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.