microsoft / microsoft/vscode-cpptools
Show errors in included header files so that the cause of failed IntelliSense (e.g. autocomplete) can be more easily discovered
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Description
Environment
- OS and Version: Windows 11
- VS Code Version:1.73.0
- C/C++ Extension Version: 1.13.3 (same for latest release)
- Other extensions you installed (and if the issue persists after disabling them): all other extensions are disabled, but the issue persists
- If using SSH remote, specify OS of remote machine: -
- A clear and concise description of what the bug is, including information about the workspace (i.e. is the workspace a single project or multiple projects, size of the project, etc): single-folder project, C-only, for Renesas RA4M2 series microcontroller (ARM cortex-m). Project size ~15MB (~1200 source files, 280k Line of code)
Bug Summary and Steps to Reproduce
Bug Summary:
There is a header file (renesas.h), with a size of 3.5MB, containing register definitions with nested structs and unions, macros, etc.
if this file is included in the ".c" file, the code autocompletion stops working and the output window shows "Quick info operation failed: FE: 'Unknown error'"
Commenting out blocks of the huge .h file will make the code completion again. It seems, some counter counting tags, language elements or whatever gets saturated.
In error state, commenting a line(or block) makes it working again, but uncommenting a previously commented line leads to error.
Unfortunately, the bug does not occur always, but if it occurs once, then it becomes permanent.
Steps to reproduce:
- open a source file (.c)
- start typing text to make the code completion window pop-up
- when it pops up, the list of expected objects are missing and the output window shows the error text "Quick info operation failed: FE: 'Unknown error'"
Expected behavior
the list of variables are shown in the pop-up window

Code sample and Logs
-------- Diagnostics - 11/9/2022, 11:00:32 PM
Version: 1.13.3
Current Configuration:
{
"name": "RA4M2",
"includePath": [
"${workspaceFolder}/src",
"${workspaceFolder}/src/apps",
"${workspaceFolder}/src/communication",
"${workspaceFolder}/src/manager",
"${workspaceFolder}/src/stack/sdk/SRC/EXAMPLE/**",
"${workspaceFolder}/ra/fsp/inc",
"${workspaceFolder}/ra/fsp/inc/api",
"${workspaceFolder}/ra/fsp/inc/instances",
"${workspaceFolder}/ra/fsp/src/rm_threadx_port",
"${workspaceFolder}/ra/microsoft/azure-rtos/threadx/common/inc",
"${workspaceFolder}/ra/arm/CMSIS_5/CMSIS/Core/Include",
"${workspaceFolder}/ra_gen",
"${workspaceFolder}/ra_cfg/fsp_cfg/bsp",
"${workspaceFolder}/ra_cfg/fsp_cfg",
"${workspaceFolder}/ra_cfg/fsp_cfg/azure/tx",
"${workspaceFolder}/ra/microsoft/azure-rtos/usbx/common/usbx_device_classes/inc",
"${workspaceFolder}/ra/microsoft/azure-rtos/usbx/common/core/inc",
"${workspaceFolder}/ra/fsp/src/r_usb_basic/src/driver/inc",
"${workspaceFolder}/ra/fsp/src/r_flash_hp",
"${workspaceFolder}/ra/fsp/src/rm_usbx_port",
"${workspaceFolder}/src/contrib/**"
],
"defines": [
"_DEBUG",
"_UNICODE",
"_RENESAS_RA_",
"SEN_PIN_CONNECTION_AVAILABLE"
],
"intelliSenseMode": "gcc-arm",
"compilerPath": "c:\\Renesas\\RA\\e2studio_v2021-10_fsp_v3.5.0\\toolchains\\gcc_arm\\gcc-arm-none-eabi-10.3-2021.10/bin/arm-none-eabi-gcc.exe",
"configurationProvider": "ms-vscode.cpptools",
"compilerPathIsExplicit": true,
"cStandardIsExplicit": false,
"cppStandardIsExplicit": false,
"intelliSenseModeIsExplicit": true,
"mergeConfigurations": false,
"browse": {
"path": [
"${workspaceFolder}/src",
"${workspaceFolder}/src/apps",
"${workspaceFolder}/src/communication",
"${workspaceFolder}/src/manager",
"${workspaceFolder}/src/stack/sdk/SRC/EXAMPLE/**",
"${workspaceFolder}/ra/fsp/inc",
"${workspaceFolder}/ra/fsp/inc/api",
"${workspaceFolder}/ra/fsp/inc/instances",
"${workspaceFolder}/ra/fsp/src/rm_threadx_port",
"${workspaceFolder}/ra/microsoft/azure-rtos/threadx/common/inc",
"${workspaceFolder}/ra/arm/CMSIS_5/CMSIS/Core/Include",
"${workspaceFolder}/ra_gen",
"${workspaceFolder}/ra_cfg/fsp_cfg/bsp",
"${workspaceFolder}/ra_cfg/fsp_cfg",
"${workspaceFolder}/ra_cfg/fsp_cfg/azure/tx",
"${workspaceFolder}/ra/microsoft/azure-rtos/usbx/common/usbx_device_classes/inc",
"${workspaceFolder}/ra/microsoft/azure-rtos/usbx/common/core/inc",
"${workspaceFolder}/ra/fsp/src/r_usb_basic/src/driver/inc",
