rename function name doesn't work in C project

Environment

• OS and Version: Windows_NT x64 10.0.18362
• VS Code Version: Code 1.88.1
• C/C++ Extension Version: 1.20.1
• If using SSH remote, specify OS of remote machine: none

Bug Summary and Steps to Reproduce

Bug Summary:

In a c project, when I try to rename function name or variables, i got :
A definition for the selected symbol could not be located.

even the function is only defined and used in merely one file.

I do the "rescan", disable and enable the cpptools and restart VSCode, none works.

Steps to reproduce:

1. rename a function
2. gives me "A definition for the selected symbol could not be located."

Expected behavior:
renaming should success

Configuration and Logs

c_cpp_properties.json
{
    "configurations": [
        {
            "name": "Win32",
            "includePath": [
                "${workspaceFolder}/**"
            ],
            "defines": [
                "_DEBUG",
                "UNICODE",
                "_UNICODE"
            ],
            "compilerPath": "C:\\Program Files\\LLVM\\bin\\clang.exe",
            "cStandard": "c17",
            "cppStandard": "c++14",
            "intelliSenseMode": "windows-clang-x64"
        }
    ],
    "version": 4
}

Other Extensions

Extension | Author (truncated) | Version
doxdocgen | csc | 1.4.0
cpptools | ms- | 1.20.1
vscode-typings | typ | 0.0.5
clang-format | xav | 1.9.0

Additional context

No response

Start by reproducing the rename failure using the reported one-file C project and the provided c_cpp_properties.json configuration. Trace the C/C++ extension's rename flow from the selected symbol and compare it with definition lookup; done means function and variable renaming succeeds under the reported Windows and Clang configuration.