Bug 20758 – __traits(getAttributes) as template argument results in broken template instances

template foo(a...) { static int x; } void attr1() {} // enum attr2 = 1; // struct attr3 {} @attr1 int x; alias f1 = foo!attr1; alias f2 = foo!(__traits(getAttributes, x)); // passes static assert(f1.mangleof == f2.mangleof); // fails, should pass static assert(__traits(isSame, f1, f2)); void main() { auto p1 = &f1.x; auto p2 = &f2.x; // passes assert(p1 == p2); // but this fails assert(&f1.x == &f2.x); } The bug seems to manifest only for attributes that are functions. If attr1 is replaced with attr2 or attr3, the assertions pass.

The runtime assertion failure is actually a regression from 2.069, introduced by this PR: https://github.com/dlang/dmd/pull/4866

@NilsLankila created dlang/dmd pull request #11183 "fix issue 20758 - __traits(getAttributes) as template argument result…" fixing this issue: - fix issue 20758 - __traits(getAttributes) as template argument results in broken template instances Using a `TupleExp` obtained by a `__traits` had for effect to instantiate a template with a `VarExp` that was never translated to a D symbol. The fix is to do the translation only when the var is for a function, which means that the intention is not to instantiate using the function *result* but well the function itself. https://github.com/dlang/dmd/pull/11183

dlang/dmd pull request #11183 "fix issue 20758 - __traits(getAttributes) as template argument result…" was merged into stable: - 5ef80bb6fdfeb538c4d28eaede8a6c8d16c53dcf by Nils Lankila: fix issue 20758 - __traits(getAttributes) as template argument results in broken template instances Using a `TupleExp` obtained by a `__traits` had for effect to instantiate a template with a `VarExp` that was never translated to a D symbol. The fix is to do the translation only when the var is for a function, which means that the intention is not to instantiate using the function *result* but well the function itself. https://github.com/dlang/dmd/pull/11183