C/C++ IntelliSense: Size of std::unique_ptr (Empty Type Optimization?)

[huhu9001]

Environment

VSCode Version: 1.120.0
OS: Linux x64 7.0.6-200.fc44.x86_64
C/C++ Extension: 1.32.2

Bug Summary and Steps to Reproduce

Bug Summary:

Steps to reproduce:

#include<memory>
int main() {
 static_assert(sizeof(std::unique_ptr<size_t[]>) == sizeof(void*));
 return 0;
}

static assertion failed C/C++(2784)
the final comparison was 16 == 8

Expected behavior:

As g++ compiles this file normally I assume there should be no error.

Configuration and Logs

-------- Diagnostics - 5/15/2026, 10:15:28 PM
Version: 1.32.2
Current Configuration:
{
 "name": "Linux",
 "includePath": [],
 "defines": [
 "_GLIBCXX_DO_NOT_USE_BUILTIN_TRAITS"
 ],
 "compilerPath": "/usr/bin/g++",
 "cStandard": "c17",
 "cppStandard": "c++23",
 "intelliSenseMode": "linux-gcc-x64",
 "compilerPathIsExplicit": true,
 "cStandardIsExplicit": true,
 "cppStandardIsExplicit": true,
 "intelliSenseModeIsExplicit": true,
 "recursiveIncludesReduceIsExplicit": false,
 "recursiveIncludesPriorityIsExplicit": false,
 "recursiveIncludesOrderIsExplicit": false,
 "compilerPathInCppPropertiesJson": "/usr/bin/g++",
 "mergeConfigurations": false,
 "recursiveIncludes": {},
 "browse": {
 "limitSymbolsToIncludedHeaders": true
 }
}
Additional Tracked Settings:
{
 "editorTabSize": 4,
 "editorInsertSpaces": true,
 "editorAutoClosingBrackets": "languageDefined",
 "filesEncoding": "utf8",
 "filesAssociations": {},
 "filesExclude": {
 "**/.git": true,
 "**/.svn": true,
 "**/.hg": true,
 "**/.DS_Store": true,
 "**/Thumbs.db": true
 },
 "filesAutoSaveAfterDelay": false,
 "editorInlayHintsEnabled": true,
 "editorParameterHintsEnabled": true,
 "searchExclude": {
 "**/node_modules": true,
 "**/bower_components": true,
 "**/*.code-search": true
 },
 "workbenchSettingsEditor": "ui"
}
cpptools version (native): 1.32.2.0
Current database path: /home/_/.cache/vscode-cpptools/ee064ba49b1a618011b06cc8cd61a68e/.browse.VC.db
Translation Unit Mappings:
[ /home/_/_/src/test/t1.cpp - source TU]:
Translation Unit Configurations:
[ /home/_/_/src/test/t1.cpp ]
 Process ID: 40301
 Memory Usage: 139 MB
 Compiler Path: /usr/bin/g++
 Include Paths:
 system include: /usr/include/c++/16
 system include: /usr/include/c++/16/x86_64-redhat-linux
 system include: /usr/include/c++/16/backward
 system include: /usr/lib/gcc/x86_64-redhat-linux/16/include
 system include: /usr/local/include
 system include: /usr/include
 Defines:
 _GLIBCXX_DO_NOT_USE_BUILTIN_TRAITS
 Standard Version: c++23
 IntelliSense Mode: linux-gcc-x64
 Other Flags:
 --g++
 --gnu_version=160101
Total Memory Usage: 139 MB

------- Workspace parsing diagnostics -------
Number of files discovered (not excluded): 96223
Number of files parsed: 6759

Other Extensions

No response

Additional context

GNU STL's std::unique_ptr seems to store the data as std::tuple<T*, std::default_delete<T>>. Likely GCC thinks std::tuple's member can be optimized away while the IDE doesn't.