Bug 20860 – OpDispatch does not work for structs with constructor and destructor

It looks like opDispatch does not work in this case: ``` struct A { this(int a) {} /// void opDispatch(string methodName, Params...)(Params params) { } ~this() {} } void main() { A(3).test(); } ```

that's an old regression (2.065). Curiously that works when you remove the parens of the call ( A(3).test; )

Oh... I see ... Since this is an really old regression, I don't think it will be fixed until the next release.

This could definitively be done for next point release. The problem seems simple to fix. Apparently it's related to the trailing tuple template parameter `Params...`, the compiler does not accept that its length is equal to 0...I'm 90% sure it's a problem of lowering, meaning that `A(3).test()` is not rewritten `A(3).opDispatch!("test")()` properly.

Expression semanticX(DotIdExp exp, Scope* sc) dmd/expressionsem.d: --- Expression semanticX(DotIdExp exp, Scope* sc) { + printf("checkpoint %d : %s\n", 0, exp.toChars()); //printf("DotIdExp::semanticX(this = %p, '%s')\n", this, toChars()); if (Expression ex = unaSemantic(exp, sc)) return ex; + printf("checkpoint %d : %s\n", 1, exp.toChars()); ... } --- gives, for the test case: > checkpoint 0 : A(int(0)).test > checkpoint 1 : ((A __slA so unaSemantic corrupts the expression. `__slA` is a special symbol created in dmd.expression.StructLiteralExp.addDtorHook(). So that's this method that does a bad rewrite (or maybe even a kind of corruption)

@RazvanN7 created dlang/dmd pull request #13374 "Fix Issue 20860 - OpDispatch does not work for structs with constructor and destructor" fixing this issue: - Fix Issue 20860 - OpDispatch does not work for structs with constructor and destructor https://github.com/dlang/dmd/pull/13374

dlang/dmd pull request #13374 "Fix Issue 20860 - OpDispatch does not work for structs with constructor and destructor" was merged into stable: - 2029bc2b5cd71c50d4863a7fc6b3936c72d044d8 by RazvanN7: Fix Issue 20860 - OpDispatch does not work for structs with constructor and destructor https://github.com/dlang/dmd/pull/13374

dlang/dmd pull request #13421 "merge stable" was merged into master: - 71b3c3c5c4b6b95ac32e58e0b6dd787cd03875d5 by RazvanN7: Fix Issue 20860 - OpDispatch does not work for structs with constructor and destructor https://github.com/dlang/dmd/pull/13421