Bug 10591 – Error: only one main allowed doesn't show location of conflicting main symbols

---a.d void main(){} --- ---b.d void main(){} --- ---main.d import a,b; --- rdmd main.d (or dmd main.d a.d b.d) =>b.d(1): Error: only one main allowed the error message should show: b.d(1): Error: only one main allowed (previously defined in a.d(1)) In more complex cases (with auto generated code or mixins etc), it can be hard to trace down location of such main symbols, so compiler should show that.

I guess I should have been more persistent about error messages: https://github.com/D-Programming-Language/dmd/pull/1753#discussion_r3403264

you wrote there: >> But maybe it doesn't matter all that much, the user can do a global search to find the offending main function. That can be hard in practice (in my cases I auto-generate my main functions to add instrumentation code; or main could be in object file where we don't have source code etc). And user shouldn't have to do such global search when compiler knows this information.

Just ran in to this, I'm actually struggling to find the offending main function in a large codebase (could be in some dependency that's wrongly configured to compile in execultable mode instead of library). Grep doesn't cut it, the compiler should tell me.

Commit pushed to master at https://github.com/dlang/dmd https://github.com/dlang/dmd/commit/03a8430a1025475d9020bd2e21fa0de6491b3f57 Merge pull request #6069 from John-Colvin/duplicatemainerror Fix issue 10591 - Error: only one main allowed doesn't show location of conflicting main symbols

Commit pushed to stable at https://github.com/dlang/dmd https://github.com/dlang/dmd/commit/03a8430a1025475d9020bd2e21fa0de6491b3f57 Merge pull request #6069 from John-Colvin/duplicatemainerror