Bug 12022 – Spurious "recursive alias declaration" with lambdas as template parameters

/////////////////////////////////// struct S(alias F) { } int f(); alias A() = S!(() => f()); A!() a; /////////////////////////////////// The recursive alias semantic is triggered by Expression::checkPurity (which calls getFuncTemplateDecl -> toAlias). Workaround: redeclare lambdas as templated functions in an eponymous template, and make sure that they do not refer to the outer template arguments (they must be passed to the templated functions in the alias declaration). Example: template A(string x) { auto f(string y)() { return p(y); } alias A = S!(f); }

(In reply to Vladimir Panteleev from comment #0) > The recursive alias semantic is triggered by Expression::checkPurity (which > calls getFuncTemplateDecl -> toAlias). It's fixed from 2.066, by the commit: https://github.com/D-Programming-Language/dmd/commit/33f2ab82bd9fb51d88927b8048d88c30ea44111e