Bug 19701 – undefined reference to `_D6object__T6hashOf

This is a regression occuring on linux and windows and started about ~ 2.084.0. Create file app.d with these 2 lines import std.string; void main(){} And execute dmd with command (this is the linux version): dmd -m64 -c -ofdlang-sample.o -unittest -Xfdocs.json -Df__dummy.html -Isource app.d && dmd -ofdlang-sample dlang-sample.o -m64 dlang-sample.o: In function `_D3std8typecons__T5TupleTaTaZQl6toHashMxFNaNbNiNfZm': app.d:(.text._D3std8typecons__T5TupleTaTaZQl6toHashMxFNaNbNiNfZm[_D3std8typecons__T5TupleTaTaZQl6toHashMxFNaNbNiNfZm]+0x19): undefined reference to `_D6object__T6hashOfTxaZQlFNaNbNiNfKxaZm' app.d:(.text._D3std8typecons__T5TupleTaTaZQl6toHashMxFNaNbNiNfZm[_D3std8typecons__T5TupleTaTaZQl6toHashMxFNaNbNiNfZm]+0x32): undefined reference to `_D6object__T6hashOfTxaZQlFNaNbNiNfKxaZm' collect2: error: ld returned 1 exit status Error: linker exited with status 1

Simpler command line (yes, -Df is mandatory): dmd -m64 -unittest -Df__dummy.html app.d On Windows, -m32 somehow links successfully, -m32mscoff doesn't.

The object files differ. With `-Df`, there's an external reference to _D6object__T6hashOfTxaZQlFNaNbNiNfKxaZm, while it's _D4core8internal4hash__T6hashOfTaZQkFNaNbNiNexaZm without that switch. Looking at object.d, that's because -Df defines `version=D_Ddoc`, so that object.hashOf isn't an alias, but a wrapper: https://github.com/dlang/druntime/blob/58dcda229e0658451325b70243fb5cb67c6cda46/src/object.d#L4080-L4115

May have been introduced by https://github.com/dlang/druntime/pull/2239

@rainers created dlang/druntime pull request #2609 "fix Issue 19701 - undefined reference to _D6object__T6hashOf" fixing this issue: - fix Issue 19701 - undefined reference to _D6object__T6hashOf use CoreDdoc instead of D_Ddoc https://github.com/dlang/druntime/pull/2609

dlang/druntime pull request #2609 "fix Issue 19701 - undefined reference to _D6object__T6hashOf" was merged into stable: - 3262245e82074bb068a367e4fee69ef1969d0982 by Rainer Schuetze: fix Issue 19701 - undefined reference to _D6object__T6hashOf use CoreDdoc instead of D_Ddoc https://github.com/dlang/druntime/pull/2609