)	Version
Bookmarks	ale	13.5.0
vite	ant	0.2.5
scratchpads	bue	1.0.0
doxdocgen	csc	1.4.0
vscode-eslint	dba	3.0.10
python-environment-manager	don	1.2.4
python-extension-pack	don	1.7.0
gitlens	eam	16.1.1
prettier-vscode	esb	11.0.0
codespaces	Git	1.17.3
copilot	Git	1.254.0
copilot-chat	Git	0.23.2
cpp-reference	Guy	0.2.5
vscode-test-explorer	hbe	2.22.1
debug-visualizer	hed	2.4.0
better-cpp-syntax	jef	1.27.1
vsc-python-indent	Kev	1.18.0
copy-json-path	Mal	1.3.0
autoclose	mar	0.0.1
file-downloader	min	1.0.13
git-web-link	mro	1.2.0
vscode-docker	ms-	1.29.3
vscode-dotnet-runtime	ms-	2.2.3
debugpy	ms-	2024.14.0
isort	ms-	2023.10.1
python	ms-	2024.22.0
vscode-pylance	ms-	2024.12.1
remote-containers	ms-	0.395.0
remote-ssh	ms-	0.116.1
remote-ssh-edit	ms-	0.87.0
remote-wsl	ms-	0.88.5
vscode-remote-extensionpack	ms-	0.26.0
cmake-tools	ms-	1.19.52
cpptools	ms-	1.23.2
cpptools-extension-pack	ms-	1.3.0
hexeditor	ms-	1.11.1
makefile-tools	ms-	0.11.13
powershell	ms-	2024.4.0
remote-explorer	ms-	0.4.3
remote-server	ms-	1.5.2
test-adapter-converter	ms-	0.2.1
vscode-speech	ms-	0.12.1
autodocstring	njp	0.6.1
parse-tree	pok	0.32.0
svelte-extractor	pro	0.0.3
make-runner	raj	1.0.3
vscode-xml	red	0.27.2
command-variable	rio	1.66.0
shader	sle	1.1.5
memento-inputs	spa	1.0.0
code-spell-checker	str	4.0.21
svelte-vscode	sve	109.4.0
ayu	tea	1.0.5
textual-syntax-highlighter	Tex	1.3.0
cmake	twx	0.0.17
vscode-lldb	vad	1.11.1
intellicode-api-usage-examples	Vis	0.2.9
vscodeintellicode	Vis	1.3.2
vim	vsc	1.29.0
debug	web	0.27.0
jinja	who	0.0.8
markdown-all-in-one	yzh	3.6.2

(5 theme extensions excluded)

A/B Experiments

vsliv368:30146709
vspor879:30202332
vspor708:30202333
vspor363:30204092
vscod805cf:30301675
vsaa593:30376534
py29gd2263:31024238
c4g48928:30535728
2i9eh265:30646982
962ge761:30841072
pythonnoceb:30776497
dsvsc014:30777825
dsvsc015:30821418
pythonmypyd1:30859725
2e7ec940:31000449
pythontbext0:30879054
cppperfnew:30980852
pythonait:30973460
dvdeprecation:31040973
dwnewjupyter:31046869
nativerepl1:31134653
pythonrstrctxt:31093868
nativeloc1:31118317
cf971741:31144450
e80f6927:31120813
iacca1:31150324
notype1:31143044
dwcopilot:31158714
h409b430:31177054
cf1a2727:31183122
c3hdf307:31184662
6074i472:31201624

Bug Summary and Steps to Reproduce

Type: Bug

Using the setting.

"editor.inlayHints.maximumLength":0 

with 0 I get

with 1 I get

with 10 I get

with 20 I get

with 40 I get

with 80 I get

This has been setup with the CPP inlay hints configuration to ensure it targets C++. I think for some reason the bug fix in microsoft/vscode#205708 is not working for C++

Configuration and Logs

[log-diagnostics.txt](https://github.com/user-attachments/files/18349107/log-diagnostics.txt)

Other Extensions

No response

Additional context

This issue was ported from the core vs-code team because they claim it is the cpp plugin issue rather than core.

microsoft/vscode#236861 (comment)

[bobbrow]

We weren't aware of the new setting. It shouldn't be too big a problem to add support for it.

[sean-mcmanus]

@bradphelan Internally we have our own maximum length that we apply (the "..." in the middle). VS Code's setting is applied by VS Code on the result we send it (the other dot dot dot (i.e. \u2026) symbol on the right).

The current hardcoded implementation of the "in the middle" truncation is in the accordion_string function (shared with VS).

[bradphelan]

The same note that I made to the core team. I think truncating in the middle is the wrong place. C++ identifiers are normally from left to right, least specific to most specific. ie:

com::microsoft::geometry::linear::cross_product

If you were going to truncate it makes more sense to truncate at the left

...ear::cross_product

rather than

com::.micro...uct

[sean-mcmanus]

@bradphelan We use accordion style truncation (inherited from VS), because for scenarios with the std libraries there are cases where the stuff on the right side is like iterator and supposedly there are many cases like that with the "ranges" library and is missing distinguishing info. But we could potentially add a setting for that.

[bradphelan]

This is still pretty random.

std::list<std...onst_iterator

is terrible. Either

::const_iterator

or

std::list<...>::const_iterator

or

std::list<>::const_iterator

but not random truncation in middle of words. In my code base I get stuff like.

which is terribly frustrating. In this case it would be surely better to truncate the namespace prefix rather than the important more specific name at the end.

There also needs to be more coordination with the base editor so that at minimum when you mouse over a truncated inlay hint you get the full type. This should also work together with a refactoring option on any auto declaration to replace it with the specific type the inlay hint is showing.

[bradphelan]

Interestingly copilot has access to the full inferred type even though the inlay hint has been truncated.

I'm not sure if it's just getting lucky hallucinating the correct type or it has pulled it from somewhere. But it would be nice if this was a simple refactoring built in.