Bug 21293 – dtoh: segfault when encountering opaque enum

Running `./src/build.d cxx-headers-test` results in a segmentation fault on macOS. Is the invocation of DMD that fails. Running the DMD command (which is printed when `./src/build.d cxx-headers-test`) inside a debugger results in this stacktrace: (lldb) r Process 40315 launched: 'dlang/dmd/generated/osx/release/64/dmd' (x86_64) Process 40315 stopped * thread #1, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=1, address=0x0) frame #0: 0x000000010012b43c dmd`_D3dmd4root5array__T5ArrayTCQBa7dsymbol7DsymbolZQBc7opSliceMNgFNaNbNiNfZANgCQCwQBwQBr at array.d:305 302 303 extern (D) inout(T)[] opSlice() inout nothrow pure @nogc 304 { -> 305 return data[0 .. length]; 306 } 307 308 extern (D) inout(T)[] opSlice(size_t a, size_t b) inout nothrow pure @nogc Target 0: (dmd) stopped. (lldb) bt * thread #1, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=1, address=0x0) * frame #0: 0x000000010012b43c dmd`_D3dmd4root5array__T5ArrayTCQBa7dsymbol7DsymbolZQBc7opSliceMNgFNaNbNiNfZANgCQCwQBwQBr at array.d:305 frame #1: 0x00000001000bb603 dmd`ToCppBuffer::visit(EnumDeclaration*) at dtoh.d:1252 frame #2: 0x000000010005044a dmd`EnumDeclaration::accept(Visitor*) at denum.d:367 frame #3: 0x00000001000bc395 dmd`ToCppBuffer::visit(TypeEnum*) at dtoh.d:1497 frame #4: 0x000000010017349a dmd`TypeEnum::accept(Visitor*) at mtype.d:6241 frame #5: 0x00000001000bcfe7 dmd`ToCppBuffer::funcToBuffer(TypeFunction*, FuncDeclaration*) at dtoh.d:1734 frame #6: 0x00000001000b9432 dmd`ToCppBuffer::visit(FuncDeclaration*) at dtoh.d:579 frame #7: 0x0000000100103e1a dmd`FuncDeclaration::accept(Visitor*) at func.d:2569 frame #8: 0x00000001000bb1e3 dmd`ToCppBuffer::visit(ClassDeclaration*) at dtoh.d:1157 frame #9: 0x000000010004a1aa dmd`ClassDeclaration::accept(Visitor*) at dclass.d:982 frame #10: 0x00000001000badd7 dmd`ToCppBuffer::includeSymbol(Dsymbol*) at dtoh.d:1095 frame #11: 0x00000001000bb0b0 dmd`ToCppBuffer::visit(ClassDeclaration*) at dtoh.d:1136 frame #12: 0x000000010004a1aa dmd`ClassDeclaration::accept(Visitor*) at dclass.d:982 frame #13: 0x00000001000badd7 dmd`ToCppBuffer::includeSymbol(Dsymbol*) at dtoh.d:1095 frame #14: 0x00000001000bb0b0 dmd`ToCppBuffer::visit(ClassDeclaration*) at dtoh.d:1136 frame #15: 0x000000010004a1aa dmd`ClassDeclaration::accept(Visitor*) at dclass.d:982 frame #16: 0x00000001000b8e6c dmd`ToCppBuffer::visit(AttribDeclaration*) at dtoh.d:456 frame #17: 0x00000001001a209f dmd`ParseTimeVisitor<ASTCodegen>::visit(StorageClassDeclaration*) at parsetimevisitor.d:77 frame #18: 0x00000001000137d2 dmd`StorageClassDeclaration::accept(Visitor*) at attrib.d:324 frame #19: 0x00000001000b8e6c dmd`ToCppBuffer::visit(AttribDeclaration*) at dtoh.d:456 frame #20: 0x00000001000b8f10 dmd`ToCppBuffer::visit(LinkDeclaration*) at dtoh.d:479 frame #21: 0x0000000100013ae2 dmd`LinkDeclaration::accept(Visitor*) at attrib.d:432 frame #22: 0x00000001000b8fe0 dmd`ToCppBuffer::visit(Module*) at dtoh.d:503 frame #23: 0x00000001000704ca dmd`Module::accept(Visitor*) at dmodule.d:1485 frame #24: 0x00000001000b86ab dmd`genCppHdrFiles(Array<Module*>&) at dtoh.d:245 frame #25: 0x000000010015e17b dmd`_D3dmd4mars7tryMainFmPPxaKSQz7globals5ParamZi at mars.d:674 frame #26: 0x000000010015f1e5 dmd`_Dmain at mars.d:972 frame #27: 0x000000010031e837 dmd`_D2rt6dmain212_d_run_main2UAAamPUQgZiZ6runAllMFZ9__lambda1MFZv + 31 frame #28: 0x000000010031e6e1 dmd`_D2rt6dmain212_d_run_main2UAAamPUQgZiZ7tryExecMFMDFZvZv + 33 frame #29: 0x000000010031e7bb dmd`_D2rt6dmain212_d_run_main2UAAamPUQgZiZ6runAllMFZv + 139 frame #30: 0x000000010031e6e1 dmd`_D2rt6dmain212_d_run_main2UAAamPUQgZiZ7tryExecMFMDFZvZv + 33 frame #31: 0x000000010031e64a dmd`_d_run_main2 + 626 frame #32: 0x000000010031e3c2 dmd`_d_run_main + 190 frame #33: 0x0000000100004360 dmd`main at mars.d:925 frame #34: 0x00007fff71f31cc9 libdyld.dylib`start + 1

Here's a reduced test case: echo 'enum foo;' | dmd -HC -

@MoonlightSentinel created dlang/dmd pull request #11843 "Fix Issue 21293 - dtoh: segfault when encountering opaque enum" fixing this issue: - Fix Issue 21293 - dtoh: segfault when encountering opaque enum Don't access non-existant members and require C++11 https://github.com/dlang/dmd/pull/11843

dlang/dmd pull request #11843 "Fix Issue 21293 - dtoh: segfault when encountering opaque enum" was merged into master: - 2d392410c08e1817f52207a086ea713902c64998 by MoonlightSentinel: Fix Issue 21293 - dtoh: segfault when encountering opaque enum Don't access non-existant members and require C++11 https://github.com/dlang/dmd/pull/11843