Bug 20520 – Runtime segfault when taking typeid of a class instanciated within an enum

The following code segfaults at runtime. No warning is displayed during compilation so I assume that the operation should be allowed. class C {} enum Foo { Bar = new C() } void main() { pragma(msg, typeid(Foo.Bar)); // Works fine: typeid(C()) auto t = typeid(Foo.Bar); // Segfault here } DMD64 D Compiler v2.090.0, no compilation flag necessary to replicate.

Tested with run.dlang.org: 2.064 to 2.068.2: Success and no output 2.069.2 to 2.070.2: Status -6 with output: ----- dmd: tocsym.c:246: virtual void toSymbol(Dsymbol*)::ToSymbol::visit(VarDeclaration*): Assertion `0' failed. linkage = 0 ----- 2.071.2: Failure with output: --- killed by signal 11 Since 2.072.2: Failure with output: Error: program killed by signal 11 This used to work before https://github.com/dlang/dmd/pull/5161 (found using Digger)

I think that the operation should not be allowed. Doing `enum Bar = new C()` results in "test.d(10): Error: variable `test.main.C` : Unable to initialize enum with class or pointer to struct. Use static const variable instead.". I assume this should outputted in the case of the bug report also.

GDC and LDC compile and run the test case just fine. It looks like DMD is not generating an initializer for the manifest constant referenced by `typeid()`. Tagging as backend issue.

@WalterBright created dlang/dmd pull request #14777 "fix Issue 20520 - Runtime segfault when taking typeid of a class inst…" fixing this issue: - fix Issue 20520 - Runtime segfault when taking typeid of a class instanciated within an enum https://github.com/dlang/dmd/pull/14777

Razvan is right. This should not compile. An enum's value should evaluate to a constant, not a pointer to the heap. Just like this does not compile: class C { } C x = new C();

(In reply to Walter Bright from comment #5) > Razvan is right. This should not compile. An enum's value should evaluate to > a constant, not a pointer to the heap. > > Just like this does not compile: > > class C { } > C x = new C(); It's an rodata constant, you support it in the same way that static C x = new C(); is supported.

dlang/dmd pull request #14777 "fix Issue 20520 - Runtime segfault when taking typeid of a class inst…" was merged into stable: - a8f32669c453dd524fa157382a0be870088bde53 by Walter Bright: fix Issue 20520 - Runtime segfault when taking typeid of a class instanciated within an enum https://github.com/dlang/dmd/pull/14777

@dkorpel updated dlang/dmd pull request #14815 "Merge stable" fixing this issue: - fix Issue 20520 - Runtime segfault when taking typeid of a class instanciated within an enum https://github.com/dlang/dmd/pull/14815

dlang/dmd pull request #14815 "Merge stable" was merged into master: - ba04b29d9e88de69e0ac8fb021410f8d509c73f5 by Walter Bright: fix Issue 20520 - Runtime segfault when taking typeid of a class instanciated within an enum https://github.com/dlang/dmd/pull/14815