compile error when using gcc14

[liwenhui-soul]

Description

version: 3.11.3
gcc version: 14.2.0

const char json_string[] = R"({"string":"Hello World","int":42,"double":3.14,"array":[1,2,"3",4.0,null],"bool":true,"object":{"string":"Hello World","int":42,"double":3.14,"array":[1,2,"3",4.0,null],"bool":true}})";

auto root = nlohmann::json::parse(json_string);

Reproduction steps

Compiling with -O2 will cause the following error，but compiling without -O2 succeeds.

Expected vs. actual results

Minimal code example

const char json_string[] = R"({"string":"Hello World","int":42,"double":3.14,"array":[1,2,"3",4.0,null],"bool":true,"object":{"string":"Hello World","int":42,"double":3.14,"array":[1,2,"3",4.0,null],"bool":true}})";

auto root = nlohmann::json::parse(json_string);

Error messages

Compiler and operating system

ubuntu-22.04

Library version

3.11.3

Validation

• The bug also occurs if the latest version from the develop branch is used.
• I can successfully compile and run the unit tests.

[Schoppenglas]

Working fine, see https://godbolt.org/z/MToMq5nE5

I am just wondering. You are stating, that you are using gcc14.1 but error message shows gcc14.2. Just a typo?

[liwenhui-soul]

Working fine, see https://godbolt.org/z/MToMq5nE5

I am just wondering. You are stating, that you are using gcc14.1 but error message shows gcc14.2. Just a typo?

Sorry, I didn't make it clear. To reproduce the issue, first add #define JSON_DIAGNOSTICS 1 before the include statements. Secondly, the compilation flags should be -O2 -Wall -Werror -DNDEBUG. The gcc version is 14.2.0
Please try again in https://godbolt.org/z/ve9acMWPn