Bug 18863 – opDispatch with WithStatement & Template Instance

The with statement does not check opDispatch with template instances. An older bug (#6400) was resolved fixing the case of a symbol. This enhancement is for template instances. See below: struct Foo(int x) { auto opDispatch(string s)() if (s == "bar") { x++; return x; } } void main() { int y = 0; with(Foo!1) { y = bar; //error: undefined identifier bar } assert(y == 2); } By contrast, the following compiles without error struct Foo { int x; auto opDispatch(string s)() if (s == "bar") { x++; return x; } } void main() { int y = 0; with(Foo(1)) { y = bar; } assert(y == 2); } Discussion thread: https://forum.dlang.org/thread/[email protected]

You've got a bug in your code: ++x has to fail for the template case, since you're trying to increment a compile-time value. This is what the call to bar is lowered to: Foo!1.opDispatch!"bar"() When you try and compile that, you get these error messages: Error: cannot modify constant 1 Error: template instance `foo.Foo!1.Foo.opDispatch!"bar"` error instantiating

*** This issue has been marked as a duplicate of issue 14145 ***