"${workspaceFolder}/ra/fsp/src/r_flash_hp",
"${workspaceFolder}/ra/fsp/src/rm_usbx_port",
"${workspaceFolder}/src/contrib/**",
"${workspaceFolder}"
],
"limitSymbolsToIncludedHeaders": true
}
}
Translation Unit Mappings:
[ C:\Work\firefly\firefly_poller\src\apps\ptxApp.c ]:
C:\Work\firefly\firefly_poller\src\apps\ptxApp.c
C:\Work\firefly\firefly_poller\ra\fsp\src\bsp\cmsis\Device\RENESAS\Include\renesas.h *
Translation Unit Configurations:
[ C:\Work\firefly\firefly_poller\src\apps\ptxApp.c ]:
Process ID: 9564
Memory Usage: 79 MB
Compiler Path: C:\Renesas\RA\e2studio_v2021-10_fsp_v3.5.0\toolchains\gcc_arm\gcc-arm-none-eabi-10.3-2021.10\bin\arm-none-eabi-gcc.exe
Includes:
C:\Work\firefly\firefly_poller\src
C:\Work\firefly\firefly_poller\src\apps
C:\Work\firefly\firefly_poller\src\communication
C:\Work\firefly\firefly_poller\src\manager
C:\Work\firefly\firefly_poller\ra\fsp\inc
C:\Work\firefly\firefly_poller\ra\fsp\inc\api
C:\Work\firefly\firefly_poller\ra\fsp\inc\instances
C:\Work\firefly\firefly_poller\ra\fsp\src\rm_threadx_port
C:\Work\firefly\firefly_poller\ra\microsoft\azure-rtos\threadx\common\inc
C:\Work\firefly\firefly_poller\ra\arm\CMSIS_5\CMSIS\Core\Include
C:\Work\firefly\firefly_poller\ra_gen
C:\Work\firefly\firefly_poller\ra_cfg\fsp_cfg\bsp
C:\Work\firefly\firefly_poller\ra_cfg\fsp_cfg
C:\Work\firefly\firefly_poller\ra_cfg\fsp_cfg\azure\tx
C:\Work\firefly\firefly_poller\ra\microsoft\azure-rtos\usbx\common\usbx_device_classes\inc
C:\Work\firefly\firefly_poller\ra\microsoft\azure-rtos\usbx\common\core\inc
C:\Work\firefly\firefly_poller\ra\fsp\src\r_usb_basic\src\driver\inc
C:\Work\firefly\firefly_poller\ra\fsp\src\r_flash_hp
C:\Work\firefly\firefly_poller\ra\fsp\src\rm_usbx_port
C:\Renesas\RA\e2studio_v2021-10_fsp_v3.5.0\toolchains\gcc_arm\gcc-arm-none-eabi-10.3-2021.10\lib\gcc\arm-none-eabi\10.3.1\include
C:\Renesas\RA\e2studio_v2021-10_fsp_v3.5.0\toolchains\gcc_arm\gcc-arm-none-eabi-10.3-2021.10\lib\gcc\arm-none-eabi\10.3.1\include-fixed
C:\Renesas\RA\e2studio_v2021-10_fsp_v3.5.0\toolchains\gcc_arm\gcc-arm-none-eabi-10.3-2021.10\arm-none-eabi\include
C:\Work\firefly\firefly_poller\src\contrib\common\utils
C:\Work\firefly\firefly_poller\src\contrib\common\memoryHandler
Defines:
_DEBUG
_UNICODE
_RENESAS_RA_
SEN_PIN_CONNECTION_AVAILABLE
Standard Version: c17
IntelliSense Mode: windows-gcc-arm
Other Flags:
--gcc
--gnu_version=100301
Total Memory Usage: 79 MB
------- Workspace parsing diagnostics -------
Number of files discovered (not excluded): 5600
Number of files parsed: 965
textDocument/hover: C:\Work\firefly\firefly_poller\ra\fsp\src\bsp\cmsis\Device\RENESAS\Include\renesas.h (id: 1233)
sending 1 changes to server
cpptools/textEditorSelectionChange
cpptools/activeDocumentChange: C:\Work\firefly\firefly_poller\src\apps\app.c
idle loop: reparsing the active document
Checking for syntax errors: C:\Work\firefly\firefly_poller\src\apps\app.c
Queueing IntelliSense update for files in translation unit of: C:\Work\firefly\firefly_poller\src\apps\app.c
sending 1 changes to server
textDocument/hover: C:\Work\firefly\firefly_poller\src\apps\app.c (id: 1234)
Quick info operation failed: FE: 'Unknown error'
using Tag Parser for quick info
cpptools/finishUpdateSquiggles
Error squiggle count: 8
Update IntelliSense time (sec): 0.533
cpptools/getSemanticTokens: C:\Work\firefly\firefly_poller\src\apps\app.c (id: 1235)
cpptools/getFoldingRanges: C:\Work\firefly\firefly_poller\src\apps\app.c (id: 1236)
cpptools/getCodeActions: C:\Work\firefly\firefly_poller\src\apps\app.c (id: 1237)
textDocument/hover: C:\Work\firefly\firefly_poller\src\apps\app.c (id: 1238)
Quick info operation failed: FE: 'Unknown error'
using Tag Parser for quick info
cpptools/getFoldingRanges: C:\Work\firefly\firefly_poller\ra\fsp\src\bsp\cmsis\Device\RENESAS\Include\renesas.h (id: 1239)
Screenshots
No response
Additional context
No response
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Reproduce the failure with the C source file and the included renesas.h header, then inspect the IntelliSense diagnostics and Quick info errors shown in the issue. Done means autocomplete and Quick info continue to work when renesas.h is included, without the reported unknown error.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- c
- Domain
- devtools
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Needs clarification
- Newbie friendliness
- 25/100